Department of Animal Sciences, Purdue University, West Lafayette, IN 47907, USA.
J Anim Sci. 2012 Dec;90(12):4414-20. doi: 10.2527/jas.2011-4801. Epub 2012 Sep 5.
Two experiments were conducted to investigate whether the choice of digestibility marker or marker concentration in corn-soybean meal diets influence apparent ileal AA digestibility (AIAAD) or the potential phytase-induced improvement in AIAAD in broiler chickens and pigs. One hundred ninety-two, 42-d-old, Ross 708 broilers were used in a 7-d study in Exp 1. The birds were allocated to 6 dietary treatments in a 2 × 3 factorial arrangement of treatments in a split-plot design. The factors were a combination of chromic oxide and titanium dioxide (0.3% or 0.5% of both markers, as-fed basis), and 3 levels of phytase inclusion [0, 500, or 1,000 phytase units (FTU)/kg]. In Exp. 2, 6 barrows fitted with a simple T-cannula at the distal ileum were allocated to 4 diets in a 6 × 4 Youden square design and 2 × 2 factorial arrangement of treatments. The factors were similar to Exp. 1, except the 500-FTU/kg phytase level was not used in Exp. 2. There were no marker type × marker concentration, phytase × marker type, or phytase × marker type × marker concentration interactions for any of the AA in either experiment. On average, AIAAD values calculated using Ti was greater (P < 0.05) than those calculated using Cr, regardless of the phytase inclusion level in both experiments. In Exp. 1, AIAAD values for His, Trp, Cys, and Pro were greater (P < 0.05) at the 0.3% than 0.5% marker concentration. The AIAAD values were consistently greater when calculated using Ti compared with Cr, irrespective of phytase level. It is concluded that the type of marker used does not influence whether a response to phytase supplementation, in terms of AIAAD, is observed.
进行了两项实验，以研究在玉米-豆粕日粮中选择消化率标记物或标记物浓度是否会影响肉鸡和猪的回肠氨基酸表观消化率（AIAAD）或潜在植酸酶对 AIAAD 的改善。在实验 1 中，使用了 192 只 42 日龄的 Ross 708 肉鸡进行了为期 7 天的研究。鸟类在分割-区组设计的处理 2×3 因子安排中被分配到 6 种日粮处理中。这些因素是氧化铬和二氧化钛的组合（以饲料为基础，0.3%或 0.5%的两种标记物），以及植酸酶添加的 3 个水平[0、500 或 1000 植酸酶单位（FTU）/kg]。在实验 2 中，6 头装有简单 T 型套管的阉公猪被分配到 4 种日粮的 6×4 约登方设计和 2×2 因子处理安排中。这些因素与实验 1 相似，除了实验 2 中没有使用 500-FTU/kg 植酸酶水平。在任何实验中，AA 都没有标记类型×标记浓度、植酸酶×标记类型或植酸酶×标记类型×标记浓度的相互作用。平均而言，使用 Ti 计算的 AIAAD 值大于（P<0.05）使用 Cr 计算的 AIAAD 值，无论两个实验中的植酸酶添加水平如何。在实验 1 中，His、Trp、Cys 和 Pro 的 AIAAD 值在 0.3%标记浓度下大于（P<0.05）0.5%标记浓度。使用 Ti 计算的 AIAAD 值始终大于使用 Cr 计算的值，无论植酸酶水平如何。结论是，所使用的标记物类型不会影响是否观察到植酸酶补充对 AIAAD 的反应。
