两种酵母对奶牛瘤胃体外发酵特性的影响

本试验旨在初步探究并比较安琪与乐斯福两种不同来源酵母对奶牛瘤胃发酵特性的作用,预测其对奶牛生产性能可能的影响,从而为研究酵母在反刍家畜生产中营养生理调控提供理论依据。采用单因子区组试验设计,两种活性酵母均设置4个添加水平(0、0.025%、0.050%、0.075%),分别以玉米秸秆和水稻秸秆为底物,采集奶牛瘤胃液进行48h的体外发酵试验。结果表明,两种酵母对两种底物体外发酵产气量、产气参数、中性洗涤纤维消失率(NDFD)均无显著影响(P0.05),但提高了玉米秸秆(P0.05)和水稻秸秆(P0.01)的DMD;添加两种酵母对玉米秸秆体外发酵液pH值及NH3-N浓度均没有表现出显著性影响(P0.05),但均显著降低了水稻秸秆体外发酵液pH值及NH3-N浓度(P0.05);乐斯福酵母对两种底物DMD的提高作用均显著高于安琪酵母(P0.05)。通过整体比较可以推断,乐斯福酵母的添加效果要明显优于安琪酵母,且以0.075%为最佳添加水平。

Effects of Two Sources of Active Yeast on in vitro Fermentation Characteristics in Dairy Cows

The objective of this trial was to preliminarily explore and compare the effects of two sources of commercial active yeast additive (Angel Yeast & Lesaffre Yeast) on the characteristics of in vitro fermentation, to predict their potential influences on the production performance of dairy cows, and to provide the regulation of nutrition physiology with theoretical basis. The study was conducted as one-factor block experimental design, and four supplemental levels (0, 0.025%, 0.050%, and 0.075%) were set for each source of active yeast. By employing the method of in vitro fermentation (48 hours), maize straw and rice straw were respectively used as the substrate. The result of this study suggests that the supplementation of active yeast did not exert a significant influence on the GP, indexes of LE model, and NDFD (P>0.05), but it elevated the DMD of maize straw (P<0.05) and rice straw (P<0.01). The supplementation of active yeast exerted a non-significant influence on the pH and NH₃-N of in vitro fermentation of maize straw (P>0.05), but it significantly affected the pH and NH₃-N of in vitro fermentation of rice straw (P<0.05). In the in vitro fermentation of both maize straw and rice straw, the treatment of Lesaffre Yeast significantly raised the DMD compared to the treatment of Angel Yeast (P<0.05). It can be inferred that the effects of Lesaffre Yeast were more desirable than those of Angel Yeast, and the optimum supplemental level of the former was 0.075%.