Effects of dietary surfactin supplementation on growth performance, intestinal digestive enzymes activities and some serum biochemical parameters of tilapia (Oreochromis niloticus) fingerlings

Abstract

This trial was conducted to investigate the effects of supplementary surfactin on growth performance, intestinal digestive enzymes activities and some serum biochemical parameters of tilapia (Oreochromis niloticus) fingerlings. Three hundred and twenty fish were randomly divided into four treatment groups with four replicates in each group and 20 fish in each replicate. The dietary surfactin levels of four treatment groups were 0 (control group), 50, 100 and 200 mg/kg. The trial period was 7 weeks. Compared with the control group, final body weight, daily feed intake, weight gain rate, feed conversion ratio and protein efficiency ratio were improved significantly by surfactin supplementation (p < 0.05). No significant differences of survival rate were found between the control group and all surfactin supplementation groups (p > 0.05). The activities of protease and lipase in intestine of surfactin supplementation groups were significantly higher than those of the control group (p < 0.05), the amylase activities were similar among all treatment groups (p > 0.05). The activities of aspartate aminotransferase and alanine aminotransferase were decreased significantly by dietary surfactin supplementation (p < 0.05), the levels of blood urea nitrogen, triglyceride, total cholesterol and low-density lipoprotein cholesterol were also decreased significantly (p < 0.05), while lysozyme activity and the high-density lipoprotein cholesterol level were increased significantly by the surfactin supplementation (p < 0.05). In conclusion, we demonstrated a promotion of growth performance and improvement of intestinal digestive enzymes activities and some serum biochemical parameters of tilapia fingerlings by dietary surfactin supplementation.