日粮蛋白质水平对乌金猪肝脏组织脂类代谢相关基因表达的影响

为探讨日粮蛋白质水平对乌金猪肝脏组织脂类代谢相关基因表达的影响,试验选取体重约15 kg的乌金猪54头,随机分为3组,每组18头,为低、中和高蛋白质组,其在15～30、30～60及60～100 kg生长阶段的蛋白质水平分别为14%、12%、10%,16%、14%、12%和18%、16%、14%。猪在体重为30、60和100 kg时屠宰,取其肝脏组织,Real-time PCR定量检测脂类代谢相关基因的表达水平。结果显示,在30、60和100 kg时,乌金猪肝脏组织中ACC、FAS、SREBP-1C基因的表达水平均随着蛋白质水平的升高而降低;CPT-Ⅰ和PPARα基因的表达水平则随着蛋白质水平的升高而升高。由此表明,日粮高蛋白质水平显著降低肝脏脂肪酸合成代谢基因(ACC、FAS和SREBP-1C)的表达(P<0.05),提高脂肪酸分解代谢基因(CPT-Ⅰ和PPARα)的表达水平(P<0.05);脂肪酸合成减少,且被氧化的量增加,两者共同作用导致用于合成甘油三酯(TG)的脂肪酸含量降低,从而减少了从肝脏组织被运输到各个组织的TG含量,使机体沉积TG的能力降低。

Effect of Dietry Protein Levels on the Expression of Hepatic Lipid Metabolism Related Genes in Wujin Pigs

The purpose of this study was to investigate the effect of dietary protein levels on the expression of hepatic lipid metabolism related genes in Wujin pig livers. Fifty-four Wujin pigs with the weight of 15 kg were randomly divided into 3 groups and 18 pigs per group,and given to three different protein levels with low dietary protein (14%,12% and 10%),medium dietary protein (16%,14% and 12%) and high dietary protein (18%,16% and 14%) during the growth stage of 15 to 30,30 to 60 and 60 to 100 kg body weight. At the body weight of 30,60 and 100 kg,pigs were slaughtered and liver samples were taken for analyzing the expression levels of lipid metabolism genes by Real-time PCR. The results showed that hepatic expression of acetyl-CoA carboxylase (ACC),fatty acid synthase (FAS) and sterol regulatory element binding protein 1c (SREBP-1c) reduced while the expression of carnitine palmitoyltransferase Ⅰ (CPT-Ⅰ) and peroxisome proliferator-activated receptorα (PPARα) increased as the protein content of diets increased. The study indicated that elevated level of dietary protein significantly decreased the expression of SREBP-1C,ACC,FAS (P<0.05),but increased the expression of CPT-Ⅰ,PPARα (P<0.05). Thus,the reduced synthesis and the increased oxidation of fatty acid collectively decreased the TG level transported to animal tissues and reduced the fat deposition in the body.