Effects of vitamin E on serum biochemical indexes and antioxidant capacity of Megalobrama amblycephala under acute high temperature stress and recovery

The purpose of this study was to investigate the effects of vitamin E(VE)on serum biochemical indices and antioxidant capacity of juvenile Megalobrama amblycephala under acute high temperature stress and recovery.180 healthy fish(45.00±0.50)g were selected and randomly divided into three groups:a control group was fed with basal diet,and two treatment groups fed with basal diet supplemented with 50 and 400 mg/kg VE,respectively.Each group has four replications.After 90 days' feeding trial,all fish were exposed to high temperature stress(32 ℃)for 1 day and recovered at 25 ℃ for 7days in a controlled temperature aquarium.The results showed that the diet supplemented with 50 mg/kg VE significantly increased the activity of intestine glutathione compared with the control group(P0.05)prior to the stress.After high temperature stress,the diet supplemented with 50 mg/kg VE significantly decreased the levels of serum aspertate aminotransferase(ALT)activity and cortisol(COR)content at 1d after stress,reduced the levels of serum alanine aminotransferase(AST)activity,triiodothyronine(T3)and COR content at 7 d recovery after stress(P0.05),and improved the serum alkaline phosphatase(ALP)activity,intestine glutathione(GSH)activity and superoxide dismutase(SOD)activity at 7d recovery after stress(P0.05)compared with the control group(P0.05).The diet supplemented with 400 mg/kg VE significantly reduced the levels of serum ALT and intestine malonaldehyde(MDA)content at 1 day after stress and 7 d recovery after stress,COR content at 7 d recovery after stress(P0.05)and increased the levels of serum ALP and T3 at 1 day after stress concentration compared with the control group(P0.05).So it is suggested that ingestion of a basal diet supplemented with VE(50-400 mg/kg diet)could help regulate the change of blood lipids,improve antioxidant capacity,alleviate the change of blood biochemical parameters in high temperature stress condition,reduce lipid peroxidation,and enhance resistance against high temperature stress in Megalobrama amblycephala.