不同蛋白水平日粮对荷斯坦公犊牛糖异生的影响

Effects of different protein levels on gluconeogenesis of Holstein bull calves

为探究不同蛋白水平日粮对荷斯坦公犊牛糖异生的影响,选取年龄和生理状态相似的10头荷斯坦公犊牛(平均为5月龄,体重(172.80±7.16)kg),随机分为2组,每组5头,分别饲喂粗蛋白水平为15.05%和21.02%的颗粒料日粮,预试期7d,正试期56d。通过葡萄糖试剂盒测定血清和肝脏葡萄糖含量,液相色谱测定氨基酸含量,qRT-PCR分析肝脏糖异生途径关键基因的mRNA表达量。结果表明,与低蛋白水平组(15.05%)相比,日粮中高蛋白水平组(21.02%)显著提高血清和肝脏中葡萄糖含量(P<0.05),且显著提高Gly、Asp、Ala、Ser、Leu、Lys、Phe、Ile、Val、Tyr、Pro、Arg、Glu和His的含量(P<0.05),且显著提高了(P<0.05)PCK1、PCK2、PC和PGC1A的mRNA表达量。综上所述,日粮中高蛋白水平(21.02%)可增加肝脏中氨基酸的含量以及糖异生途径关键基因的mRNA表达,进而加快葡萄糖的生成,进一步为犊牛提供能量。

To investigate the effects of different protein levels on gluconeogenesis of Holstein bull calves,ten Hostein bull calves at similar age and physiological state(average age of 5 months old,weight of(172.80±7.16)kg)were randomly divided into two groups with five calves in each group.Pellet diets with crude protein levels of 15.05% and21.02% were fed for seven days in the pre-trial periods and 56 days in the pilot period.The glucose content in serum and liver was measured by glucose kit,the content of amino acids was determined by liquid chromatography,and qRT-PCR was employed for analysis of mRNA expression of key genes in the gluconeogenesis pathway.The results showed that compared with the low protein level group(15.05%),the high-protein level group(21.02%)significantly increased the glucose content in serum and liver(P<0.05)and significantly increased the content of Gly,Asp,Ala,Ser,Leu,Lys,Phe,Ile,Val,Tyr,Pro,Arg and Glu in liver(P<0.05);The mRNA expression of PCK1、PCK2、PC and PGC1 A were also significantly increased(P<0.05).In conclusion,the high protein level(21.02%)in the diet can increase the content of amino acids in the liver and mRNA expression of key genes of gluconeogenesis pathway,thus accelerating the production of glucose to further provide energy for calves.