Dietary vitamin E requirements and growth performance of young-of-the-year beluga, Huso huso (L.) (Chondrostei: Acipenseridae) [RESEARCH ARTICLE]
An eight-week feeding trial was conducted using a flow-though system to determine the dietary requirements for vitamin E of young-of-the-year (YOY) beluga, Huso huso (L.), in relation to growth performance. Six diets, including the control diet (basal diet without vitamin E supplementation) and five diets supplemented with 25, 50, 100, 200, and 400 mg vitamin E (Dl-all-rac-á-tocopherol acetate) kg-1, were fed to triplicate groups of fish (mean initial body weight 49.7 ± 0.1 g). At the end of the trial, growth factors such as final body weight, weight gain (WG), feed conversion ratio (FCR), protein efficiency ratio (PER), specific growth rate (SGR), daily growth rate (DGR), and survival rate were determined. The values of WG, SGR, and DGR in the fish fed diet not supplemented with vitamin E were significantly lower than those of the fish fed the five supplemented diets. The final body weight and PER in fish fed diet not supplemented with vitamin E were significantly lower than fish fed diets supplemented with 25, 50, 100, and 200 mg vitamin E kg diet-1, but were similar in the control group and the group fed feed with 400 mg vitamin E kg diet-1. Moreover, the FCR in the fish fed the diet that was not supplemented with vitamin E was significantly higher compared to other groups. Based on observations, no mortality or any signs of deficiency were observed among the fish fed the control and other diets. Based on broken-line analysis, the dietary vitamin E requirement is in the range of 26.6-29.6 mg kg-1 dry diet based on the maximum values of WG, SGR, and minimum FCR, and can be added to the diet for the improved growth of this species.
A.S. Amlashi, B. Falahatkar [+]
Fisheries Department, Faculty of Natural Resources
University of Guilan, Sowmeh Sara, 1144, Guilan, Iran
Department of Animal and Poultry Science, College of Abureihan, University of Tehran, Tehran, Iran