Potential of poultry by-product meal as a main protein source in diets formulated for juvenile sobaity (Sparidentex hasta)

A 60-day feeding trial was conducted to evaluate the potential of using poultry by-product meal (PBM) as a partial replacement for fish meal (FM) in the diets for juvenile sobaity. Six iso-nitrogenous and iso-lipidic diets were formulated to contain graded levels of PBM, at 0 (as control diet), 15, 25, 35, 45, and 55% of FM replacement. Each diet was fed to groups of 20 juvenile sobaity in triplicate 300-L tanks, three times a day to apparent satiation. Survival, feed conversion ratio and efficiency ratio showed that there were no significant differences between fish fed PBM based diets compared to fish fed the reference diet. Growth performance and protein efficiency ratio of fish fed the PBM15 and 25 were higher than in other treatments. The somatic indices, biochemical content of whole body and fillet, hematological factors were not significantly affected by the replacement level of FM with PBM, with the exception of serum cholesterol and triglyceride content. The results of the present study indicated that PBM is a suitable replacement for fish meal in juvenile sobaity diet up to 55% substitution.