Tuna by-product meal as a dietary protein source replacing fishmeal in juvenile Korean rockfish Sebastes schlegeli

Abstract This study was conducted to evaluate the use of tuna by-product meal (TBM) as a substitute for fishmeal in juvenile Korean rockfish (Sebastes schlegeli) diets. Five isonitrogenous (52% crude protein) and isocaloric (4.9 kcal/g) diets were prepared. Control diet (Con) was formulated to contain brown fishmeal, whereas 25, 50, 75, and 100% of fishmeal was substituted with the same percentage of TBM in the TBM25, TBM50, TBM75, and TBM100 diets, respectively. Three replicate groups of fish (initial weight, 29.5 ± 0.6 g) were fed one of the five diets for 12 weeks. The mean weight gain of fish fed the Con and TBM25 diets was significantly higher than that of fish fed the TBM100 diet (P