Evaluation of dietary fermented tuna by-product meal in juvenile Olive flounder, Paralichthys olivaceus

Abstract

An 8-week feeding trial was conducted to evaluate the effects of dietary fermented tuna by-product meal (FTBM) as a fishmeal (FM) replacer in juvenile olive flounder, Paralichthys olivaceus. Triplicate groups of 20 fish averaging 11.06 ± 0.11 g (mean ± SD) were fed one of the five experimental diets replacing FM with FTBM at 0 %, 12.5 %, 25 %, 37.5 % or 50 % (denoted as FTBM0, FTBM12.5, FTBM25, FTBM37.5, and FTBM50, respectively). All experimental diets were prepared to be isonitrogenous and isocaloric. After the feeding trial, weight gain, specific growth rate and feed efficiency from fish fed FTBM0 and FTBM12.5 diets were significantly higher (P < 0.05) than those from fish fed the other diets. Also, fish fed FTBM0 and FTBM12.5 showed significantly higher (P < 0.05) resistance to Edwarsiella tarda infection compared to the other treatments. However, whole body proximate composition, glutamic pyruvic transaminase, total protein and non-specific immune parameters (superoxide dismutase and lysozyme activities) showed no significant differences among fish fed all the experimental diets (P > 0.05). These results indicated that dietary fermented tuna by-product meal could replace up to 12.5 % of fishmeal in juvenile olive flounder, Paralichthys olivaceus.