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

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.