Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada T6G 2P5.
Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada T6G 2P5; Department of Animal Sciences, Animal Nutrition Group, Wageningen University, Wageningen, The Netherlands (6700 AH).
Poult Sci. 2022 Jan;101(1):101518. doi: 10.1016/j.psj.2021.101518. Epub 2021 Oct 10.
A robust model that estimates the ME intake over broiler breeder lifetime is essential for formulating diets with optimum nutrient levels. The experiment was conducted as a randomized controlled trial with 40 Ross 708 broiler breeder pullets reared on 1 of 10 target growth trajectories, which were designed with 2 levels of cumulative BW gain in prepubertal growth phase and 5 levels of timing of growth around puberty. This study investigated the effect of growth pattern on energy efficiency of birds and tested the effects of dividing data into daily, 4-d, weekly, 2-wk, and 3-wk periods and the inclusion of random terms associated with individual maintenance ME and ADG requirements, and age on ME partitioning model fit and predictive performance. Model [I] was: MEI = a × BW + c × ADG + d × ADG + e × EM + ε, where MEI was daily ME intake (kcal/d); BW in kg; ADG was positive ADG; ADG was negative ADG (g/d); EM was egg mass (g/d); ε was the model residual. Models [II to IV] were nonlinear mixed models based on the model [I] with inclusion of a random term for individual maintenance requirement, age, and ADG, respectively. Model [II] - 3 wk was chosen as the most parsimonious based on lower autocorrelation bias, closer fit of the estimates to the actual data (lower model MSE and closer R to 1), and greater predictive performance among the models. Estimated ME partitioned to maintenance in model [II] - 3 wk was 100.47 ± 7.43 kcal/kg, and the ME requirement for ADG, ADG, and EM were 3.49 ± 0.37; 3.16 ± 3.91; and 2.96 ± 0.13 kcal/g, respectively. Standard treatment had lower residual heat production (RHP; -0.68 kcal/kg BW) than high early growth treatment (0.79 kcal/kg BW), indicating greater efficiency in utilizing the ME consumed. Including random term associated with individual maintenance ME in a 3-wk chunk size provided a robust, biologically sound life-time energy partitioning model for breeders.
需要建立一个稳健的模型来估计肉鸡种鸡一生中的 ME 摄入量，以制定具有最佳营养水平的日粮。该试验采用随机对照试验设计，选择 40 只 Ross 708 肉鸡种母鸡，在 10 种目标生长轨迹中的 1 种条件下饲养，这些轨迹设计了 2 个预生殖生长阶段的累积 BW 增益水平和 5 个青春期生长时间水平。本研究探讨了生长模式对鸟类能量效率的影响，并测试了将数据分为每日、4 天、每周、2 周和 3 周期以及包括与个体维持 ME 和 ADG 需求相关的随机项和年龄对 ME 分配模型拟合和预测性能的影响。模型 [I] 为：MEI = a × BW + c × ADG + d × ADG + e × EM + ε，其中 MEI 为每日 ME 摄入量（kcal/d）；BW 为体重（kg）；ADG 为正 ADG；ADG 为负 ADG（g/d）；EM 为蛋重（g/d）；ε 为模型残差。模型 [II 至 IV] 是基于模型 [I] 的非线性混合模型，分别纳入了个体维持需求、年龄和 ADG 的随机项。基于较低的自相关偏差、估计值与实际数据更接近（模型 MSE 较低，R 更接近 1）以及模型之间更好的预测性能，选择模型 [II] - 3 周作为最简约模型。在模型 [II] - 3 周中，分配给维持的 ME 估计值为 100.47 ± 7.43 kcal/kg，ADG、ADG 和 EM 的 ME 需求分别为 3.49 ± 0.37、3.16 ± 3.91 和 2.96 ± 0.13 kcal/g。标准处理的残余热产生（RHP；-0.68 kcal/kg BW）低于高早期生长处理（0.79 kcal/kg BW），表明在利用消耗的 ME 方面效率更高。在 3 周的时间内纳入与个体维持 ME 相关的随机项，为种鸡提供了一个稳健、合理的终生能量分配模型。
