There is a need to develop feeding strategies to prevent the adverse effect of concentrate feeding in high-performance horses fed energy-dense diets aiming to maintain their health and welfare. The objective of this study is to determine the effect of a VistaEQ product containing 4% live yeast Saccharomyces cerevisiae (S. cerevisiae), with activity 5 × 108 colony-forming unit/g and fed 2 g/pony per day, on faecal microbial populations when supplemented with high-starch and high-fibre diets using Illumina next generation sequencing of the V3-V4 region of the 16S ribosomal RNA gene. The four treatments were allocated to eight mature Welsh section A pony geldings enrolled in a 4-period × 8 animal crossover design. Each 19-day experimental period consisted of an 18-day adaptation phase and a single collection day, followed by a 7-day wash out period. After DNA extraction from faeces and library preparation, α-diversity and linear discriminant analysis effect size were performed using 16S metagenomics pipeline in Quantitative Insights Into Microbial Ecology (QIIME™) and Galaxy/Hutlab. Differences between the groups were considered significant when linear discriminant analysis score was >2 corresponding to P < 0.05. The present study showed that S. cerevisiae used was able to induce positive changes in the equine microbiota when supplemented to a high-fibre diet: it increased relative abundance (RA) of Lachnospiraceae and Dehalobacteriaceae family members associated with a healthy core microbiome. Yeast supplementation also increased the RA of fibrolytic bacteria (Ruminococcus) when fed with a high-fibre diet and reduced the RA of lactate producing bacteria (Streptococcus) when a high-starch diet was fed. In addition, yeast increased the RA of acetic, succinic acid producing bacterial family (Succinivibrionaceae) and butyrate producing bacterial genus (Roseburia) when fed with high-starch and high-fibre diets, respectively. VistaEQ supplementation to equine diets can be potentially used to prevent acidosis and increase fibre digestibility. It may help to meet the energy requirements of performance horses while maintaining gut health.

有必要制定喂养策略，以防止浓缩饲料在旨在维持其健康和福祉的高能量马饲喂高能饮食中的不利影响。这项研究的目的是确定含有4％活性酵母啤酒酵母（S. cerevisiae）的VistaEQ产品的效果，活性为5×10 8当使用Illumina下一代16S核糖体RNA基因的V3-V4区域测序补充高淀粉和高纤维日粮时，在粪便微生物种群上以菌落形成单位/克为单位，每天以2 g /马来饲喂。将这四种处理分配给以4周期×8动物交叉设计参与的8个成熟的威尔士切片A小马gel毛。每个19天的实验阶段包括一个18天的适应阶段和一个收集日，然后是7天的清除期。从粪便中提取DNA并进行文库制备后，使用《微生物生态学定量见解》（QIIME™）中的16S宏基因组学流水线进行α多样性和线性判别分析的效果大小。）和Galaxy / Hutlab。当线性判别分析得分> 2对应于P <0.05时，两组之间的差异被认为是显着的。本研究表明，当添加高纤维饮食时，酿酒酵母能够诱导马微生物群发生正向变化：它增加了与健康核心微生物组相关的链霉菌科和Dehalobacteriaceaeae家族成员的相对丰度（RA）。喂高纤维饮食时，补充酵母还增加了溶纤菌（Ruminococcus）的RA，降低了产乳酸菌（Streptococcus）的RA。）喂高淀粉饮食时。此外，当分别饲喂高淀粉和高纤维日粮时，酵母增加了乙酸，产琥珀酸的细菌家族（Succinivibrionaceae）和产丁酸盐的细菌属（Roseburia）的RA 。VistaEQ补充马饮食可潜在地预防酸中毒并增加纤维的消化率。它可能有助于满足马匹的能量需求，同时保持肠道健康。