Effects of dietary vitamin E level on growth and tissue lipid peroxidation of soft-shelled turtle, Pelodiscus sinensis (Wiegmann)

A feeding trial was conducted to determine the effect of dietary vitamin E supplementation on growth, liver lipid peroxidation and liver and muscle vitamin E level of soft-shelled turtle, Pelodiscus sinensis. Eight experimental diets analysed to contain 0-457 IU vitamin E kg^-1 were fed to juvenile soft-shelled turtle of 4.8 g initial body weight for 12 weeks. Weight gain (WG) of the turtles fed the diet containing no vitamin E was significantly lower than those fed diets containing 83-457 IU vitamin E kg^-1 (P<0.05). Feed conversion ratio and protein efficiency ratio showed similar trends to that of WG. No significant difference (P>0.05) was found in whole-body composition among turtles fed the different diets. Dietary vitamin E requirement using WG as the response and estimated using the broken-line regression model is approximately 88 IU kg^-1. Liver and muscle vitamin E content increased when dietary vitamin E level increased. Ascorbate-induced lipid peroxidation in liver tissue of turtles fed diets containing 0 and 17 IU vitamin E kg^-1 was significantly (P<0.05) greater than those fed diets containing high vitamin E (=>35 IU kg^-1).