Effect of Partial Replacing Fish Meal with Wheat Gluten on Growth Indices and Carcass Composition of Caspian Kutum (Rutilus Kutum)

Inroduction & One of the problems of aquaculture is low access to fish meal, which increases demand and reduction in production rates. A lot of efforts have been made to find suitable alternatives that plant protein sources are among the most important substituents. The aim of this study is to investigate the effect of partial replacing fish meal with wheat gluten on growth indices, survival, and carcass composition of Caspian kutum (Rutilus kutum). Wheat gluten was replaced at four levels including 0, 10%, 20% and 30% with fishmeal in three replicates. A total number of 240 kutum frys weighing 0.33±0.06g were distributed into twelve 100-L fiberglass tanks with a density of 20 fish per tank. Fish were fed four isonitrogenous and isocaloric diets for 8 weeks. At the end of the trial, growth indices and carcass composition were measured. Final weight, total length, body weight increase, specific growth rate, average daily growth and protein efficiency ratio in control group were significantly higher than other treatments (P<0.05). Wheat gluten at the level of 30% and control had the highest and the lowest feed conversion ratio, respectively. The highest survival rate was recorded in 30% wheat gluten that showed significant difference with control (p<0.05). A significant difference in content of carcass protein was observed between control and fish fed 10% wheat gluten with fish fed 20% wheat gluten (P<0.05).  According to obtained findings, wheat gluten at used levels is not optimal for kutum and cannot substitute the fish meal.