为了研究饲喂高精料日粮对泌乳期山羊肝脏糖脂代谢的影响,试验选用16只健康经产泌乳中期关中奶山羊,随机分为3组,低精料组(LC,n=5)、长期高精料组(HL,n=7)和短期高精料组(HS,n=4)。实验结束后采集血液和肝脏组织。结果显示,与LC组相比,HL和HS组奶山羊血糖和肝糖原水平显著升高(P<0.05),血液中甘油三酯(TG)水平显著降低(P<0.05),胆固醇(Tch)含量没有显著变化(P>0.05);HS组山羊肝脏TG和Tch水平显著增加(P<0.05),HL组无显著变化(P>0.05)。HL组肝脏中丙酮酸羧化酶(PC)和葡萄糖转运蛋白2(GLUT2)mRNA表达水平显著上调;HS组肝脏PC、固醇调节元件结合蛋白1(SREBP1)、硬脂酰辅酶A去饱和酶(SCD)、二酰基甘油酰基转移酶(DGAT)和3-羟基-3-甲基戊二酰辅酶A还原酶(HMGCR)mRNA表达水平显著升高(P<0.05),SREBP-2有升高的趋势(P=0.76),肉碱棕榈酰转移酶-1(CPT-1)和胆固醇7α-羟化酶(CYP7α1)mRNA表达显著下降(P<0.05);线粒体型磷酸烯醇式丙酮酸羧激酶(PCK2)蛋白表达水平显著升高(P<0.05)。以上结果表明,短期饲喂高精料日粮能增强肝脏糖异生能力,促进肝脏胆固醇和脂肪合成;而长期饲喂高精料日粮能增强肝脏糖异生作用,但对胆固醇和脂肪代谢相关基因的表达没有影响。
The aim of this study was to investigate the effects of short-term and long-term feeding with a high concentrate diet on glucose and lipid metabolism in the liver of lactating goats.Sixteen mid-lactating goats were randomly divided into three groups:one group was fed with a high concentrate diet for 4 weeks(HS;65%concentrate diet,n=4);one group was fed with a high concentrate diet for 19 weeks(HL;65%concentration diet,n=7);and the control group was fed with a low concentrate diet during the whole experimental period(LC;35% concentrate diet,n=5).Compared with the LC group,the HS and HL groups showed significantly increased levels of plasma glucose and hepatic glycogen and markedly decreased triglyceride(TG)levels in plasma,but total cholesterol(Tch)in plasma showed no significant difference(P>0.05).The concentrations of hepatic TG and Tch were significantly increased in the HS group(P<0.05)but not in the HL group(P<0.05).Compared with the LC group,the HL group showed significantly upregulated transcript levels of the genes encoding pyruvic carboxylase and glucose transporter 2 in the liver(P <0.05).In the HS group,the transcript levels of genes encoding pyruvic carboxylase,sterol regulation element-binding protein-1,stearoylCoA desaturase,diacylgycerol acyltransferase,and 3-hydroxy-3-methyl glutaryl coenzyme A reductase in the liver were markedly increased,as was the protein level of phosphoenol pyruvate carboxykinase 2.The transcript levels of the gene encodingsterol regulation element-binding protein-2 tended to be higher(0.05
引文
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