The effects of vitamin E on antiacid stress ability in juvenile soft-shelled turtles ( Pelodiscus sinensis)

Abstract

We determined the effect of dietary supplementation with vitamin E (0-, 50-, 250-, 500-, 1000- and 5000-mg/kg diet for 4 weeks) on antistress ability in juvenile soft-shelled turtle ( Pelodiscus sinensis). Half of the turtles per dose group were treated by acid stress for 24 h. The results showed that phagocytosis of blood cells in the control group significantly decreased after acid stress while the other five groups had no significant changes compared with those of before stress. Serum bacteriolytic activity in the control group and the group supplemented with 50-mg vitamin E/kg diet significantly decreased after acid stress. The other four groups showed no significant differences compared with those before stress. Serum bactericidal activities in all groups notably decreased after acid stress, but the difference of serum bactericidal activity in before and after stress had a decreased tendency from the control group to the highest dose group. Serum cortisol levels in the control group were significantly increased while the other five groups had no notable increases after acid stress. Liver vitamin E levels in all groups had no notable changes compared with those before stress but there was a tendency to decrease after acid stress. These results suggest that acid stress depress immune function and increase serum cortisol levels in turtles while vitamin E alleviate the adverse effects caused by acid stress.