Previous research within our laboratory determined the optimal male Ross 708 dIle:dLys ratio for the starter phase to be greater than recent breeder recommendations (70 vs. 67%). Thus, the current objective was to assess the subsequent growth phase (grower) in order to evaluate the optimal dIle:dLys ratio for maximized growth performance of Ross 708 × Ross YP male broilers. On d of hatch, 2,400 chicks were equally allocated to 96 pens and fed a common starter diet. On d 14, pen weights were equalized by block (12 replications/treatments). Experimental grower diets (d 14–28) were created from a common Deficient (53% dIle:dLys) corn and soybean meal-based diet. After batching, half of the Deficient diet was used to create the Summit diet (83% dIle:dLys). The remaining 5 experimental diets ranged from 58 to 78% dIle:dLys and were blended proportions of the Deficient and Summit diets. A practical control diet (PRAC-CON; 68% dIle:dLys) was manufactured separately to verify the blended control diet (BLEND-CON; 68% dIle:dLys). All dIle:dLys ratios were estimated using quadratic regression (QR; 95% of the asymptote), as well as linear and quadratic broken line models (LBL; QBL). Based on the current data and using multiple regression models the estimated ratios ranged from 62 to 68% for BW and BWG, and 67-70% for FCR and are similar to the current breeder nutrient specifications for the grower phase. Further research should evaluate dIle:dLys requirements of male Ross 708 × Ross YP broilers during the remaining grow-out phases.

我们实验室之前的研究确定了起始阶段的最佳雄性 Ross 708 dIle:dLys 比率高于最近的饲养员建议（70% 对 67%）。因此，当前的目标是评估随后的生长阶段（肉鸡），以评估最佳 dIle:dLys 比率，以实现 Ross 708 × Ross YP 雄性肉鸡的最大生长性能。在孵化日，2,400 只雏鸡被平均分配到 96 个围栏并喂食共同的起始日粮。在第 14 天，通过块（12 次重复/处理）平衡栏重量。实验性种植者日粮（第 14-28 天）由常见的缺乏（53% dIle:dLys）玉米和豆粕为基础的日粮制成。分批后，一半的缺陷日粮用于制作 Summit 日粮（83% dIle:dLys）。其余 5 种实​​验日粮的 dIle 介于 58% 至 78% 之间：dLys 和 Deficient 和 Summit 饮食的混合比例。实用的控制饮食（PRAC-CON ; 单独生产 68% dIle:dLys) 以验证混合对照饮食 ( BLEND-CON ; 68% dIle:dLys)。所有 dIle:dLys 比率均使用二次回归（QR；渐近线的 95%）以及线性和二次折线模型（LBL；QBL）估计。根据当前数据并使用多元回归模型，BW 和 BWG 的估计比率范围为 62% 至 68%，FCR 的估计比率为 67-70%，与当前育种阶段的育种营养规格相似。进一步的研究应该评估雄性 Ross 708 × Ross YP 肉鸡在剩余养成阶段的 dIle:dLys 要求。