The present study evaluated production performance responses to Ile supplementation in laying hens fed low crude protein (LCP), amino acid (AA) balanced diets. A total of 179 Shaver white pullets were distributed into 30 battery cages (6 birds/cage, n = 6) and observed over the course of 27 wk in a 2-phase (20 to 27 and 28 to 46 wk of age) feeding program. Five isocaloric diets were formulated for standardized ileal digestible (SID) Lys intake of 750 and 710 mg/D in phase 1 and 2, respectively, and included a positive control with standard levels of crude protein (CP) (CON; 18 and 16% CP for phases 1 and 2), and 4 LCP diets (16 and 14% CP for phase 1 and 2, respectively) with graded levels of Ile to satisfy SID Ile:Lys ratios of 70 (Ile70), 80 (Ile80), 90 (Ile90), and 100% (Ile100). Based on analyzed dietary AA, the calculated SID Ile:Lys of LCP diets were 75, 84, 88, 99% and 66, 72, 82, 95% for phase 1 and 2, respectively. Dietary treatments significantly (P < 0.05) affected feed intake, hen-day egg production (HDEP), egg weight (EW), feed conversion ratio, and egg quality (Haugh unit) and composition (yolk to albumen). Lowering dietary CP negatively affected HDEP with a 3.3 and 1.5% reduction in phase 1 and 2, respectively, and this was restored with the addition of Ile (P < 0.001) suggesting that Ile was limiting in the LCP basal diet. Average EW was reduced in Ile100 only; however, the Ile:Lys appeared to influence egg size uniformity, with Ile90 producing a greater proportion of large (56 g ≤ EW > 63 g) eggs, suggesting that Ile may be used to manipulate EW at the expense of HDEP. Overall, the results indicated that CP in laying hen diets can be reduced by 2% units if fortified with synthetic AA (Met, Lys, Thr, Trp) + Ile, with optimal responses observed between 82 and 88% SID Ile:Lys.

中文翻译：

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剃须刀白母鸡的鸡蛋产量和质量对增加异亮氨酸补充的反应是在20至46周龄之间添加了合成氨基酸的低粗蛋白玉米豆粕日粮。

本研究评估了饲喂低粗蛋白（LCP），氨基酸（AA）均衡饮食的蛋鸡对Ile补充的生产性能响应。将总共​​179个剃须刀白色小母鸡分配到30个电池笼中（每笼6只鸟，n = 6），并在2周（20至27周龄和28至46周龄）饲喂程序中观察27周。配制了五种等热量日粮，分别在第1和第2阶段对标准化回肠易消化（SID）Lys摄入量分别为750和710 mg / D，其中包括阳性对照和标准水平的粗蛋白（CP）（CON； 18％和16％阶段1和2的CP，以及4种LCP饮食（阶段1和2的CP分别为16％和14％），其Ile分级水平满足SID Ile：Lys比率为70（Ile70），80（Ile80），90 （Ile90）和100％（Ile100）。根据分析的饮食AA，计算出的SID Ile：第一阶段和第二阶段的LCP饮食的Lys分别为75、84、88、99％和66、72、82、95％。饮食处理（P <0.05）显着影响采食量，日产蛋量（HDEP），蛋重（EW），饲料转化率，蛋品质（Haugh单位）和组成（蛋黄至蛋白）。降低饮食中的CP对HDEP产生负面影响，第一阶段和第二阶段分别降低3.3％和1.5％，添加Ile可以恢复HDEP（P <0.001），表明Ile在LCP基础饮食中是有限的。平均EW仅在Ile100中降低；但是，Ile：Lys似乎会影响蛋的大小均匀性，Ile90会产生更大比例的大蛋（56 g≤EW> 63 g），这表明Ile可以用来以牺牲HDEP的代价来操纵EW。总体，