ABSTRACT
Fish industry is deeply dependent on complex and high quality diet consisting of dried food, vitamins and micro/macro-elements. The suitable dose of each essential nutrient is different based on the fish species, their age and physiological conditions. In this study, effects of two recommended doses of riboflavin (20 and 30 mg vitamin per each kg taken dried food) on growth, hematological and immunological parameters of fingerling rainbow trout (Oncorhynchus mykiss) were investigated. The results showed that although treatment with riboflavin could improve biometric and immunological parameters of the fishes, the higher concentration (30mg) had no extra-positive effects on these factors. Furthermore, both doses decreased hematopoietic activity of this fish. Totally, our results showed that treatment of this fishes with 20 mg riboflavin per kg dried food is more efficient than treatment with 30 mg riboflavin per kg dried food.
