Effects of Dietary Clostridium butyricum on the Growth, Digestive Enzyme Activity, Antioxidant Capacity, and Resistance to Nitrite Stress of Penaeus monodon

The present study investigated the effects of the dietary probiotic Clostridium butyricum (CB) on the growth, intestine digestive enzyme activity, antioxidant capacity and resistance to nitrite stress, and body composition of Penaeus monodon. For 56 days, shrimps were fed diets containing different levels of C. butyricum (1 x 10(9) CFU g(-1)), 0% (control), 0.5% (CB1), 1.0% (CB2), and 2.0% (CB3), as treatment groups, followed by an acute nitrite stress test for 48 h. The results indicated that dietary supplementation of C. butyricum increased the growth of shrimp in the CB2 and CB3 groups. The survival rate of shrimp increased after nitrite stress for 24 and 48 h. The intestine amylase and trypsin activities increased in all three C. butyricum groups, while the lipase activity was only affected in the CB3 group. The superoxide dismutase (SOD) activity as well as heat shock protein 70 (hsp70) and ferritin gene expression levels were increased in the intestines of shrimps cultured under normal conditions for 56 days, while the catalase (CAT) activity was not changed and glutathione peroxidase (GPx) activity was only increased in the CB2 and CB3 groups. After exposure to nitrite stress for 24 and 48 h, the intestine antioxidant enzyme (SOD, CAT, and GPx) activity and gene (hsp70 and ferritin) expression levels in the three C. butyricum groups were higher than those of the control. C. butyricum had no effects on the whole body composition of the shrimp. These results revealed that C. butyricum improved the growth as well as enhanced the intestine digestive enzyme and antioxidant activities of P. monodon against nitrite stress, and C. butyricum may be a good probiotic for shrimp aquaculture.