Department of Dairy and Animal Science, Pennsylvania State University, University Park 16802, USA.
J Dairy Sci. 2010 Feb;93(2):682-92. doi: 10.3168/jds.2009-2379.
The goal of this experiment was to investigate the effect of yeast culture (Saccharomyces cerevisiae) on rumen fermentation, nutrient utilization, and ammonia and methane emission from manure in dairy cows. Eight ruminally cannulated Holstein cows were allocated to 2 dietary treatments in a crossover design. Treatments were control (no yeast culture) and XP (yeast culture, fed at 56 g/head per day; XP, Diamond V Mills Inc., Cedar Rapids, IA). Dry matter intake, milk yield, milk composition, and body weight were similar between treatments. Milk urea nitrogen concentration was also not affected by treatment. Rumen pH was similar between the control and XP treatments, but rumen ammonia concentration tended to be lower with XP than with the control. Treatment had no effect on concentrations of total or individual volatile fatty acids, protozoal counts, polysaccharide-degrading activities (except amylase activity that tended to be increased by XP), or methane production in the rumen. Urinary N losses did not differ significantly between treatments, but allantoin and total purine derivative excretions and the estimated microbial N outflow from the rumen tended to be increased by XP compared with the control treatment. Total-tract apparent digestibility of dietary nutrients was not affected by XP. Milk fatty acid composition was also not altered by XP supplementation. Cumulative (253 h) ammonia and methane emissions from manure, measured in a steady-state gas emission system, were slightly decreased by XP. Overall, the yeast culture tested had little effect on ruminal fermentation, digestibility, or N losses, but tended to reduce rumen ammonia concentration and increase microbial protein synthesis in the rumen, and decreased ammonia and methane emissions from manure.
本实验旨在研究酵母培养物（酿酒酵母）对奶牛瘤胃发酵、养分利用以及粪便中氨和甲烷排放的影响。采用交叉试验设计，将 8 头瘤胃瘘管荷斯坦奶牛分配到 2 种饲粮处理中。处理组为对照组（无酵母培养物）和 XP 组（酵母培养物，每天每头 56 g；XP，Diamond V Mills Inc.，爱荷华州锡达拉皮兹）。两组的干物质采食量、产奶量、乳成分和体重无差异。处理对乳尿素氮浓度也无影响。对照组和 XP 组的瘤胃 pH 相似，但 XP 组的瘤胃氨浓度趋于低于对照组。处理对总挥发性脂肪酸和单体挥发性脂肪酸浓度、纤毛虫计数、多糖降解活性（仅淀粉酶活性有增加趋势）或瘤胃甲烷产量均无影响。尿氮损失在两组间无显著差异，但 XP 组的尿囊素和总嘌呤衍生物排泄以及估计的瘤胃微生物氮流出量趋于高于对照组。XP 对日粮养分的全肠道表观消化率没有影响。乳脂肪酸组成也不受 XP 补充的影响。通过稳态气体排放系统测定，粪便中累积（253 h）氨和甲烷排放量略有减少。总体而言，试验所用的酵母培养物对瘤胃发酵、消化率或氮损失影响较小，但趋于降低瘤胃氨浓度，增加瘤胃微生物蛋白质合成，并减少粪便中氨和甲烷排放。
