Table_1_Comparing the Microbial Community in Four Stomach of Dairy Cattle, Yellow Cattle and Three Yak Herds in Qinghai-Tibetan Plateau.DOCX

Yak (Bos grunniens) is an unique ruminant species in the Qinghai-Tibetan Plateau (QTP). The ruminant gastrointestinal tract (GIT) microbiota is not only associated with the nutrients metabolism, but also contributes to the host’s local adaptation. Examining the microbiota between cattle and yak in different geography could improve our understanding about the role of microbiota in metabolism and adaptation. To this end, we compared the microbiota in rumen, reticulum, omasum, and abomasum of dairy cattle, yellow cattle, and three yak herds (WQ yak, SZ yak, and ZB yak) lived in different altitude, based on sequencing the bacterial 16S rRNA gene on Illumina Miseq. The bacterial diversity was significantly different among five breeds, whereas the difference among four stomach regions is limited. The phyla Bacteroidetes and Firmicutes were the dominated bacteria regardless of breeds and regions. The nonmetric multidimensional scaling (NMDS) results showed that the microbiota in dairy cattle, yellow cattle and WQ yak significantly differed from that in SZ yak and ZB yak for all four stomach compartments. Canonical correlation analysis revealed that Prevotella and Succiniclasticum spp. were abundant in dairy cattle, yellow cattle and WQ yak, whereas the Christensenellaceae R7 group and the Lachnospiraceae UCG 008 group were prevalent in SZ yak and ZB yak. Moreover, the microbiota in WQ yak was significantly different from that in SZ yak and ZB yak, which were characterized by the higher relative abundance Romboutsia spp., Eubacterium coprostanoligenes, Acetobacter spp., Mycoplasma spp., and Rikenellaceae RC9 group. Overall, these results improves our knowledge about the GIT microbiota composition of QTP ruminant.

牦牛（Bos grunniens）是青藏高原（Qinghai-Tibetan Plateau, QTP）特有的反刍动物物种。反刍动物胃肠道（gastrointestinal tract, GIT）微生物群不仅与宿主的营养代谢密切相关，更在宿主的本地适应过程中发挥重要作用。探究不同地理环境下牛与牦牛的微生物群差异，有助于深化我们对微生物群在代谢与适应过程中功能的认知。为此，本研究基于Illumina Miseq平台对细菌16S rRNA基因进行测序，比较了栖息于不同海拔的奶牛、黄牛以及三个牦牛类群（WQ牦牛、SZ牦牛与ZB牦牛）的瘤胃、网胃、瓣胃和皱胃内的微生物群。结果显示，五个类群的细菌多样性存在显著差异，而四个胃区域间的差异相对有限。无论类群与区域如何，拟杆菌门（Bacteroidetes）与厚壁菌门（Firmicutes）均为优势细菌类群。非度量多维尺度分析（nonmetric multidimensional scaling, NMDS）结果表明，奶牛、黄牛与WQ牦牛的微生物群，在四个胃室中均与SZ牦牛及ZB牦牛的微生物群存在显著差异。典型关联分析显示，普雷沃氏菌属（Prevotella）与琥珀酸单胞菌属（Succiniclasticum）在奶牛、黄牛及WQ牦牛中丰度较高，而克里斯滕森菌科R7群与毛螺菌科UCG 008群在SZ牦牛和ZB牦牛中更为普遍。此外，WQ牦牛的微生物群与SZ、ZB牦牛亦存在显著差异，其特征为更高相对丰度的Romboutsia属、产甾醇真杆菌（Eubacterium coprostanoligenes）、醋酸杆菌属（Acetobacter）、支原体属（Mycoplasma）以及理研菌科RC9群。综上，本研究结果深化了我们对青藏高原反刍动物胃肠道微生物群组成的认知。