不同水平的奎那酸单宁对以苜蓿（Medicago sativa）干草为单一日粮的沙特努比亚羊氮利用和生长性能的影响。

Effect of different levels of Quebracho tannin on nitrogen utilization and growth performance of Najdi sheep fed alfalfa (Medicago sativa) hay as a sole diet.

机构信息

Department of Animal Production and Breeding, Faculty of Agriculture and Veterinary Medicine, Qassim University, Buriedah, Saudi Arabia.

出版信息

Anim Sci J. 2009 Oct;80(5):532-41. doi: 10.1111/j.1740-0929.2009.00662.x.

DOI:10.1111/j.1740-0929.2009.00662.x

PMID:20163617

Abstract

A commercial tannin source (Quebracho tannin, QT), containing 75% condensed tannins (CT) in dry matter (DM) was used to evaluate the effects of addition of different levels of QT to alfalfa hay on the in vitro degradation kinetics of organic matter (OM) and nitrogen (N) in experiment 1 (Exp. 1), N utilization and microbial N synthesis (MNS) in experiment 2 (Exp. 2) and growth performance of growing Najdi lambs in experiment 3 (Exp. 3). Alfalfa hay was treated with QT at the levels of 0, 1, 2 and 3% of DM to form four treatments of QT0, QT1, QT2 and QT3 to have actual levels of CT being 0, 0.75, 1.5 and 2.25% of DM, respectively. Degradation rate and the effective degradability of N were significantly decreased (P < 0.05) for QT2 and QT3 as compared with the QT0. In Exp. 2, digestibility coefficients for OM, neutral detergent fiber and acid detergent fiber were significantly decreased (P < 0.05) at QT3, whereas QT1 and QT2 showed no difference to QT0. In the metabolism trial (Exp. 2), digested N (DN) and urinary N (UN) excretion for QT2 and QT3 were significantly decreased (P < 0.05) compared to QT0 and QT1. The DN and UN as percentage of N intake were 79.2, 76.9, 75.5 and 69.8%; and 24.4, 22.6, 19.9 and 19.6% for QT0, QT1, QT2 and QT3, respectively. QT2 had the highest MNS and the lowest value was in QT3, the MNS of the treatments were 18.1, 18.7, 19.2 and 15.8 g/day for QT0, QT1, QT2 and QT3, respectively. In the growth trial of 56 days duration (Exp. 3, n = 24 lambs), the addition of QT at the level of QT2 enhanced (P < 0.05) the average daily gain and feed conversion rate compared with the QT0, while, QT1 and QT3 had intermediate values. It is concluded that alfalfa hay treated with QT at the level of 2% of DM could be used to protect alfalfa N from ruminal degradation that would lead to improve growth performance of lambs.

摘要

一种商业单宁源（Quebracho 单宁，QT），干物质（DM）中含有 75%的浓缩单宁（CT），用于评估在苜蓿干草中添加不同水平的 QT 对有机物（OM）和氮（N）的体外降解动力学的影响。在实验 1（Exp.1）中，在实验 2（Exp.2）中氮利用和微生物氮合成（MNS）以及生长 Najdi 羔羊的生长性能。苜蓿干草用 QT 处理，DM 水平分别为 0、1、2 和 3%，形成 QT0、QT1、QT2 和 QT3 四个处理，实际 CT 水平分别为 DM 的 0、0.75、1.5 和 2.25%。与 QT0 相比，QT2 和 QT3 的降解率和有效降解氮显著降低（P<0.05）。在实验 2 中，OM、中性洗涤剂纤维和酸性洗涤剂纤维的消化系数在 QT3 时显著降低（P<0.05），而 QT1 和 QT2 与 QT0 没有差异。在代谢试验（Exp.2）中，与 QT0 和 QT1 相比，QT2 和 QT3 的消化氮（DN）和尿氮（UN）排泄显著降低（P<0.05）。DN 和 UN 占氮摄入量的百分比分别为 79.2%、76.9%、75.5%和 69.8%；QT0、QT1、QT2 和 QT3 分别为 24.4%、22.6%、19.9%和 19.6%。QT2 的 MNS 最高，QT3 的最低，处理的 MNS 分别为 18.1、18.7、19.2 和 15.8 g/d 用于 QT0、QT1、QT2 和 QT3。在为期 56 天的生长试验（Exp.3，n=24 只羔羊）中，与 QT0 相比，DM 水平为 2%的 QT 添加水平可提高（P<0.05）平均日增重和饲料转化率，而 QT1 和 QT3 则处于中间值。综上所述，在苜蓿干草中添加 2%DM 的 QT 可防止苜蓿氮在瘤胃中降解，从而提高羔羊的生长性能。