Evaluation of skate meal and sablefish viscera meal as fish meal replacement in diets for P acific threadfin ( P olydactylus sexfilis )

The objectives of this study were to investigate the nutritional value of skate meal and sablefish viscera meal from A laskan fishery processing and to ascertain their suitability as replacements for pollock fishmeal in diets for Pacific threadfin ( P olydactylus sexfilis) . Test diets were made by replacing 50% or 100% protein from fish meal in the control diet with skate or sablefish viscera meal. The test diets and a commercial feed were each assigned to four tanks with eight juvenile fish (9.7 g) per tank in an indoor flow‐through culture system. After 6 weeks, Pacific threadfin fed skate meal‐50% and ‐100% substituted diets exhibited similar weight gains (374%; 369%) and feed conversion ratios (1.29; 1.27) as those fed the control diet (345%; 1.30 respectively) ( P  > 0.05). In contrast, Pacific threadfin fed the sablefish viscera meal‐50% substituted diet exhibited significantly lower weight gain (112%) than fish fed the control diets ( P  < 0.05). The fish fed the control diet and skate meal substituted diets also achieved significantly higher ( P  < 0.05) weight gain than those fed the commercial feed (288%). In conclusion, skate meal can fully replace the commercial fishmeal in a Pacific threadfin diet without adversely effecting growth performance.