Effect of dietary methionine on growth performance, lipid metabolism and antioxidant capacity of large yellow croaker (Larimichthys crocea) fed with high lipid diets

A 10-week feeding trial was conducted to evaluate the effect of dietary methionine (MET) on the growth performance, lipid metabolism and liver antioxidant function in juvenile large yellow croaker (Larimichthys crocea) fed with high lipid diets (HLDs). Large yellow croaker with an initial average weight of 8.59 g, were fed with basic HLD (lipid level at 18%, HL), basic HLD supplemented with 0.6% MET (HL/L-MET) and basic HLD supplemented with 1.2% MET (HL/H-MET). Results indicated that dietary MET did not affect weight gain, specific growth rate and feed efficiency ratio (P > 0.05). The MET supplementation in large yellow croaker also did not affect the content of total lipid in whole body (HL = 9.57, HL/L-MET = 8.92 and HL/H-MET = 8.71%), liver (7.34, 16.68 and 14.37%) and muscle (10.87, 12.11 and 9.94%) (P > 0.05). However, MET supplementation reduced the size and number of liver lipid droplets as dietary MET increased. Meanwhile, supplementation of MET in HLDs reduced serum total cholesterol (2.65, 2.14 and 1.91 mmol/L), low-density lipoprotein-cholesterol (0.27, 0.21 and 0.16 mmol/L) and triglyceride (4.80, 2.43 and 1.96 mmol/L) (P