Effects of Dietary Corn Gluten Meal on Growth Performance and Cholesterol Metabolism in Juvenile Snakehead (Ophiocephalus argus) Fed Practical Diets

An 8-week growth trial was conducted to investigate the effects of dietary corn gluten meal (CGM) levels on growth performance and cholesterol metabolism of juvenile snakehead (Ophiocephalus argus). Six isonitrogenous (crude protein 47%) and isolipidic (crude lipid 11.5%) practical diets were formulated by replacing 0 (D1, control), 6.2 (D2), 12.3 (D3), 18.5 (D4), 22.2 (D5), and 28.4% (D6) fish meal (FM) protein with CGM protein. No significant difference in survival rate was found among dietary treatments (P>0.05). No significant differences were observed in feed intake (FI), final body weight (FBW), weight gain rate (WGR), feed efficiency rate (FER) and protein productive value (PPV) among fish fed D1-D3 (P>0.05). However, these indices significantly decreased with increasing CGM protein from 18.5%(D4) to 28.4%(D6) of diet (P<0.05). Whole-body lipid content of fish fed D6 (28.4%) was significantly lower than that of fish fed D1 (control) (P<0.05). The plasma and liver total cholesterol, free cholesterol, cholesterol esters, LDL-C, and HDL-C levels were affected by dietary CGM protein levels. Broken line analysis based on WGR or PPV indicated that the maximum CGM protein level for the optimal growth of juvenile snakehead was 12.06% or 12.56% respectively.