Effects of salinity on growth, nutrient composition, fatty acid composition and energy metabolism of Scylla paramamosain during indoor overwintering

Three salinities (4 parts per thousand, 12 parts per thousand and 25 parts per thousand) were selected to determine the effects of different salinities on the growth, survival, nutrition and energy metabolism of Scylla paramamosain during indoor overwintering. Growth performance (survival rate, condition factor, hepatopancreatic index, weight gain rate and specific growth rate), nutrient composition (ash, moisture, crude fat, crude protein and total nitrogen), fatty acids, energy metabolites (glycogen, glucose, triglycerides, cholesterol and lactic acid) and energy metabolic enzymes (hexokinase, pyruvate kinase, lactate dehydrogenase and succinate dehydrogenase) were measured and calculated. The results showed that S. paramamosain exhibited the best growth and survival at 25 parts per thousand and worst at 4 parts per thousand after overwintering. In addition to consuming crude fat, excess protein was also broken down to provide energy in the 4 parts per thousand and 12 parts per thousand groups. The content of unsaturated fatty acids in the 25 parts per thousand group was higher after overwintering. Glycogen and glucose consumption and triglycerides, cholesterol and lactic acid production were lowest in the 25 parts per thousand group. The activity of hexokinase, pyruvate kinase, lactate dehydrogenase and succinate dehydrogenase was highest in the 4 parts per thousand group and lowest in the 25 parts per thousand group. The activity of hexokinase, pyruvate kinase, lactate dehydrogenase and succinate dehydrogenase in the hepatopancreas was higher than in the muscle. In conclusion, S. paramamosain uses less energy, has more unsaturated fatty acids and has a higher survival rate at a salinity of 25 parts per thousand after overwintering. The results of this study provide helpful information the indoor overwintering S. paramamosain in aquaculture production systems.