Department of Animal Science, Texas A&M University, College Station, Texas, 77843, USA.
J Anim Sci Biotechnol. 2013 Feb 27;4(1):7. doi: 10.1186/2049-1891-4-7.
Protein is quantitatively the most expensive nutrient in swine diets. Hence it is imperative to understand the physiological roles played by amino acids in growth, development, lactation, reproduction, and health of pigs to improve their protein nutrition and reduce the costs of pork production. Due to incomplete knowledge of amino acid biochemistry and nutrition, it was traditionally assumed that neonatal, post-weaning, growing-finishing, and gestating pigs could synthesize sufficient amounts of all "nutritionally nonessential amino acids" (NEAA) to support maximum production performance. Therefore, over the past 50 years, much emphasis has been placed on dietary requirements of nutritionally essential amino acids as building blocks for tissue proteins. However, a large body of literature shows that NEAA, particularly glutamine, glutamate, arginine and proline regulate physiological functions via cell signaling pathways, such as mammalian target of rapamycin, AMP-activated protein kinase, extracellular signal-related kinase, Jun kinase, mitogen-activated protein kinase, and NEAA-derived gaseous molecules (e.g., nitric oxide, carbon monoxide, and hydrogen sulfide). Available evidence shows that under current feeding programs, only 70% and 55% of dietary amino acids are deposited as tissue proteins in 14-day-old sow-reared piglets and in 30-day-old pigs weaned at 21 days of age, respectively. Therefore, there is an urgent need to understand the roles and dietary requirements of NEAA in swine nutrition. This review highlights the basic biochemistry and physiology of absorption and utilization of amino acids in young pigs to enhance the efficacy of utilization of dietary protein and to minimize excretion of nitrogenous wastes from the body.
蛋白质是猪饲料中最昂贵的营养物质。因此，了解氨基酸在生长、发育、泌乳、繁殖和猪健康中的生理作用对于提高其蛋白质营养水平和降低猪肉生产成本至关重要。由于对氨基酸生物化学和营养的不完全了解，传统上认为新生仔猪、断奶后仔猪、生长育肥猪和妊娠母猪能够合成足够数量的所有“营养非必需氨基酸”（NEAA）以支持最大的生产性能。因此，在过去的 50 年中，人们非常重视营养必需氨基酸作为组织蛋白质构建块的膳食需求。然而，大量文献表明，NEAA，特别是谷氨酰胺、谷氨酸、精氨酸和脯氨酸通过细胞信号通路（如哺乳动物雷帕霉素靶蛋白、AMP 激活蛋白激酶、细胞外信号调节激酶、Jun 激酶、丝裂原激活蛋白激酶和 NEAA 衍生的气态分子（如一氧化氮、一氧化碳和硫化氢）来调节生理功能。现有证据表明，在当前的饲养方案下，只有 70%和 55%的日粮氨基酸分别沉积在 14 日龄母猪饲养的仔猪和 21 日龄断奶的 30 日龄仔猪的组织蛋白中。因此，迫切需要了解 NEAA 在猪营养中的作用和膳食需求。本综述强调了幼猪吸收和利用氨基酸的基本生物化学和生理学，以提高日粮蛋白质的利用效率，并最大限度地减少氮废物从体内排出。
