Obesity is an important equine welfare issue. Whilst dietary restriction is the most effective weight-loss tool, individual animals range in their weight-loss propensity. Gastrointestinal-derived bacteria play a fundamental role in host-health and have been associated with obesity and weight-loss in other species. This study evaluated the faecal microbiome (next-generation sequencing of 16S rRNA genes) of 15 obese Welsh Mountain pony mares, in the same 11-week period across 2 years (n = 8 Year 1; n = 7 Year 2). Following a 4-week acclimation period (pre-diet phase) during which time individuals were fed the same hay to maintenance (2% body mass (BM) as daily dry matter (DM) intake), animals underwent a 7-week period of dietary restriction (1% BM hay as daily DM intake). Faeces were sampled on the final 3 days of the pre-diet phase and the final 3 days of the dietary restriction phase. Bacterial communities were determined using Next Generation Sequencing of amplified V1-V2 hypervariable regions of bacterial 16S rRNA. Losses in body mass ranged from 7.11 to 11.59%. Changes in the faecal microbiome composition following weight-loss included a reduction in the relative abundance of Firmicutes and Tenericutes and a reduction in indices of bacterial diversity. Pre-diet diversity was negatively associated with weight-loss. Pre-diet faecal acetate concentration was a strong predictor of subsequent weight-loss and negatively associated with Sphaerochaeta (Spirochaetes phylum) abundance. When animals were divided into 3 groups (high, mid, low) based overall weight loss, pre-diet bacterial community structure was found to have the greatest divergence between the high and low weight-loss groups (R = 0.67, p < 0.01), following PERMANOVA and ANOSIM analysis. Weight-loss in this group of ponies was associated with lower pre-diet faecal bacterial diversity and greater pre-diet acetate concentration. Overall, these data support a role for the faecal microbiome in weight-loss propensity in ponies and provide a baseline for research evaluating elements of the faecal microbiome in predicting weight-loss success in larger cohorts.

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马胃肠道微生物组：减肥的影响

肥胖是马的重要福利问题。饮食限制是最有效的减肥手段，但个别动物的减肥倾向不尽相同。胃肠道细菌在宿主健康中起着基本作用，并且与其他物种的肥胖和体重减轻有关。这项研究评估了15个肥胖的威尔士山小马母马的粪便微生物组（16S rRNA基因的下一代测序），在相同的11周期间（共2年）（n = 8年； n = 7年2年）。在为期4周的适应期（饮食前阶段）后，在此期间给个体饲喂相同的干草以维持体重（相当于每日干物质（DM）摄入量的2％体重（BM）），对动物进行了7周的饮食限制（每日DM摄入量为1％BM干草）。在预饮食阶段的最后三天和饮食限制阶段的最后三天对粪便进行采样。使用细菌16S rRNA的扩增的V1-V2高变区的下一代测序确定细菌群落。体重损失为7.11％至11.59％。减肥后粪便微生物组组成的变化包括硬菌和Tenericutcuts相对丰度的降低以及细菌多样性指数的降低。进食前的多样性与减肥负相关。饮食前的粪便乙酸盐浓度是随后体重减轻的有力预测指标，并且与Sphaerochaeta（Spirochaetes phylum）的丰度负相关。将动物按总体体重分为三组（高，中，低），在进行PERMANOVA和ANOSIM分析后，发现高和低体重减轻组之间的饮食前细菌群落结构差异最大（R = 0.67，p <0.01）。这组小马的体重减轻与较低的饮食前粪便细菌多样性和较高的饮食前乙酸盐浓度有关。总体而言，这些数据支持粪便微生物组在小马的体重减轻倾向中的作用，并为研究评估粪便微生物组的元素预测较大人群减肥成功的研究提供基准。