Assessing the suitability of soybean meal as a protein source for Argyrosomus Regius (Asso, 1801) (Sciaenidae): A nutritional evaluation

Abstract

The meagre (Argyrosomus regius) is a carnivorous fish which requires diets with higher protein content, causing
an increment in diets cost. A way to diminish this cost is to use vegetable meals like soybean meal (SB). So the
aim of this trial was to determine the optimum inclusion level of defatted soybean meal in experimental diets for
this species. 800 fishes (165 g) were distributed in 8 tanks, two replicates per treatment. Four isoproteic (50% CP)
and isolipidic (17% Cl) diets were formulated with four levels of soybean meal inclusion, 0, 15, 30 and 45%. The
trial lasted 107 days. Meagre fed diets 15 and 30% obtained the highest final weight. There were no significant
differences among treatments in the feed conversion rate (FCR) and the protein efficiency (PER). According to the
quadratic regression, the optimum SB inclusion to maximize thermal growth coefficient (TGC) was 26.4% and for
FCR was 27.6%. No significant differences were observed in energy, protein and amino acid retention among
diets. The inclusion of SB in meagre diets can generate a decrease in the use of fish meal and in turn reduce the
cost of producing meagre Mediterranean aquaculture industry.