Egg Yolk Lecithin as a Dietary Supplement in Juvenile Silver Pompano, Trachinotus blochii: Effects on Growth and Health Parameters

A 50-day feeding trial was conducted to determine the nutraceutical effect of a phospholipid, egg yolk lecithin (EYL) on juvenile silver pompano (Trachinotus blochii). The initial weight of the fish was (14.32 +/- 0.12) g. The different dietary supplementation levels of EYL included 0% (EYL0), 1% (EYL1), 2% (EYL2), 3% (EYL3), and 4% (EYL4). EYL supplementation has a positive impact on the growth and feed utilization of fish. The specific growth rate and weight gain percentage were significantly greater in the treatment group fed with 3% EYL. Feed utilization was observed to be highest in EYL3 as feed efficiency ratio (FER) and protein efficiency ratio (PER) were higher in this treatment group when compared with all other treatment groups. The survival rate was observed to be 100% in all the treatment groups. Hemoglobin (Hb), mean corpuscular volume (MCV), packed cell volume (PCV), and red blood cells (RBC) values were greater for EYL2, EYL3 and EYL4 whereas mean corpuscular hemoglobin concentration (MCHC) was unaffected by EYL supplementation. Nitro blue tetrazolium (NBT) activity was highest in the EYL3 group. Dietary EYL supplementation significantly decreased blood glucose levels in the fish. Highest catalase (CAT) activity in the gills and liver was observed in the treatment group EYL0. Superoxide dismutase (SOD) activity in the liver was unaffected and SOD activity in gills tended to decrease toward EYL3 but increased in EYL4. A significant reduction in the serum total protein concentration, serum globulin concentration, and an increase in serum albumin concentration and A:G ratio with respect to an increase in EYL indicate improved health. Serum triglycerides, creatinine, and uric acid were unaffected by EYL supplementation. However, HDL-cholesterol exhibited an increasing trend with an increasing EYL but decreased thereafter in EYL4. These findings suggest a potential benefit of EYL inclusion above 1% up to 3% in the diets for promoting growth and health in juvenile silver pompano.