Effects of dietary vitamin E on growth performance, body composition, antioxidant capacity, and some immune responses in Caspian trout (Salmo caspius)

This study was conducted to evaluate the effect of dietary vitamin E on growth performance, feed utilization, biochemical properties and some immune responses in Caspian trout, Salmo caspius. Six experimental diets were formulated with semi-purified ingredients supplemented with vitamin E in the form of DL-α-tocopherol acetate to provide the actual vitamin E concentrations of 4.9 (the basal diet), 8.6, 17.4, 35.4, 78.8 and 137.0 mg kg−1 diet, respectively. Each diet was assigned to three replicate groups of Caspian trout (initial average weight of 9.73 ± 0.34 g) for eight weeks. Weight gain ratio (WGR), specific growth rate (SGR), and protein efficiency ratio (PER) were found to be significantly enhanced by increasing dietary vitamin E level and reached to the highest values in fish fed with 78.8 mg kg−1 vitamin E supplemented diet (P