Effects of Dietary Surfactin Supplementation on Growth Performance, Intestinal Digestive Enzymes Activities, and Hepatic Antioxidant Potential of American Eel (Anguilla rostrata) Elvers

The 70-day trial was conducted to investigate the effects of surfactin on growth performance, intestinal digestive enzymes activities, and hepatic antioxidant potential on American eel (Anguilla rostrata) at elver stage. Six hundred American eel elvers were randomly divided into five treatments with three replicates per group, 40 fish per replicate. Dietary surfactin levels of the five treatment groups were 0, 25, 50, 100, and 200 mg/kg, respectively. Final body weight, weight gain rate, and feed efficiency were significantly affected by surfactin supplementation (P<0.05). There were no significant differences in feeding rate and survival rate among all groups (P>0.05). Protease and lipase activity in the intestine were significantly increased by surfactin supplementation (P<0.05), and amylase activity was similar among all groups (P>0.05). Malondialdehyde level, total antioxidation capacity level, and activities of superoxide dismutase, and glutathione peroxidase in intestine of fish were significantly (P<0.05) affected. No significant differences in CAT activities were found among all groups (P>0.05). The results demonstrated that dietary 25 mg/kg surfactin supplementation improves growth performance, some digestive enzyme activities in the intestine, and hepatic antioxidant potential of American eel at elver stage.