Effects of wall-broken mulberry leaf meal on growth performance, antioxidant capacity, and intestinal and liver histology of Largemouth Bass

ABSTRACT Objective This study was conducted to evaluate the effects of wall-broken mulberry leaf meal (WBMLM) on growth, antioxidant capacity, and intestinal and liver histology of Largemouth Bass Micropterus nigricans. Methods Fish (initial body weight [mean ± SD] = 33.34 ± 0.26 g) were fed diets containing WBMLM at 0% (WBMLM0; control group), 5% (WBMLM5), and 10% (WBMLM10). Each diet was randomly assigned to triplicate groups of 20 fish, and the fish were fed twice daily for 7 weeks. Results The results showed that fish receiving the WBMLM10 diet had a significantly lower growth performance than those fed WBMLM0, while no significant difference was found between the WBMLM0 and WBMLM5 groups or between the WBMLM5 and WBMLM10 groups. Serum glutamic-pyruvic transaminase, total cholesterol, and low-density lipoprotein content of fish that were fed WBMLM5 and WBMLM10 were significantly lower than those of fish fed WBMLM0. Serum total protein content and alkaline phosphatase activity increased with increasing dietary WBMLM level, while glucose and triglyceride content decreased. Fish that were fed WBMLM5 and WBMLM10 had significantly higher hepatic total superoxide dismutase activities than the WBMLM0 group, and no significant difference was observed between the WBMLM5 and WBMLM10 groups. Hepatic total antioxidative capacity activity was significantly higher in fish receiving WBMLM10 than in the other two groups. The intestinal muscle thickness of the WBMLM5 group was significantly higher than that of the other two groups, and no significant difference was observed between the WBMLM0 and WBMLM10 groups. Fish that were fed WBMLM10 showed hepatic cell vacuolation and nuclear migration and had a significantly higher lipid droplet area than the control group. Conclusions The results indicated that adding up to 5% WBMLM to the diet of Largemouth Bass could improve their antioxidant capacity, immunity, and intestinal and liver health.