不同精粗比日粮对泌乳山羊肝脏蛋白质代谢及乳蛋白含量的影响  

Effect of Different Forage Ratio Diet on Hepatic Protein Metabolism and Milk Protein Content in Lactating Goat(Capra hircus)

作　　者：张树坤[1] 姜雪元[1] 倪迎冬[1] 张源淑[1] 沈向真[1] 

机构地区：[1]南京农业大学农业部动物生理生化重点开放实验室,南京210095

出　　处：《农业生物技术学报》2013年第4期413-420,共8页Journal of Agricultural Biotechnology

基　　金：国家重点基础研究发展规划(973)项目(No.2011CB100802);江苏高校优势学科建设工程资助项目

摘　　要：肝脏在机体蛋白质代谢调控中起着重要的作用。为了揭示不同精粗饲料比条件下山羊肝脏蛋白质代谢与乳蛋白合成和分泌的关系,本研究选用8只健康的泌乳中期山羊(Capra hircus),随机分为两组,日粮精粗比分别为4∶6(低精料组)和6∶4(高精料组),采用2×2拉丁方设计,2次重复。取乳样,测定产奶量和乳中蛋白质含量。肝脏活体穿刺取样,二维凝胶电泳结合MAIDI-TOF-TOF质谱的方法分析肝脏内蛋白质代谢相关蛋白/酶表达的差异。与低精料组相比,高精料组山羊日平均产奶量显著增高(P<0.05),而乳中蛋白质含量无显著差异(P>0.05)。蛋白组学结果表明,当精料比例提高时,肝脏参与蛋白质代谢的延长因子-Tu、谷氨酸脱氢酶、腺苷高半胱氨酸酶上调;而26S蛋白酶体调节亚基7和血清前白蛋白下调,即肝脏本身合成血清前白蛋白和小肽能力下降;同时氨基酸分解代谢和抗氧化应激作用加强。高精料饲喂泌乳期山羊,其肝脏中氨基酸消耗增多,同时小肽合成减少,竞争消耗了乳蛋白合成的原料,可能不利于乳蛋白的合成。本研究结果为研究肝脏对乳蛋白合成的影响提供了线索。The liver plays an important role in the regulation of protein metabolism in body. The purpose of this research is to reveal the relationship between protein synthesis and secretion and liver protein metabolism in goats（Capra hircus） under different dietary patterns. Eight healthy mid-lactation goats were randomly divided into two groups, using 2 × 2 Latin square design with two replications. Dietary concentrate to forage ratios were 4： 6 and 6： 4. Milk samples were taken to measure milk yield and milk protein levels, and liver samples were collected by living donor liver biopsy. The differential expression proteins in the goat liver were extracted and separated by two-dimensional electrophoresis （2-DE） and MAIDI-TOF-TOE The daily milk yield of high-concentrate group（6： 4 group）was significantly higher than that of the low-concentrate group（4： 6 group, P 〈0.05）, but milk protein content was no significant difference between two groups （P〉0.05）. The results of proteomics showed that in high-concentrate group（6： 4 group）, elongation factor Tu and glutamate dehydrogenase and adenosine homocysteine enzyme involved in protein metabolism had higher expression,while 26S proteasome regulatory subunit 7 and serum prealbumin involved in protein metabolism had low expression. The ability to synthesize small peptide and lactalbumin was decreased in the liver, while the catabolism of amino acids and the role of oxidative stress were enhanced. The liver metabolism had an important influence to milk protein synthesis and metabolism. It was not conducive to synthesis milk protein for lactation goats fed high-concentrate diets because the consumption of amino acids increased and the synthesis of small peptide decreased. So he raw material for milk protein synthetic was consumed too much and its mechanism will be worth further study. The results of this study provided a clue to research the liver impact of milk protein synthesis.

关 键 词：高精料日粮 泌乳山羊 肝脏 蛋白代谢 蛋白表达谱 乳蛋白 

分 类 号：S823.5[农业科学—畜牧学]