Stocking densities of Colossoma macropomum in the initial grow out phase using biofloc technology

Stocking densities of Colossoma macropomum in the initial grow out phase using biofloc technology | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Stocking densities of Colossoma macropomum in the initial grow out phase using biofloc technology Renato Henrique Costa Montelo, Raphael Brito Santos, Michelle Midori Sena Fugimura, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-3977429/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 9 You are reading this latest preprint version Abstract The objective was to identify the best stocking density in the initial fattening phase of tambaqui ( Colossoma macropomum ) using biofloc technology (BFT) and evaluate the effects of the densities on water quality, zootechnical performance and the metabolic profile of fish and production costs. Juveniles (56.5 ± 1.69 g) were reared in the densities: 15 (BFT15), 30 (BFT30) and 45 (BFT45) fish.m − 3 , in triplicate, for 80 days. The use of BFT inoculum at the beginning contributed the maintenance of adequate ammonia and nitrite concentrations at all densities, though with a higher nitrite concentration in BFT45. Electrical conductivity (EC), nitrite, total suspended solids (TSS), pH, alkalinity and hardness were different ( p < 0.05) between BFT15 and BFT45. EC and TSS increased according to the increase in density, and were higher in BFT45. The highest final weight, weight gain, daily weight gain and specific growth rate were observed in BFT15, while the apparent feed conversion was lower for BFT15 and BFT30 compared to BFT45 ( p < 0.05). Biomass and productivity were higher ( p < 0.05) in BFT45. The values of hematocrit, number of erythrocytes and the hemoglobin concentration were higher in BFT45 ( p < 0.05). Regarding production costs, the highest average feed expenditure occurred in BFT45; however, expenditure with electricity was lower at this density. The increase in biomass in BFT45 generated the reduction of the partial average cost (ACp). It can therefore be concluded that the best stocking density for initial fattening of tambaqui is 45 fish.m − 3 , since it presents better productivity and biomass, lower ACp and average expenditure on electricity when using BFT. Economy intensification Amazonian fish aquaculture production sustainable systems Figures Figure 1 Figure 2 Figure 3 1. Introduction The tambaqui ( Colossoma macropomum ), is native to the Amazon and has economic importance in South and Central America and in Asian countries (Woynárovich and Van Anrooy 2019 ; Mair and Lucente 2020 ; FAO 2020; 2023). In Brazil, it was the second most produced and exported fish species in 2022, and part of this success is due its suitability for production, such as good adaptation to different breeding systems and high stocking density (Hilsdorf et al. 2022 ). Among the various possibilities for tambaqui production, the extensive system, which carried out in excavated nurseries, is the most used by fish farmers, and productivity in the grow out phase can be from 0.3 to 1.2 kilos m 2 year − 1 (Valenti et al. 2021 ). However, there have been advances in production technology, such as the emergency supplementary aeration strategy, which can reduce production costs and improve fish performance, and increase production to up to 1.76 kilograms m − 2 year − 1 (Izel-Silva et al. 2020 ). The intensive tambaqui production systems, such as in net tanks, achieve productivity in the grow out phase of 8 to 24 kg.m − 3 per cycle (Frisso et al. 2020 ). However, this system requires constant renewal of water, which can cause eutrophication of the environments where they are installed, in addition to being more vulnerable to sanitary problems (Bueno et al. 2015 ; Flickinger et al. 2020 ). In a water recirculation system (WRS), the productivity in the grow out phase can reach 2.5 to 15 kg.m − 3 per cycle (Lima et al. 2019 ; Silva et al. 2021 ; Santos et al. 2021 ; Rodrigues et al. 2023 ), in addition to reducing land occupation and water consumption, thus intensifying production and improving resource management (Assis et al. 2020 ). Another super-intensive system that can intensify production of tambaqui and other species of fish native to the Amazon is biofloc technology (BFT) (Dos Santos et al. 2021 a; 2023a; 2023b ; Izel-Silva et al. 2024). This is presented as an alternative for super intensification and optimization of water and area use (Emerenciano et al. 2017 ). BFT has a lower environmental impact and high productivity in the grow out phase of tambaqui and pacu ( Piaractus mesopotamicus ) from 11.38 to 34.16 kg.m − 3 per cycle (Dos Santos et al. 2021 a; Pellegrin et al. 2023 ). Systems using BFT are based on the in situ production of microorganisms with little or no water exchange (Krummenauer et al. 2014 ). With regard to technical aspects, intense and constant aeration is necessary in order to maintain the bioflocs suspended and the necessary oxygen levels to meet the demands of the animals, as well as nitrification (Avnimelech 2012 ). These processes occur simultaneously in the system through the activities of chemoautotrophic and heterotrophic microorganisms, using the inorganic and organic carbon (Ebeling et al. 2006 ; Timmons and Ebeling 2010 ). Super-intensive aquaculture systems require not only technical knowledge of production, but also efficient cost analyses (Valenti et al. 2021 ). Effective planning results in high productivity and reduced financial expenses, thus improving the profitability of the enterprise (Rego et al. 2017 ; Fore et al. 2018 ). As such, the present study determined the best stocking density for the initial fattening phase of tambaqui in a BFT system, and used the water quality, zootechnical performance, metabolic profile of the fish and production costs as indicators. 2. Materials and Methods 2.1 Acclimation and ethical approval At the aquaculture Experimental Station of INPA (National Institute for Amazonian Research), Amazonas, Brazil, juvenile tambaqui (40.0 ± 0.05 g) were acclimated for 25 days in 500 L tanks and fed twice a day with commercial feed (36% crude protein) until they reached a weight of 56.5 ± 1.69 g. Before the start of the experiment, a parasitological analysis of individuals was performed to confirm the absence of the acanthocephalan Neoechinorhyncus buttnerae , the most harmful parasite in tambaqui farming (Moraes et al. 2023). This study was carried out in accordance with the standards of the National Council for Control of Animal Experimentation (CONCEA, 2015 ) and approved by the Ethics Commission on the Use of Animals (CEUA) at INPA (Protocol No. 025/2018). 2.2 Experimental design The experimental design adopted was a completely randomized one with three triplicate treatments (15 (BFT15), 30 (BFT30) and 45 (BFT45) fish.m − 3 ) and had a duration of 80 days. Nine fiberglass tanks of 2 m 3 useful volume each were used, with constant aeration from a 2.3 hp radial compressor, distributed via a 1/2" internal diameter microporous hose, so as to ensure the maintenance of the concentration of dissolved oxygen over 5 mg.L − 1 during the experiment. Fish were fed three times a day with commercial extruded omnivore feed, with 36% (2 to 5 mm) and 32% (4 to 6 mm) crude protein (Oishi et al. 2010 ; Buzollo et al. 2019 ; Welengane et al. 2019 ). The feed supply considered the stored biomass: 5% between 50 and 100 g and 3% above 100 g. The adjustment of the feed was done according to biometrics performed every 20 days, with the fish previously anesthetized in eugenol (0.5 mL.L − 1 ) and using a precision electronic scale (Prix®, BCS21). 2.3 Formation and maintenance of bioflocs Each experimental unit received 1,200 L (60% of the tank volume) of biofloc inoculum from a previously matured biofloc culture (Zemor et al. 2019 ). The maturation of the bioflocs was performed with the daily application of sugar as a source of organic carbon and also during the first 15 days of grow out. A C:N ratio of 20:1 was adopted to stimulate microbial development in the experimental environment (Emerenciano et al. 2017 ). After this period, fertilization with organic carbon was performed only when the concentration of total ammonia present in the system was ≥ 1 mg L − 1 , using the ratio of 6:1 (C:N). 2.4 Water quality Temperature (ºC), dissolved oxygen (mg.L − 1 ), electrical conductivity (mS.cm − 1 ) and pH were measured twice daily with a digital multiparameter probe (YSI Inc, Yellow Spring, OH, USA). Weekly, the sedimentable solids (SS) were measured in an Imhoff cone and clarification was done with the use of sedimentators, whenever they presented values over 50 mL.L − 1 (Hargreaves 2013 ). For the analyses of total ammonia, nitrogen (Verdouw et al. 1978 ), nitrite and alkalinity (Boyd and Tucker 1992 ), hardness (APHA 2005 ) and total suspended solids (TSS) (adapted by Strickland and Parsons 1972 ) samples of 500 mL of water were taken twice a week. 2.5 Zootechnical performance At the end of the experiment, the animals were anesthetized with eugenol (Inoue et al. 2011 ) and the following zootechnical variables were evaluated: weight gain (WG) = final mean weight – initial mean weight; daily mean weight gain (DW) = (final weight – initial weight)/number of days; specific growth rate (SGR) = [(ln (final weight) – ln (initial weight))/number of days] x 100; apparent feed conversion (AFC) = amount of feed offered/initial weight gain; survival (S%) = (final number of fish/initial number of fish) x 100; and productivity = biomass gain/tank volume (m 3 ). 2.6 Metabolic profile Blood tests were performed on four animals per experimental unit (n = 12.treatment − 1 ). After anesthetized the fish with eugenol (0.5 mL.L − 1 ), blood collection was performed, via venipuncture of vessels located in the caudal region, with syringes containing 10% EDTA solution. The following were determined: hematocrit (Ht), using the microhematocrit method; number of erythrocytes (RBC), with a formalin-citrate solution, hemoglobin concentration (Hb), using the cyanmethemoglobin method. The hematimetric indices mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC) and mean corpuscular hemoglobin (MCH) were calculated from the values of Ht, RBC and Hb. The plasma, obtained by centrifugation, was used for glucose analysis via the enzymatic-colorimetric method (©Diagnóstica Catarinense; glucose, REF. 434-MS 80022230067), total protein (P t ) via the colorimetric biuret method (©ANALISA - PP CAT 418 − 250 ML) and cholesterol using the colorimetric enzymatic method (©ANALISA-Trinder). 2.7 Cost analysis In this study, the partial effective operating cost (EOC P ) was evaluated. The EOC P are costs directly linked to production, i.e., expenses such as feed, alkalinizers and electricity. The EOC P was determined according to the proposal of Martin et al. ( 1998 ). $${EOCp}_{}=\sum _{i=1}^{n}{P}_{i}{Q}_{i}$$ To determine the average cost (AC) of production, the model proposed by Campos ( 2003 ) was used. The AC is the ratio between P EOC and quantity produced (Q). $${AC}_{p}=\frac{EOCp}{Q}$$ 2.8 Statistics The results of the evaluated parameters were submitted to the Shapiro-Wilk normality and Levene homogeneity tests. When the data met the assumptions of normality, they were submitted to one-way analysis of variance (ANOVA) and, in cases of significant difference, the means were compared using the Tukey test ( p < 0.05). When the initial principles of normality and homoscedasticity we not met, the nonparametric Kruskal-Wallis test was applied. For the survival and hematocrit data, arcsine transformations of the square root were initially done. 3. Results 3.1 Water quality The mean values of temperature and dissolved oxygen (DO) showed statistical differences ( p < 0.05) for the three densities, with an inverse relationship between DO and the densities (Table 1 ). Electrical conductivity, nitrite, total suspended solids (TSS), pH, alkalinity and total hardness showed differences ( p < 0.05) between BFT15 and BFT45, with a direct relationship between the first three variables and the increase in density, with the highest values occurring in BFT45. The sedimentable solids (SS) increased significantly with increasing densities, and BFT45 had highest average value, while pH and alkalinity values decreased with increasing density ( p < 0.05). Table 1 Mean ± standard deviation of the physical and chemical variables of the water in the rearing of Colossoma macropomum with biofloc technology at different densities (15, 30 and 45 fish.m − 3 ) during the 80 days of the experiment. VARIABLES TREATMENTS T15 T30 T45 Temperature (°C) 25.61 ± 0.52 a 25.78 ± 0.53 b 25.83 ± 0.50 c Dissolved oxygen (mg.L − 1 ) 6.93 ± 0.22ª 6.61 ± 0.23 b 6.46 ± 0.28 c Electrical conductivity (µS.cm − 1 ) 797.90 ± 101.43 a 881 ± 145.75ª b 951.42 ± 291.98 b pH 7.95 ± 0.13 a 7.74 ± 0.10 b 7.64 ± 0.11 c Alkalinity (mg.L − 1 CaCO 3 ) 196.75 ± 78.10 a 172.35 ± 69.26ª b 138.19 ± 59.34 b Total ammonia (mg.L − 1 NH 3 + NH 4 ) 0.03 ± 0.05 a 0.07 ± 0.09 a 0.08 ± 0.09 a Nitrite (mg.L − 1 NO 2 ) 0.05 ± 0.05 a 0.07 ± 0.54ª b 0.21 ± 0.38 b Hardness (mg.L − 1 CaCO 3 ) 131.15 ± 19.30 a 153.01 ± 13.32 b 140.84 ± 27.53 b SS (mL.L − 1 ) 22.31 ± 10.53 a 28.17 ± 9.55ª b 35.69 ± 16.66 b TSS (mg.L − 1 ) 188.42 ± 26.12 a 241.29 ± 23.07 a 245.86 ± 29.64 a SS = Settleable solids; TSS = total suspended solids. Different letters between columns indicate statistically significant differences ( p < 0.05). The concentrations of total ammonia showed greater oscillations during the experiment in the two highest stocking densities (Fig. 1 ). However, the mean values for total ammonia were less than 0.09 mg.L − 1 , and there was no significant difference between treatments (Table 1 ). The profile of nitrite concentrations, peaking in the fifth week in BFT45, was less than 2 mg.L − 1 (Fig. 2 ). The BFT45 treatment presented a significantly higher mean value ( p < 0.05) in relation to BFT15 and BFT30 (Table 1 ). The sedimentable solids (SS) profile showed the highest value in the seventh week (100 mL.L − 1 ) in the BFT45 treatment (Fig. 3 ). SS showed significant differences between BFT15 and BFT45 treatments ( p < 0.05) (Table 1 ). 3.2 Zootechnical performance The results of the zootechnical parameters evaluated in the juvenile tambaqui are presented in Table 2 . The mean values of final weight (FW), weight gain (WG), daily weight gain (DW) and specific growth rate (SGR) of the fish were significantly higher ( p < 0.05) at the lowest density (BFT15), while the apparent feed conversion (AFC) was lower in BFT15 and BFT30 compared to BFT45. However, the average values of biomass and fish productivity was significantly higher ( p < 0.05) in the highest density (BFT45) in relation to the other densities evaluated. The survival rate of the fish ranged between 100 and 97.33 ± 4.62%, with no statistical difference between treatments ( p > 0.05). Table 2 Mean ± standard deviation of zootechnical variables of Colossoma macropomum reared using biofloc technology (BFT) at different stocking densities (15, 30 and 45 fish.m − 3 ) during the 80 days of the experiment. VARIABLES TREATMENTS T15 T30 T45 Initial weight (g) 57.40 ± 2.40 a 56.08 ± 1.05 a 55.96 ± 1.65 a Final weight (g) 178.00 ± 7.14 a 136.84 ± 13.86 b 114.59 ± 4.82 b Weight gain (g) 120.6 ± 4.16 a 80.75 ± 14.27 b 58.86 ± 5.66 b Daily weight gain (g) 1.51 ± 0.06 a 0.94 ± 0.28 b 0.73 ± 0.07 b Specific growth rate (%.day − 1 ) 1.42 ± 0.02 a 1.11 ± 0.13 b 0.90 ± 0.08 b Survival (%) 100 ± 0.00 a 99.33 ± 1.15 a 97.33 ± 4.62 a AFC 1.45 ± 0.09 a 1.93 ± 0.39 a 2.17 ± 0.12 b Biomass (kg) 5.34 ± 0.21 a 8.11 ± 0.67 b 10.05 ± 0.15 c Productivity (kg.m − 3 ) 2.67 ± 0.10 a 4.05 ± 0.34 b 5.03 ± 0.08 c AFC = apparent feed conversion. Different letters between columns indicate statistically significant differences ( p < 0.05). 3.3 Blood parameters The mean values of blood parameters for the tambaqui are presented in Table 3 . With the exception of hematocrit (Ht), number of erythrocytes (RBC) and hemoglobin concentration ( p < 0.05), all the other parameters showed no statistical differences between the treatments. Table 3 Mean ± standard deviation of blood parameters of Colossoma macropomum reared using biofloc technology (BFT) at different stocking densities (T15 = 15, T30 = 30 and T45 = 45 fish.m − 3 ) during the 80 days of the experiment. VARIABLES TREATMENTS T15 T30 T45 Hematocrit (%) 32.71 ± 0.44 ab 31.42 ± 1.06 a 34.17 ± 1.05 b RBC (106.µl − 1 ) 1.83 ± 0.18 ab 1.64 ± 0.18 a 2.10 ± 0.04 b Hemoglobin (g.dl − 1 ) 8.83 ± 1.59 ab 9.96 ± 0.38 a 11.41 ± 0.59 b Glucose (mg.dl − 1 ) 58.35 ± 5.35 a 57.25 ± 5.33 a 84.30 ± 21.95 a MCV (fl) 183.70 ± 11.36 a 195.38 ± 25.57 a 164.10 ± 6.91 a MCH (pg) 49.74 ± 9.97 a 61.16 ± 4.19 a 54.88 ± 3.84 a MCHC (g.dl − 1 ) 27.07 ± 4.91 a 31.55 ± 2.07 a 33.48 ± 0.95 a Cholesterol (mg.dl − 1 ) 86.41 ± 7.37 a 87.07 ± 9.39 a 112.34 ± 37.64 a Total proteins (g.dl − 1 ) 3.02 ± 0.18 a 3.09 ± 0.21 a 4.15 ± 1.17 a RBC = number of erythrocytes; MCV = mean corpuscular volume; MCH = mean corpuscular hemoglobin; MCHC = mean corpuscular hemoglobin concentration. Different letters between columns indicate statistically significant differences ( p < 0.05). 3.4 Cost analysis The increase in density provided growth in the biomass produced, with BFT30 presenting biomass 51.87% higher than BFT15, while BFT45 was 23.92% higher than BFT30 and 88.20% higher than BFT15. Despite this, the increase in density also reflected in a rise in total costs. The highest expenditure on feed was with BFT45 (US $ 15.37 or US $ 1.51 kg − 1 ), while BFT15 presented the lowest expenditure (US $ 5.46 or US $ 1.02 kg − 1 ). Expenditure on electricity was the same for all densities since the same aeration system was used for all the densities. Nonetheless, the increase in biomass reduced the average cost, which was lower for BFT45 (US $ 7.08 kg − 1 ), compared to the other densities (Table 4 ). Table 4 Description of expenditures related to feed, electricity, total cost and the average cost per kilogram of Colossoma macropomum reared using biofloc technology. 15 30 45 Biomass (kg) 5.34 8.11 10.05 Feed (US $ ) 5.46 11.03 15.37 AC feed (US $ .kg − 1 ) 1.02 1.36 1.53 Electricity (US $ ) 71.11 71.11 71.11 AC elec (US $ .kg − 1 ) 13.32 8.77 7.08 EOC P (US $ ) 76.56 82.14 86.48 AC P (US $ .kg − 1 ) 14.34 10.13 8.60 Dollar conversion: August 2023 (US$ 1.00 = R$ 4.965) AC feed : average cost with feed; AC elec : average cost with electricity; EOC P : partial effective operating cost; AC P : partial average cost. The partial effective operating cost (EOC P ) had a direct relationship with density, i.e., the increase in density to 45 fish.m − 3 caused an elevation of EOC P by 12.95% in comparison with 15 fish.m − 3 . However, in relation to the partial average cost (ACp) values, the behavior of the costs was the opposite in relation to P EOC, due to the positive impact caused by the increase in biomass. Accordingly, the density of 15 fish.m − 3 presented an ACp 66.64% higher than that of 45 fish.m − 3 . 4. Discussion 4.1 Water quality The importance of water temperature in BFT systems is associated with its influence on the formation and stabilization time of microorganisms, as well as on the maintenance of the environment (Hostins et al. 2015 ). Additionally, metabolic activity in fish is regulated by temperature. In the present study, the water temperature (25.61 ± 0.52 and 25.83 ± 0.50 ºC) was lower than those considered ideal (29–32°C) for tambaqui (Amanajás et al. 2018 ), which suggests lower fish performance due to low water temperature. Dos Santos et al. ( 2021 a) reported that zootechnical results in BFT systems may be better at temperatures within the thermal comfort range of animals. Water quality is important for maintaining the health and good zootechnical performance of animals, especially in closed systems, where the stocking density can interfere with the quality of the animals, since the supply of nutrients is related to the amount of animals inserted in the system (Dos Santos et al. 2021b ). In the present study, variations in dissolved oxygen (DO), although with differences in mean values (Table 1 ), did not interfere with the homeostasis of this species (> 5 mg.L − 1 ) (Gomes et al. 2010 ). However, the increase in stocking densities influenced DO consumption, mainly due to the increase in organic matter in the solids. These results corroborate those described by Dos Santos et al. ( 2021 a), who evaluated different stocking densities for tambaqui (23.74 ± 0.22 g) in a BFT system and clear water during grow out. The DO concentration of over 5 mg.L − 1 guaranteed the process of nitrification and suspension of bioflocs (Ebeling et al. 2006 ; Samocha 2019 ). In the BFT system, the feed in the water and the oxidation of nitrogen compounds cause the consumption of alkalinity and, consequently, changes in pH (Ebeling et al. 2006 ; Dos Santos et al. 2023b ). In this study, the increase in feed supply in the higher stocking densities generated a demand for inorganic carbon due to the greater activity of the bacterial community, which caused a reduction in pH and alkalinity at the higher densities (Table 1 ). When pH is maintained between 7.0 and 9.0, this favors the development of heterotrophic and nitrifying bacteria (Chen et al. 2006 ). The pH was within the appropriate range for the bacteria and tambaqui, i.e., between 6.0 and 8.0 (Aride et al. 2007 ; Wood et al. 2018 ). Furtado et al. ( 2011 ) reported that, for Litopenaeus vannamei , alkalinity values of < 100 mg.L − 1 CaCO 3 compromise the nitrification process in BFT systems. With alkalinity values maintained at levels greater than 100 mg.L − 1 CaCO 3 , even in BFT45, the system remained at adequate levels, which ensured the metabolization of nitrogen compounds and, consequently, the water quality for the species. Similar results were described by Dos Santos et al. ( 2023a ) and Izel Silva et al. ( 2024 ), using BFT for juvenile tambaqui and matrinxã ( Brycon amazonicus ) larvae, respectively, which shows the efficiency of the system when under appropriate conditions and the good adaptation of animals to it. Hardness showed inverse values to alkalinity, with a significant increase in the higher densities (BFT30 and BFT45), which probably occurred due to the calcium in the feed and the pH corrections with dolomitic limestone (CaMgCO 3 ). Similar behavior was described by Dos Santos et al. ( 2021b ), who evaluated different stocking densities and the inclusion of probiotics for tambaqui in a BFT system and achieved values of 197 mg.L − 1 of CaCO 3 at the highest density tested. The same occurred for Izel Silva et al. ( 2024 ), who evaluated different concentrations of solids for matrinxã and observed a mean hardness concentration of 119.1 ± 7.04 mL.L − 1 of CaCO 3 in the highest concentration of solids. Copatti et al. ( 2019 ), who evaluated different pH (5.5, 7.0 and 9.0) under the influence of different hardness concentrations in water for juvenile Piaractus mesopotamicus , concluded that hardness above 120 mg.L − 1 ensures the health of animals when exposed to alkaline or acidic pH. The present study corroborates these authors, confirming that increased hardness in water can improve the condition of the animals. Ensuring adequate alkalinity of the water also increased the total hardness, as well as the electrical conductivity, which is commonly used to assess the availability of nutrients in aquatic ecosystems, as well as the salts present in the system (Boyd 2015 ). Since the use of an alkalinizer was more frequent in the densities of 30 and 45 fish.m − 3 , the amount of salt from the sodium bicarbonate was higher, as well as the amount of organic matter generated, due to the higher densities. Similar results in relation to higher concentration of solids and greater use of alkalinizers were described by Izel Silva et al. ( 2024 ). In this study, the mean values were < 1,000 µScm − 1 (Table 1 ), within what is recommended by Boyd ( 1998 ) and Boyd and Tucker ( 1998 ). The low concentrations of total ammonia and nitrite demonstrate the efficiency of the nitrification in the BFT system. Nitrite, in particular, despite presenting peaks in BFT15 and BFT45 ( p < 0.05), was below the lethal concentration (LC 50 − 96h ) determined for tambaqui (1.82 mg.L − 1 ) at all the densities evaluated (Costa et al. 2004 ). Likewise, the concentrations of total ammonia, which were within the limits considered appropriate for the species (LC 50 − 96 h = 141.38 mg.L − 1 NH 3 + NH 4 ) (Souza Bastos et al. 2017 ). This was possible due to the use of a mature BFT inoculum and maintaining the pH within the appropriate range for the microbial community, which ensured a stable environment (Chen et al. 2006 ). However, with the increase in stocking density, there is an increase in nitrogen in the environment (Wood et al. 2016 ). This influences the multiplication process of the microorganisms that make up the bioflocs, causing an increase in solids, which interfere with the concentrations of SS, TSS and turbidity, as well as increasing the concentration of CO 2 and reducing both the alkalinity and pH of the water (Ebeling et al. 2006 ; Dos Santos et al. 2021 a; Fernando Silva et al. 2024). In this study, the increase in the stocking density of the tambaqui increased the production of solids, due to the feed in the water and animal excreta. Although there is no information on tolerance limits for SS and TSS for tambaqui in the literature, these parameters remained within the range suggested for other freshwater fish species such as Nile tilapia ( Oreochromis niloticus ) (SS = 5–50 mL.L − 1 and SST up to 500 mg.L − 1 ) (Avnimelech 2015 ). These results corroborate the study by Dos Santos et al. ( 2021 a) for tambaqui, where the SS (up to 12.83 ± 6.79 ml.L − 1 ) and TSS (up to 491.19 ± 23.70 mg.L − 1 ) did not negatively influence its production and shows the good adaptation of the species to the BFT system. Similarly, Izel-Silva et al. (2024) defined the best TSS concentration as between 200 and 350 mg.L − 1 for B. amazonicus larvae. However, excess solids should be avoided, as high concentrations can interfere with water quality and the ability of aquatic organisms to assimilate the nutrients in the system (Zemor et al. 2019 ), causing instability in ammonia and nitrite concentrations, as well as increasing aeration demand. Thus, it can be suggested that the concentrations of SS and TSS, in the present study, did not impair the nitrification process in the system. 4.2 Performance and metabolic profile In general, zootechnical indices are affected by an increase in the number of animals per m 3 , in which a lower density generally provides better use of food and reduces the risks of stress to animals (Krummenauer et al. 2011 ; Sampaio and Freire 2016 ). In addition, it reduces competition for space and food, generating greater productivity at the end of the cycle (Haridas et al. 2017 ). In this study, the zootechnical results (final weight, weight gain, daily weight gain, specific growth rate and AFC) were negatively affected by the increase in stocking density. These results corroborate those described by Dos Santos et al. ( 2021 a), who evaluated different stocking densities (50, 100 and 200 fish.m − 3 ) for juvenile (± 20 g) tambaqui in a BFT system. Similarly, Haridas et al. ( 2017 ) evaluated different densities (200, 250, 300 and 350 fish.m − 3 ) for Nile tilapia (± 1 g) in a BFT system and observed results similar to these in relation to animal growth. These findings suggest that competition for food and space can affect the zootechnical performance of animals, regardless of size, and can be harmful even in fish that are younger and are in a more accelerated growth phase. However, tambaqui productivity and biomass were higher in BFT45, since fish survival reached values above 95% and did not differ between densities. The results of the present study were superior to others described for tambaqui under different breeding conditions, as observed by Fiúza et al. ( 2015 ), who evaluated different salinities (0, 5, 10 and 15 g.L − 1 ) in a recirculation system, and achieved productivity of 2.3 kg.m − 3 at the lowest salinity. Izel Silva et al. ( 2020 ) tested different aeration strategies in an excavated nursery system without water renewal and obtained productivity of 1.76 kg.m − 2 . Costa et al. ( 2019 ), when evaluating the effect of different stocking densities (1 to 2 kg.m − 3 .year), showed that the stability of the BFT system provided better conditions for the grow out of the tambaqui. The maintenance of the physical and chemical parameters of the water also influences the production process, such as the water temperature that was below the limit considered ideal for tambaqui (Table 1 ). According to Amanajás and Val ( 2023 ), tambaqui can grow and reproduce at a minimum temperature of up to 25 ºC; however, increasing the temperature to 29 ºC increases the growth rate by 4.2% day − 1 . In aquatic animals, lower temperatures decrease metabolism, reduce appetite, and worsen feed conversion (Amanajás and Val 2023 ; Dos Santos et al. 2021b ). Thus, it is possible that this was the factor that contributed to the reduction in the zootechnical performance of the animals in the present study. The present study corroborates the results described by Pellegrin et al. ( 2023 ), who evaluated different stocking densities (200, 400, 600, 800 and 1,000 fish.m − 3 ) of P. mesopotamicus (± 35 g) for 45 days and reported values of zootechnical parameters that were inversely proportional to the densities. These authors also observed that the hematological parameters were altered by the higher densities, which caused a stress response in animals. The metabolic profile of fish is used as a tool to assess the stress conditions of animals during grow out (Affonso et al. 2012 ; Fazio 2019 ; Silva et al. 2020 ; Dos Santos et al. 2021 a; 2023b ;). According to Costa et al. ( 2019 ), high stocking densities can alter the behavior of animals as a result of the variations in water quality and the availability of physical spaces for basal activities. For the parameters that express the capacity for oxygen transport to the animal tissues (Ht, Hb and RBC), the differences observed between BFT30 and BFT45 is not a function of stocking density, since BFT15 did not differ statistically from the other densities evaluated (Table 3 ). These results corroborate those described by Dos Santos et al. ( 2021 a), who evaluated different densities (50, 100 and 200 fish.m -3 ) for juvenile tambaqui (23.74 ± 0.22 g) and did not observe changes in blood parameters related to stocking densities, suggesting that the BFT system is able to maintain the homeostatic balance of animals when under stressors. The effect of BFT on the maintenance of fish health conditions was also observed by Haridas et al. ( 2017 ) and Dos Santos et al. ( 2023a ) for Nile tilapia under different densities and tambaqui fed with different protein levels, respectively. Both studies suggest that the BFT system maintained the improvement in animal health during bacterial challenge. In our study, the high rates of survival of the tambaqui, associated with the maintenance of the blood parameters of the fish, suggest the benefits of the BFT system. 4.3 Cost analysis Cost analysis is used to evaluate the efficiency of spending and compare production systems appropriately. In this sense, studies on production systems should be evaluated from the technical and economic point of view, because it is not always the environment that presents the best zootechnical performance that gives the greatest economic return. In addition, the intensification of the process can generate gains in productivity, but it also increases the cost of production (Hanson et al. 2013; Rego et al. 2017 ). Expenditure on feed and electricity in this study was higher than those of traditional systems for the grow out of tambaqui that were described by Lima (2020). These results corroborate those described by Rego et al. ( 2017 ), who compared traditional and BFT systems for L. vannamei and observed that the BFT system had higher productivity; however, the increase in density increased the expenditure on feed and electricity. Notwithstanding, in the present study, despite expenditure on electricity being greater, production was more economically efficient and resulted in a lower cost per kilogram (AC elec ) and lower AC p , in the highest density evaluated for tambaqui (45 fish.m − 3 ). This was due to the positive impact of the biomass gain, which was higher than the increases generated by the greater costs. Overall, the results can be improved through different routes. Dos Santos et al. ( 2021 a) emphasize the need to work with adequate densities and suggest that it is possible to produce tambaqui at high densities. However, the authors warn that high stocking densities can cause competitiveness for space and food, in addition to generating greater energy expenditure in the maintenance of homeostasis and loss of zootechnical performance (e.g., worsening of AFC, reduction in SGR and lower final weight), which directly impacts production costs. In the BFT system, the animals need to be as close as possible to their ideal breeding conditions in order to maximize productive performance. In this sense, Amanajás and Val ( 2023 ) state that it is important to pay attention to the thermal comfort of the tambaqui (29 to 32 ºC). Therefore, in this study, an increase in temperature could improve the AFC and SGR of the tambaqui and, consequently, reduce production costs. Dos Santos et al. ( 2023a ) state that the grow out of tambaqui in BFT systems can be carried out with feed that has a low protein content, thus reducing the cost of the feed. In addition, these feeds can mitigate the negative effect of nitrogen and help to reduce the use of organic and inorganic carbon sources to control these compounds, which could be a strategy to reduce the total cost of production in BFT systems. Braga et al. ( 2016 ) found the same for the marine shrimp L. vannamei when evaluating commercial feed for a semi-intensive system and formulated feeds for super-intensive BFT system. The authors obtained a significant improvement in zootechnical performance, as well as in water quality parameters with the feed formulated specifically for the BFT system, in addition to improving economic results. As for expenditures involving electricity, the main cause is the need for constant aeration throughout the production cycle. For the intensive system, Izel Silva et al. ( 2020 ) showed that the adaptive capacity of the tambaqui, the low oxygen concentration, implied a lower demand for electrical power, without loss of performance and with a lower effective operating cost. Furthermore, traditional systems are low cost, mainly due to the low degree of technification, but they also imply low productivity, in addition to increasing the demand for the use of natural resources, which can negatively influence the environment (Valenti et al. 2021 ). Therefore, a production plan with a specific feed supply for the super intensive system can be an alternative for maximizing zootechnical results, without causing an increase in apparent feed conversion. In addition, designing the electrical system to better meet the demands of biological processes of the fish and microorganisms can reduce electricity costs. (Hargreaves 2013 ). In this regard, establishing the correct dimensioning of the aeration system can directly affect the investment and the cost of production. 5. Conclusions The results of this study indicate that the BFT system is efficient for the initial grow out of juvenile tambaqui in densities with up to 45 fish.m -3 , without compromising water quality, zootechnical performance and physiological conditions of fish. Therefore, a density of 45 fish.m -3 is recommended at this stage in the grow out of tambaqui in a BFT system, seeking better productivity, a reduction in costs related to electricity and the average cost of production in general, thus optimizing natural resources in a more intensive and sustainable production system. Declarations Acknowledgments The authors thank the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), the Fundação de Amparo à Pesquisa do Estado do Amazonas (FAPEAM) and the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) for all their support. Ethical Approval and Consent to participate: Not applicable. Human and Animal Ethics: This study was approved by the INPA Ethics Committee (protocol No. 025/2018). For Humans: Not applicable. Consent for publication: The authors consent to the publication of the work. Availability of supporting data: Not applicable. Funding: This study was partially funded by the INCT ADAPTA II project, which is sponsored by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) (Process No. 465540/2014-7), and by FAPEAM - Fundação de Amparo à Pesquisa do Estado do Amazonas (Agreement 062.1187/2017) FAPEAM (PROSPAM, Process No. 01.02.016301.03188/2021 and Produtividade-CT&I, Process No. 62784.UNI910.1277.05082022), PDPG-Amazônia Legal/ Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES (Process No. 88887.510257/2020-00). Competing Interests : The authors declare that they have no known competing financial/personal interests. Author Contributions: Renato Henrique Costa Monte: Formal Analysis, Investigation, Methodology, Project Administration, Writing – Original Draft Preparation Raphael Brito dos Santos: Formal Analysis, Investigation, Methodology, Writing – Review & Editing Michelle M. S. Fugimura: Investigation, Validation, Writing – Review & Editing Eduardo Akifumi Ono: Writing – Review & Editing Fellipy Augusto Holanda Chaves: Investigation, Methodology, Writing – Review & Editing Cristiano Campos Mattioli: Writing – Review & Editing Elizabeth Gusmão Affonso: Conceptualization, Funding Acquisition, Supervision, Validation, Writing – Review & Editing References Affonso EG, Polez VLP, Corrêa CF, Mazon AF, Araújo MRR, Moraes G, Rantin FT (2002) Blood parameters and metabolites in the teleost fish Colossoma macropomum exposed to sulfide or hypoxia. Comp Biochem Physiol C Toxicol Pharmacol 133:375–382. https://doi.org/10.1016/S1532-0456(02)00127-8 Affonso EG, Ferreira MB, Brasil EM, Pereira Filho M, Roubach R, Ono EA (2012) Hematological responses as indicators of the pond culture of tambaqui, Colossoma macropomum (Cuvier, 1818), with and without water exchange. Adap Aqua Biota, 10:21–27. Acessed: https://repositorio.inpa.gov.br/handle/1/21451 Amanajás RD, Silva JM, Val AL (2018) Growing in the dark warmth: the case of Amazonian fish Colossoma macropomum . Front Mar Sci 5:492. https://doi.org/10.3389/fmars.2018.00492 Amanajás RD, Val AL (2023) Thermal biology of tambaqui ( Colossoma macropomum ): General insights for aquaculture in a changing world. Rev Aquac 15:480–490. https://doi.org/10.1111/raq.12732 APHA (2005) Standard Methods for the Examination of Water and Wastewater. American Public Health Association/American Water Works Association/Water Environment Federation, Washington DC Aride PHR, Roubach R, Val AL (2007) Tolerance response of tambaqui Colossoma macropomum (Cuvier) to water pH. Aquac Res 38:588–594. https://doi.org/10.1111/j.1365-2109.2007.01693.x Assis YPAS, Porto LD, De Melo NFAC, Palheta GDA, Luz RK, Favero GC (2020) Feed restriction as a feeding management strategy in Colossoma macropomum juveniles under recirculating aquaculture system (RAS). Aquaculture 529. https://doi.org/10.1016/j.aquaculture.2020.735689 Avnimelech Y (1999) Carbon/nitrogen ratio as a control element in aquaculture systems. Aquaculture 176:227–235. https://doi.org/10.1016/S0044-8486(99)00085-X Avnimelech Y (2012) Biofloc Technology for Super-Intensive Shrimp Culture - In book: Biofloc Technology: A Practical Guidebook. Publisher: World Aquaculture Society Louisiana, United States. 2rd ed, pp 167–188 https://doi.org/10.13140/2.1.4575.0402 Avnimelech Y (2015) Biofloc technology: A practical guide book. The World Aquaculture Society. ISBN: 978-188880-7226 Basumatary B, Verma AK, Kushwaha S, Verma MK (2023) Global research trends and performance measurement on biofloc technology (BFT): a systematic review based on computational techniques. Aquacult Int. https://doi.org/10.1007/s10499-023-01162-z Braga A, Magalhães V, Hanson T, Morris TC, Samocha TM (2016) The effects of feeding commercial feed formulated for semi-intensive systems on Litopenaeus vannamei production and its profitability in a hyper-intensive biofloc-dominated system. Aquac Rep 3:172–177. https://doi.org/10.1016/j.aqrep.2016.03.002 Boyd CE, Tucker CS (1992) Water quality and pond soil analyses for aquaculture. Alabama Agriculture Experiment Station, Auburn University, Auburn Boyd CE (1998) Water Quality in Ponds for Aquaculture. Auburn University, Birmingham Boyd CE, Tucker CS (1998) Pond aquaculture water quality management. Kluwer Academic, Boston Boyd CE (2015) Water quality: An introduction. Springer Nature. Auburn University, Alabama. https://doi.org/10.1007/978-3-319-17446-4 Brandão FR, Gomes LC, Chagas EC, Araújo LD (2004) Densidade de estocagem de juvenis de tambaqui durante a recria em tanques-rede. Pesq Agropec Bras 39:357–362 Bueno GW, Ostrensky A, Canzi C, de Matos FT, Roubach R (2015) Implementation of aquaculture parks in Federal Government waters in Brazil. Rev Aquac 7:1–12. https://doi.org/10.1111/raq.12045 Buzollo H, Sandre LCGD, Neira LM, Nascimento TMTD, Jomori RK, Carneiro DJ (2019) Digestible protein requirements and muscle growth in juvenile tambaqui ( Colossoma macropomum ). Aquac Res 25:669–679. https://doi.org/10.1111/anu.12888 Campos R (2003) Tipologia dos produtores de ovinos e caprinos no estado do Ceará. Rev. Econ. Nordeste 34:85–112. Accessed November 20, 2023. http://repositorio.ufc.br/handle/riufc/1161 Chagas EC, Gomes LDC, Martins H, Roubach R, Lourenço JNP (2005) Tambaqui growth reared in cages in a floodplain lake under different feeding rate. Pesq Agropec Bras 40:833–835. https://doi.org/10.1590/s0100-204x2005000800015 Chagas EC, Gomes LDC, Martins H, Roubach R (2007) Tambaqui productivity reared in cages with different feeding rations. Ciência Rural 37:1109–1115. https://doi.org/10.1590/s0103-84782007000400031 Chen S, Ling J, Blancheton JP (2006) Nitrification kinetics of biofilm as affected by water quality factors. Aquac Eng 34:179–197. https://doi.org/10.1016/j.aquaeng.2005.09.004 COMEX STAT (2023) Ministério da Indústria, Comércio Exterior e Serviços – Governo Federal Brasil. Versão 2.0.3. Dados extraídos da SISCOMEX pela EMBRAPA Pesca e Aquicultura. Accessed November 20, 2023. http://comexstat.mdic.gov.br/pt/sobre CONCEA (2015) Conselho Nacional De Controle De Experimentação Animal - CONCEA. Resolução normativa n.º 25, de 29 de setembro de 2015. Baixa o Capítulo Introdução Geral do Guia Brasileiro de Produção, Manutenção ou Utilização de Animais para Atividades de Ensino ou Pesquisa Científica do Conselho Nacional de Controle e Experimentação Animal – CONCEA. Diário Oficial da República Federativa do Brasil, Brasília, DF, 2 out. 2015. Accessed November 20, 2023 Copatti CE, Baldisserotto B, Souza CF, Garcia LO (2019) Protective effect of high hardness in pacu juveniles ( Piaractus mesopotamicus ) under acidic or alkaline pH: biochemical and hematological variables. Aquaculture 502:250–257. https://doi.org/10.1016/j.aquaculture.2018.12.028 Costa OTF, Ferreira DJS, Mendonça FLP, Fernandes MN (2004) Susceptibility of the Amazonian fish, Colossoma macropomum (Serrasalminae), to short-term exposure to nitrite. Aquaculture 232:627–636. https://doi.org/10.1016/S0044-8486(03)00524-6 Costa OTF, Dias LC, Malmann CSY, Ferreira CAL, Carmo IB, Wischneski AG, Sousa RL, Cavero BAS, Lameiras JLV, Dos Santos MC (2019) The effects of stocking density on the hematology, plasma protein profile and immunoglobulin production of juvenile tambaqui ( Colossoma macropomum ) farmed in Brazil. Aquaculture 499:260–268. https://doi.org/10.1016/j.aquaculture.2018.09.040 Da Silva TVN, Dos Santos CF, Dos Santos JML, Schmitz MJ, Ramírez JRB, Torres MF, Barbas LAL, Sampaio LA, Verde PE, Tesser MB, Monserrat JM (2023) Effects of dietary inclusion of lyophilized açai berries ( Euterpe oleracea ) on growth metrics, metabolic and antioxidant biomarkers, and skin color of juvenile tambaqui ( Colossoma macropomum ). Aquac Int 31:1031–1056. https://doi.org/10.1007/s10499-022-01014-2 Dos Santos DKM, Kojima JT, Santana TM, Castro DP, Serra PT, Dantas NSM, Fonseca FAL, Mariúba LAM, Gonçalves LU (2021b) Farming tambaqui ( Colossoma macropomum ) in static clear water versus a biofloc system with or without Bacillus subtilis supplementation. Aquac Int 29:207–218. https://doi.org/10.1007/s10499-020-00618-w Dos Santos RB, Izel-Silva J, Fugimura MMS, Suita SM, Ono EA, Affonso EG (2021a) Growth performance and health of juvenile tambaqui, Colossoma macropomum , in a biofloc system at different stocking densities. Aquac Res 52:3549–3559. https://doi.org/10.1111/are.15196 Dos Santos RB, Izel-Silva J, Medeiros PA, Fugimura MMS, Freitas TM, Gallani SU, Claudiano GS, Ono EA, Affonso EG (2023b) Immunophysiology of tambaqui fed with different levels of dietary protein in biofloc and clear water system. Aquac Int 1–13. https://doi.org/10.1007/s10499-023-01205-5 Dos Santos RB, Izel-Silva J, Medeiros PA, Fugimura MMS, Freitas TM, Ono EA, Claudiano GS, Affonso EG (2023a) Dietary protein requirement for tambaqui cultivated in biofloc and clear water systems. Aquac Int 1–20. https://doi.org/10.1007/s10499-023-01047-1 Ebeling JM, Timmons MB, Bisogni JJ (2006) Engineering analysis of the stoichiometry of photoautotrophic, autotrophic, and heterotrophic removal of ammonia-nitrogen in aquaculture systems. Aquaculture 257:346–358. https://doi.org/10.1016/j.aquaculture.2006.03.019 Emericiano M, Gaxiola G, Cuzon G (2013) Biofloc Technology (BFT): A Review for Aquaculture Application and Animal Food Industry. Biomass Now – Cultivation and Utilization, Intec. 301–328. Accessed November 20, 2023. https://doi.org/10.5772/53902 Emerenciano MGC, Martínez-Córdova LR, Martínez-Porchas M, Miranda-Baeza A (2017) Biofloc technology (BFT): a tool for water quality management in aquaculture. In: Tutu H, editor. Water Quality. London (UK): Intech Open; 5:92–109. https://doi.org/10.5772/66416 FAO, Agriculture Organization of the United Nations (2020) Food and. Colossoma macropomum introduced to Thailand from Hong Kong, Singapore. Introduced Species Fact Sheets. Accessed November 20, 2023. http://www.fao.org/fishery/introsp/3885/en FAO, Agriculture Organization of the United Nations (2023) Food and. Fisheries Global Information System (FIGIS). Fisheries Division, FAO. Accessed November 20, 2023. https://www.fao.org/fishery/en/figis Fazio F (2019) Fish hematology analysis as an important tool of aquaculture: A review. Aquaculture 500:237–242. https://doi.org/10.1016/j.aquaculture.2018.10.030 Fiúza LS, Aragão NM, Ribeiro Junior HP, Moraes MG, Rocha IRCB, Lustosa Neto AD, Sousa RR, Madrid RMM, Oliveira EG, Costa FHF (2015) Effects of salinity on the growth, survival, haematological parameters and osmoregulation of tambaqui Colossoma macropomum juveniles. Aquac Res 46:1–9. https://doi.org/10.1111/are.12224 Flickinger DL, Dantas DP, Proença DC, David FS, Valenti WC (2020) Phosphorus in the culture of the Amazon river prawn ( Macrobrachium amazonicum ) and tambaqui ( Colossoma macropomum ) farmed in monoculture and in integrated multitrophic systems. J World Aquac Soc 51:1002–1023. https://doi.org/10.1111/jwas.12655 Flores Nava A, Brown A (2020) Peces nativos de água dulce de América del Sur de interés para la acuicultura: Una síntesis del estado de desarrollo tecnológico de su cultivo. Serie Acuicultura en Latinoamérica. 1st ed. FAO. ISBN 978-92-5-306658-2 Fore M, Frank K, Norton K, Svendsen E, Alfredsen JA, Dempster T, Eguiraun H, Watson W, Stahl A, Sunde LM, Schellewald C, Skøien K, Alver MO, Berchmans D (2018) Precision fish farming: A new framework to improve production in aquaculture. Biosyst Eng 173:176–193. https://doi.org/10.1016/j.biosystemseng.2017.10.014 Frisso RM, Matos FT, Moro GV, Mattos BO (2020) Stocking density of Amazon fish ( Colossoma macropomum ) farmed in a continental neotropical reservoir with a net cages system. Aquaculture 529:735702. https://doi.org/10.1016/j.aquaculture.2020.735702 Furtado PS, Poersch LH, Wasielesky W (2011) Effect of calcium hydroxide, carbonate and sodium bicarbonate on water quality and zootechnical performance of shrimp Litopenaeus vannamei reared in bio-flocs technology (BFT) systems. Aquaculture 321:130–135. https://doi.org/10.1016/j.aquaculture.2011.08.034 Gomes LC, Simões LN, Araújo-Lima CARM (2010) Tambaqui ( Colossoma macropomum ). In: Baldisserotto B and Gomes LC (Ed.). Espécies nativas para piscicultura no Brasil. 2.ed. Santa Maria: Ed. UFSM, 2:175–204 Hargreaves JA (2013) Biofloc Production Systems for Aquaculture. Southern Regional Aquaculture Center SRAC. Publ, pp 1–12 Haridas H, Verma AK, Rathore G, Prakash C, Sawant PB, Babitha Rani AM (2017) Enhanced growth and immuno-physiological response of genetically improved farmed tilapia in indoor biofloc units at different stocking densities. Aquac Res 48:4346–4355. https://doi.org/10.1111/are.13256 Hilsdorf AWS, Hallerman E, Valladão GMR, Zaminhan-Hassemer M, Hashimoto DT, Dairiki JK, Takahashi LS, Albergaria FC, Gomes ME, Venturieri RLL, Moreira RG, Cyrino JEP (2022) The farming and husbandry of Colossoma macropomum : From Amazonian waters to sustainable production. Rev Aquac 14:993–1027. https://doi.org/10.1111/raq.12638 Hostins B, Braga A, Lopes DL, Wasielesky W, Poersch LH (2015) Effect of temperature on nursery and compensatory growth of pink shrimp Farfantepenaeus brasiliensis reared in a super-intensive biofloc system. Aquac Eng 66:62–67. https://doi.org/10.1016/j.aquaeng.2015.03.002 Inoue LAKA, Boijink CL, Ribeiro PT, Silva AMDD, Affonso EG (2011) Avaliação de respostas metabólicas do tambaqui exposto ao eugenol em banhos anestésicos. Acta Amaz 41:327–332. https://doi.org/10.1590/S0044-59672011000200020 Inoue LAKA, Bezerra AC, Miranda WS, Muniz AW, Boijink CL (2014) Cultivo de tambaqui em gaiolas de baixo volume: efeito da densidade de estocagem na produção de biomassa. Ciênc Anim Bras 15:437–443. https://doiorg/10.1590/1089-6891v15i426758 Izel Silva J, Ono EA, Queiroz MN, Dos Santos RB, Affonso EG (2020) Aeration strategy in the intensive culture of tambaqui, Colossoma macropomum , in the tropics. Aquaculture 529:735644. https://doi.org/10.1016/j.aquaculture.2020.735644 Izel Silva J, Dos Santos RB, Medeiros PA, Suita SM, Wasielesky W Jr, Fugimura MMS, Affonso EG (2024) Brycon amazonicus larviculture cannibalism is reduced in biofloc systems. Aquaculture 579:740180. https://doi.org/10.1016/j.aquaculture.2023.740180 Krummenauer D, Peixoto S, Cavalli RO, Poersch LH, Wasielesky W (2011) Superintensive culture of white shrimp, Litopenaeus vannamei , in a biofloc technology system in Southern Brazil at different stocking densities. J World Aquac Soc 42:726–733. https://doi.org/10.1111/j.1749-7345.2011.00507.x Krummenauer D, Samocha T, Poersch L, Lara G, Wasielesky W (2014) The reuse of water on the culture of pacific white shrimp, Litopenaeus vannamei , in BFT system. J World Aquac Soc 45:3–14. https://doi.org/10.1111/jwas.12093 Lima J, Montagner D, Duarte SS, Yoshioka ETO, Dias MKR, Tavares Dias M (2019) Recirculating system using biological aerated filters on tambaqui fingerling farming. Pesq Agropec Bras 54:00294. https://doi.org/10.1590/S1678-3921.pab2019.v54.00294 Lima CAS, Machado Bussons MRF, de Oliveira AT, Aride PHR, de Almeida O’Sullivan FL, Pantoja-Lima J (2020) Socioeconomic and profitability analysis of tambaqui Colossoma macropomum fish farming in the state of Amazonas, Brazil. Aquac Econ Manag 24:406–421. https://doi.org/10.1080/13657305.2020.1765895 Lovshin LL, Silva AB, Fernandez JA, Carneiro-Sobrinho A (1974) Preliminary pond culture test of pirapitinga Colossoma bidens , and tambaqui Colossoma macropomum , from the Amazon River basin. FAO Informes De Pesca 159:185–193 Mair G, Lucente D (2020) What are farmed types in aquaculture and why do they matter? FAO Aquac Newsl. 2020;61:40–42. Accessed November 20, 2023 Martin NB, Serra R, Oliveira MDM, Ângelo JA, Okawa H (1998) Sistema integrado de custos agropecuários - CUSTAGRI. Informações Econômicas 28:7–28. Accessed November 20, 2023. http://www.iea.sp.gov.br/ftpiea/ie/1998/tec1-0198.pdf Mesquita RCT, Galvão JA, Savbay-da-Silva LK, Eloy LR, Godoy LC, Streit DP Jr (2018) Protocol for tambaqui production based on stocking density and sex. Rev Bras Hig Sanid Anim 12:146–155. 10.5935/1981-2965.20180014 Oishi CA, Nwanna LC, Pereira Filho M (2010) Optimum dietary protein requirement for Amazonian Tambaqui, Colossoma macropomum Cuvier, 1818, fed fish meal free diets. Acta Amaz 40:757–762. https://doi.org/10.1590/S0044-59672010000400017 Pedroza Filho MX, Rodrigues APO, Rezende FP (2015) Dinâmica da produção de tambaqui e demais peixes redondos no Brasil. Brasília. DF: CNA 7:1–5. Accessed November 20, 2023. https://ainfo.cnptia.embrapa.br/digital/bitstream/item/141367/1/CNPASA-2015-aa7.pdf Pellegrin L, Copatti CE, de Sá Britto Pinto D, Nitz LF, Wasielesky W, Garcia L (2023) Effect of different stocking densities on hematological parameters and zootechnical performance of pacu ( Piaractus mesopotamicus ) in the BFT system. Aquaculture 576:739852. https://doi.org/10.1016/j.aquaculture.2023.739852 Rego MAS, Sabbag OJ, Soares R, Peixoto S (2017) Financial viability of inserting the biofloc technology in a marine shrimp Litopenaeus vannamei farm: a case study in the state of Pernambuco, Brazil. Aquac Int 25:473–483. https://doi.org/10.1007/s10499-016-0044-7 Rodrigues APO, Lima AF, Lima LKF, Ramos AMJ, Brignol FD, Freitas LEL, Moro GV (2023) Crescimento do tambaqui em sistema de renovação continua de água em tanques circulares. Palmas, TO: Embrapa Pesca e Aquicultura 24p. - (Boletim de Pesquisa e Desenvolvimento / Embrapa Pesca e Aquicultura, ISSN 2358–6273; 29) Samocha TM (2019) Sustainable Biofloc Systems for, Sustainable Biofloc Systems for Marine Shrimp. https://doi.org/10.1016/C2018-0-02628-6 Sampaio FDF, Freire CA (2016) An overview of stress physiology of fish transport: changes in water quality as a function of transport duration. Fish Fish 17:1055–1072. https://doi.org/10.1111/faf.12158 Santos L, Pereira Filho M, Sobreira C, Ituassú D, Fonseca FAL (2010) Exigência proteica de juvenis de tambaqui ( Colossoma macropomum ) após privação alimentar. Acta Amazonica 40:597–604. https://doi.org/10.1590/S0044-59672010000300021 Santos FAC, Boaventura TP, Julio GSC, Cortezzi PP, Figueiredo LG, Favero GC, Palheta GDA, Melo NFAC, Luz RK (2021) Growth performance and physiological parameters of Colossoma macropomum in a recirculating aquaculture system (RAS): Importance of stocking density and classification. Aquaculture 534:736274. https://doi.org/10.1016/j.aquaculture.2020.736274 Silva CR, Gomes LC, Brandão FR (2007) Effect of feeding rate and frequency on tambaqui ( Colossoma macropomum ) growth, production and feeding costs during the first growth phase in cages. Aquaculture 264:135–139. https://doi.org/10.1016/j.aquaculture. 2006.12.007 Silva CA, Fujimoto RY (2015) Crescimento de tambaqui em resposta a densidade de estocagem em tanques-rede. Acta amazônica 45:323–332. https://doi.org/10.1590/1809-4392201402205 Silva ACC, De Barros AF, Mendonça FMF, Gama KFS, Marcos R, Povh JA, Fornari DC, Hoshiba MA, De Abreu JS (2020) Performance and economic viability of tambaqui, Colossoma macropomum , selectively bred for weight gain. Acta Amaz 50:108–114. https://doi.org/10.1590/1809-4392201901992 Silva WS, Ferreira AL, Neves LC, Ferreira NS, Palheta GDA, Takata R, Luz RK (2021) Effects of stocking density on survival, growth and stress resistance of juvenile tambaqui ( Colossoma macropomum ) reared in a recirculating aquaculture system (RAS). Aquac Int 29:609–621. https://doi.org/10.1007/s1049 9-021-00647-z Sousa RGC, Piñeyro JIG, Cardoso NA, Andrade JE, Silva JG, Barbosa HTB (2016b) Stocking density and its effects to the zootechnical development of young tambaqui in an intensive production system. Densidade de estocagem e seus efeitos sobre o desenvolvimento zootécnico de juvenis de tambaqui em sistema intensivo de produção. ActaFish 4:80–92. https://doi.org/10.2312/Actafish.2016.4.1.80-92 Sousa RGC, Prado GF, Pyñeiro JIG, NETO EBBN (2016a) Avaliação do ganho de peso do tambaqui cultivado com diferentes taxas de proteıńas na alimentação. Rev Bio Amaz 6:40–45. https://doi.org/10.18561/2179-5746/biotaamazonia.v6n1p40-45 Souza Bastos LR, Val AL, Wood CM (2017) Are Amazonian fish more sensitive to ammonia? Toxicity of ammonia to eleven native species. Hydrobiologia 789:143–155. https://doi.org/10.1007/s10750-015-2623-4 Strickland JD, Parsons TR (1972) A practical handbook of seawater analysis. Fisheries Research Board of Canada, Ottawa Timmons MB, Ebeling JM (2010) Recirculating aquaculture systems. Cayuga Aqua Ventures, New York Valenti WC, Barros HP, Moraes Valenti P, Bueno GW, Cavalli RO (2021) Aquaculture in Brazil: past, present and future. Aquaculture Rep 19:100611. https://doi.org/10.1016/j.aqrep.2021.100611 Verdouw H, Van Echteld CJA, Dekkers EMJ (1978) Ammonia determination based on indophenol formation with sodium salicylate. Water Res 12:3992–3999. https://doi.org/10.1016/0043-1354(78)90107-0 Zemor JC, Wasielesky W, Fóes GK, Poersch LH (2019) The use of clarifiers to remove and control the total suspended solids in large-scale ponds for production of Litopenaeus vannamei in a biofloc system. Aquac Eng 85:74–79. https://doi.org/10.1016/j.aquaeng.2019.03.001 Welengane E, Sado RY, Bicudo ÁJDA (2019) Protein-sparing effect by dietary lipid increase in juveniles of the hybrid fish tambatinga (♀ Colossoma macropomum × ♂ Piaractus brachypomus ). Aquac Nutr 25:1272–1280. https://doi.org/10.1111/anu.12941 Wood CM, Souza Netto JG, Wilson JM, Duarte RM, Val AL (2016) Nitrogen metabolism in tambaqui ( Colossoma macropomum ), a Neotropical model teleost: hypoxia, temperature, exercise, feeding, fasting, and high environmental ammonia. J Comp Physiol 187:135–151. https://doi.org/10.1007/s00360-016-1027-8 Wood CM, Gonzalez RJ, Ferreira MS, Braz Mota S, Val AL (2018) The physiology of the Tambaqui ( Colossoma macropomum ) at pH 8.0. J Comp Physiol 188:393–408. https://doi.org/10.1007/s00360-017-1137-y Woynárovich A, Van Anrooy R (2019) Field guide to the culture of tambaqui ( Colossoma macropomum , Cuvier, 1816). FAO Fisheries and Aquaculture Technical Paper 624. FAO. 624:1–121. Accessed November 20, 2023. https://www.fao.org/3/CA2955EN/ca2955en.pdf 7.Statements & Declarations Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 03 Jul, 2024 Reviews received at journal 09 Jun, 2024 Reviewers agreed at journal 30 May, 2024 Reviewers agreed at journal 21 Mar, 2024 Reviewers agreed at journal 11 Mar, 2024 Reviewers invited by journal 03 Mar, 2024 Editor assigned by journal 23 Feb, 2024 Submission checks completed at journal 22 Feb, 2024 First submitted to journal 21 Feb, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-3977429","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":274441905,"identity":"03f47477-61a8-4ac8-8135-264e0f01238b","order_by":0,"name":"Renato Henrique Costa Montelo","email":"","orcid":"","institution":"Nilton Lins University","correspondingAuthor":false,"prefix":"","firstName":"Renato","middleName":"Henrique Costa","lastName":"Montelo","suffix":""},{"id":274441906,"identity":"7a581ff8-49b7-447c-ba3f-e545d7423441","order_by":1,"name":"Raphael Brito Santos","email":"","orcid":"","institution":"Federal University of Amazonas, UFAM","correspondingAuthor":false,"prefix":"","firstName":"Raphael","middleName":"Brito","lastName":"Santos","suffix":""},{"id":274441907,"identity":"5e33e363-4f04-4ebc-a819-ee05371d00da","order_by":2,"name":"Michelle Midori Sena Fugimura","email":"","orcid":"","institution":"Federal University of Western Pará, UFOPA","correspondingAuthor":false,"prefix":"","firstName":"Michelle","middleName":"Midori Sena","lastName":"Fugimura","suffix":""},{"id":274441908,"identity":"2002e689-2994-43e2-b5a3-8edc6fb08a19","order_by":3,"name":"Eduardo Akifumi Ono","email":"","orcid":"","institution":"Nova Aqua","correspondingAuthor":false,"prefix":"","firstName":"Eduardo","middleName":"Akifumi","lastName":"Ono","suffix":""},{"id":274441909,"identity":"dfeb807a-8023-431a-9053-8db64cf400f5","order_by":4,"name":"Fellipy Augusto Holanda Chaves","email":"","orcid":"","institution":"National Institute for Amazonian Research, INPA, LAFAP","correspondingAuthor":false,"prefix":"","firstName":"Fellipy","middleName":"Augusto Holanda","lastName":"Chaves","suffix":""},{"id":274441910,"identity":"a8d643ba-be0d-4112-968c-0022ebe53abe","order_by":5,"name":"Cristiano Campos Mattioli","email":"","orcid":"","institution":"National Institute for Amazonian Research, INPA, LAFAP","correspondingAuthor":false,"prefix":"","firstName":"Cristiano","middleName":"Campos","lastName":"Mattioli","suffix":""},{"id":274441911,"identity":"6155c9dd-3204-4bbb-ae2e-5e8dcb3dc8f3","order_by":6,"name":"Elizabeth Gusmão Affonso","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA4klEQVRIiWNgGAWjYBADHn4GBjYYhw2fSjiQkWwgVYuNwQFitZjzrzH+dKPGhsf4RvKzBx8qGOT5xQ6wPa7Ao8Vyxhsz6ZxjaTxmN9LMDWecYTCcOTuB3fAMHi0GN86YMeewHQZqSTCT5m1jSDC4ncAG9BheLcafc/4d5jGekf6NSC3newykc9sO8xhI5BBpi+UMtjLp3L40Hokzb8okZ5yRAPolsd0QnxZz/sObP+d8s7Hnb0/fJvGhwkaeXzr52EO8DpNIgLIEwAwJIGbEpwGohf8AlAVnjIJRMApGwShAAwDUPEiiObKkLAAAAABJRU5ErkJggg==","orcid":"","institution":"National Institute for Amazonian Research, INPA, LAFAP","correspondingAuthor":true,"prefix":"","firstName":"Elizabeth","middleName":"Gusmão","lastName":"Affonso","suffix":""}],"badges":[],"createdAt":"2024-02-22 03:39:41","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-3977429/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-3977429/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":51634587,"identity":"c45727d6-22a6-4353-b2ff-a9487f6140e6","added_by":"auto","created_at":"2024-02-26 10:42:59","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":79040,"visible":true,"origin":"","legend":"\u003cp\u003eAverage concentration of total ammonia (mg.L\u003csup\u003e-1\u003c/sup\u003e) in the rearing of \u003cem\u003eColossoma macropomum\u003c/em\u003e with biofloc technology (BFT), in different stocking densities (15, 30 and 45 fish.m\u003csup\u003e-3\u003c/sup\u003e) over 12 weeks.\u003c/p\u003e","description":"","filename":"Picture1.png","url":"https://assets-eu.researchsquare.com/files/rs-3977429/v1/ca316473f95a31b479580499.png"},{"id":51634586,"identity":"c7dc8838-2348-4881-a0a2-77e76b89de33","added_by":"auto","created_at":"2024-02-26 10:42:59","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":72153,"visible":true,"origin":"","legend":"\u003cp\u003eAverage nitrite concentration (mg.L\u003csup\u003e-1\u003c/sup\u003e) in the rearing of \u003cem\u003eColossoma macropomum\u003c/em\u003e with biofloc technology (BFT), in different stocking densities (15, 30 and 45 fish.m\u003csup\u003e-3\u003c/sup\u003e) over 12 weeks.\u003c/p\u003e","description":"","filename":"Picture2.png","url":"https://assets-eu.researchsquare.com/files/rs-3977429/v1/0f52ae58a46d2b243b639e63.png"},{"id":51634588,"identity":"0756d970-4f6e-44b4-8331-5427ffc96f6b","added_by":"auto","created_at":"2024-02-26 10:42:59","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":76100,"visible":true,"origin":"","legend":"\u003cp\u003eAverage concentration of settleable solids (mL.L\u003csup\u003e-1\u003c/sup\u003e) in the rearing \u003cem\u003eColossoma macropomum\u003c/em\u003e with biofloc technology (BFT) in different stocking densities (15, 30 and 45 fish.m\u003csup\u003e-3\u003c/sup\u003e) over 12 weeks.\u003c/p\u003e","description":"","filename":"Picture3.png","url":"https://assets-eu.researchsquare.com/files/rs-3977429/v1/c2ff767fb71d0b13ea1d130e.png"},{"id":51634656,"identity":"c3ee8d0a-e997-4060-a4ad-0439659653dd","added_by":"auto","created_at":"2024-02-26 10:51:01","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":679041,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-3977429/v1/045b8608-d96e-46c4-a521-42ae5a161d78.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Stocking densities of Colossoma macropomum in the initial grow out phase using biofloc technology","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eThe tambaqui (\u003cem\u003eColossoma macropomum\u003c/em\u003e), is native to the Amazon and has economic importance in South and Central America and in Asian countries (Woyn\u0026aacute;rovich and Van Anrooy \u003cspan citationid=\"CR87\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Mair and Lucente \u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; FAO 2020; 2023). In Brazil, it was the second most produced and exported fish species in 2022, and part of this success is due its suitability for production, such as good adaptation to different breeding systems and high stocking density (Hilsdorf et al. \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eAmong the various possibilities for tambaqui production, the extensive system, which carried out in excavated nurseries, is the most used by fish farmers, and productivity in the grow out phase can be from 0.3 to 1.2 kilos m\u003csup\u003e2\u003c/sup\u003e year\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e (Valenti et al. \u003cspan citationid=\"CR81\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). However, there have been advances in production technology, such as the emergency supplementary aeration strategy, which can reduce production costs and improve fish performance, and increase production to up to 1.76 kilograms m\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e year\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e (Izel-Silva et al. \u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). The intensive tambaqui production systems, such as in net tanks, achieve productivity in the grow out phase of 8 to 24 kg.m\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e per cycle (Frisso et al. \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). However, this system requires constant renewal of water, which can cause eutrophication of the environments where they are installed, in addition to being more vulnerable to sanitary problems (Bueno et al. \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2015\u003c/span\u003e; Flickinger et al. \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e2020\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn a water recirculation system (WRS), the productivity in the grow out phase can reach 2.5 to 15 kg.m\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e per cycle (Lima et al. \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Silva et al. \u003cspan citationid=\"CR75\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Santos et al. \u003cspan citationid=\"CR71\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Rodrigues et al. \u003cspan citationid=\"CR67\" class=\"CitationRef\"\u003e2023\u003c/span\u003e), in addition to reducing land occupation and water consumption, thus intensifying production and improving resource management (Assis et al. \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Another super-intensive system that can intensify production of tambaqui and other species of fish native to the Amazon is biofloc technology (BFT) (Dos Santos et al. \u003cspan citationid=\"CR71\" class=\"CitationRef\"\u003e2021\u003c/span\u003ea; 2023a; \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2023b\u003c/span\u003e; Izel-Silva et al. 2024). This is presented as an alternative for super intensification and optimization of water and area use (Emerenciano et al. \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). BFT has a lower environmental impact and high productivity in the grow out phase of tambaqui and pacu (\u003cem\u003ePiaractus mesopotamicus\u003c/em\u003e) from 11.38 to 34.16 kg.m\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e per cycle (Dos Santos et al. \u003cspan citationid=\"CR71\" class=\"CitationRef\"\u003e2021\u003c/span\u003ea; Pellegrin et al. \u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e2023\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eSystems using BFT are based on the \u003cem\u003ein situ\u003c/em\u003e production of microorganisms with little or no water exchange (Krummenauer et al. \u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). With regard to technical aspects, intense and constant aeration is necessary in order to maintain the bioflocs suspended and the necessary oxygen levels to meet the demands of the animals, as well as nitrification (Avnimelech \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2012\u003c/span\u003e). These processes occur simultaneously in the system through the activities of chemoautotrophic and heterotrophic microorganisms, using the inorganic and organic carbon (Ebeling et al. \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Timmons and Ebeling \u003cspan citationid=\"CR80\" class=\"CitationRef\"\u003e2010\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eSuper-intensive aquaculture systems require not only technical knowledge of production, but also efficient cost analyses (Valenti et al. \u003cspan citationid=\"CR81\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). Effective planning results in high productivity and reduced financial expenses, thus improving the profitability of the enterprise (Rego et al. \u003cspan citationid=\"CR66\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Fore et al. \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). As such, the present study determined the best stocking density for the initial fattening phase of tambaqui in a BFT system, and used the water quality, zootechnical performance, metabolic profile of the fish and production costs as indicators.\u003c/p\u003e"},{"header":"2. Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Acclimation and ethical approval\u003c/h2\u003e \u003cp\u003eAt the aquaculture Experimental Station of INPA (National Institute for Amazonian Research), Amazonas, Brazil, juvenile tambaqui (40.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05 g) were acclimated for 25 days in 500 L tanks and fed twice a day with commercial feed (36% crude protein) until they reached a weight of 56.5\u0026thinsp;\u0026plusmn;\u0026thinsp;1.69 g. Before the start of the experiment, a parasitological analysis of individuals was performed to confirm the absence of the acanthocephalan \u003cem\u003eNeoechinorhyncus buttnerae\u003c/em\u003e, the most harmful parasite in tambaqui farming (Moraes et al. 2023).\u003c/p\u003e \u003cp\u003eThis study was carried out in accordance with the standards of the National Council for Control of Animal Experimentation (CONCEA, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2015\u003c/span\u003e) and approved by the Ethics Commission on the Use of Animals (CEUA) at INPA (Protocol No. 025/2018).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Experimental design\u003c/h2\u003e \u003cp\u003eThe experimental design adopted was a completely randomized one with three triplicate treatments (15 (BFT15), 30 (BFT30) and 45 (BFT45) fish.m\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e) and had a duration of 80 days. Nine fiberglass tanks of 2 m\u003csup\u003e3\u003c/sup\u003e useful volume each were used, with constant aeration from a 2.3 hp radial compressor, distributed via a 1/2\" internal diameter microporous hose, so as to ensure the maintenance of the concentration of dissolved oxygen over 5 mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e during the experiment.\u003c/p\u003e \u003cp\u003eFish were fed three times a day with commercial extruded omnivore feed, with 36% (2 to 5 mm) and 32% (4 to 6 mm) crude protein (Oishi et al. \u003cspan citationid=\"CR63\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Buzollo et al. \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Welengane et al. \u003cspan citationid=\"CR84\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). The feed supply considered the stored biomass: 5% between 50 and 100 g and 3% above 100 g. The adjustment of the feed was done according to biometrics performed every 20 days, with the fish previously anesthetized in eugenol (0.5 mL.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) and using a precision electronic scale (Prix\u0026reg;, BCS21).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Formation and maintenance of bioflocs\u003c/h2\u003e \u003cp\u003eEach experimental unit received 1,200 L (60% of the tank volume) of biofloc inoculum from a previously matured biofloc culture (Zemor et al. \u003cspan citationid=\"CR83\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). The maturation of the bioflocs was performed with the daily application of sugar as a source of organic carbon and also during the first 15 days of grow out. A C:N ratio of 20:1 was adopted to stimulate microbial development in the experimental environment (Emerenciano et al. \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). After this period, fertilization with organic carbon was performed only when the concentration of total ammonia present in the system was \u0026ge;\u0026thinsp;1 mg L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, using the ratio of 6:1 (C:N).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e2.4 Water quality\u003c/h2\u003e \u003cp\u003eTemperature (\u0026ordm;C), dissolved oxygen (mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e), electrical conductivity (mS.cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) and pH were measured twice daily with a digital multiparameter probe (YSI Inc, Yellow Spring, OH, USA). Weekly, the sedimentable solids (SS) were measured in an Imhoff cone and clarification was done with the use of sedimentators, whenever they presented values over 50 mL.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e (Hargreaves \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2013\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eFor the analyses of total ammonia, nitrogen (Verdouw et al. \u003cspan citationid=\"CR82\" class=\"CitationRef\"\u003e1978\u003c/span\u003e), nitrite and alkalinity (Boyd and Tucker \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e1992\u003c/span\u003e), hardness (APHA \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2005\u003c/span\u003e) and total suspended solids (TSS) (adapted by Strickland and Parsons \u003cspan citationid=\"CR79\" class=\"CitationRef\"\u003e1972\u003c/span\u003e) samples of 500 mL of water were taken twice a week.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e2.5 Zootechnical performance\u003c/h2\u003e \u003cp\u003eAt the end of the experiment, the animals were anesthetized with eugenol (Inoue et al. \u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e2011\u003c/span\u003e) and the following zootechnical variables were evaluated: weight gain (WG)\u0026thinsp;=\u0026thinsp;final mean weight \u0026ndash; initial mean weight; daily mean weight gain (DW) = (final weight \u0026ndash; initial weight)/number of days; specific growth rate (SGR) = [(ln (final weight) \u0026ndash; ln (initial weight))/number of days] x 100; apparent feed conversion (AFC)\u0026thinsp;=\u0026thinsp;amount of feed offered/initial weight gain; survival (S%) = (final number of fish/initial number of fish) x 100; and productivity\u0026thinsp;=\u0026thinsp;biomass gain/tank volume (m\u003csup\u003e3\u003c/sup\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e2.6 Metabolic profile\u003c/h2\u003e \u003cp\u003eBlood tests were performed on four animals per experimental unit (n\u0026thinsp;=\u0026thinsp;12.treatment\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e). After anesthetized the fish with eugenol (0.5 mL.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e), blood collection was performed, via venipuncture of vessels located in the caudal region, with syringes containing 10% EDTA solution. The following were determined: hematocrit (Ht), using the microhematocrit method; number of erythrocytes (RBC), with a formalin-citrate solution, hemoglobin concentration (Hb), using the cyanmethemoglobin method. The hematimetric indices mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC) and mean corpuscular hemoglobin (MCH) were calculated from the values of Ht, RBC and Hb. The plasma, obtained by centrifugation, was used for glucose analysis via the enzymatic-colorimetric method (\u0026copy;Diagn\u0026oacute;stica Catarinense; glucose, REF. 434-MS 80022230067), total protein (P\u003csub\u003et\u003c/sub\u003e) via the colorimetric biuret method (\u0026copy;ANALISA - PP CAT 418\u0026thinsp;\u0026minus;\u0026thinsp;250 ML) and cholesterol using the colorimetric enzymatic method (\u0026copy;ANALISA-Trinder).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003e2.7 Cost analysis\u003c/h2\u003e \u003cp\u003eIn this study, the partial effective operating cost (EOC\u003csub\u003eP\u003c/sub\u003e) was evaluated. The EOC\u003csub\u003eP\u003c/sub\u003e are costs directly linked to production, i.e., expenses such as feed, alkalinizers and electricity. The EOC\u003csub\u003eP\u003c/sub\u003e was determined according to the proposal of Martin et al. (\u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e1998\u003c/span\u003e).\u003cdiv id=\"Equa\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equa\" name=\"EquationSource\"\u003e\n$${EOCp}_{}=\\sum _{i=1}^{n}{P}_{i}{Q}_{i}$$\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eTo determine the average cost (AC) of production, the model proposed by Campos (\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2003\u003c/span\u003e) was used. The AC is the ratio between \u003csub\u003eP\u003c/sub\u003eEOC and quantity produced (Q).\u003cdiv id=\"Equb\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equb\" name=\"EquationSource\"\u003e\n$${AC}_{p}=\\frac{EOCp}{Q}$$\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e2.8 Statistics\u003c/h2\u003e \u003cp\u003eThe results of the evaluated parameters were submitted to the Shapiro-Wilk normality and Levene homogeneity tests. When the data met the assumptions of normality, they were submitted to one-way analysis of variance (ANOVA) and, in cases of significant difference, the means were compared using the Tukey test (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05). When the initial principles of normality and homoscedasticity we not met, the nonparametric Kruskal-Wallis test was applied. For the survival and hematocrit data, arcsine transformations of the square root were initially done.\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results","content":"\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Water quality\u003c/h2\u003e \u003cp\u003eThe mean values of temperature and dissolved oxygen (DO) showed statistical differences (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05) for the three densities, with an inverse relationship between DO and the densities (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Electrical conductivity, nitrite, total suspended solids (TSS), pH, alkalinity and total hardness showed differences (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05) between BFT15 and BFT45, with a direct relationship between the first three variables and the increase in density, with the highest values occurring in BFT45. The sedimentable solids (SS) increased significantly with increasing densities, and BFT45 had highest average value, while pH and alkalinity values decreased with increasing density (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation of the physical and chemical variables of the water in the rearing of \u003cem\u003eColossoma macropomum\u003c/em\u003e with biofloc technology at different densities (15, 30 and 45 fish.m\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e) during the 80 days of the experiment.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eVARIABLES\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003eTREATMENTS\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eT15\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eT30\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eT45\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTemperature (\u0026deg;C)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e25.61\u0026thinsp;\u0026plusmn;\u0026thinsp;0.52\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e25.78\u0026thinsp;\u0026plusmn;\u0026thinsp;0.53\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e25.83\u0026thinsp;\u0026plusmn;\u0026thinsp;0.50\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDissolved oxygen (mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6.93\u0026thinsp;\u0026plusmn;\u0026thinsp;0.22\u0026ordf;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6.61\u0026thinsp;\u0026plusmn;\u0026thinsp;0.23\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6.46\u0026thinsp;\u0026plusmn;\u0026thinsp;0.28\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eElectrical conductivity (\u0026micro;S.cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e797.90\u0026thinsp;\u0026plusmn;\u0026thinsp;101.43\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e881\u0026thinsp;\u0026plusmn;\u0026thinsp;145.75\u0026ordf;\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e951.42\u0026thinsp;\u0026plusmn;\u0026thinsp;291.98\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003epH\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7.95\u0026thinsp;\u0026plusmn;\u0026thinsp;0.13\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7.74\u0026thinsp;\u0026plusmn;\u0026thinsp;0.10\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7.64\u0026thinsp;\u0026plusmn;\u0026thinsp;0.11\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAlkalinity (mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e CaCO\u003csub\u003e3\u003c/sub\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e196.75\u0026thinsp;\u0026plusmn;\u0026thinsp;78.10\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e172.35\u0026thinsp;\u0026plusmn;\u0026thinsp;69.26\u0026ordf;\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e138.19\u0026thinsp;\u0026plusmn;\u0026thinsp;59.34\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal ammonia (mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e NH\u003csub\u003e3\u003c/sub\u003e\u0026thinsp;+\u0026thinsp;NH\u003csub\u003e4\u003c/sub\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.03\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.07\u0026thinsp;\u0026plusmn;\u0026thinsp;0.09\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.08\u0026thinsp;\u0026plusmn;\u0026thinsp;0.09\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNitrite (mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e NO\u003csub\u003e2\u003c/sub\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.05\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.07\u0026thinsp;\u0026plusmn;\u0026thinsp;0.54\u0026ordf;\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.21\u0026thinsp;\u0026plusmn;\u0026thinsp;0.38\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHardness (mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e CaCO\u003csub\u003e3\u003c/sub\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e131.15\u0026thinsp;\u0026plusmn;\u0026thinsp;19.30\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e153.01\u0026thinsp;\u0026plusmn;\u0026thinsp;13.32\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e140.84\u0026thinsp;\u0026plusmn;\u0026thinsp;27.53\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSS (mL.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e22.31\u0026thinsp;\u0026plusmn;\u0026thinsp;10.53\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e28.17\u0026thinsp;\u0026plusmn;\u0026thinsp;9.55\u0026ordf;\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e35.69\u0026thinsp;\u0026plusmn;\u0026thinsp;16.66\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTSS (mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e188.42\u0026thinsp;\u0026plusmn;\u0026thinsp;26.12\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e241.29\u0026thinsp;\u0026plusmn;\u0026thinsp;23.07\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e245.86\u0026thinsp;\u0026plusmn;\u0026thinsp;29.64\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003eSS\u0026thinsp;=\u0026thinsp;Settleable solids; TSS\u0026thinsp;=\u0026thinsp;total suspended solids. Different letters between columns indicate statistically significant differences (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05).\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThe concentrations of total ammonia showed greater oscillations during the experiment in the two highest stocking densities (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). However, the mean values for total ammonia were less than 0.09 mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, and there was no significant difference between treatments (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe profile of nitrite concentrations, peaking in the fifth week in BFT45, was less than 2 mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The BFT45 treatment presented a significantly higher mean value (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05) in relation to BFT15 and BFT30 (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The sedimentable solids (SS) profile showed the highest value in the seventh week (100 mL.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) in the BFT45 treatment (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). SS showed significant differences between BFT15 and BFT45 treatments (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05) (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Zootechnical performance\u003c/h2\u003e \u003cp\u003eThe results of the zootechnical parameters evaluated in the juvenile tambaqui are presented in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. The mean values of final weight (FW), weight gain (WG), daily weight gain (DW) and specific growth rate (SGR) of the fish were significantly higher (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05) at the lowest density (BFT15), while the apparent feed conversion (AFC) was lower in BFT15 and BFT30 compared to BFT45. However, the average values of biomass and fish productivity was significantly higher (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05) in the highest density (BFT45) in relation to the other densities evaluated. The survival rate of the fish ranged between 100 and 97.33\u0026thinsp;\u0026plusmn;\u0026thinsp;4.62%, with no statistical difference between treatments (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation of zootechnical variables of \u003cem\u003eColossoma macropomum\u003c/em\u003e reared using biofloc technology (BFT) at different stocking densities (15, 30 and 45 fish.m\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e) during the 80 days of the experiment.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eVARIABLES\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003eTREATMENTS\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eT15\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eT30\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eT45\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInitial weight (g)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e57.40\u0026thinsp;\u0026plusmn;\u0026thinsp;2.40\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e56.08\u0026thinsp;\u0026plusmn;\u0026thinsp;1.05\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e55.96\u0026thinsp;\u0026plusmn;\u0026thinsp;1.65\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFinal weight (g)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e178.00\u0026thinsp;\u0026plusmn;\u0026thinsp;7.14\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e136.84\u0026thinsp;\u0026plusmn;\u0026thinsp;13.86\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e114.59\u0026thinsp;\u0026plusmn;\u0026thinsp;4.82\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWeight gain (g)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e120.6\u0026thinsp;\u0026plusmn;\u0026thinsp;4.16\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e80.75\u0026thinsp;\u0026plusmn;\u0026thinsp;14.27\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e58.86\u0026thinsp;\u0026plusmn;\u0026thinsp;5.66\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDaily weight gain (g)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.51\u0026thinsp;\u0026plusmn;\u0026thinsp;0.06\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.94\u0026thinsp;\u0026plusmn;\u0026thinsp;0.28\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.73\u0026thinsp;\u0026plusmn;\u0026thinsp;0.07\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSpecific growth rate (%.day\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.42\u0026thinsp;\u0026plusmn;\u0026thinsp;0.02\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.11\u0026thinsp;\u0026plusmn;\u0026thinsp;0.13\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.90\u0026thinsp;\u0026plusmn;\u0026thinsp;0.08\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSurvival (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e100\u0026thinsp;\u0026plusmn;\u0026thinsp;0.00\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e99.33\u0026thinsp;\u0026plusmn;\u0026thinsp;1.15\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e97.33\u0026thinsp;\u0026plusmn;\u0026thinsp;4.62\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAFC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.45\u0026thinsp;\u0026plusmn;\u0026thinsp;0.09\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.93\u0026thinsp;\u0026plusmn;\u0026thinsp;0.39\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.17\u0026thinsp;\u0026plusmn;\u0026thinsp;0.12\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBiomass (kg)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5.34\u0026thinsp;\u0026plusmn;\u0026thinsp;0.21\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8.11\u0026thinsp;\u0026plusmn;\u0026thinsp;0.67\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e10.05\u0026thinsp;\u0026plusmn;\u0026thinsp;0.15\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eProductivity (kg.m\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.67\u0026thinsp;\u0026plusmn;\u0026thinsp;0.10\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4.05\u0026thinsp;\u0026plusmn;\u0026thinsp;0.34\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5.03\u0026thinsp;\u0026plusmn;\u0026thinsp;0.08\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003eAFC\u0026thinsp;=\u0026thinsp;apparent feed conversion. Different letters between columns indicate statistically significant differences (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05).\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003e3.3 Blood parameters\u003c/h2\u003e \u003cp\u003eThe mean values of blood parameters for the tambaqui are presented in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. With the exception of hematocrit (Ht), number of erythrocytes (RBC) and hemoglobin concentration (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05), all the other parameters showed no statistical differences between the treatments.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation of blood parameters of \u003cem\u003eColossoma macropomum\u003c/em\u003e reared using biofloc technology (BFT) at different stocking densities (T15\u0026thinsp;=\u0026thinsp;15, T30\u0026thinsp;=\u0026thinsp;30 and T45\u0026thinsp;=\u0026thinsp;45 fish.m\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e) during the 80 days of the experiment.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eVARIABLES\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003eTREATMENTS\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eT15\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eT30\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eT45\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHematocrit (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e32.71\u0026thinsp;\u0026plusmn;\u0026thinsp;0.44\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e31.42\u0026thinsp;\u0026plusmn;\u0026thinsp;1.06\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e34.17\u0026thinsp;\u0026plusmn;\u0026thinsp;1.05\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRBC (106.\u0026micro;l\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.83\u0026thinsp;\u0026plusmn;\u0026thinsp;0.18\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.64\u0026thinsp;\u0026plusmn;\u0026thinsp;0.18\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.10\u0026thinsp;\u0026plusmn;\u0026thinsp;0.04\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHemoglobin (g.dl\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8.83\u0026thinsp;\u0026plusmn;\u0026thinsp;1.59\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9.96\u0026thinsp;\u0026plusmn;\u0026thinsp;0.38\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e11.41\u0026thinsp;\u0026plusmn;\u0026thinsp;0.59\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGlucose (mg.dl\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e58.35\u0026thinsp;\u0026plusmn;\u0026thinsp;5.35\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e57.25\u0026thinsp;\u0026plusmn;\u0026thinsp;5.33\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e84.30\u0026thinsp;\u0026plusmn;\u0026thinsp;21.95\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMCV (fl)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e183.70\u0026thinsp;\u0026plusmn;\u0026thinsp;11.36\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e195.38\u0026thinsp;\u0026plusmn;\u0026thinsp;25.57\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e164.10\u0026thinsp;\u0026plusmn;\u0026thinsp;6.91\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMCH (pg)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e49.74\u0026thinsp;\u0026plusmn;\u0026thinsp;9.97\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e61.16\u0026thinsp;\u0026plusmn;\u0026thinsp;4.19\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e54.88\u0026thinsp;\u0026plusmn;\u0026thinsp;3.84\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMCHC (g.dl\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e27.07\u0026thinsp;\u0026plusmn;\u0026thinsp;4.91\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e31.55\u0026thinsp;\u0026plusmn;\u0026thinsp;2.07\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e33.48\u0026thinsp;\u0026plusmn;\u0026thinsp;0.95\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCholesterol (mg.dl\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e86.41\u0026thinsp;\u0026plusmn;\u0026thinsp;7.37\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e87.07\u0026thinsp;\u0026plusmn;\u0026thinsp;9.39\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e112.34\u0026thinsp;\u0026plusmn;\u0026thinsp;37.64\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal proteins (g.dl\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.02\u0026thinsp;\u0026plusmn;\u0026thinsp;0.18\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.09\u0026thinsp;\u0026plusmn;\u0026thinsp;0.21\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4.15\u0026thinsp;\u0026plusmn;\u0026thinsp;1.17\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003eRBC\u0026thinsp;=\u0026thinsp;number of erythrocytes; MCV\u0026thinsp;=\u0026thinsp;mean corpuscular volume; MCH\u0026thinsp;=\u0026thinsp;mean corpuscular hemoglobin; MCHC\u0026thinsp;=\u0026thinsp;mean corpuscular hemoglobin concentration. Different letters between columns indicate statistically significant differences (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05).\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003e3.4 Cost analysis\u003c/h2\u003e \u003cp\u003eThe increase in density provided growth in the biomass produced, with BFT30 presenting biomass 51.87% higher than BFT15, while BFT45 was 23.92% higher than BFT30 and 88.20% higher than BFT15. Despite this, the increase in density also reflected in a rise in total costs.\u003c/p\u003e \u003cp\u003eThe highest expenditure on feed was with BFT45 (US\u003cspan\u003e$\u003c/span\u003e 15.37 or US\u003cspan\u003e$\u003c/span\u003e 1.51 kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e), while BFT15 presented the lowest expenditure (US\u003cspan\u003e$\u003c/span\u003e 5.46 or US\u003cspan\u003e$\u003c/span\u003e 1.02 kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e). Expenditure on electricity was the same for all densities since the same aeration system was used for all the densities. Nonetheless, the increase in biomass reduced the average cost, which was lower for BFT45 (US\u003cspan\u003e$\u003c/span\u003e 7.08 kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e), compared to the other densities (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDescription of expenditures related to feed, electricity, total cost and the average cost per kilogram of \u003cem\u003eColossoma macropomum\u003c/em\u003e reared using biofloc technology.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e45\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBiomass (kg)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e5.34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e8.11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e10.05\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFeed (US\u003cspan\u003e$\u003c/span\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e5.46\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e11.03\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e15.37\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAC\u003csub\u003efeed\u003c/sub\u003e(US\u003cspan\u003e$\u003c/span\u003e.kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.02\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.36\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.53\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eElectricity (US\u003cspan\u003e$\u003c/span\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e71.11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e71.11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e71.11\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAC\u003csub\u003eelec\u003c/sub\u003e (US\u003cspan\u003e$\u003c/span\u003e.kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e13.32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e8.77\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e7.08\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEOC\u003csub\u003eP\u003c/sub\u003e (US\u003cspan\u003e$\u003c/span\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e76.56\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e82.14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e86.48\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAC\u003csub\u003eP\u003c/sub\u003e (US\u003cspan\u003e$\u003c/span\u003e.kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e14.34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e10.13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e8.60\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003eDollar conversion: August 2023 (US$ 1.00\u0026thinsp;=\u0026thinsp;R$ 4.965) AC\u003csub\u003efeed\u003c/sub\u003e: average cost with feed; AC\u003csub\u003eelec\u003c/sub\u003e: average cost with electricity; EOC\u003csub\u003eP\u003c/sub\u003e: partial effective operating cost; AC\u003csub\u003eP\u003c/sub\u003e: partial average cost.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThe partial effective operating cost (EOC\u003csub\u003eP\u003c/sub\u003e) had a direct relationship with density, i.e., the increase in density to 45 fish.m\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e caused an elevation of EOC\u003csub\u003eP\u003c/sub\u003e by 12.95% in comparison with 15 fish.m\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e. However, in relation to the partial average cost (ACp) values, the behavior of the costs was the opposite in relation to \u003csub\u003eP\u003c/sub\u003eEOC, due to the positive impact caused by the increase in biomass. Accordingly, the density of 15 fish.m\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e presented an ACp 66.64% higher than that of 45 fish.m\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e.\u003c/p\u003e \u003c/div\u003e"},{"header":"4. Discussion","content":"\u003cdiv id=\"Sec17\" class=\"Section2\"\u003e \u003ch2\u003e4.1 Water quality\u003c/h2\u003e \u003cp\u003eThe importance of water temperature in BFT systems is associated with its influence on the formation and stabilization time of microorganisms, as well as on the maintenance of the environment (Hostins et al. \u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). Additionally, metabolic activity in fish is regulated by temperature. In the present study, the water temperature (25.61\u0026thinsp;\u0026plusmn;\u0026thinsp;0.52 and 25.83\u0026thinsp;\u0026plusmn;\u0026thinsp;0.50 \u0026ordm;C) was lower than those considered ideal (29\u0026ndash;32\u0026deg;C) for tambaqui (Amanaj\u0026aacute;s et al. \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2018\u003c/span\u003e), which suggests lower fish performance due to low water temperature. Dos Santos et al. (\u003cspan citationid=\"CR71\" class=\"CitationRef\"\u003e2021\u003c/span\u003ea) reported that zootechnical results in BFT systems may be better at temperatures within the thermal comfort range of animals.\u003c/p\u003e \u003cp\u003eWater quality is important for maintaining the health and good zootechnical performance of animals, especially in closed systems, where the stocking density can interfere with the quality of the animals, since the supply of nutrients is related to the amount of animals inserted in the system (Dos Santos et al. \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2021b\u003c/span\u003e). In the present study, variations in dissolved oxygen (DO), although with differences in mean values (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e), did not interfere with the homeostasis of this species (\u0026gt;\u0026thinsp;5 mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) (Gomes et al. \u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e2010\u003c/span\u003e). However, the increase in stocking densities influenced DO consumption, mainly due to the increase in organic matter in the solids. These results corroborate those described by Dos Santos et al. (\u003cspan citationid=\"CR71\" class=\"CitationRef\"\u003e2021\u003c/span\u003ea), who evaluated different stocking densities for tambaqui (23.74\u0026thinsp;\u0026plusmn;\u0026thinsp;0.22 g) in a BFT system and clear water during grow out. The DO concentration of over 5 mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e guaranteed the process of nitrification and suspension of bioflocs (Ebeling et al. \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Samocha \u003cspan citationid=\"CR68\" class=\"CitationRef\"\u003e2019\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn the BFT system, the feed in the water and the oxidation of nitrogen compounds cause the consumption of alkalinity and, consequently, changes in pH (Ebeling et al. \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Dos Santos et al. \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2023b\u003c/span\u003e). In this study, the increase in feed supply in the higher stocking densities generated a demand for inorganic carbon due to the greater activity of the bacterial community, which caused a reduction in pH and alkalinity at the higher densities (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). When pH is maintained between 7.0 and 9.0, this favors the development of heterotrophic and nitrifying bacteria (Chen et al. \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2006\u003c/span\u003e). The pH was within the appropriate range for the bacteria and tambaqui, i.e., between 6.0 and 8.0 (Aride et al. \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2007\u003c/span\u003e; Wood et al. \u003cspan citationid=\"CR86\" class=\"CitationRef\"\u003e2018\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eFurtado et al. (\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e2011\u003c/span\u003e) reported that, for \u003cem\u003eLitopenaeus vannamei\u003c/em\u003e, alkalinity values of \u0026lt;\u0026thinsp;100 mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e CaCO\u003csub\u003e3\u003c/sub\u003e compromise the nitrification process in BFT systems. With alkalinity values maintained at levels greater than 100 mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e CaCO\u003csub\u003e3\u003c/sub\u003e, even in BFT45, the system remained at adequate levels, which ensured the metabolization of nitrogen compounds and, consequently, the water quality for the species. Similar results were described by Dos Santos et al. (\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2023a\u003c/span\u003e) and Izel Silva et al. (\u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e2024\u003c/span\u003e), using BFT for juvenile tambaqui and matrinx\u0026atilde; (\u003cem\u003eBrycon amazonicus\u003c/em\u003e) larvae, respectively, which shows the efficiency of the system when under appropriate conditions and the good adaptation of animals to it.\u003c/p\u003e \u003cp\u003eHardness showed inverse values to alkalinity, with a significant increase in the higher densities (BFT30 and BFT45), which probably occurred due to the calcium in the feed and the pH corrections with dolomitic limestone (CaMgCO\u003csub\u003e3\u003c/sub\u003e). Similar behavior was described by Dos Santos et al. (\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2021b\u003c/span\u003e), who evaluated different stocking densities and the inclusion of probiotics for tambaqui in a BFT system and achieved values of 197 mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e of CaCO\u003csub\u003e3\u003c/sub\u003e at the highest density tested. The same occurred for Izel Silva et al. (\u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e2024\u003c/span\u003e), who evaluated different concentrations of solids for matrinx\u0026atilde; and observed a mean hardness concentration of 119.1\u0026thinsp;\u0026plusmn;\u0026thinsp;7.04 mL.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e of CaCO\u003csub\u003e3\u003c/sub\u003e in the highest concentration of solids. Copatti et al. (\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2019\u003c/span\u003e), who evaluated different pH (5.5, 7.0 and 9.0) under the influence of different hardness concentrations in water for juvenile \u003cem\u003ePiaractus mesopotamicus\u003c/em\u003e, concluded that hardness above 120 mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e ensures the health of animals when exposed to alkaline or acidic pH. The present study corroborates these authors, confirming that increased hardness in water can improve the condition of the animals.\u003c/p\u003e \u003cp\u003eEnsuring adequate alkalinity of the water also increased the total hardness, as well as the electrical conductivity, which is commonly used to assess the availability of nutrients in aquatic ecosystems, as well as the salts present in the system (Boyd \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). Since the use of an alkalinizer was more frequent in the densities of 30 and 45 fish.m\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e, the amount of salt from the sodium bicarbonate was higher, as well as the amount of organic matter generated, due to the higher densities. Similar results in relation to higher concentration of solids and greater use of alkalinizers were described by Izel Silva et al. (\u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). In this study, the mean values were \u0026lt;\u0026thinsp;1,000 \u0026micro;Scm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e), within what is recommended by Boyd (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e1998\u003c/span\u003e) and Boyd and Tucker (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e1998\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe low concentrations of total ammonia and nitrite demonstrate the efficiency of the nitrification in the BFT system. Nitrite, in particular, despite presenting peaks in BFT15 and BFT45 (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05), was below the lethal concentration (LC\u003csub\u003e50\u0026thinsp;\u0026minus;\u0026thinsp;96h\u003c/sub\u003e) determined for tambaqui (1.82 mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) at all the densities evaluated (Costa et al. \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2004\u003c/span\u003e). Likewise, the concentrations of total ammonia, which were within the limits considered appropriate for the species (LC\u003csub\u003e50\u0026thinsp;\u0026minus;\u0026thinsp;96 h\u003c/sub\u003e = 141.38 mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e NH\u003csub\u003e3\u003c/sub\u003e\u0026thinsp;+\u0026thinsp;NH\u003csub\u003e4\u003c/sub\u003e) (Souza Bastos et al. \u003cspan citationid=\"CR78\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). This was possible due to the use of a mature BFT inoculum and maintaining the pH within the appropriate range for the microbial community, which ensured a stable environment (Chen et al. \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2006\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eHowever, with the increase in stocking density, there is an increase in nitrogen in the environment (Wood et al. \u003cspan citationid=\"CR85\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). This influences the multiplication process of the microorganisms that make up the bioflocs, causing an increase in solids, which interfere with the concentrations of SS, TSS and turbidity, as well as increasing the concentration of CO\u003csub\u003e2\u003c/sub\u003e and reducing both the alkalinity and pH of the water (Ebeling et al. \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Dos Santos et al. \u003cspan citationid=\"CR71\" class=\"CitationRef\"\u003e2021\u003c/span\u003ea; Fernando Silva et al. 2024). In this study, the increase in the stocking density of the tambaqui increased the production of solids, due to the feed in the water and animal excreta. Although there is no information on tolerance limits for SS and TSS for tambaqui in the literature, these parameters remained within the range suggested for other freshwater fish species such as Nile tilapia (\u003cem\u003eOreochromis niloticus\u003c/em\u003e) (SS\u0026thinsp;=\u0026thinsp;5\u0026ndash;50 mL.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e and SST up to 500 mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) (Avnimelech \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). These results corroborate the study by Dos Santos et al. (\u003cspan citationid=\"CR71\" class=\"CitationRef\"\u003e2021\u003c/span\u003ea) for tambaqui, where the SS (up to 12.83\u0026thinsp;\u0026plusmn;\u0026thinsp;6.79 ml.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) and TSS (up to 491.19\u0026thinsp;\u0026plusmn;\u0026thinsp;23.70 mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) did not negatively influence its production and shows the good adaptation of the species to the BFT system. Similarly, Izel-Silva et al. (2024) defined the best TSS concentration as between 200 and 350 mg.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e for \u003cem\u003eB. amazonicus\u003c/em\u003e larvae. However, excess solids should be avoided, as high concentrations can interfere with water quality and the ability of aquatic organisms to assimilate the nutrients in the system (Zemor et al. \u003cspan citationid=\"CR83\" class=\"CitationRef\"\u003e2019\u003c/span\u003e), causing instability in ammonia and nitrite concentrations, as well as increasing aeration demand. Thus, it can be suggested that the concentrations of SS and TSS, in the present study, did not impair the nitrification process in the system.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section2\"\u003e \u003ch2\u003e4.2 Performance and metabolic profile\u003c/h2\u003e \u003cp\u003eIn general, zootechnical indices are affected by an increase in the number of animals per m\u003csup\u003e3\u003c/sup\u003e, in which a lower density generally provides better use of food and reduces the risks of stress to animals (Krummenauer et al. \u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e2011\u003c/span\u003e; Sampaio and Freire \u003cspan citationid=\"CR69\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). In addition, it reduces competition for space and food, generating greater productivity at the end of the cycle (Haridas et al. \u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e2017\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn this study, the zootechnical results (final weight, weight gain, daily weight gain, specific growth rate and AFC) were negatively affected by the increase in stocking density. These results corroborate those described by Dos Santos et al. (\u003cspan citationid=\"CR71\" class=\"CitationRef\"\u003e2021\u003c/span\u003ea), who evaluated different stocking densities (50, 100 and 200 fish.m\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e) for juvenile (\u0026plusmn;\u0026thinsp;20 g) tambaqui in a BFT system. Similarly, Haridas et al. (\u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e2017\u003c/span\u003e) evaluated different densities (200, 250, 300 and 350 fish.m\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e) for Nile tilapia (\u0026plusmn;\u0026thinsp;1 g) in a BFT system and observed results similar to these in relation to animal growth. These findings suggest that competition for food and space can affect the zootechnical performance of animals, regardless of size, and can be harmful even in fish that are younger and are in a more accelerated growth phase.\u003c/p\u003e \u003cp\u003eHowever, tambaqui productivity and biomass were higher in BFT45, since fish survival reached values above 95% and did not differ between densities. The results of the present study were superior to others described for tambaqui under different breeding conditions, as observed by Fi\u0026uacute;za et al. (\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2015\u003c/span\u003e), who evaluated different salinities (0, 5, 10 and 15 g.L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) in a recirculation system, and achieved productivity of 2.3 kg.m\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e at the lowest salinity. Izel Silva et al. (\u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e2020\u003c/span\u003e) tested different aeration strategies in an excavated nursery system without water renewal and obtained productivity of 1.76 kg.m\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e. Costa et al. (\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2019\u003c/span\u003e), when evaluating the effect of different stocking densities (1 to 2 kg.m\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e.year), showed that the stability of the BFT system provided better conditions for the grow out of the tambaqui.\u003c/p\u003e \u003cp\u003eThe maintenance of the physical and chemical parameters of the water also influences the production process, such as the water temperature that was below the limit considered ideal for tambaqui (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). According to Amanaj\u0026aacute;s and Val (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2023\u003c/span\u003e), tambaqui can grow and reproduce at a minimum temperature of up to 25 \u0026ordm;C; however, increasing the temperature to 29 \u0026ordm;C increases the growth rate by 4.2% day\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. In aquatic animals, lower temperatures decrease metabolism, reduce appetite, and worsen feed conversion (Amanaj\u0026aacute;s and Val \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Dos Santos et al. \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2021b\u003c/span\u003e). Thus, it is possible that this was the factor that contributed to the reduction in the zootechnical performance of the animals in the present study.\u003c/p\u003e \u003cp\u003eThe present study corroborates the results described by Pellegrin et al. (\u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e2023\u003c/span\u003e), who evaluated different stocking densities (200, 400, 600, 800 and 1,000 fish.m\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e) of \u003cem\u003eP. mesopotamicus\u003c/em\u003e (\u0026plusmn;\u0026thinsp;35 g) for 45 days and reported values of zootechnical parameters that were inversely proportional to the densities. These authors also observed that the hematological parameters were altered by the higher densities, which caused a stress response in animals.\u003c/p\u003e \u003cp\u003eThe metabolic profile of fish is used as a tool to assess the stress conditions of animals during grow out (Affonso et al. \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2012\u003c/span\u003e; Fazio \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Silva et al. \u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Dos Santos et al. \u003cspan citationid=\"CR71\" class=\"CitationRef\"\u003e2021\u003c/span\u003ea; \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2023b\u003c/span\u003e;). According to Costa et al. (\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2019\u003c/span\u003e), high stocking densities can alter the behavior of animals as a result of the variations in water quality and the availability of physical spaces for basal activities. For the parameters that express the capacity for oxygen transport to the animal tissues (Ht, Hb and RBC), the differences observed between BFT30 and BFT45 is not a function of stocking density, since BFT15 did not differ statistically from the other densities evaluated (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThese results corroborate those described by Dos Santos et al. (\u003cspan citationid=\"CR71\" class=\"CitationRef\"\u003e2021\u003c/span\u003ea), who evaluated different densities (50, 100 and 200 fish.m\u003csup\u003e-3\u003c/sup\u003e) for juvenile tambaqui (23.74\u0026thinsp;\u0026plusmn;\u0026thinsp;0.22 g) and did not observe changes in blood parameters related to stocking densities, suggesting that the BFT system is able to maintain the homeostatic balance of animals when under stressors. The effect of BFT on the maintenance of fish health conditions was also observed by Haridas et al. (\u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e2017\u003c/span\u003e) and Dos Santos et al. (\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2023a\u003c/span\u003e) for Nile tilapia under different densities and tambaqui fed with different protein levels, respectively. Both studies suggest that the BFT system maintained the improvement in animal health during bacterial challenge. In our study, the high rates of survival of the tambaqui, associated with the maintenance of the blood parameters of the fish, suggest the benefits of the BFT system.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec19\" class=\"Section2\"\u003e \u003ch2\u003e4.3 Cost analysis\u003c/h2\u003e \u003cp\u003eCost analysis is used to evaluate the efficiency of spending and compare production systems appropriately. In this sense, studies on production systems should be evaluated from the technical and economic point of view, because it is not always the environment that presents the best zootechnical performance that gives the greatest economic return. In addition, the intensification of the process can generate gains in productivity, but it also increases the cost of production (Hanson et al. 2013; Rego et al. \u003cspan citationid=\"CR66\" class=\"CitationRef\"\u003e2017\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eExpenditure on feed and electricity in this study was higher than those of traditional systems for the grow out of tambaqui that were described by Lima (2020). These results corroborate those described by Rego et al. (\u003cspan citationid=\"CR66\" class=\"CitationRef\"\u003e2017\u003c/span\u003e), who compared traditional and BFT systems for \u003cem\u003eL. vannamei\u003c/em\u003e and observed that the BFT system had higher productivity; however, the increase in density increased the expenditure on feed and electricity. Notwithstanding, in the present study, despite expenditure on electricity being greater, production was more economically efficient and resulted in a lower cost per kilogram (AC\u003csub\u003eelec\u003c/sub\u003e) and lower AC\u003csub\u003ep\u003c/sub\u003e, in the highest density evaluated for tambaqui (45 fish.m\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e). This was due to the positive impact of the biomass gain, which was higher than the increases generated by the greater costs.\u003c/p\u003e \u003cp\u003eOverall, the results can be improved through different routes. Dos Santos et al. (\u003cspan citationid=\"CR71\" class=\"CitationRef\"\u003e2021\u003c/span\u003ea) emphasize the need to work with adequate densities and suggest that it is possible to produce tambaqui at high densities. However, the authors warn that high stocking densities can cause competitiveness for space and food, in addition to generating greater energy expenditure in the maintenance of homeostasis and loss of zootechnical performance (e.g., worsening of AFC, reduction in SGR and lower final weight), which directly impacts production costs.\u003c/p\u003e \u003cp\u003eIn the BFT system, the animals need to be as close as possible to their ideal breeding conditions in order to maximize productive performance. In this sense, Amanaj\u0026aacute;s and Val (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2023\u003c/span\u003e) state that it is important to pay attention to the thermal comfort of the tambaqui (29 to 32 \u0026ordm;C). Therefore, in this study, an increase in temperature could improve the AFC and SGR of the tambaqui and, consequently, reduce production costs.\u003c/p\u003e \u003cp\u003eDos Santos et al. (\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2023a\u003c/span\u003e) state that the grow out of tambaqui in BFT systems can be carried out with feed that has a low protein content, thus reducing the cost of the feed. In addition, these feeds can mitigate the negative effect of nitrogen and help to reduce the use of organic and inorganic carbon sources to control these compounds, which could be a strategy to reduce the total cost of production in BFT systems. Braga et al. (\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2016\u003c/span\u003e) found the same for the marine shrimp \u003cem\u003eL. vannamei\u003c/em\u003e when evaluating commercial feed for a semi-intensive system and formulated feeds for super-intensive BFT system. The authors obtained a significant improvement in zootechnical performance, as well as in water quality parameters with the feed formulated specifically for the BFT system, in addition to improving economic results.\u003c/p\u003e \u003cp\u003eAs for expenditures involving electricity, the main cause is the need for constant aeration throughout the production cycle. For the intensive system, Izel Silva et al. (\u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e2020\u003c/span\u003e) showed that the adaptive capacity of the tambaqui, the low oxygen concentration, implied a lower demand for electrical power, without loss of performance and with a lower effective operating cost. Furthermore, traditional systems are low cost, mainly due to the low degree of technification, but they also imply low productivity, in addition to increasing the demand for the use of natural resources, which can negatively influence the environment (Valenti et al. \u003cspan citationid=\"CR81\" class=\"CitationRef\"\u003e2021\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eTherefore, a production plan with a specific feed supply for the super intensive system can be an alternative for maximizing zootechnical results, without causing an increase in apparent feed conversion. In addition, designing the electrical system to better meet the demands of biological processes of the fish and microorganisms can reduce electricity costs. (Hargreaves \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). In this regard, establishing the correct dimensioning of the aeration system can directly affect the investment and the cost of production.\u003c/p\u003e \u003c/div\u003e"},{"header":"5. Conclusions","content":"\u003cp\u003eThe results of this study indicate that the BFT system is efficient for the initial grow out of juvenile tambaqui in densities with up to 45 fish.m\u003csup\u003e-3\u003c/sup\u003e, without compromising water quality, zootechnical performance and physiological conditions of fish. Therefore, a density of 45 fish.m\u003csup\u003e-3\u003c/sup\u003e is recommended at this stage in the grow out of tambaqui in a BFT system, seeking better productivity, a reduction in costs related to electricity and the average cost of production in general, thus optimizing natural resources in a more intensive and sustainable production system.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors thank the Coordena\u0026ccedil;\u0026atilde;o de Aperfei\u0026ccedil;oamento de Pessoal de N\u0026iacute;vel Superior (CAPES),\u0026nbsp;the\u0026nbsp;Funda\u0026ccedil;\u0026atilde;o de Amparo \u0026agrave; Pesquisa do Estado do Amazonas\u0026nbsp;(FAPEAM)\u0026nbsp;and the Conselho Nacional de Desenvolvimento Cient\u0026iacute;fico e Tecnol\u0026oacute;gico (CNPq) for all their support.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eEthical Approval and Consent to participate:\u003c/em\u003e Not applicable.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eHuman and Animal Ethics:\u0026nbsp;\u003c/em\u003eThis study was approved by the INPA Ethics Committee (protocol No. 025/2018). For Humans: Not applicable.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eConsent for publication:\u0026nbsp;\u003c/em\u003eThe authors consent to the publication of the work.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eAvailability of supporting data:\u003c/em\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eFunding:\u0026nbsp;\u003c/em\u003eThis study was partially funded by the INCT ADAPTA II project, which is sponsored by the Conselho Nacional de Desenvolvimento Cient\u0026iacute;fico e Tecnol\u0026oacute;gico (CNPq) (Process No. 465540/2014-7), and by FAPEAM -\u0026nbsp;Funda\u0026ccedil;\u0026atilde;o de Amparo \u0026agrave; Pesquisa do Estado do Amazonas (Agreement 062.1187/2017) FAPEAM (PROSPAM, Process No. 01.02.016301.03188/2021 and Produtividade-CT\u0026amp;I, Process No. 62784.UNI910.1277.05082022), PDPG-Amaz\u0026ocirc;nia Legal/\u0026nbsp;Coordena\u0026ccedil;\u0026atilde;o de Aperfei\u0026ccedil;oamento de Pessoal de N\u0026iacute;vel Superior\u0026nbsp;- CAPES (Process No. 88887.510257/2020-00).\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eCompeting Interests\u003c/em\u003e\u003cem\u003e:\u0026nbsp;\u003c/em\u003eThe authors declare that they have no known competing financial/personal interests.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eAuthor Contributions:\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eRenato Henrique Costa Monte: Formal Analysis, Investigation, Methodology, Project Administration, Writing \u0026ndash; Original Draft Preparation\u003c/p\u003e\n\u003cp\u003eRaphael Brito dos Santos: Formal Analysis, Investigation, Methodology, Writing \u0026ndash; Review \u0026amp; Editing\u003c/p\u003e\n\u003cp\u003eMichelle M. S. Fugimura: Investigation, Validation, Writing \u0026ndash; Review \u0026amp; Editing\u003c/p\u003e\n\u003cp\u003eEduardo Akifumi Ono: Writing \u0026ndash; Review \u0026amp; Editing\u003c/p\u003e\n\u003cp\u003eFellipy Augusto Holanda Chaves: Investigation, Methodology, Writing \u0026ndash; Review \u0026amp; Editing\u003c/p\u003e\n\u003cp\u003eCristiano Campos Mattioli: Writing \u0026ndash; Review \u0026amp; Editing\u003c/p\u003e\n\u003cp\u003eElizabeth Gusm\u0026atilde;o Affonso: Conceptualization, Funding Acquisition, Supervision, Validation, Writing \u0026ndash; Review \u0026amp; Editing\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAffonso EG, Polez VLP, Corr\u0026ecirc;a CF, Mazon AF, Ara\u0026uacute;jo MRR, Moraes G, Rantin FT (2002) Blood parameters and metabolites in the teleost fish \u003cem\u003eColossoma macropomum\u003c/em\u003e exposed to sulfide or hypoxia. Comp Biochem Physiol C Toxicol Pharmacol 133:375\u0026ndash;382. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/S1532-0456(02)00127-8\u003c/span\u003e\u003cspan address=\"10.1016/S1532-0456(02)00127-8\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAffonso EG, Ferreira MB, Brasil EM, Pereira Filho M, Roubach R, Ono EA (2012) Hematological responses as indicators of the pond culture of tambaqui, \u003cem\u003eColossoma macropomum\u003c/em\u003e (Cuvier, 1818), with and without water exchange. Adap Aqua Biota, 10:21\u0026ndash;27. Acessed: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://repositorio.inpa.gov.br/handle/1/21451\u003c/span\u003e\u003cspan address=\"https://repositorio.inpa.gov.br/handle/1/21451\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAmanaj\u0026aacute;s RD, Silva JM, Val AL (2018) Growing in the dark warmth: the case of Amazonian fish \u003cem\u003eColossoma macropomum\u003c/em\u003e. Front Mar Sci 5:492. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3389/fmars.2018.00492\u003c/span\u003e\u003cspan address=\"10.3389/fmars.2018.00492\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAmanaj\u0026aacute;s RD, Val AL (2023) Thermal biology of tambaqui (\u003cem\u003eColossoma macropomum\u003c/em\u003e): General insights for aquaculture in a changing world. Rev Aquac 15:480\u0026ndash;490. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1111/raq.12732\u003c/span\u003e\u003cspan address=\"10.1111/raq.12732\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAPHA (2005) Standard Methods for the Examination of Water and Wastewater. American Public Health Association/American Water Works Association/Water Environment Federation, Washington DC\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAride PHR, Roubach R, Val AL (2007) Tolerance response of tambaqui \u003cem\u003eColossoma macropomum\u003c/em\u003e (Cuvier) to water pH. Aquac Res 38:588\u0026ndash;594. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1111/j.1365-2109.2007.01693.x\u003c/span\u003e\u003cspan address=\"10.1111/j.1365-2109.2007.01693.x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAssis YPAS, Porto LD, De Melo NFAC, Palheta GDA, Luz RK, Favero GC (2020) Feed restriction as a feeding management strategy in \u003cem\u003eColossoma macropomum\u003c/em\u003e juveniles under recirculating aquaculture system (RAS). Aquaculture 529. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.aquaculture.2020.735689\u003c/span\u003e\u003cspan address=\"10.1016/j.aquaculture.2020.735689\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAvnimelech Y (1999) Carbon/nitrogen ratio as a control element in aquaculture systems. Aquaculture 176:227\u0026ndash;235. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/S0044-8486(99)00085-X\u003c/span\u003e\u003cspan address=\"10.1016/S0044-8486(99)00085-X\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAvnimelech Y (2012) Biofloc Technology for Super-Intensive Shrimp Culture - In book: Biofloc Technology: A Practical Guidebook. Publisher: World Aquaculture Society Louisiana, United States. 2rd ed, pp 167\u0026ndash;188 \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.13140/2.1.4575.0402\u003c/span\u003e\u003cspan address=\"10.13140/2.1.4575.0402\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAvnimelech Y (2015) Biofloc technology: A practical guide book. The World Aquaculture Society. ISBN: 978-188880-7226\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBasumatary B, Verma AK, Kushwaha S, Verma MK (2023) Global research trends and performance measurement on biofloc technology (BFT): a systematic review based on computational techniques. Aquacult Int. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s10499-023-01162-z\u003c/span\u003e\u003cspan address=\"10.1007/s10499-023-01162-z\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBraga A, Magalh\u0026atilde;es V, Hanson T, Morris TC, Samocha TM (2016) The effects of feeding commercial feed formulated for semi-intensive systems on \u003cem\u003eLitopenaeus vannamei\u003c/em\u003e production and its profitability in a hyper-intensive biofloc-dominated system. Aquac Rep 3:172\u0026ndash;177. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.aqrep.2016.03.002\u003c/span\u003e\u003cspan address=\"10.1016/j.aqrep.2016.03.002\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBoyd CE, Tucker CS (1992) Water quality and pond soil analyses for aquaculture. Alabama Agriculture Experiment Station, Auburn University, Auburn\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBoyd CE (1998) Water Quality in Ponds for Aquaculture. Auburn University, Birmingham\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBoyd CE, Tucker CS (1998) Pond aquaculture water quality management. Kluwer Academic, Boston\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBoyd CE (2015) Water quality: An introduction. Springer Nature. Auburn University, Alabama. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/978-3-319-17446-4\u003c/span\u003e\u003cspan address=\"10.1007/978-3-319-17446-4\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBrand\u0026atilde;o FR, Gomes LC, Chagas EC, Ara\u0026uacute;jo LD (2004) Densidade de estocagem de juvenis de tambaqui durante a recria em tanques-rede. Pesq Agropec Bras 39:357\u0026ndash;362\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBueno GW, Ostrensky A, Canzi C, de Matos FT, Roubach R (2015) Implementation of aquaculture parks in Federal Government waters in Brazil. Rev Aquac 7:1\u0026ndash;12. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1111/raq.12045\u003c/span\u003e\u003cspan address=\"10.1111/raq.12045\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBuzollo H, Sandre LCGD, Neira LM, Nascimento TMTD, Jomori RK, Carneiro DJ (2019) Digestible protein requirements and muscle growth in juvenile tambaqui (\u003cem\u003eColossoma macropomum\u003c/em\u003e). Aquac Res 25:669\u0026ndash;679. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1111/anu.12888\u003c/span\u003e\u003cspan address=\"10.1111/anu.12888\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCampos R (2003) Tipologia dos produtores de ovinos e caprinos no estado do Cear\u0026aacute;. Rev. Econ. Nordeste 34:85\u0026ndash;112. Accessed November 20, 2023. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://repositorio.ufc.br/handle/riufc/1161\u003c/span\u003e\u003cspan address=\"http://repositorio.ufc.br/handle/riufc/1161\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChagas EC, Gomes LDC, Martins H, Roubach R, Louren\u0026ccedil;o JNP (2005) Tambaqui growth reared in cages in a floodplain lake under different feeding rate. Pesq Agropec Bras 40:833\u0026ndash;835. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1590/s0100-204x2005000800015\u003c/span\u003e\u003cspan address=\"10.1590/s0100-204x2005000800015\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChagas EC, Gomes LDC, Martins H, Roubach R (2007) Tambaqui productivity reared in cages with different feeding rations. Ci\u0026ecirc;ncia Rural 37:1109\u0026ndash;1115. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1590/s0103-84782007000400031\u003c/span\u003e\u003cspan address=\"10.1590/s0103-84782007000400031\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChen S, Ling J, Blancheton JP (2006) Nitrification kinetics of biofilm as affected by water quality factors. Aquac Eng 34:179\u0026ndash;197. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.aquaeng.2005.09.004\u003c/span\u003e\u003cspan address=\"10.1016/j.aquaeng.2005.09.004\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCOMEX STAT (2023) Minist\u0026eacute;rio da Ind\u0026uacute;stria, Com\u0026eacute;rcio Exterior e Servi\u0026ccedil;os \u0026ndash; Governo Federal Brasil. Vers\u0026atilde;o 2.0.3. Dados extra\u0026iacute;dos da SISCOMEX pela EMBRAPA Pesca e Aquicultura. Accessed November 20, 2023. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://comexstat.mdic.gov.br/pt/sobre\u003c/span\u003e\u003cspan address=\"http://comexstat.mdic.gov.br/pt/sobre\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCONCEA (2015) Conselho Nacional De Controle De Experimenta\u0026ccedil;\u0026atilde;o Animal - CONCEA. Resolu\u0026ccedil;\u0026atilde;o normativa n.\u0026ordm; 25, de 29 de setembro de 2015. Baixa o Cap\u0026iacute;tulo Introdu\u0026ccedil;\u0026atilde;o Geral do Guia Brasileiro de Produ\u0026ccedil;\u0026atilde;o, Manuten\u0026ccedil;\u0026atilde;o ou Utiliza\u0026ccedil;\u0026atilde;o de Animais para Atividades de Ensino ou Pesquisa Cient\u0026iacute;fica do Conselho Nacional de Controle e Experimenta\u0026ccedil;\u0026atilde;o Animal \u0026ndash; CONCEA. Di\u0026aacute;rio Oficial da Rep\u0026uacute;blica Federativa do Brasil, Bras\u0026iacute;lia, DF, 2 out. 2015. Accessed November 20, 2023\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCopatti CE, Baldisserotto B, Souza CF, Garcia LO (2019) Protective effect of high hardness in pacu juveniles (\u003cem\u003ePiaractus mesopotamicus\u003c/em\u003e) under acidic or alkaline pH: biochemical and hematological variables. Aquaculture 502:250\u0026ndash;257. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.aquaculture.2018.12.028\u003c/span\u003e\u003cspan address=\"10.1016/j.aquaculture.2018.12.028\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCosta OTF, Ferreira DJS, Mendon\u0026ccedil;a FLP, Fernandes MN (2004) Susceptibility of the Amazonian fish, \u003cem\u003eColossoma macropomum\u003c/em\u003e (Serrasalminae), to short-term exposure to nitrite. Aquaculture 232:627\u0026ndash;636. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/S0044-8486(03)00524-6\u003c/span\u003e\u003cspan address=\"10.1016/S0044-8486(03)00524-6\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCosta OTF, Dias LC, Malmann CSY, Ferreira CAL, Carmo IB, Wischneski AG, Sousa RL, Cavero BAS, Lameiras JLV, Dos Santos MC (2019) The effects of stocking density on the hematology, plasma protein profile and immunoglobulin production of juvenile tambaqui (\u003cem\u003eColossoma macropomum\u003c/em\u003e) farmed in Brazil. Aquaculture 499:260\u0026ndash;268. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.aquaculture.2018.09.040\u003c/span\u003e\u003cspan address=\"10.1016/j.aquaculture.2018.09.040\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDa Silva TVN, Dos Santos CF, Dos Santos JML, Schmitz MJ, Ram\u0026iacute;rez JRB, Torres MF, Barbas LAL, Sampaio LA, Verde PE, Tesser MB, Monserrat JM (2023) Effects of dietary inclusion of lyophilized a\u0026ccedil;ai berries (\u003cem\u003eEuterpe oleracea\u003c/em\u003e) on growth metrics, metabolic and antioxidant biomarkers, and skin color of juvenile tambaqui (\u003cem\u003eColossoma macropomum\u003c/em\u003e). Aquac Int 31:1031\u0026ndash;1056. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s10499-022-01014-2\u003c/span\u003e\u003cspan address=\"10.1007/s10499-022-01014-2\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDos Santos DKM, Kojima JT, Santana TM, Castro DP, Serra PT, Dantas NSM, Fonseca FAL, Mari\u0026uacute;ba LAM, Gon\u0026ccedil;alves LU (2021b) Farming tambaqui (\u003cem\u003eColossoma macropomum\u003c/em\u003e) in static clear water versus a biofloc system with or without \u003cem\u003eBacillus subtilis\u003c/em\u003e supplementation. Aquac Int 29:207\u0026ndash;218. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s10499-020-00618-w\u003c/span\u003e\u003cspan address=\"10.1007/s10499-020-00618-w\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDos Santos RB, Izel-Silva J, Fugimura MMS, Suita SM, Ono EA, Affonso EG (2021a) Growth performance and health of juvenile tambaqui, \u003cem\u003eColossoma macropomum\u003c/em\u003e, in a biofloc system at different stocking densities. Aquac Res 52:3549\u0026ndash;3559. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1111/are.15196\u003c/span\u003e\u003cspan address=\"10.1111/are.15196\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDos Santos RB, Izel-Silva J, Medeiros PA, Fugimura MMS, Freitas TM, Gallani SU, Claudiano GS, Ono EA, Affonso EG (2023b) Immunophysiology of tambaqui fed with different levels of dietary protein in biofloc and clear water system. Aquac Int 1\u0026ndash;13. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s10499-023-01205-5\u003c/span\u003e\u003cspan address=\"10.1007/s10499-023-01205-5\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDos Santos RB, Izel-Silva J, Medeiros PA, Fugimura MMS, Freitas TM, Ono EA, Claudiano GS, Affonso EG (2023a) Dietary protein requirement for tambaqui cultivated in biofloc and clear water systems. Aquac Int 1\u0026ndash;20. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s10499-023-01047-1\u003c/span\u003e\u003cspan address=\"10.1007/s10499-023-01047-1\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eEbeling JM, Timmons MB, Bisogni JJ (2006) Engineering analysis of the stoichiometry of photoautotrophic, autotrophic, and heterotrophic removal of ammonia-nitrogen in aquaculture systems. Aquaculture 257:346\u0026ndash;358. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.aquaculture.2006.03.019\u003c/span\u003e\u003cspan address=\"10.1016/j.aquaculture.2006.03.019\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eEmericiano M, Gaxiola G, Cuzon G (2013) Biofloc Technology (BFT): A Review for Aquaculture Application and Animal Food Industry. Biomass Now \u0026ndash; Cultivation and Utilization, Intec. 301\u0026ndash;328. Accessed November 20, 2023. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.5772/53902\u003c/span\u003e\u003cspan address=\"10.5772/53902\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eEmerenciano MGC, Mart\u0026iacute;nez-C\u0026oacute;rdova LR, Mart\u0026iacute;nez-Porchas M, Miranda-Baeza A (2017) Biofloc technology (BFT): a tool for water quality management in aquaculture. In: Tutu H, editor. Water Quality. London (UK): Intech Open; 5:92\u0026ndash;109. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.5772/66416\u003c/span\u003e\u003cspan address=\"10.5772/66416\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFAO, Agriculture Organization of the United Nations (2020) Food and. \u003cem\u003eColossoma macropomum\u003c/em\u003e introduced to Thailand from Hong Kong, Singapore. Introduced Species Fact Sheets. Accessed November 20, 2023. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://www.fao.org/fishery/introsp/3885/en\u003c/span\u003e\u003cspan address=\"http://www.fao.org/fishery/introsp/3885/en\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFAO, Agriculture Organization of the United Nations (2023) Food and. Fisheries Global Information System (FIGIS). Fisheries Division, FAO. Accessed November 20, 2023. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.fao.org/fishery/en/figis\u003c/span\u003e\u003cspan address=\"https://www.fao.org/fishery/en/figis\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFazio F (2019) Fish hematology analysis as an important tool of aquaculture: A review. Aquaculture 500:237\u0026ndash;242. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.aquaculture.2018.10.030\u003c/span\u003e\u003cspan address=\"10.1016/j.aquaculture.2018.10.030\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFi\u0026uacute;za LS, Arag\u0026atilde;o NM, Ribeiro Junior HP, Moraes MG, Rocha IRCB, Lustosa Neto AD, Sousa RR, Madrid RMM, Oliveira EG, Costa FHF (2015) Effects of salinity on the growth, survival, haematological parameters and osmoregulation of tambaqui \u003cem\u003eColossoma macropomum\u003c/em\u003e juveniles. Aquac Res 46:1\u0026ndash;9. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1111/are.12224\u003c/span\u003e\u003cspan address=\"10.1111/are.12224\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFlickinger DL, Dantas DP, Proen\u0026ccedil;a DC, David FS, Valenti WC (2020) Phosphorus in the culture of the Amazon river prawn (\u003cem\u003eMacrobrachium amazonicum\u003c/em\u003e) and tambaqui (\u003cem\u003eColossoma macropomum\u003c/em\u003e) farmed in monoculture and in integrated multitrophic systems. J World Aquac Soc 51:1002\u0026ndash;1023. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1111/jwas.12655\u003c/span\u003e\u003cspan address=\"10.1111/jwas.12655\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFlores Nava A, Brown A (2020) Peces nativos de \u0026aacute;gua dulce de Am\u0026eacute;rica del Sur de inter\u0026eacute;s para la acuicultura: Una s\u0026iacute;ntesis del estado de desarrollo tecnol\u0026oacute;gico de su cultivo. Serie Acuicultura en Latinoam\u0026eacute;rica. 1st ed. FAO. ISBN 978-92-5-306658-2\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFore M, Frank K, Norton K, Svendsen E, Alfredsen JA, Dempster T, Eguiraun H, Watson W, Stahl A, Sunde LM, Schellewald C, Sk\u0026oslash;ien K, Alver MO, Berchmans D (2018) Precision fish farming: A new framework to improve production in aquaculture. Biosyst Eng 173:176\u0026ndash;193. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.biosystemseng.2017.10.014\u003c/span\u003e\u003cspan address=\"10.1016/j.biosystemseng.2017.10.014\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFrisso RM, Matos FT, Moro GV, Mattos BO (2020) Stocking density of Amazon fish (\u003cem\u003eColossoma macropomum\u003c/em\u003e) farmed in a continental neotropical reservoir with a net cages system. Aquaculture 529:735702. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.aquaculture.2020.735702\u003c/span\u003e\u003cspan address=\"10.1016/j.aquaculture.2020.735702\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFurtado PS, Poersch LH, Wasielesky W (2011) Effect of calcium hydroxide, carbonate and sodium bicarbonate on water quality and zootechnical performance of shrimp \u003cem\u003eLitopenaeus vannamei\u003c/em\u003e reared in bio-flocs technology (BFT) systems. Aquaculture 321:130\u0026ndash;135. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.aquaculture.2011.08.034\u003c/span\u003e\u003cspan address=\"10.1016/j.aquaculture.2011.08.034\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGomes LC, Sim\u0026otilde;es LN, Ara\u0026uacute;jo-Lima CARM (2010) Tambaqui (\u003cem\u003eColossoma macropomum\u003c/em\u003e). In: Baldisserotto B and Gomes LC (Ed.). Esp\u0026eacute;cies nativas para piscicultura no Brasil. 2.ed. Santa Maria: Ed. UFSM, 2:175\u0026ndash;204\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHargreaves JA (2013) Biofloc Production Systems for Aquaculture. Southern Regional Aquaculture Center SRAC. Publ, pp 1\u0026ndash;12\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHaridas H, Verma AK, Rathore G, Prakash C, Sawant PB, Babitha Rani AM (2017) Enhanced growth and immuno-physiological response of genetically improved farmed tilapia in indoor biofloc units at different stocking densities. Aquac Res 48:4346\u0026ndash;4355. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1111/are.13256\u003c/span\u003e\u003cspan address=\"10.1111/are.13256\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHilsdorf AWS, Hallerman E, Vallad\u0026atilde;o GMR, Zaminhan-Hassemer M, Hashimoto DT, Dairiki JK, Takahashi LS, Albergaria FC, Gomes ME, Venturieri RLL, Moreira RG, Cyrino JEP (2022) The farming and husbandry of \u003cem\u003eColossoma macropomum\u003c/em\u003e: From Amazonian waters to sustainable production. Rev Aquac 14:993\u0026ndash;1027. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1111/raq.12638\u003c/span\u003e\u003cspan address=\"10.1111/raq.12638\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHostins B, Braga A, Lopes DL, Wasielesky W, Poersch LH (2015) Effect of temperature on nursery and compensatory growth of pink shrimp \u003cem\u003eFarfantepenaeus brasiliensis\u003c/em\u003e reared in a super-intensive biofloc system. Aquac Eng 66:62\u0026ndash;67. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.aquaeng.2015.03.002\u003c/span\u003e\u003cspan address=\"10.1016/j.aquaeng.2015.03.002\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eInoue LAKA, Boijink CL, Ribeiro PT, Silva AMDD, Affonso EG (2011) Avalia\u0026ccedil;\u0026atilde;o de respostas metab\u0026oacute;licas do tambaqui exposto ao eugenol em banhos anest\u0026eacute;sicos. Acta Amaz 41:327\u0026ndash;332. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1590/S0044-59672011000200020\u003c/span\u003e\u003cspan address=\"10.1590/S0044-59672011000200020\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eInoue LAKA, Bezerra AC, Miranda WS, Muniz AW, Boijink CL (2014) Cultivo de tambaqui em gaiolas de baixo volume: efeito da densidade de estocagem na produ\u0026ccedil;\u0026atilde;o de biomassa. Ci\u0026ecirc;nc Anim Bras 15:437\u0026ndash;443. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doiorg/10.1590/1089-6891v15i426758\u003c/span\u003e\u003cspan address=\"https://doi10.1590/1089-6891v15i426758\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eIzel Silva J, Ono EA, Queiroz MN, Dos Santos RB, Affonso EG (2020) Aeration strategy in the intensive culture of tambaqui, \u003cem\u003eColossoma macropomum\u003c/em\u003e, in the tropics. Aquaculture 529:735644. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.aquaculture.2020.735644\u003c/span\u003e\u003cspan address=\"10.1016/j.aquaculture.2020.735644\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eIzel Silva J, Dos Santos RB, Medeiros PA, Suita SM, Wasielesky W Jr, Fugimura MMS, Affonso EG (2024) \u003cem\u003eBrycon amazonicus\u003c/em\u003e larviculture cannibalism is reduced in biofloc systems. Aquaculture 579:740180. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.aquaculture.2023.740180\u003c/span\u003e\u003cspan address=\"10.1016/j.aquaculture.2023.740180\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKrummenauer D, Peixoto S, Cavalli RO, Poersch LH, Wasielesky W (2011) Superintensive culture of white shrimp, \u003cem\u003eLitopenaeus vannamei\u003c/em\u003e, in a biofloc technology system in Southern Brazil at different stocking densities. J World Aquac Soc 42:726\u0026ndash;733. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1111/j.1749-7345.2011.00507.x\u003c/span\u003e\u003cspan address=\"10.1111/j.1749-7345.2011.00507.x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKrummenauer D, Samocha T, Poersch L, Lara G, Wasielesky W (2014) The reuse of water on the culture of pacific white shrimp, \u003cem\u003eLitopenaeus vannamei\u003c/em\u003e, in BFT system. J World Aquac Soc 45:3\u0026ndash;14. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1111/jwas.12093\u003c/span\u003e\u003cspan address=\"10.1111/jwas.12093\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLima J, Montagner D, Duarte SS, Yoshioka ETO, Dias MKR, Tavares Dias M (2019) Recirculating system using biological aerated filters on tambaqui fingerling farming. Pesq Agropec Bras 54:00294. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1590/S1678-3921.pab2019.v54.00294\u003c/span\u003e\u003cspan address=\"10.1590/S1678-3921.pab2019.v54.00294\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLima CAS, Machado Bussons MRF, de Oliveira AT, Aride PHR, de Almeida O\u0026rsquo;Sullivan FL, Pantoja-Lima J (2020) Socioeconomic and profitability analysis of tambaqui \u003cem\u003eColossoma macropomum\u003c/em\u003e fish farming in the state of Amazonas, Brazil. Aquac Econ Manag 24:406\u0026ndash;421. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1080/13657305.2020.1765895\u003c/span\u003e\u003cspan address=\"10.1080/13657305.2020.1765895\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLovshin LL, Silva AB, Fernandez JA, Carneiro-Sobrinho A (1974) Preliminary pond culture test of pirapitinga \u003cem\u003eColossoma bidens\u003c/em\u003e, and tambaqui \u003cem\u003eColossoma macropomum\u003c/em\u003e, from the Amazon River basin. FAO Informes De Pesca 159:185\u0026ndash;193\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMair G, Lucente D (2020) What are farmed types in aquaculture and why do they matter? FAO Aquac Newsl. 2020;61:40\u0026ndash;42. Accessed November 20, 2023\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMartin NB, Serra R, Oliveira MDM, \u0026Acirc;ngelo JA, Okawa H (1998) Sistema integrado de custos agropecu\u0026aacute;rios - CUSTAGRI. Informa\u0026ccedil;\u0026otilde;es Econ\u0026ocirc;micas 28:7\u0026ndash;28. Accessed November 20, 2023. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://www.iea.sp.gov.br/ftpiea/ie/1998/tec1-0198.pdf\u003c/span\u003e\u003cspan address=\"http://www.iea.sp.gov.br/ftpiea/ie/1998/tec1-0198.pdf\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMesquita RCT, Galv\u0026atilde;o JA, Savbay-da-Silva LK, Eloy LR, Godoy LC, Streit DP Jr (2018) Protocol for tambaqui production based on stocking density and sex. Rev Bras Hig Sanid Anim 12:146\u0026ndash;155. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.5935/1981-2965.20180014\u003c/span\u003e\u003cspan address=\"10.5935/1981-2965.20180014\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOishi CA, Nwanna LC, Pereira Filho M (2010) Optimum dietary protein requirement for Amazonian Tambaqui, \u003cem\u003eColossoma macropomum\u003c/em\u003e Cuvier, 1818, fed fish meal free diets. Acta Amaz 40:757\u0026ndash;762. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1590/S0044-59672010000400017\u003c/span\u003e\u003cspan address=\"10.1590/S0044-59672010000400017\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePedroza Filho MX, Rodrigues APO, Rezende FP (2015) Din\u0026acirc;mica da produ\u0026ccedil;\u0026atilde;o de tambaqui e demais peixes redondos no Brasil. Bras\u0026iacute;lia. DF: CNA 7:1\u0026ndash;5. Accessed November 20, 2023. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://ainfo.cnptia.embrapa.br/digital/bitstream/item/141367/1/CNPASA-2015-aa7.pdf\u003c/span\u003e\u003cspan address=\"https://ainfo.cnptia.embrapa.br/digital/bitstream/item/141367/1/CNPASA-2015-aa7.pdf\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePellegrin L, Copatti CE, de S\u0026aacute; Britto Pinto D, Nitz LF, Wasielesky W, Garcia L (2023) Effect of different stocking densities on hematological parameters and zootechnical performance of pacu (\u003cem\u003ePiaractus mesopotamicus\u003c/em\u003e) in the BFT system. Aquaculture 576:739852. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.aquaculture.2023.739852\u003c/span\u003e\u003cspan address=\"10.1016/j.aquaculture.2023.739852\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRego MAS, Sabbag OJ, Soares R, Peixoto S (2017) Financial viability of inserting the biofloc technology in a marine shrimp \u003cem\u003eLitopenaeus vannamei\u003c/em\u003e farm: a case study in the state of Pernambuco, Brazil. Aquac Int 25:473\u0026ndash;483. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s10499-016-0044-7\u003c/span\u003e\u003cspan address=\"10.1007/s10499-016-0044-7\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRodrigues APO, Lima AF, Lima LKF, Ramos AMJ, Brignol FD, Freitas LEL, Moro GV (2023) Crescimento do tambaqui em sistema de renova\u0026ccedil;\u0026atilde;o continua de \u0026aacute;gua em tanques circulares. Palmas, TO: Embrapa Pesca e Aquicultura 24p. - (Boletim de Pesquisa e Desenvolvimento / Embrapa Pesca e Aquicultura, ISSN 2358\u0026ndash;6273; 29)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSamocha TM (2019) Sustainable Biofloc Systems for, Sustainable Biofloc Systems for Marine Shrimp. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/C2018-0-02628-6\u003c/span\u003e\u003cspan address=\"10.1016/C2018-0-02628-6\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSampaio FDF, Freire CA (2016) An overview of stress physiology of fish transport: changes in water quality as a function of transport duration. Fish Fish 17:1055\u0026ndash;1072. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1111/faf.12158\u003c/span\u003e\u003cspan address=\"10.1111/faf.12158\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSantos L, Pereira Filho M, Sobreira C, Ituass\u0026uacute; D, Fonseca FAL (2010) Exig\u0026ecirc;ncia proteica de juvenis de tambaqui (\u003cem\u003eColossoma macropomum\u003c/em\u003e) ap\u0026oacute;s priva\u0026ccedil;\u0026atilde;o alimentar. Acta Amazonica 40:597\u0026ndash;604. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1590/S0044-59672010000300021\u003c/span\u003e\u003cspan address=\"10.1590/S0044-59672010000300021\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSantos FAC, Boaventura TP, Julio GSC, Cortezzi PP, Figueiredo LG, Favero GC, Palheta GDA, Melo NFAC, Luz RK (2021) Growth performance and physiological parameters of \u003cem\u003eColossoma macropomum\u003c/em\u003e in a recirculating aquaculture system (RAS): Importance of stocking density and classification. Aquaculture 534:736274. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.aquaculture.2020.736274\u003c/span\u003e\u003cspan address=\"10.1016/j.aquaculture.2020.736274\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSilva CR, Gomes LC, Brand\u0026atilde;o FR (2007) Effect of feeding rate and frequency on tambaqui (\u003cem\u003eColossoma macropomum\u003c/em\u003e) growth, production and feeding costs during the first growth phase in cages. Aquaculture 264:135\u0026ndash;139. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.aquaculture. 2006.12.007\u003c/span\u003e\u003cspan address=\"10.1016/j.aquaculture. 2006.12.007\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSilva CA, Fujimoto RY (2015) Crescimento de tambaqui em resposta a densidade de estocagem em tanques-rede. Acta amaz\u0026ocirc;nica 45:323\u0026ndash;332. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1590/1809-4392201402205\u003c/span\u003e\u003cspan address=\"10.1590/1809-4392201402205\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSilva ACC, De Barros AF, Mendon\u0026ccedil;a FMF, Gama KFS, Marcos R, Povh JA, Fornari DC, Hoshiba MA, De Abreu JS (2020) Performance and economic viability of tambaqui, \u003cem\u003eColossoma macropomum\u003c/em\u003e, selectively bred for weight gain. Acta Amaz 50:108\u0026ndash;114. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1590/1809-4392201901992\u003c/span\u003e\u003cspan address=\"10.1590/1809-4392201901992\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSilva WS, Ferreira AL, Neves LC, Ferreira NS, Palheta GDA, Takata R, Luz RK (2021) Effects of stocking density on survival, growth and stress resistance of juvenile tambaqui (\u003cem\u003eColossoma macropomum\u003c/em\u003e) reared in a recirculating aquaculture system (RAS). Aquac Int 29:609\u0026ndash;621. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s1049 9-021-00647-z\u003c/span\u003e\u003cspan address=\"10.1007/s1049 9-021-00647-z\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSousa RGC, Pi\u0026ntilde;eyro JIG, Cardoso NA, Andrade JE, Silva JG, Barbosa HTB (2016b) Stocking density and its effects to the zootechnical development of young tambaqui in an intensive production system. Densidade de estocagem e seus efeitos sobre o desenvolvimento zoot\u0026eacute;cnico de juvenis de tambaqui em sistema intensivo de produ\u0026ccedil;\u0026atilde;o. ActaFish 4:80\u0026ndash;92. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.2312/Actafish.2016.4.1.80-92\u003c/span\u003e\u003cspan address=\"10.2312/Actafish.2016.4.1.80-92\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSousa RGC, Prado GF, Py\u0026ntilde;eiro JIG, NETO EBBN (2016a) Avalia\u0026ccedil;\u0026atilde;o do ganho de peso do tambaqui cultivado com diferentes taxas de proteıńas na alimenta\u0026ccedil;\u0026atilde;o. Rev Bio Amaz 6:40\u0026ndash;45. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.18561/2179-5746/biotaamazonia.v6n1p40-45\u003c/span\u003e\u003cspan address=\"10.18561/2179-5746/biotaamazonia.v6n1p40-45\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSouza Bastos LR, Val AL, Wood CM (2017) Are Amazonian fish more sensitive to ammonia? Toxicity of ammonia to eleven native species. Hydrobiologia 789:143\u0026ndash;155. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s10750-015-2623-4\u003c/span\u003e\u003cspan address=\"10.1007/s10750-015-2623-4\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eStrickland JD, Parsons TR (1972) A practical handbook of seawater analysis. Fisheries Research Board of Canada, Ottawa\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTimmons MB, Ebeling JM (2010) Recirculating aquaculture systems. Cayuga Aqua Ventures, New York\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eValenti WC, Barros HP, Moraes Valenti P, Bueno GW, Cavalli RO (2021) Aquaculture in Brazil: past, present and future. Aquaculture Rep 19:100611. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.aqrep.2021.100611\u003c/span\u003e\u003cspan address=\"10.1016/j.aqrep.2021.100611\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVerdouw H, Van Echteld CJA, Dekkers EMJ (1978) Ammonia determination based on indophenol formation with sodium salicylate. Water Res 12:3992\u0026ndash;3999. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/0043-1354(78)90107-0\u003c/span\u003e\u003cspan address=\"10.1016/0043-1354(78)90107-0\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZemor JC, Wasielesky W, F\u0026oacute;es GK, Poersch LH (2019) The use of clarifiers to remove and control the total suspended solids in large-scale ponds for production of \u003cem\u003eLitopenaeus vannamei\u003c/em\u003e in a biofloc system. Aquac Eng 85:74\u0026ndash;79. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.aquaeng.2019.03.001\u003c/span\u003e\u003cspan address=\"10.1016/j.aquaeng.2019.03.001\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWelengane E, Sado RY, Bicudo \u0026Aacute;JDA (2019) Protein-sparing effect by dietary lipid increase in juveniles of the hybrid fish tambatinga (♀ \u003cem\u003eColossoma macropomum\u003c/em\u003e \u0026times; ♂ \u003cem\u003ePiaractus brachypomus\u003c/em\u003e). Aquac Nutr 25:1272\u0026ndash;1280. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1111/anu.12941\u003c/span\u003e\u003cspan address=\"10.1111/anu.12941\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWood CM, Souza Netto JG, Wilson JM, Duarte RM, Val AL (2016) Nitrogen metabolism in tambaqui (\u003cem\u003eColossoma macropomum\u003c/em\u003e), a Neotropical model teleost: hypoxia, temperature, exercise, feeding, fasting, and high environmental ammonia. J Comp Physiol 187:135\u0026ndash;151. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s00360-016-1027-8\u003c/span\u003e\u003cspan address=\"10.1007/s00360-016-1027-8\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWood CM, Gonzalez RJ, Ferreira MS, Braz Mota S, Val AL (2018) The physiology of the Tambaqui (\u003cem\u003eColossoma macropomum\u003c/em\u003e) at pH 8.0. J Comp Physiol 188:393\u0026ndash;408. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s00360-017-1137-y\u003c/span\u003e\u003cspan address=\"10.1007/s00360-017-1137-y\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWoyn\u0026aacute;rovich A, Van Anrooy R (2019) Field guide to the culture of tambaqui (\u003cem\u003eColossoma macropomum\u003c/em\u003e, Cuvier, 1816). FAO Fisheries and Aquaculture Technical Paper 624. FAO. 624:1\u0026ndash;121. Accessed November 20, 2023. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.fao.org/3/CA2955EN/ca2955en.pdf\u003c/span\u003e\u003cspan address=\"https://www.fao.org/3/CA2955EN/ca2955en.pdf\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e 7.Statements \u0026amp; Declarations\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"","identity":"aquaculture-international","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"","snPcode":"10499","submissionUrl":"https://submission.nature.com/new-submission/10499/3","title":"Aquaculture International","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"","reportingPortfolio":"VoR Journals","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Economy, intensification, Amazonian fish, aquaculture production, sustainable systems","lastPublishedDoi":"10.21203/rs.3.rs-3977429/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-3977429/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe objective was to identify the best stocking density in the initial fattening phase of tambaqui (\u003cem\u003eColossoma macropomum\u003c/em\u003e) using biofloc technology (BFT) and evaluate the effects of the densities on water quality, zootechnical performance and the metabolic profile of fish and production costs. Juveniles (56.5\u0026thinsp;\u0026plusmn;\u0026thinsp;1.69 g) were reared in the densities: 15 (BFT15), 30 (BFT30) and 45 (BFT45) fish.m\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e, in triplicate, for 80 days. The use of BFT inoculum at the beginning contributed the maintenance of adequate ammonia and nitrite concentrations at all densities, though with a higher nitrite concentration in BFT45. Electrical conductivity (EC), nitrite, total suspended solids (TSS), pH, alkalinity and hardness were different (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05) between BFT15 and BFT45. EC and TSS increased according to the increase in density, and were higher in BFT45. The highest final weight, weight gain, daily weight gain and specific growth rate were observed in BFT15, while the apparent feed conversion was lower for BFT15 and BFT30 compared to BFT45 (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05). Biomass and productivity were higher (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05) in BFT45. The values of hematocrit, number of erythrocytes and the hemoglobin concentration were higher in BFT45 (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05). Regarding production costs, the highest average feed expenditure occurred in BFT45; however, expenditure with electricity was lower at this density. The increase in biomass in BFT45 generated the reduction of the partial average cost (ACp). It can therefore be concluded that the best stocking density for initial fattening of tambaqui is 45 fish.m\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e, since it presents better productivity and biomass, lower ACp and average expenditure on electricity when using BFT.\u003c/p\u003e","manuscriptTitle":"Stocking densities of Colossoma macropomum in the initial grow out phase using biofloc technology","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-02-26 10:42:54","doi":"10.21203/rs.3.rs-3977429/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-07-03T07:08:13+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-06-10T02:50:15+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"153640247493078572565396967305085995169","date":"2024-05-30T14:04:19+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"9539b6cb-2a68-47ac-9465-15fbaccdc2d8","date":"2024-03-21T13:06:35+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"00cef00d-21d2-4acb-914c-70c7810cab9b","date":"2024-03-11T06:49:10+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-03-04T03:08:14+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-02-23T07:09:52+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-02-23T00:48:25+00:00","index":"","fulltext":""},{"type":"submitted","content":"Aquaculture International","date":"2024-02-22T02:59:58+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"","identity":"aquaculture-international","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"","snPcode":"10499","submissionUrl":"https://submission.nature.com/new-submission/10499/3","title":"Aquaculture International","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"","reportingPortfolio":"VoR Journals","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"ff04ca1d-c31f-430b-af5a-778c33b98458","owner":[],"postedDate":"February 26th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2024-08-01T05:21:41+00:00","versionOfRecord":[],"versionCreatedAt":"2024-02-26 10:42:54","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-3977429","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-3977429","identity":"rs-3977429","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}