Effects of dietary menhaden oil, soybean oil and soybean lecithin oil at different ratios on growth, body composition and blood chemistry of juvenile Litopenaeus vannamei

A 10-week feeding experiment was conducted to evaluate the nutritional value of menhaden oil (MO), soybean oil (SO) and soybean lecithin oil (SL) at different ratios (MO/SO/SL) in practical diets for juvenile Litopenaeus vannamei by determining their effects on survival, growth, blood chemistry and fatty acid composition of hepatopancreas and muscle tissue. Eight isonitrogenous and isolipidic diets were formulated using 3% MO(3/0/0), 3% SO(0/3/0), 3% SL(0/0/3), 1% MO + 1% SO + 1% SL (1/1/1), 1% SO + 2% SL (0/1/2), 1% MO + 2% SL (1/0/2), 2% SO + 1% SL (0/2/1) and 2% MO +1% SL (2/0/1), respectively. There were no significant differences in body weight gain among all treatments. However, shrimp fed diets with SL supplementation showed significantly (P < 0.05) higher survival than those fed diets without SL supplementation (3% MO and 3% SO diets). The fatty acid (FA) composition of hepatopancreas and muscle tissue reflected, to a certain extent, FA composition of the test diets. Shrimp fed the 3% SL diets showed significantly (P < 0.05) higher triglyceride (TG) concentration in serum than those fed the other experimental diets. Shrimp fed diets containing SL have relatively higher total cholesterol (TC) and phospholipid (PL) concentration in serum than those fed the diets without SL (3% MO and 3% SO). The results of the present investigation are encouraging and confirmed soybean lecithin supplement in shrimp practical diets, when sufficiently high levels of phospholipid are present, survival is enhanced.