The aim of this study was to investigate the rumen microbial diversity and functionality in buffaloes fed with a blend of essential oils (BEO) using LSD switch over design. The BEO consisting of blend of Trachyspermum copticum (Ajwain) oil, Cymbopogon citratus (lemon grass) oil and Syzygium aromaticum (clove bud) oleoresin mixed in equal proportion, was fed at the rate of 0, 0.75 and 1.5 ml/100 kg of body weight in 0 (control), 0.75 and 1.5 groups, respectively. The metatranscriptomic libraries of the rumen microbiome were represented by 7 domains, 84 phyla, 64 archeal genera and 663 bacterial genera with Bacteroidetes and Firmicutes constituting 80% of phyla abundance irrespective of feeding regime. Methanogenic archaea was represented by 22 phyla with Methanobrevibacter as the major genus. BEO feeding reduced the abundance of Methanococcus and Thermoplasma (P < 0.05) at all levels. The results revealed that the feeding of BEO shifted the archeal and bacterial population at very low magnitude. The study explored the vast diversity of buffalo rumen bacteria and archaea, and the diverse wealth of rumen enzymes (CAZymes), which revealed that a major part of CAZymes comes from the less known rumen microbes indicating alternative paths of fiber degradation along with the very well known ones.

本研究的目的是使用 LSD 切换设计研究饲喂混合精油 (BEO) 的水牛的瘤胃微生物多样性和功能。由等比例混合的Trachyspermum copticum (Ajwain) 油、Cymbopogon citratus (柠檬草) 油和Syzygiumaromaticum (丁香芽) 油树脂组成的BEO 以0、0.75和 1.5 毫升/100 公斤身体的比例喂食重量分别为 0（对照）、0.75 和 1.5 组。瘤胃微生物组的宏转录组文库由 7 个域、84 个门、64 个古菌属和 663 个细菌属代表，其中拟杆菌和厚壁菌构成了 80% 的门丰度，而与饲养方式无关。产甲烷古菌由 22 个门代表甲烷短杆菌属为主要属。BEO馈送减少的丰度甲烷和热原体（P 各级<0.05）。结果表明，饲喂 BEO 以非常低的幅度改变了古菌和细菌种群。该研究探索了水牛瘤胃细菌和古细菌的巨大多样性，以及各种丰富的瘤胃酶 (CAZymes)，这表明 CAZymes 的主要部分来自鲜为人知的瘤胃微生物，表明纤维降解的替代途径以及非常好的已知的。