Estimating ruminal crude protein degradation with in situ and chemical fractionation procedures
Estimating ruminal crude protein degradation with in situ and chemical fractionation procedures
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DOI：
10.1016/s0377-8401(00)00146-2
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发表时间：
2000-06-30
影响因子：
3.2
通讯作者：
Susenbeth, A
中科院分区：
文献类型：
--
作者：
Shannak, S;Südekum, KH;Susenbeth, A
本研究的目的是利用康奈尔净碳水化合物和蛋白质系统 (CNCPS) 的饲料粗蛋白 (CP) 分级作为估计原位试验中获得的饲料的未降解膳食蛋白质 (UDP) 值的基础。此外，实验还比较了饲料的原位 UDP 值和根据蛋白质分散性指数估计的 CP 溶解度。将 11 种乳制品配合饲料和 21 种饲料放入聚酯袋中，并在三头公牛的瘤胃中孵育。假定瘤胃通过率分别为2% h(-1)、5% h(-1) 和8% h(-1) 时，原位UDP 值的范围分别为63 至616、129 至785 和167 至842 g kg(-1) CP。当从数据集中排除鱼粉数据 (n=2) 时，基于 CP 和细胞壁浓度以及 CNCPS 分级方案的 A、B 和 C 部分的多元回归方程分别解释了假设瘤胃通过率为 2%、5% 和 8% h(-1) 时 UDP 值变化的 87%、93% 和 94%。我们得出的结论是，原位 UDP 值是许多奶牛蛋白质评估系统中的一个关键变量，可以根据 CNCPS 通过饲料 CP 的化学分级来可靠且准确地预测。在假设的瘤胃通过率分别为2%、5%和8%h(-1)时，根据蛋白质分散性指数估算UDP值的确定系数仅为0.30、0.29和0.33。因此，蛋白质分散性指数也不适合作为本研究中使用的饲料的 UDP 值的预测因子。 (C) 2000 Elsevier Science B.V. 保留所有权利。
The objective of this study was to utilize the fractionation of feed crude protein (CP) of the Cornell net carbohydrate and protein system (CNCPS) as a basis for estimating undegraded dietary protein (UDP) values of feedstuffs obtained from in situ trials. In addition, the experiments comprised a comparison between in situ UDP values of feedstuffs and CP solubility estimated from the protein dispersibility index. Eleven dairy compound feeds and 21 feedstuffs were inserted in polyester bags and incubated in the rumen of three steers. Values for in situ UDP at assumed ruminal passage rates of 2, 5, and 8% h(-1), respectively, ranged from 63 to 616, 129 to 785, and 167 to 842 g kg(-1) of CP. When fish meal data (n=2) were excluded from the data set, multiple regression equations that were based on concentrations of CP and cell wall, and on the A, B, and C fractions of the CNCPS fractionation schedule, explained 87, 93, and 94%, respectively, of the variation in UDP values at assumed ruminal passage rates of 2, 5, and 8% h(-1). We conclude that in situ UDP values, which serve as one key variable in many protein evaluation systems for dairy cattle, may be reliably and accurately predicted from chemical fractionation of feed CP according to the CNCPS. The coefficients of determination of estimating UDP values at assumed ruminal passage rates of 2, 5, and 8% h(-1), respectively, from the protein dispersibility index were only 0.30, 0.29, and 0.33. Hence, the protein dispersibility index was nor suitable as a predictor of UDP values for the feedstuffs used in the present study. (C) 2000 Elsevier Science B.V. All rights reserved.