In this study, 18 Tibetan sheep were assigned into four groups by age and sex, namely young ewes (E1, n = 5), young rams (R1, n = 3), adult ewes (EA, n = 5) and adult rams (RA, n =5) to profile the bacterial composition of Tibetan sheep and to explore the impacts of sex and age on rumen microbiota using high-throughput sequencing method of amplicon of 16S rRNA V3–V4 region. The results indicated that all effective tags for 18 samples were clustered into 5429 OTUs (Operation taxonomic Units, OTUs) with an absolute abundance > 1 at a similarity level > 97%. The rumen bacterial composition of female adult sheep was more diverse than male adult sheep and yearling female sheep. SILVA database was used to annotate taxonomic information for each representative sequence using the RDP classifier, the results showed that Bacteroidetes, Firmicutes, Verrucomicrobia and Proteobacteria were the most dominant phyla, representing 56.68%, 28.81%, 6.71% and 1.73% of reads from all samples on average, respectively. At the genus level, Rikenellaceae_RC9_gut_group, and Prevotella_1 were most abundant with relative abundance of 12.98% and 11.19%, respectively. Relative abundance of Bacteroidetes in EA was greater than RA (p = 0.014), relative abundance of Firmicutes in RA was greater than EA (p < 0.001), and the relative abundance of Spirochaetae in E1 was greater than R1 (p = 0.038). Shifting genera between the sexes belonged to Order Bacteroidales and Clostridiales, both changed substantially across sex in adult sheep (p < 0.01). The abundance of Bacteroidetes in female sheep and Firmicutes and Planctomycetes in male sheep significantly increased with age (p < 0.05), while the abundance of Spirochaetae in female sheep and Cyanobacteria in male sheep decreased with age (p < 0.05). Shifting genera between age groups belonged to order Bacteroidales and Clostridial. The abundance of order Bacteroidales in female sheep increased with age (p = 0.046), and the abundance of order Clostridiales in male sheep increased with age (p = 0.006), while it decreased with age in female sheep (p = 0.030). In summary, this study profiled the bacterial composition characteristics of Tibetan sheep and concluded that physiological factors, e.g. sex and age, shaped the bacterial composition, which expands our knowledge of the rumen of ruminant animals residing on the Qinghai-Tibetan Plateau.

在这项研究中，按年龄和性别将18只藏绵羊分为四组，即母羊（E1，n  = 5），公羊（R1，n  = 3），成年母羊（EA，n  = 5）和成年公羊。 （RA，n = 5）使用高通量16S rRNA V3–V4区扩增子测序方法，分析藏绵羊的细菌组成，并探讨性别和年龄对瘤胃微生物的影响。结果表明，所有18个样品的有效标签都被聚集成5429个OTU（操作分类单位，OTU），绝对丰度> 1，相似度> 97％。成年雌性绵羊的瘤胃细菌组成比成年雄性和一岁雌性绵羊的瘤胃细菌组成更多样化。使用RDP分类器，使用SILVA数据库注释每个代表性序列的分类学信息，结果表明，拟杆菌，固件，疣状微生物和变形杆菌是最主要的门，分别占所有样本读数的56.68％，28.81％，6.71％和1.73％。在属的水平，Rikenellaceae_RC9_gut_group和Prevotella_1最为丰富，分别为12.98％和11.19％，相对丰度。EA中拟杆菌的相对丰度大于RA（p  = 0.014），RA中Firmicutes的相对丰度大于EA（p  <0.001），E1中Spirochaetae的相对丰度大于R1（p  = 0.038）。男女之间的转移属属于细菌纲和梭状芽胞杆菌，成年绵羊的性别都发生了显着变化（p  <0.01）。随着年龄的增长，雌性羊中的拟杆菌含量以及雄性羊中的菌类和扁平菌的数量均显着增加（p  <0.05），雌性羊中的螺旋藻的数量和蓝细菌的蓝细菌的数量随着年龄的增长而降低（p  <0.05）。年龄组之间的转变属细菌纲和梭菌纲。随着年龄的增长，雌性绵羊中细菌类细菌的丰度增加（p  = 0.046），并且该类细菌的丰度公羊的梭菌随着年龄的增长而增加（p  = 0.006），而女羊的梭菌则随着年龄的增长而降低（p  = 0.030）。总而言之，这项研究概述了藏绵羊的细菌组成特征，并得出结论，认为生理因素（例如性别和年龄）决定了细菌组成，从而扩大了我们对青藏高原反刍动物瘤胃的认识。