Impact of Bacillus coagulans ATCC7050 supplementation on growth, gut microbiota, and immunity in rainbow trout exposed to pretilachlor.

This study investigates the effects of Bacillus coagulans ATCC7050 probiotic supplementation on the growth performance, immune function, antioxidant activity, and liver health of rainbow trout (Oncorhynchus mykiss) exposed to the herbicide pretilachlor. Over 30 days, the fish were fed diets supplemented with B. coagulans (1 × 10⁶ or 1 × 10⁸ CFU/g) and/or 12.5% pretilachlor. Probiotic supplementation significantly enhanced growth parameters and reduced the feed conversion ratio, whereas herbicide exposure had the opposite effect (p = 0.000). Immune responses, including lysozyme activity and total immunoglobulin levels, were improved by probiotic treatment but suppressed by pretilachlor exposure (p = 0.001). Additionally, the probiotic increased antioxidant enzyme activity and reduced markers of oxidative stress. Liver function indicators elevated due to herbicide exposure were mitigated by B. coagulans supplementation (p = 0.028). These findings underscore the potential of B. coagulans to counteract herbicide-induced toxicity, supporting fish health and promoting more sustainable aquaculture practices.