The interaction of dietary niacin and lipid affects the growth, antioxidant capacity and lipid metabolism of male Eriocheir sinensis

A 60-day feeding trial was conducted to determine the effects of the interaction of dietary niacin and lipid on the growth, antioxidant capacity and lipid metabolism in male Eriocheir sinensis. A total 162 crabs (initial weight, 33.27 ± 0.84 g) were fed with six semi-purified diets containing L6N0 (6% lipid and 0 mg/kg niacin), L6N400 (6% lipid and 400 mg/kg niacin), L6N800 (6% lipid and 800 mg/kg niacin), L12N0 (12% lipid and 0 mg/kg niacin), L12N400 (12% lipid and 400 mg/kg niacin), L12N800 (12% lipid and 800 mg/kg niacin), respectively. Elevated levels of niacin and lipid improved growth performance of crabs, but there were no significant differences. Crabs fed with 400 mg/kg niacin diets had higher hepatopancreas index (HSI) and lipase (LPS) than that of the other groups. Niacin promoted the accumulation of lipid in the hepatopancreas, but excessive accumulation led to more oxidative stress in crabs. In conclusion, excess lipid and niacin enhanced the growth performance of male Chinese mitten crabs by promoting the accumulation of lipid in the body at the expense of impairing their immune capacity. Crabs fed with 6% lipid and 400 mg/kg niacin diet had an advantage in lipid metabolism, without a significant decrease in antioxidant capacity, achieving a balance in growth performance and immunity.