Dose–dependent effect of Bacillus subtilis on aquaculture pond ecosystems

Dose–dependent effect of Bacillus subtilis on aquaculture pond ecosystems | 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 Dose–dependent effect of Bacillus subtilis on aquaculture pond ecosystems Weiming Liu, Xiaolong Bo, Yanhao Cao, Jianchun Xiao, Run Zhang, and 5 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8258694/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 18 Mar, 2026 Read the published version in World Journal of Microbiology and Biotechnology → Version 1 posted 11 You are reading this latest preprint version Abstract Bacillus subtilis has shown potential as a probiotic for water quality regulation in aquaculture, but its dose-dependent effects remain insufficiently studied. This study established low-concentration (2.25×105 CFU·mL-1, L) and high-concentration (4.50×105 CFU·mL-1, H) treatment groups, integrating water quality analysis, spectrophotometry, and 16S rRNA high-throughput sequencing to dynamically monitor physicochemical parameters (transparency, dissolved oxygen, pH, ammonia nitrogen, sediment redox potential), chlorophyll content, and microbial community changes at the aquaculture water and sediment at 0, 6, 24, and 48 h. Results demonstrated that the high dose delivered faster and larger declines in ammonia nitrogen and chlorophyll a/b/c, accompanied by a transient nitrite rise (6 h) and a brief DO dip that resolved by 24 - 48 h. The low dose produced steadier improvements with smaller oxygen perturbations and greater short-term stability. Sediment redox potential increased at 6 - 24 h under both doses, indicating a shift toward more oxidizing conditions at the sediment–water interface. In the water column, Firmicutes (with transient Exiguobacterium) were enriched while Proteobacteria remained stable; in sediment, Proteobacteria, Firmicutes, and Chloroflexi dominated, with Thiobacillus and Lysobacter increasing under both doses (more pronounced in H). Predicted functional profiles showed stronger enrichment in H at 6 h for nitrogen transformations (ureolysis; nitrite respiration, nitrate respiration; nitrate reduction), while categories annotated as animal parasites/symbionts declined and chemoheterotrophy and chitinolysis remained high. Collectively, these findings support a practical dosing strategy: high dose for rapid remediation (acute nitrogen removal and algal control) and low dose for routine maintenance with minimal disturbance. Bacillus subtilis Sediment - water microbiome Dose–response Nitrogen transformation Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 18 Mar, 2026 Read the published version in World Journal of Microbiology and Biotechnology → Version 1 posted Editorial decision: Revision requested 26 Dec, 2025 Reviews received at journal 24 Dec, 2025 Reviews received at journal 19 Dec, 2025 Reviewers agreed at journal 08 Dec, 2025 Reviews received at journal 05 Dec, 2025 Reviewers agreed at journal 03 Dec, 2025 Reviewers agreed at journal 03 Dec, 2025 Reviewers invited by journal 03 Dec, 2025 Editor assigned by journal 02 Dec, 2025 Submission checks completed at journal 02 Dec, 2025 First submitted to journal 02 Dec, 2025 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. 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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-8258694","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":554995029,"identity":"6083459e-9c85-456e-8fff-4e7ac870ee4d","order_by":0,"name":"Weiming Liu","email":"","orcid":"","institution":"Sichuan Agricultural University","correspondingAuthor":false,"prefix":"","firstName":"Weiming","middleName":"","lastName":"Liu","suffix":""},{"id":554995030,"identity":"d2ddd6e3-14c2-40af-97f2-c6eb5d594e93","order_by":1,"name":"Xiaolong Bo","email":"","orcid":"","institution":"Sichuan Agricultural 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