Effects of microbe-derived antioxidants on growth, digestive and aminotransferase activities, and antioxidant capacities in the hepatopancreas of Eriocheir sinensis under ammonia nitrogen stress

This study evaluated the effects of feeding a microbial-derived antioxidant diet (MA) for 56 days on the growth performance of Eriocheir sinensis, as well as on digestive and metabolic enzyme activity and antioxidant capacity under ammonia stress (400 mg/L ammonia nitrogen for 48 h). The weight gain at 28d and the specific growth rate at 56ds for crabs in the MA group were significantly higher than those in the control diet (C) group (p < 0.05). Compared with the C group, the color of the hepatopancreas in the MA group was significantly improved (p < 0.05). A significant decrease in the level of Hemolymph ammonia was found in the microbial antioxidant ammonia-N (MA_A) group (p < 0.05), which may be related to the decrease of transaminase (AST, ALT, GDH) activities caused by MA diet (p < 0.05). There is a significant increase in the digestive enzyme activities (Trypsin and Lipase), which reduced the accumulation of triglycerides in the hepatopancreas in the (MA_A) group (p < 0.05). In addition, the antioxidant damage of crabs in hepatopancreas caused by ammonia nitrogen toxicity could also significantly be improved by MA fed in the (MA_A) group (p < 0.05). microbe-derived antioxidants (supplemented with 0.2% in feeds) can protect the health of hepatopancreas, promote growth, and improve the ability to resist ammonia nitrogen stress for E.sinensis.