Cieslak D G, Benevenga N J
J Nutr. 1984 Oct;114(10):1871-7. doi: 10.1093/jn/114.10.1871.
A threonine-deficient amino acid mixture was developed by decreasing the level of threonine in a well-balanced amino acid mixture while measuring the response in daily gain and protein retention in young growing rats. The diet that contained the highest level of threonine and yet permitted further responses in growth and protein retention was used to define a threonine-deficient amino acid mixture. This mixture was used to provide three dietary levels of threonine (0.38, 0.43 or 0.48%) in combination with three levels of relative excess of all other amino acids (0, 25 or 50% relative excess). Food intake, weight gain and changes in carcass composition were measured in the 21-day study. When voluntary food intake is used as a covariate in the analysis of these data, the level of the threonine-deficient amino acid mixture is positively correlated with body weight, dry matter, crude protein and ash gains and negatively associated with lipid deposition. However, there were no significant effects of amino acid excess on any of the responses when differences in voluntary food intake are accounted for in the statistical analysis. These data demonstrate that some aspects of threonine imbalance (food intake and lipid deposition) are dependent on the dietary level of threonine. The major effects of threonine imbalance are due to decreased voluntary food intake rather than changes in the efficiency of use of ingested threonine.
通过降低均衡氨基酸混合物中的苏氨酸水平，同时测量幼龄生长大鼠的日增重和蛋白质潴留反应，开发了一种缺乏苏氨酸的氨基酸混合物。含有最高水平苏氨酸且仍能使生长和蛋白质潴留产生进一步反应的日粮被用于定义一种缺乏苏氨酸的氨基酸混合物。该混合物用于提供三种日粮水平的苏氨酸（0.38%、0.43%或0.48%），并与三种水平的所有其他氨基酸相对过量（相对过量0%、25%或50%）相结合。在为期21天的研究中测量了食物摄入量、体重增加和胴体组成变化。当在这些数据的分析中使用自愿食物摄入量作为协变量时，缺乏苏氨酸的氨基酸混合物水平与体重、干物质、粗蛋白和灰分增加呈正相关，与脂质沉积呈负相关。然而，当在统计分析中考虑自愿食物摄入量的差异时，氨基酸过量对任何反应均无显著影响。这些数据表明，苏氨酸失衡的某些方面（食物摄入量和脂质沉积）取决于日粮中的苏氨酸水平。苏氨酸失衡的主要影响是由于自愿食物摄入量减少，而不是摄入苏氨酸的利用效率变化。
