Department of Animal Science, University of Minnesota, St. Paul, MN.
Department of Animal Science, University of Minnesota, St. Paul, MN.
J Equine Vet Sci. 2021 Jan;96:103306. doi: 10.1016/j.jevs.2020.103306. Epub 2020 Oct 19.
Although contributions of the equine gut microbiome to forage utilization are well recognized, the impact of alfalfa (Medicago sativa L.) lignification on the equine gut microbiome remains unknown; thus, we characterized microbial communities in the equine gut when feeding reduced lignin (RL) and conventional (CON) alfalfa hays to adult stock-type horses. Dietary treatments were fed to six horses in a crossover study. Experimental periods consisted of a 9-day dietary adaptation phase followed by a 5-day total fecal collection phase, during which horses were housed in individual box stalls and manure was removed on a continuous 24-hour basis. At 12-hour intervals, manure was mixed, frozen, and processed for V4, 16S rRNA amplicon MiSeq sequencing. Reduced lignin alfalfa did not shift microbiome composition equally across all horses; however, each subject's microbiome responded to hay lignin content in an individualized manner, mostly, in terms of beta diversity. Amplicon sequence variants affiliated to Akkermansia, Fibrobacter succinogenes, Treponema, and Paludibacter fluctuated significantly when RL alfalfa was fed, with abundance patterns unique to each horse. Horse-specific associations between individual gut microbiome traits and characteristics of the digested CON or RL alfalfa were also observed, mainly in regards to dry matter digestibility and mean fecal particle size. These results indicate that the horse gut microbiome responds in an individualized manner to changes in the amount of acid detergent lignin in alfalfa hay, potentially impacting several feed digestibility characteristics. The implications of these horse-specific responses to hay lignification, for metabolic health and performance, remain to be elucidated.
虽然马的肠道微生物群对饲料利用的贡献已得到充分认识，但苜蓿（Medicago sativa L.）木质素的木质化对马肠道微生物群的影响尚不清楚；因此，我们对喂食低木质素（RL）和常规（CON）苜蓿干草的成年马的肠道微生物群进行了特征描述。在交叉研究中，对六匹马进行了饮食处理。实验期包括 9 天的饮食适应期和 5 天的总粪便收集期，在此期间，马被关在单独的畜栏中，粪便会持续 24 小时被清除。每隔 12 小时，粪便会被混合、冷冻并进行 V4、16S rRNA 扩增子 MiSeq 测序。低木质素苜蓿并没有在所有马匹中同等地改变微生物群落组成；然而，每个个体的微生物群落都以个性化的方式对干草木质素含量做出反应，主要是在β多样性方面。当喂食 RL 苜蓿时，阿克曼氏菌（Akkermansia）、纤维丁酸弧菌（Fibrobacter succinogenes）、密螺旋体（Treponema）和波动杆菌（Paludibacter）的扩增子序列变异显著波动，且每个马的丰度模式都具有独特性。还观察到个体肠道微生物群特征与消化的 CON 或 RL 苜蓿的个体特征之间存在特定于马的关联，主要涉及干物质消化率和平均粪便颗粒大小。这些结果表明，马的肠道微生物群会以个性化的方式对苜蓿干草中酸性洗涤剂木质素的含量变化做出反应，这可能会影响几种饲料消化特性。这些对干草木质化的马特异性反应对代谢健康和性能的影响仍有待阐明。
