Effects of overwintering on proximate composition, fatty acid composition, serum parameters, antioxidant status, and lipid metabolism in Onychostoma macrolepis

Abstract

AbstractTo investigate the metabolic adaptation and lipid utilization to overwintering in Onychostoma macrolepis (27.05 ± 1.79 g), fish were sampled at 0, 75, and 150 days, respectively. Fish were randomly reared into three outdoor tanks (water temperature range:0–10°C). After overwintering, body weight, viscera index, hepatopancreas index, and intraperitoneal fat index were significantly lower than before (p < 0.05). In liver, the contents of monounsaturated fatty acid and polyunsaturated fatty acid (PUFA) were observed to be the lowest and the highest after 150 days of overwintering, respectively (p < 0.05). In serum, the concentrations of triglyceride (TG) and total cholesterol significantly decreased while the activities of alanine aminotransferase and aspartate aminotransferase significantly increased at Day 75 (p < 0.05). Hepatic antioxidant activities were significantly lower whereas malondialdehyde content was significantly higher at Day 150 (p < 0.05). Serum antioxidant indexes were similar to those in liver. During overwintering, the decrease of TG contents in tissues was influenced by the upregulation of lipidolysis genes. These results indicate that lipids were continuously mobilized as physiological fuels throughout overwintering. Overwintering could result in poor antioxidant status and higher lipid peroxidation level in O. macrolepis.