Replacement of anchovy meal with salmon by-product meal in the diet of juvenile red sea bream, Pagrus major

Abstract

Abstract To determine the optimum level of anchovy fish meal (FM) replacement with salmon by-product meal (SM) in the diet of juvenile red sea bream, Pagrus major, five diets were prepared as follows: FM as the main protein source in the control diet (C), and SM replaced 25%, 50%, 75%, and 100% of the FM protein, referred to as S25, S50, S75, and S100, respectively. At the end of an 8 week rearing period, there were no significant differences in growth, nutrient digestibility, or retention efficiency among fish that were fed the C, S25, S50, and S75 diets (P > 0.05), except for retention efficiency of phosphorus. However, fish that were fed the S100 diet showed significantly lower growth performance compared with the C diet (P < 0.05). The optimal dietary levels of SM for final weight, specific growth rate, and weight gain (%) were 28.4%, 30.0%, and 28.7%, respectively, when the data were evaluated using quadratic polynomial regression analysis. The phosphorus load was significantly reduced in all SM-based diets compared with that in the control diet (P = 0.001). The results suggested that SM can replace at least 28.4% of FM protein in the diet of juvenile red sea bream without affecting growth, and that an ecological benefit can be achieved from SM-based diets by reducing the phosphorus load to the environment.