Effects of varying levels of dietary vitamin E (-tocopherol) on growth performance, proximate and fatty acid composition of juvenile silver pomfret (Pampus argenteus Euphrasen, 1788)

摘要

This study investigated the effects of elevated dietary levels of vitamin E (-tocopherol) on growth performance, proximate composition and fatty acid profiles of juvenile silver pomfret, Pampus argenteus. Three semi-purified experimental diets were formulated to contain 49% protein and 16% lipid. High docosahexaenoic acid (DHA) tuna oil was added to the diets to supplement DHA. A graded level of vitamin E (0-, 50-, and 100mgkg(-1)) was added to experimental diets 1 to 3, respectively. Analyzed vit. E levels were 155.2, 195.3 and 236.4mgkg(-1) in diets 1, 2 and 3, respectively. The experiment was conducted for 12weeks with juvenile silver pomfret (29.6 +/- 7.6g) using a flow-through system consisting of nine 1-m(3) tanks. Each treatment had three replicates and fish were stocked at the rate of 20m(-3). Growth performance and feed utilization parameters of fish fed diets 2 and 3 were significantly (P0.05) higher than in fish fed diet 1, but the parameters in diets 2 and 3 did not differ significantly (P>0.05). Although whole body protein levels were not influenced by the dietary vit. E levels, whole body lipid in fish fed diet 2 was significantly higher than in fish fed the other diets. The whole body vit. E levels in fish fed diet 2 (22.6mgkg(-1)) and diet 3 (24.1mgkg(-1)) were significantly (P0.05) higher than in those fed diet 1 (18.2mgkg(-1)). Whole body total saturated fatty acids were significantly lower, and DHA levels higher in fish fed diets 2 and 3 than those fed diet 1. The results of the present study suggest that increasing dietary supplementation of vit. E in high lipid diets enhances the growth performance of fish and that a dietary level of 196mgkg(-1) vit. E is suitable for the growth of silver pomfret.