Effects of polysaccharide from Endothelium corneum gigeriae galli on growth, digestive, intestinal antioxidant capacity and serum biochemical indices of Lates calcarifer

To investigate the effects of dietary polysaccharide from Endothelium corneum gigeriae galli (PEGG) supplementation on the growth, digestive, intestinal antioxidant capacity and serum biochemical indices of Lates calcarifer and to provide references for the application of PEGG in healthy culture of L. calcarifer, we had fed juvenile L. calcarifer Body mass of (11.85±1.66) g by basal diets with PEGG at 0 (Control group), 5 (Low-dose group), 20 (Medium-dose group) and 80 g·kg⁻¹ (High-dose group) for eight weeks. The results show that compared with the control group, PEGG supplementation groups could: 1) increase the final body mass, weight gain rate and specific growth rate of juvenile L. calcarifer, and the difference was significant in the high-dose group (P<0.05); 2) increase the digestive enzyme activity significantly (P<0.05); 3) improve the histological structure of intestine significantly, indicating that PEGG increased the fold height, fold width and muscular thickness significantly (P<0.05); 4) enhance the antioxidant capacity significantly. The superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) activity, concentration of glutathione (GSH) and total antioxidant capacity (T-AOC) increased in the PEGG supplementation groups, while malondialdehyde (MDA) concentration decreased significantly (P<0.05); 5) improve the serum biochemical indices. Cholesterol in all the treatment groups decreased significantly, while ALT and AST in the medium-dose group decreased significantly (P<0.05). In conclusion, dietary PEGG can improve the digestive capacity, antioxidant capacity and serum biochemical indices of juvenile L. calcarifer, and promote the growth performance. The optimal PEGG supplementation level is 20 g·kg⁻¹.