Dietary soybean lecithin affects growth performance, fillet biochemical composition and digestive enzyme activity in Sparidentex hasta juvenile

ABSTRACT An eight-week study was conducted on silvery-black porgy (Sparidentex hasta) juveniles to evaluate four isoproteic, isolipidic and isoenergetic different diets (50% crude protein, 20% crude lipids, 18.5？MJ？kg？1) containing graded levels of soybean lecithin (SBL) (0, 30, 60 and 90？g？kg？1 diet) at the expense of fish oil (FO). Fish fed the 60？g SBL kg？1 diet had significantly higher weight gain (32.4%) and feed intake (8.8？g fish？1) than the control group (SBL 0) (P？<？0.05). The fillet fatty acid (FA) profiles were correlated with the FA profile of the experimental diets. Fish fed with SBL-supplemented diets had higher fillet phosphatidylcholine levels than the control group (P？<？0.05). Plasma total immunoglobulin was higher in fish fed 60 and 90？g SBL kg？1 diets than in the other groups (P？<？0.05). Total protease activity was higher in fish fed the 90？g SLB kg？1 diet than other treatments (P？<？0.05). Results indicated that substitution of dietary FO with SBL diet up to 67% (60？g SLB kg？1 diet) improved somatic growth performance and profoundly affected the fillet fatty acid profile in silvery-black porgy juveniles