Optimizing Carbon Sources in Biofloc Technology for Sustainable Aquaculture: A Meta‐Analytical Review

ABSTRACT Aquaculture intensification is increasingly constrained by high water demand, nutrient‐rich effluents and disease risk, increasing interest in biofloc technology (BFT) as a waste‐recycling, low‐exchange production model. However, BFT performance depends strongly on the carbon source used to adjust the carbon‐to‐nitrogen (C/N) ratio and stimulate heterotrophic ammonia assimilation. This PRISMA‐guided meta‐analytical review synthesized 92 eligible studies across fish and shrimp BFT systems to identify consistent effects of carbon type, C/N management and dosing strategy. Across species, maintaining C/N at about 10 to 20 to 1 improved water quality by reducing total ammonia nitrogen (TAN) and nitrite and promoting stable floc formation. Carbon chemistry shaped floc nutrition, feed use, growth and health outcomes. Health evidence indicated that molasses is a practical conventional carbon source, tapioca and starch‐based substrates support stronger stress mitigation and growth‐health stability, and mannan oligosaccharides provide the clearest disease‐resistance benefit. For Nile tilapia, pooled feed conversion ratio (FCR) was 1.563 and pooled specific growth rate (SGR) was 2.481 percent day −1 , both p < 0.001, with high heterogeneity, I 2 > 99%, linked mainly to carbon regimes. Readily fermentable sugars, especially sugarcane molasses, improved feed efficiency and growth by generating protein‐rich, palatable flocs, while moderately degradable starches, particularly tapioca‐type substrates, supported more stable growth‐health coupling. Poorly fermentable or operationally volatile substrates, including cellulose‐rich brans and rapidly exhausted glucose, destabilized microbial dynamics and reduced performance. Future studies should standardize C/N accounting, floc metrics, oxidative‐stress and immune biomarkers, disease‐challenge protocols, microbiome and histopathological endpoints, while integrating by‐product testing, techno‐economic analysis and life‐cycle assessment to guide carbon‐smart regenerative aquaculture.