Inhibitory activity of probiotic Bacillus subtilis BF12 against Vibrio parahaemolyticus infection and its growth-promoting effects on juvenile Penaeus monodon

In an attempt to elucidate the Vibrio inhibitory activity of saline tilapia green water, we have isolated Bacillus subtilis BF12, exhibiting potent secreted antibiotic effects against Vibrio parahaemolyticus. We tested B. subtilis BF12 pathogenicity to Penaeus monodon and its efficacy to protect the shrimp against V. parahaemolyticus infection. The results indicate that B. subtilis BF12 is not pathogenic to shrimp since no mortalities was observed in all treatment groups. The feeding trial shows that shrimp in the treated group exhibited higher survival and improved growth performance. The infection challenge test with pathogenic V. parahaemolyticus administered orally indicates that the group receiving the probiotic has significantly higher survival rates. Lower counts of V. parahaemolyticus in the gut of the probiotic treated group were also recorded. Collectively our results indicate that the application of probiotic B. subtilis BF12 is an effective, practical and applicable means to prevent V. parahaemolyticus infection in P. monodon culture.