常用饲料的组成差异及其瘤胃降解特性的研究

Study on Compositions and Rumen Degradability Characteristics of Common Feeds in Beef Cattle

本研究采用常规分析法、康奈尔净碳水化合物一蛋白质体系（CNCPS）和尼龙袋降解法研究常用能量饲料（玉米、稻谷、麦麸、米糠）和蛋白质饲料（豆粕、棉籽粕、菜籽粕）的组成差异以及有机物和蛋白质在肉牛瘤胃中的降解特性。结果表明：能量饲料中谷物籽实类饲料（玉米、稻谷）的非结构性碳水化舍物（NSC）、糖类（CA）及淀粉和果胶（CBl）的含量均显著高于糠麸类饲料（麦麸、米糠），中性洗涤纤维（NDF）和可利用纤维（CB2）的含量则低于糠麸类饲料（P〈0．05），且谷物籽实类饲料的非蛋白氮（PA）含量比糠麸类饲料低12％～17％（P〈0．05）；3种蛋白质饲料中菜粕的蛋白质快速降解（PA）和不可降解蛋白质（PC）含量均最高，真蛋白（PB）含量最低，而豆粕和棉粕的各蛋白组分含量差异均不显著（P〉0．05），但豆粕的CA和CBl分别高出棉粕13％和14％（P〈0．05），且其不可利用纤维（CC）含量显著低于棉粕（P〈0．05）；谷物籽实类饲料在瘤胃内的有机物（0M）和粗蛋白（CP）的慢速降解部分（b）和潜在降解部分（a＋b）均显著地高于糠麸类饲料（P〈0．05），蛋白饲料中豆粕的0M和CP的有效降解率均最高。由此可见，能量饲料和蛋白饲料中分别以玉米和豆粕的营养组成最优；不同类型的饲料原料在瘤胃内的降解特性与其可利用性的养分组成有关。

This study was conducted to investigate the compositions and the degradation characteristics of organic matter （OM） and protein in tureen by proximate analysis and Cornell net Carbohydrate and Protein System （CNCPS） analysis and nylon bag method. The results showed that the level of non-structural carbohydrate （NSC）, sugar （CA）, starch, pectin（CB1） in cereal grains feedstuffs were higher than those in bran feeds （P〈0.05）. However, neutral detergent fiber （NDF） and available fiber （CB2） levels were significantly lower （P〈O.05） than that in bran feeds. The content of non- protein nitrogen （PA） in cereal grains was lower about 12%~17% than that in bran feeds （P〈O.05） . The rapeseed meal had the highest non-protein nitrogen （PA） and bound protein （PC）, while the lowest true protein （PB） in the three protein feeds. The various protein fractions were not significantly different （P〉0.05） between the soybean meal and the cottonseed meal, but the content of CA and CB1 in soybean meal were higher about 13% and 14% （P〈0.05） than those of cottonseed meal, the unavailable fiber （CC） of soybean meal was significantly lower than that of cottonseed meal （P〈O.05）. The rapid degradation and potential degradation of OM and CP in the rumen of cereal grain feeds were significantly higher than bran diets （P〈O.05）. The effective degradability of OM and CP in rumen of soybean meal feed was the highest. Thus, the corn and soybean meal compositions, and the degradation characteristics in components availability. in the energy feeds and protein feeds had the most optimal the rumen of different types of feedstuffs were related to the