Effect of dietary supplementation of Saccharomyces cerevisiae on the ruminal microbiota and epithelium in lactating cattle during subacute ruminal acidosis

目前的商业乳制品生产系统依赖于富含可快速发酵的碳水化合物的饮食来提高生产效率。然而，饲喂这样的饮食可导致挥发性脂肪酸（VFA）和乳酸在瘤胃内积累，引起瘤胃酸中毒。瘤胃酸中毒是高产奶牛中一种非常常见的消化系统疾病，尤其是在产犊后，因为奶牛被引入能量密集的饮食以支持牛奶产量。瘤胃酸中毒可降低奶牛的采食量，损伤瘤胃上皮，引起蹄叶炎、肝损伤和死亡。 在泌乳的初始阶段，由于瘤胃酸中毒引起的饲料消耗量减少可导致其他健康风险，如酮症。接受直接饲喂微生物（DFM）（如酿酒酵母）的奶牛已显示出饲料消耗、瘤胃条件的改善，并因此改善了整个泌乳期的性能和代谢。本研究项目的目的是调查奶牛饲喂酿酒酵母的潜在效益。该计划将衡量奶牛的表现并监测健康指标。还将使用先进的分子和微生物学方法来评估瘤胃微生物群和瘤胃上皮的变化。

Current commercial dairy production systems rely on diets rich in rapidly fermentable carbohydrates to improve production efficiency. However, feeding such diets can lead to accumulation of volatile fatty acids (VFA) and lactate within the rumen causing ruminal acidosis. Ruminal acidosis is a very common digestive disorder in high-producing cows, especially after calving, as cows are introduced to energy-dense diets to support milk production. Ruminal acidosis can reduce feed consumption of cows, damage the rumen epithelium, and cause laminitis, liver abscesses and death. Reduced feed consumption caused by ruminal acidosis during the initial phase of lactation can lead to other health risks such as ketosis. Cows receiving direct-fed microbials (DFM) such as Saccharomyces cerevisiae have shown improvement in feed consumption, ruminal conditions, and consequently, improvement in performance and metabolism throughout lactation. The aim of this research project is to investigate the potential benefits of feeding Saccharomyces cerevisiae to dairy cattle. The program will measure cows' performance and monitor health indicators. Advanced molecular and microbiological methods will also be used to assess changes in the rumen microbiota and the ruminal epithelium.