Animal Science Department, Faculty of Agriculture, University of Zabol, Iran 98661-5538.
Poult Sci. 2012 Mar;91(3):771-7. doi: 10.3382/ps.2011-01818.
In a dose-response study, dietary levels of standardized ileal digestible methionine (dMet), lysine (dLys), and threonine (dThr) were optimized by response surface methodology (RSM) using a central composite rotatable design in starting broiler chicks that were feed-deprived 2 d posthatch. In total, 60 floor pens of 6 birds each were assigned to 15 diets of central composite rotatable design containing 5 levels of dMet (0.42-0.58%), dLys (0.88-1.32%), and dThr (0.53-0.87%) from 3 to 16 d of age. Experimental levels of dMet, dLys, and dThr significantly affected bird performance. The second-order models for BW gain and feed conversion ratio (FCR) were generated. The response surface analysis showed significant quadratic models for BW gain and FCR. The crossproduct of amino acids was significant for FCR but not significant for BW gain. Canonical analyses on BW gain and FCR models showed that the maximum BW gain at the stationary point may be obtained with 0.54, 1.12, and 0.78% of dMet, dLys, and dThr in the diet, respectively, and the minimum FCR at the stationary point may be obtained with 0.53, 1.13, and 0.75% of dMet, dLys, and dThr in diet, respectively. Estimated ideal ratios of dMet and dThr to dLys were 48 and 70% for BW gain and 47 and 66% for FCR. Canonical analysis revealed the most important amino acids in the models of BW gain and FCR were Lys and Thr, respectively.
在一项剂量反应研究中，采用响应面法（RSM）通过中心组合旋转设计，对饲粮中标准化回肠可消化蛋氨酸（dMet）、赖氨酸（dLys）和苏氨酸（dThr）的水平进行优化，该研究使用的是刚孵出后 2 天即被断料的雏鸡。共设置 60 个 6 只鸡/栏的地板饲养笼，每个饲养笼分配到含有 5 种水平 dMet（0.42-0.58%）、dLys（0.88-1.32%）和 dThr（0.53-0.87%）的中心组合旋转设计的 15 种饲粮中，从 3 日龄到 16 日龄进行试验。试验饲粮中 dMet、dLys 和 dThr 的水平显著影响了鸡的生产性能。生成了体重增长和饲料转化率（FCR）的二阶模型。响应面分析表明，体重增长和 FCR 存在显著的二次模型。氨基酸的互作效应对 FCR 有显著影响，但对体重增长没有显著影响。对体重增长和 FCR 模型的典型分析表明，在稳定点时，获得最大体重增长的最佳饲粮中 dMet、dLys 和 dThr 水平可能分别为 0.54%、1.12%和 0.78%，而获得最小 FCR 的最佳饲粮中 dMet、dLys 和 dThr 水平可能分别为 0.53%、1.13%和 0.75%。估计的 dMet 和 dThr 对 dLys 的理想比值分别为体重增长的 48%和 70%，以及 FCR 的 47%和 66%。典型分析揭示了在体重增长和 FCR 模型中最重要的氨基酸分别为 Lys 和 Thr。
