Glycine is a nutritionally essential amino acid for maximal growth of milk-fed young pigs
Glycine is a nutritionally essential amino acid for maximal growth of milk-fed young pigs
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DOI：
10.1007/s00726-014-1758-3
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发表时间：
2014-08-01
期刊：
影响因子：
3.5
通讯作者：
Wu, Guoyao
中科院分区：
文献类型：
--
作者：
Wang, Weiwei;Dai, Zhaolai;Wu, Guoyao
牛奶蛋白质中的氨基酸分析显示，甘氨酸的含量相对较低。本研究在仔猪中进行，以验证母乳喂养的新生儿需要在饲粮中添加甘氨酸以达到最大生长的假设。14日龄仔猪随机分为4组处理（15头/组），分别在液态奶替代品中添加0、0.5、1或2%的甘氨酸（干物质基础）。每8 h饲喂一次（3次/天），连续饲喂2周。泌乳量（32.0 ~ 32.5 g干物质/kg体重/天）在对照组和添加甘氨酸的仔猪之间无显著差异。与对照仔猪相比，饲粮中添加0.5%、1%和2%甘氨酸可显著提高血浆中甘氨酸和丝氨酸浓度（P < 0.05）、日增重和体重（P < 0.05），但不影响体组成，同时可显著降低血浆中氨、尿素和谷氨酰胺浓度（P < 0.05），且呈剂量依赖性。饲粮中添加0.5%、1%和2%甘氨酸可提高（P < 0.05）小肠绒毛高度、甘氨酸转运（ususing chambers测量）、GLYT1 mRNA水平和抗氧化能力（表现为还原性谷胱甘肽浓度升高、氧化谷胱甘肽/还原性谷胱甘肽比例降低）。这些新结果首次表明，甘氨酸是奶饲仔猪最大蛋白质增加的营养必需氨基酸。这些发现不仅提高了对蛋白质营养的理解，而且对设计更好的配方奶粉来喂养人类婴儿，特别是低出生体重婴儿和早产儿具有重要意义。
Analysis of amino acids in milk protein reveals a relatively low content of glycine. This study was conducted with young pigs to test the hypothesis that milk-fed neonates require dietary glycine supplementation for maximal growth. Fourteen-day-old piglets were allotted randomly into one of four treatments (15 piglets/treatment), representing supplementation with 0, 0.5, 1 or 2 % glycine (dry matter basis) to a liquid milk replacer. Food was provided to piglets every 8 h (3 times/day) for 2 weeks. Milk intake (32.0-32.5 g dry matter/kg body weight per day) did not differ between control and glycine-supplemented piglets. Compared with control piglets, dietary supplementation with 0.5, 1 and 2 % glycine increased (P < 0.05) plasma concentrations of glycine and serine, daily weight gain, and body weight without affecting body composition, while reducing plasma concentrations of ammonia, urea, and glutamine, in a dose-dependent manner. Dietary supplementation with 0.5, 1 and 2 % glycine enhanced (P < 0.05) small-intestinal villus height, glycine transport (measured using Ussing chambers), mRNA levels for GLYT1, and anti-oxidative capacity (indicated by increased concentrations of reduced glutathione and a decreased ratio of oxidized glutathione to reduced glutathione). These novel results indicate, for the first time, that glycine is a nutritionally essential amino acid for maximal protein accretion in milk-fed piglets. The findings not only enhance understanding of protein nutrition, but also have important implications for designing improved formulas to feed human infants, particularly low birth weight and preterm infants.