Effects of the Dietary Fermented Tuna By‐product Meal on Growth, Blood Parameters, Nonspecific Immune Response, and Disease Resistance in Juvenile Olive Flounder, <scp><i>Paralichthys olivaceus</i></scp>

Abstract

Abstract This study evaluated the effects of dietary fermented tuna by‐product meal (FTBM) in juvenile olive flounder, Paralichthys olivaceus . Five diets were formulated to replace fishmeal (FM) with FTBM at 0% (FTBM 0 ), 12.5% (FTBM 12.5 ), 25.0% (FTBM 25 ), 37.5% (FTBM 37.5 ), or 50% (FTBM 50 ). After 8 wk, weight gain, specific growth rate, and feed efficiency of fish fed FTBM 0 and FTBM 12.5 diets were significantly higher than fish fed the other diets ( P &lt; 0.05). Also, mean cumulative survival rates (%) of fish fed the FTBM 0 and FTBM 12.5 diets were significantly higher than those fed FTBM 50 diet at Day 9 postchallenge with Edwardsiella tarda ( P &lt; 0.05). Protein efficiency ratio of fish fed FTBM 0 and FTBM 12.5 diets was significantly higher ( P &lt; 0.05) than fish fed diets FTBM 37.5 and FTBM 50 . Broken‐line regression analysis of weight gain showed an optimal FM replacement level of 10.65% with FTBM. Therefore, the optimal dietary inclusion of FTBM in juvenile olive flounder diets could be greater than 10.65% but less than 12.5% without any adverse physiological effects on fish health.