Effect of high-level fish meal replacement by pea and rice concentrate protein on growth, nutrient utilization and fillet quality in gilthead seabream ( Sparus aurata, L.)

Abstract

Partial replacement of fish meal by a vegetable mixture (Pea Protein Concentrate (PPC) and Rice Protein Concentrate (RPC)) was carried out in on-growing gilthead seabream (initial average weight 174 g). The experimental diets were isoproteic (48% CP) and isolipidic (18%) with 0, 30, 60 and 90% of fish meal substitution, supplemented with Methionine and Lysine. Fish were distributed in 12 tanks with 20 fish per tank. At the end of the trial (80 days), fish survival was 90% and there were no differences in growth parameters except for fish fed the 90% (326 g and SGR: 0.78% day − 1 ) diet. No significant differences were found in feed intake ratio (FI), which was around 1.70 to 1.96 g 100 g fish − 1 day − 1 , feed conversion ratio, around 1.9 to 2.4 and protein efficiency ratio, which ranged from 0.96 to 1.2. No statistical differences were observed in biometric parameters. In the retention of amino acids ingested there were no statistical differences among diets, although fish fed the 60 diet obtained the highest values in all EAA compared with other diets. In both ingested and digested amino acids, a higher retention of His and lower retention of Met was observed. Regarding sensory analysis, there were no statistical differences in triangular test for fish fed the various diets.