Dietary vitamin E requirement of mrigal, Cirrhinus mrigala fry

A 12-week feeding trial was conducted using a flow-though system to determine the dietary requirement of vitamin E for mrigal fry in relation to growth performance, carcass composition and erythrocyte fragility. Five semi purified diets containing 19, 66, 120, 165 and 216 mg vitamin E ( dl-α-tocopheryl acetate)/kg diet were fed to triplicate groups of fish (initial weight 0.68±0.01 g/fish). Significant higher weight gain, specific growth rate, protein efficiency ratio and lower feed conversion ratio were observed in fish fed 120 mg vitamin E/kg diet than the other diets. Addition of vitamin E to the basal diet did not significantly affect whole body protein, crude fat, ash and moisture. However, the addition of vitamin E in basal diet significantly increased the deposition of vitamin E in the fish up to 216 mg/kg vitamin E. With the increasing level of vitamin E, erythrocyte fragility values was reduced. The erythrocyte fragility was maximum in fish fed 19 mg/kg vitamin E. Based on the broken-line analysis, the dietary vitamin E requirement was 99 mg/kg dry diet based on maximum weight gain.