This experiment was conducted to examine the effect of dietary types on the nutritive value of fish meal diets for yellowtail Seriola quinqueradiata. Four types of fish meal-based diets were prepared by pelleting the same dietary ingredients: single moist pellets (MP), steam pellets (SP), extruded pellets (EP), and extruded-moist pellets (EMP), which were single moist pellets prepared after grinding the EP. They were fed to fingerling yellowtail by a restricted feeding rate for 30 days in 0.8ton aquaria. The fish actively accepted MP, EP, and EMP, and there were no significant differences in the growth rate, feed efficiency, protein efficiency ratio, and nutrient retention rates among the three dietary groups. On the other hand, the fish did not so actively accept SP, and this resulted in a lower growth and feed performance than that of the other three dietary groups. However, the dietary treatment scarcely affected their blood and body composition. These results indicate that both MP and EP have higher nutritive values than SP on the fish meal-based diet for yellowtail.
