Research Article Effects of Partial Substitution of Fish Meal by Soybean Meal with or without Heat-Killed Lactobacillus plantarum (LP20) on Growth Performance, Digestibility, and Immune Response of

Copyright © 2015 Mahmoud A. O. Dawood et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. A 56-day feeding trial was conducted to evaluate the effects of supplemented diets with heat-killed Lactobacillus plantarum (HK-LP) with graded levels of soybeanmeal (SBM) on growth, digestibility, blood parameters, and immune response of Seriola dumerili (initial weight, 25.05 ± 0.1 g). Seven isonitrogenous and isolipidic practical diets were formulated to contain 0%, 15%, 30%, and 45 % SBM, and each SBM level was supplemented with HK-LP at 0.0 and 0.1%. Fish fed diet which contains 30 % SBM with HK-LP grew significantly faster than the other groups with notable feed intake and protein retention. Further, protein gain, whole body protein content, protease activity, protein, and lipid digestibility were significantly increased for all fish groups except for fish fed diet which contains 45 % SBM with or without HK-LP. Interestingly, lysozyme activity was significantly enhanced in fish fed diets that contain 15 % and 30 % SBM with HK-LP. Hematocrit, peroxidase, and bactericidal activities revealed a significant increase in 30 % SBM with HK-LP group. In addition, fish fed diets which contain 0 % and 30 % SBM with HK-LP showed higher tolerance against low-salinity stress compared with other groups. In conclusion, the addition of HK-LP to amberjack diets appeare