Effect of maternal protein restriction on lipid metabolism in Meishan piglets at weaning

Abstract

The present study aimed to determine the effects of maternal protein restriction on lipid metabolism of piglets at weaning and the associated underlying mechanism employing Meishan pigs as model. Sixteen Meishan sows were assigned to the control group and the maternal protein restriction group (MPR). The treated group was fed a low-protein diet containing 6% protein during pregnancy followed by 7% protein during lactation, whereas the control group received 12% and 14% protein during pregnancy and lactation, respectively. Blood and subcutaneous fat of piglets were sampled at weaning. The results showed that in MPR piglets' body weight and backfat thickness were significantly decreased compared to control piglets ( P < 0.05). Leptin mRNA expression was significantly down-regulated and the leptin content showed a decreased tendency ( P = 0.10) in subcutaneous fat of MPR group though the serum leptin concentration was unchanged. The lipolytic lipase activity (including Hormone sensitive lipase, HSL and adipose tissue triglyceride lipase, ATGL) in subcutaneous fat was significantly increased in MPR group ( P < 0.05). The fatty acid synthase (FAS) mRNA expression decreased significantly ( P < 0.05) although CCTTA enhancer-binding protein (C/EBP-β) and peroxisome proliferators-activated receptor γ (PPAR-γ) mRNA expression showed no obviously changes in MPR group compared with the control. Furthermore, though no alteration was detected for total perilipin protein level, the mRNA expression of perilipin was significantly decreased and the phosphorylation level of perilipin protein demonstrated an increased tendency ( P = 0.09) in the MPR group. The present study indicates that the lower lipid deposition in piglets of maternal protein restriction group at weaning may be mediated by the increased lipolysis in the subcutaneous fat demonstrated by increased lipolytic lipase activity and higher perilipin phosphorylation level. These alterations may influence the lipid metabolism of later life.