Vázquez-Añón M, Kratzer D, González-Esquerra R, Yi I G, Knight C D
E-SCI, Olivet, MI 49076, USA.
Poult Sci. 2006 Apr;85(4):693-705. doi: 10.1093/ps/85.4.693.
The purpose of this paper was to compile all available literature comparing the relative performance of 2-hydroxy-4-methylthio butanoic acid (HMTBA) with DL-methionine (DLM) in broiler chickens and using multiple regression techniques, to estimate the predicted dose responses and relative performance of the 2 Met compounds for gain and feed conversion (FC). A database was developed that contained all available broiler studies in which HMTBA and DLM were both present in the same study; weight gain was recorded; Met addition, age of birds, and duration of study were defined; and an unsupplemented control treatment was present. Sixty-two references complied with these criteria and included 100 experiments with 427 observations for HMTBA and 411 for DLM. Multiple regression analysis of the database was used to identify the experimental and dietary conditions that contributed to the gain and FC responses of each source of Met activity. All identified variables contributed similarly to each Met source prediction model and both gain and FC models described a quadratic dose response. Under the average conditions of the database, the predicted responses for gain and FC models did not significantly differ between HMTBA and DLM. However, a trend was observed (P < or = 0.1) for the peak gain response for HMTBA to be numerically greater than DLM, suggesting benefits of HMTBA over DLM in the region of supplementation that is commercially relevant. The experimental and nutritional conditions that contribute to the response to HTMBA and DLM were identified and are discussed in the paper. This statistical approach provided a means to summarize the results obtained from a multitude of studies conducted over the last 5 decades and has provided a meaningful estimate of the relative performance of the 2 sources of Met activity. The lack of differences between the 2 predicted models under experimental and commercial conditions supports an overall conclusion of equal performance of DLM and HTMBA when compared on an equal molar basis.
本文旨在汇总所有比较2-羟基-4-甲硫基丁酸（HMTBA）与DL-蛋氨酸（DLM）在肉鸡中相对性能的现有文献，并使用多元回归技术来估计这两种蛋氨酸化合物在增重和饲料转化率（FC）方面的预测剂量反应及相对性能。建立了一个数据库，其中包含所有HMTBA和DLM同时存在于同一研究中的肉鸡研究；记录了体重增加情况；确定了蛋氨酸添加量、鸡的年龄和研究持续时间；并且存在未补充的对照处理。62篇参考文献符合这些标准，包括100项实验，其中有427个HMTBA观测值和411个DLM观测值。对该数据库进行多元回归分析，以确定有助于每种蛋氨酸活性来源的增重和饲料转化率反应的实验和日粮条件。所有确定的变量对每个蛋氨酸来源预测模型的贡献相似，增重和饲料转化率模型均描述了二次剂量反应。在数据库的平均条件下，HMTBA和DLM在增重和饲料转化率模型的预测反应上没有显著差异。然而，观察到一种趋势（P≤0.1），即HMTBA的峰值增重反应在数值上大于DLM，这表明在商业相关的补充区域中，HMTBA比DLM更具优势。本文确定并讨论了有助于对HMTBA和DLM产生反应的实验和营养条件。这种统计方法提供了一种手段来总结过去50年中进行的大量研究的结果，并对两种蛋氨酸活性来源的相对性能提供了有意义的估计。在实验和商业条件下，两个预测模型之间缺乏差异支持了在等摩尔基础上比较时，DLM和HMTBA性能相当的总体结论。
