Dietary powder and molecular imprinted polymer nanoencapsulated sodium propionate to enhance growth performance, digestive enzymes activity, antioxidant defense and mucosal immune response in African cichlid (Labidochromis lividus) fingerlings

Abstract This study was conducted to examine the effects of powder sodium propionate (P-SP) and SP loaded molecular imprinted polymer (MIP) nanoparticles (MIP-SP NPs) on growth, skin mucosal immune parameters and digestive and liver enzymes activities of African cichlid (Labidochromis lividus) fingerlings. The synthetized MIP-SP particles were characterized via FE-SEM/EDS, TEM, FTIR and ICP-OES techniques. Fish with an average weight of 500±2 mg were stocked into 12 experimental units and fed with experimental diets prepared by supplementation of basal diet (control) with MIP NPs, P-SP (5 g SP Kg−1 of dry diet) and MIP-SP NPs for 8 weeks. The findings demonstrated that growth performance parameters improved in the MIP-SP NPs followed by the P-SP dietary group compared to the control groups (P<0.05). The activity of digestive enzymes of lipase, trypsin, protease and alkaline phosphatase was higher in the fish fed with SP-supplemented diets than the controls (P<0.05). The highest activity of protease and lipase enzymes was observed in the MIP-SP NPs dietary group (P<0.05). The alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels of liver tissue decreased in the SP dietary groups, while the catalase (CAT), superoxide dismutase (SOD) and alkaline phosphatase (ALP) levels increased in comparison to the control groups (P<0.05). The highest SOD and ALP levels were observed in the fish fed with the MIP-SP NPs-supplemented diet (P<0.05). The skin mucosal immune indices including alternative haemolytic complement activity (ACH50), lysozyme and total immunoglobulin (Ig) levels increased in the MIP-SP NPs and P-SP dietary groups in comparison to the controls (P<0.05). The findings indicated that sodium propionate encapsulated in molecular imprinted polymer nanoparticles could enhance the efficiency of dietary SP in African cichlid fish.