Amelioration of Cd-induced bioaccumulation, oxidative stress and immune damage by probiotic Bacillus coagulans in common carp (Cyprinus carpio L.)

Heavy metal cadmium contamination is a serious environmental issue affecting the food safety of aquatic products and the healthy development of aquaculture. Developing a safe and effective strategy to control cadmium levels in fish is of great importance. In this study, we attempted to isolate novel Bacillus coagulans strains from the intestinal contents of common carp and to evaluate their cadmium tolerance and removal abilities. The effect of the isolated strains on the prevention of cadmium toxicity in common carp was also investigated. A total of ten strains were isolated from the intestine of common carp, among which strain SCC-19 exhibited the highest cadmium tolerance and removal ability. Next, 270 fish were exposed to 0.5 mg/L waterborne cadmium and/or 108 cfu/g dietary Bacillus coagulans SCC-19 for 60 days, and the growth performance, bioaccumulation, oxidative stress and immune response of common carp were determined. The results indicated that dietary supplementation with Bacillus coagulans SCC-19 could restore growth performance, reduce cadmium accumulation in the liver and kidney, restore nonspecific immune and antioxidative capabilities following cadmium exposure in common carp. The results of this study imply that diet with Bacillus coagulans SCC-19 could effectively protect common carp and to combat cadmium toxicity. The results of this study may establish a foundation for further research exploring the possibility of Bacillus coagulans as a feed additive to alleviate cadmium toxicity in aquatic animals.