Significant differences in the estimation of amino acid requirements exist between the available factorial methods. This study aimed to compare current factorial models used to estimate the individual and population standardised ileal digestible (SID) lysine (Lys) requirements of growing pigs during a 26-day feeding phase. Individual daily feed intake and BW data from 40 high-performance pigs (25-kg initial BW) were smoothed by linear regression. Body weight gain was constant (regression slope not different from 0) for all the pigs. The CV of the SID Lys requirements ranged from 22% at the beginning of the trial to 8% at the end. The population Brazilian tables (BT-2017) and National Research Council (NRC-2012) SID Lys requirements for the average pig were 16% higher than the average requirement estimated by the individual precision-feeding model (IPF), but similar to the estimated for the population assuming that population requirements are those of the 80th-percentile pig of the population (IPF-80). Meaning that, the IPF-80, BT-2017, and NRC-2012 models would yield similar recommendations when pigs are group-fed in conventional multi-phase systems. Additionally, the IPF-80 estimates are independent of the phase length, whereas the BT-2017 and NRC-2012 models use average population values in the middle of the feeding phase for the calculations and therefore, conventional requirement estimations decrease as the length of the feeding phase increases. In conclusion, the BT-2017 and NRC-2012 methods were calibrated for maximum population responses, which explains why these methods yield higher values than those estimated for the average pig by the IPF model. This study shows the limitations of conventional factorial methods to estimate amino acid requirements for precision-feeding systems.

中文翻译：

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当前的析因方法对生长猪的模拟氨基酸需求有所不同。

在可用的析因方法之间，氨基酸需求的估算存在显着差异。这项研究旨在比较当前的析因模型，这些模型用于评估在26天的饲养阶段中生长猪的个体和种群标准化回肠可消化（SID）赖氨酸（Lys）需求。通过线性回归对40头高性能猪（初始体重25公斤）的个体日饲料摄入量和体重数据进行了平滑处理。所有猪的体重增加都是恒定的（回归斜率不等于0）。SID Lys要求的CV从试验开始时的22％到结束时的8％不等。巴西人口表（BT-2017）和国家研究委员会（NRC-2012）的SID Lys对普通猪的需求量比单独精确饲喂模型（IPF）估算的平均需求量高16％，但与估算值相似假设人口需求是人口中第80个猪的需求（IPF-80）。这意味着，在常规多相系统中对猪群喂时，IPF-80，BT-2017和NRC-2012模型将产生类似的建议。此外，IPF-80的估算值与相位长度无关，而BT-2017和NRC-2012模型使用进料阶段中间的平均总体值进行计算，因此，传统的需求估算值随着馈线长度的增加而减小。喂养阶段增加。结论，BT-2017和NRC-2012方法针对最大种群响应进行了校准，这解释了为什么这些方法产生的值要比IPF模型为普通猪估计的值高。这项研究显示了常规因子分析方法在估算精确进料系统氨基酸需求方面的局限性。