Dietary vitamin E requirement of hybrid striped bass (Morone chrysops female x M-saxatilis male)

This study was conducted to determine the dietary vitamin E requirement of juvenile hybrid striped bass (Morone chrysops female x Morone saxatilis mal e). Semi-purified diets supplemented with 0.2 mg Se kg(-1) from Na2SeO3 and either 0 (basal), 10, 20, 40, 60, or 80 mg vitamin E kg(-1) as DL-alpha-to copheryl acetate were fed to hybrid striped bass initially averaging 1.8 +/ - 0.1 g (mean +/- SD) for 12 weeks. Fish fed the basal diet, which containe d 5.8 mg alpha-tocopherol kg(-1) dry weight, were darker in colour and had reduced weight gain, as well as generally reduced haematocrit values compar ed with fish fed diets supplemented with vitamin E. In addition, fish fed d iets containing less than 20 mg supplemental vitamin E kg(-1) had significa ntly (P < 0.05) reduced weight gain and feed efficiency compared with those fed diets supplemented with vitamin E at 20-80 mg kg(-1). Dietary suppleme ntation of vitamin E caused incremental increases in the concentration of a lpha-tocopherol in both plasma and liver tissues. However, hybrid striped b ass fed graded levels of vitamin E did not exhibit a dose response in terms of ascorbic acid-stimulated lipid peroxidation of hepatic microsomes. Regr ession analysis of weight gain data using the broken-line model indicated a minimum vitamin E requirement (+/- SE) of 28 (+/- 3) mg kg(-1) dry diet. B ased on these data, the dietary vitamin E requirement of hybrid striped bas s appears to be similar to that determined for other fish species.