Effects of bullet tuna Auxis rochei broth-supplemented diet on growth performance in yearling yellowtail Seriola quinqueradiata

Bullet tuna Auxis rochei broth is food-processing wastewater obtained after boiling fish and is rich in free amino acids and peptides. To efficiently utilize bullet tuna broth as fish feed, we investigated the effects of bullet tuna broth-supplemented diet on the growth performance in yearling yellowtail Seriola quinqueradiata. Fish meal (FM) and 30% FM-replaced with soybean meal (SBM) diets were used as basal diets. The effects of bullet tuna broth on growth performance were confirmed with or without supplementation to the basal diets (100 mL/kg diet). After 6 weeks of feeding trial, the growth performance (i.e., body weight, weight gain, specific growth rate and feed efficiency) was characterized as FM+Broth diet group>FM diet group>SBM+Broth diet group>SBM diet group. We conclude that supplementation of bullet tuna broth to yearling yellowtail diets improves the growth performance.