关键词: 能量摄入, 丙酮酸羧化酶, 磷酸烯醇式丙酮酸羧激酶, 奶牛

Abstract: The objective of the present study was to investigate the effect of energy intake during the dry period on the expression of Pyruvate carboxylase (PC) and Phosphoenolpyrevate carboxykinase (PEPCK) mRNA in the liver of periparturient diary cows. Thirty healthy multiparous Holstein cows were randomly allocated into three groups and fed on 100% energy diet (standard diets), 120% energy diet and 80% energy diet，respectively, beginning at the 28th day before parturition. After calving, all the cows were offered the lactation ration ad libitum until the 56th day postpartum. Quantitative PCR analysis of RNA from liver biopsy samples obtained on days -28、-14、+1、+14、+28、and +56 relative to calving indicated that PC and PEPCK mRNA expression were responsive to diet. Abundance of PC mRNA was the highest in the 80% energy diet cows during experimental period. Liver PEPCK mRNA abundance increased after parturition in the low energy diet group of cows compared with the other groups of cows except a period of the first 14d postpartum. The results demonstrate that the low energy diet during the dry period could improve the liver glyconeogenesis in the periparturient diary cows.

Key words: Energy intake, PCmRNA, PEPCKmRNA, Diary cows