Effects of dietary protein and lipids on blood parameters and superoxide anion production in the grouper, Epinephelus coioides (Serranidae: Epinephelinae)

Ann-Chang Cheng, Chia-Yung Chen, Chyng-Hwa Liou, and Ching-Fong Chang (2006) Effects of dietary protein and lipids on blood parameters and superoxide anion production in the grouper, Epinephelus coioides (Serranidae: Epinephelinae). Zoological Studies 45(4): xxx-xxx. The objectives of this study were to investigate the effects of dietary lipid and protein levels on blood parameters, body composition, body indices, and the production of superoxide anions in the grouper, Epinephelus coioides (Serranidae: Epinephelinae). The effects of acute cold stress on the production of superoxide anions were also studied. A feeding trial was conducted for 12 wk on 200 juvenile groupers (10 g) per cage placed in a 2-tontank with a recirculation system. In total, 4 dietary treatments with a 2 × 2 factorial array were conducted. Treatments had either low (L, 31%) or moderate (M, 47%) crude protein (P) combined with either moderate (M, 10%) or high (H, 18%) fat (F). Fish were hand-fed to apparent satiation. Consumption of the high-fat, low-protein (LP-HF) diet resulted in abnormally increased levels of plasma glucose, triglycerides, and cholesterol, lower production of superoxide anions, and poor growth performance, which is consistent with higher body lipid content, viscerosomatic index, intraperitoneal fat, and hepatosomatic index of the fish. However, consumption of the moderate-protein, high-fat (MP-HF) diet decreased the impaired metabolism and increased the production of superoxide anions in the grouper. Grouper fed the high-fat (LP-HF and MP-HF) diets produced significantly higher levels of superoxide anions after acute cold shock (stress) compared to the control fish. In summary, our data suggest that high dietary fat results in increased fat deposition, and plasma triglyceride and glucose levels in grouper. High dietary lipid enhanced the immune response of grouper after acute cold shock.