The effect of dietary soybean meal on growth, nutrient utilization efficiency, and digestibility of juvenile common dentex, Dentex dentex (Actinopterygii: Perciformes: Sparidae)

Abstract

Background. The aim of this work was to study the growth of juvenile dentex fed on cooking-extruded diets, determine the level of substitution of fishmeal by soybean meal may be without affecting the growth in this species and its digestibility. Materials and Methods. The availability of defatted soybean meal as a substitute for fish meal was evaluated in juvenile (41 g on average) dentex by feeding diets containing 0%-60% soybean meal, for 97 days. Results. Survival at the end of the experiment was high (80%) except for the fish fed diets with 50% and 60% substitution. Growth, feed gain ratio, and protein efficiency ratio (PER) were slightly reduced at higher soybean meal levels. Fish fed diets containing 0% to 40% of soybean meal grew significantly more and FCR was lower than fish fed other diets. No differences were obtained for protein digestibility coefficients of experimental diets (20%,30%, 40%, and 50% SBM). Conclusion. The results confirm the best protein level for optimum growth seems to be around 50% and 12% lipid level, and maximum soybean meal substitution of 40%.