Dietary phosphatidylcholine affects growth performance, antioxidant capacity and lipid metabolism of Chinese mitten crab (Eriocheir sinensis)

Abstract

This study determined the effects of dietary phosphatidylcholine (PC) levels on growth performance, antioxidant capacity and lipid metabolism of juvenile Eriocheir sinensis. Six isolipidic and isonitrogenous diets were formulated with six graded levels of PC (0%, 1.36%, 2.76%, 4.34%, 5.74% and 7.10%) and fed to juvenile E. sinensis (0.52 ± 0.01 g) for eight weeks. The crabs in the PC-added groups had a better feed conversion ratio and higher final body weight, weight gain and specific growth rate than those in the PC-devoid group. The dietary PC supplement increased antioxidant capacity and reduced lipid peroxidation in the hepatopancreas of E. sinensis. The crabs fed the diet with PC addition showed lower whole-body total lipid contents than those fed the diet without PC addition. The diets supplemented with moderate PC promoted whole-body protein deposition. The total lipid content of the hepatopancreas was also markedly decreased in the PC-added groups, while the total lipid content in muscle showed an opposite trend in the hepatopancreas. In addition, the appropriate dietary PC facilitated the deposition of long-chain polyunsaturated fatty acids (especially C20:5n-3 and C22:6n-3) in muscle and hepatopancreas. The quantitative real-time PCR exhibited that the dietary PC reduced lipid deposition in the hepatopancreas of E. sinensis possibly through inhibiting lipid synthesis as well as facilitating lipid oxidation and transport. Based on the weight gain and specific growth rate, the broken-line regression analysis suggested that the optimum PC requirement of juvenile E. sinensis should be in the range of 2.89% - 2.95% of the diet by weight.