摘要：

在乳制品的开发过程中,乳蛋白是评估牛乳营养价值的重要指标。饲料配方优化是当下实现奶牛生产提质增效的重点工作之一。目前,饲喂过瘤胃氨基酸虽是提高奶牛乳蛋白合成最直接且高效的途径,但多数研究仅限于单一的限制性氨基酸,忽略了对氨基酸营养平衡体系的认识。在奶牛机体内,氨基酸营养作为乳蛋白合成的底物与信号物质,影响着乳腺对血液氨基酸的吸收与利用,但其分子代谢机制尚不明晰。本研究主要从氨基酸对奶牛乳腺蛋白合成的影响及调控两方面进行分析,首先概述了乳蛋白合成的基本途径,必需氨基酸、非必需氨基酸、组合必需氨基酸对乳蛋白产量及浓度的影响;其次详细介绍了必需氨基酸与组合必需氨基酸的供给对奶牛采食量、血液氨基酸浓度、血流量、乳腺细胞的影响,同时在细胞分子角度讨论了乳腺细胞培养所需氨基酸的最优添加剂量,以及必需氨基酸对氨基酸转运载体和信号通路的特异性调节。综上,通过对奶牛乳腺蛋白合成影响因素和分子调控机制的探讨,有助于优化饲料中理想的氨基酸配比与科学的生产模式,为氨基酸营养提高乳蛋白合成的相关研究提供理论参考。

关键词: 奶牛, 乳蛋白, 氨基酸, 乳腺细胞, 营养调控

Abstract:

With the development of dairy products,milk protein is an important index to evaluate the nutritional value of milk.Optimizing feed formulation is one of the key tasks to improve the quality and efficiency of dairy cow production.At present,although feeding rumen-protected amino acids is the most direct and efficient way to improve milk protein synthesis of dairy cows,most studies only focus on a single limiting amino acid,ignoring the understanding of amino acid nutritional balance.Amino acid nutrition,as the source and signal substance of milk protein synthesis,affects the absorption and utilization of blood amino acids by cows,but its molecular mechanisms is still unclear.Therefore,this article mainly analyzed the effects and regulation of amino acids on protein synthesis in dairy cows.Firstly,it described the basic pathway of milk protein synthesis and the influence of essential amino acids,non-essential amino acids and combined essential amino acids on milk protein yield and concentration.Secondly,it introduced the impact of the supply of essential amino acids and combined essential amino acids on feed intake,blood amino acid concentration,blood flow and mammary gland cells of dairy cows,while emphasizing the optimal supplemental dose of amino acids required for mammary gland cell culture and the specific regulation of essential amino acids on amino acid transporters and signaling pathways in cellular molecular angle.In summary,through the discussion of the factors and molecular regulation mechanism of mammary gland protein synthesis,it can not only help to optimize the ideal amino acid ratio in feed and scientific production mode,but also provide theoretical reference for improving the synthesis of milk protein by amino acid nutrition in related filed.

Key words: Dairy cow, Milk protein, Amino acids, Mammary gland cells, Nutritional regulation