Buse K K, Morris D L, Diaz H L, Drehmel O R, Kononoff P J
Department of Animal Science, University of Nebraska-Lincoln, Lincoln 68503.
Milk Specialties Global, Eden Prairie, MN 55344.
JDS Commun. 2022 Feb 10;3(2):101-105. doi: 10.3168/jdsc.2021-0139. eCollection 2022 Mar.
Hydrolyzed feather meal (HFM) is a feedstuff high in rumen undegraded protein (RUP) that can be used as an effective source of metabolizable protein for dairy cattle. Because the production process may vary, the rumen degradability and intestinal digestibility of HFM may also vary. Additionally, some processes may incorporate additional blood into the final product to result in feather meal with poultry blood. To determine the rumen degradability and intestinal digestibility of these products, several laboratory assays can be used; the common assays are the mobile bag (MOB), modified three-step (MTS), and Ross (ROS) assays. Although all 3 assays determine RUP digestibility, they vary in whether they are performed in situ, in vitro, or both. The objective of this study was to evaluate the ruminal degradability and intestinal digestibility of HFM originating from processes that differ in their inclusion of blood, and to compare the MOB, MTS, and ROS assays. Ten samples of HFM, which were identified by the suppliers as HFM with little blood (n = 5) and with more blood (n = 5), were spot-sampled, collected from 10 production plants across the United States, and subjected to all 3 assays. Assay type had an effect on RUP, total-tract crude protein (CP) digestibility, and the amount of RUP digested. A significant effect was observed on RDP and RUP concentrations for blood inclusion; no effect was detected for total-tract CP digestibility. We found no difference in RUP digestibility for assay or blood inclusion. There was also no interaction of the effect of assay or blood inclusion. Results suggest that even though there are differences in chemical composition in HFM associated with the inclusion of blood, such as ash and crude fat, few if any differences are observed in intestinal digestion of protein. Although the assays varied in their estimates of rumen undegraded protein, MOB and MTS yielded the most similar values. However, all 3 assays resulted in similar estimates of RUP digestibility.
水解羽毛粉（HFM）是一种瘤胃未降解蛋白（RUP）含量较高的饲料，可作为奶牛可代谢蛋白的有效来源。由于生产工艺可能不同，HFM的瘤胃降解率和肠道消化率也可能有所差异。此外，一些工艺可能会在最终产品中掺入额外的血液，从而生产出血液含量不同的羽毛粉。为了测定这些产品的瘤胃降解率和肠道消化率，可以使用几种实验室检测方法；常见的检测方法有移动袋法（MOB）、改良三步法（MTS）和罗斯法（ROS）。尽管这三种检测方法都能测定RUP的消化率，但它们在是原位检测、体外检测还是两者兼用方面存在差异。本研究的目的是评估来自不同血液掺入量生产工艺的HFM的瘤胃降解率和肠道消化率，并比较MOB、MTS和ROS检测方法。从美国各地的10家生产厂随机抽取了10个HFM样本，供应商将其鉴定为低血含量（n = 5）和高血含量（n = 5）的HFM，并对所有样本进行了这三种检测。检测类型对RUP、全肠道粗蛋白（CP）消化率以及消化的RUP量有影响。观察到血液掺入对RDP和RUP浓度有显著影响；未检测到对全肠道CP消化率有影响。我们发现检测方法或血液掺入量对RUP消化率没有差异。检测方法或血液掺入量的影响也没有相互作用。结果表明，尽管与血液掺入相关的HFM化学成分存在差异，如灰分和粗脂肪，但在蛋白质的肠道消化方面几乎没有观察到差异。尽管这三种检测方法对瘤胃未降解蛋白的估计有所不同，但MOB和MTS得出的值最为相似。然而，所有三种检测方法对RUP消化率的估计结果相似。
