VITAMIN-E REQUIREMENT OF PENAEUS-VANNAMEI

An 8-week feeding trial was conducted to determine the dietary vitamin E requirement of the white-legged shrimp, Penaeus vannamei, using sem i-purified diets. Shrimp exhibited significantly increased weight gain when fed increasing levels of vitamin E from 0 to 100 mg/kg diet, whe reas no significant difference in growth was observed for shrimp fed d iets containing vitamin E from 100 to 600 mg/kg. The vitamin E require ment of shrimp based on growth and estimated by the method of broken-l ine regression was 99 mg/kg diet. There was no difference in survival. The present study also indicated that vitamin E was an effective anti oxidant preventing ascorbic acid-stimulated lipid peroxidation in mito chondrial and microsomal membranes, oxidative spoilage of shrimp tail muscle during frozen storage (- 60-degrees-C) and peroxidation of diet ary lipid. Dietary vitamin E levels of approximately 25 and 100 mg/kg diet were found to be required for suppressing ascorbic acid-stimulate d mitochondrial and microsomal membrane lipid peroxidation in shrimp h epatopancreas and muscle, respectively. The synthetic antioxidant, but ylated hydroxytoluene (BHT), was an effective antioxidant in vitro by protecting dietary lipid from peroxidation, but it was less effective in tissue protection and exhibited no inhibitory effect on ascorbic ac id-stimulated mitochondrial and microsomal membrane lipid peroxidation . However, growth reduction of shrimp resulting from vitamin E-deficie ncy could be prevented by supplementation of BHT at 0.02% of the dieta ry lipid content.