Study On Regulation Of Hepatic Microsomal Triglyceride Transfer Protein Gene Expression On Periparturient Dairy Cows

In this study,we conducted three items :multiparous dairy cows intaked different energy standard,new-born bovine hepatocytes cultured in vitro,and quantitive RT-PCR applied, to detect the abundance of hepatic MTPmRNA of the periparturient dairy cows which were fed with different energy standard feeds, to detect the abundance of hepatic cell MTPmRNA in primary hepatocytes culture which were treated with different concentrations of leptin,insulin,glucagon,glucose,NEFA and BHBA. The objective from cellular and molecular levels was to understand the level and effect of MTPmRNA expression from the conditions of energy metabolism,neuroendocrine factors and metabolic products on periparturient dairy cows,to understand the regulation mechanism of regulatory protein for assembly and secretion of VLDL.The results in vivo experiment showed that the relative abundance of MTPmRNA in liver from all the treated cows tended to a gradual increasing during last two weeks gestation, reached a peak from 1 to 14d after parturition, and then fell after a raise. Abundance of MTPmRNA in liver of the cows fed with 120% energy diet was significantly higher than that of the cows fed with 80% energy diet during day 1 to 56 postpartum, and than that of the cows fed with 100% energy diet at day 14 postpartum (P<0.01). Abundance of MTPmRNA in liver of the cows fed with 100% energy diets was significantly higher than that of the cows fed with 80% energy diet at day 1 and 28 postpartum (P<0.01 or P<0.05) .It was concluded that dietary energy density during dry milk period could impact abundance of MTPmRNA in liver of early lactation cows. The different energy standard could effect MTPmRNA expression.The abundance of MTPmRNA enhanced significantly on periparturient dairy cows,which intaked high energy...