Commensal microorganisms are essential to the normal development and function of many aspects of animal biology. However, the dynamic shift patterns of the microbiota of different gut segments in sheep and the correlation between fat type large-tailed phenotype and microbiota remain poorly unknown. This study therefore sought to assess the composition and distribution of the intestinal microbiome, and compared the difference of gut microbiota from different gastrointestinal segments within breeds and same intestinal sections between breeds. For these analyses, 16S rRNA V4 regions from 4 gut sections prepared from each of six individuals (3 from each breed) were sequenced to detect the microbiome composition in these samples. These analyses revealed the presence of 51,173 operational taxonomic units distributed across 24 phyla and 420 genera in these samples, with Firmicutes and Bacteroidetes being the most prevalent phyla of microbes present in these samples. Moreover, the bacterial composition showed distinct microbial communities in different gastrointestinal segments within breed, but showed similar and relative fixed bacterial abundance in the same intestinal segments from individuals of different breeds. We also found that only a few bacterial species (Lachnospiraceae, Akkermansia) were needed to distinguish between Small-tailed Han sheep (STH) and Large-tailed Han sheep (LTH) and their metabolic process maybe influence the fat type large-tailed phenotype formation in sheep. The functional profile analysis revealed that the environment information processing, genetic information processing, and metabolic pathways were enriched in all samples. The main functional roles of the gut microbiota were amino acid metabolism, replication and repair, carbohydrate metabolism, and membrane transport. Finally, our findings suggested that distinguished gut species between STH and LTH have relative fixed and the potential correlation is existing between the intestinal microorganisms and the large-tailed phenotype trait formation of sheep, which may offer clues for further investigation to detect the roles of intestinal microbiota in the metabolism and fat deposition in the tail of sheep.

共生微生物对动物生物学许多方面的正常发育和功能至关重要。然而，绵羊不同肠道段微生物群的动态变化模式以及脂肪型大尾表型与微生物群之间的相关性仍然鲜为人知。因此，本研究试图评估肠道微生物群的组成和分布，并比较品种内不同胃肠道段和品种间相同肠道切片的肠道微生物群差异。对于这些分析，对来自 6 个个体（每个品种 3 个）中的每一个制备的 4 个肠道切片的 16S rRNA V4 区域进行测序，以检测这些样品中的微生物组组成。这些分析揭示了 51、173 个操作分类单元分布在这些样本中的 24 个门和 420 个属中，其中厚壁菌门和拟杆菌门是这些样本中最普遍的微生物门。此外，细菌组成在品种内的不同胃肠道段显示出不同的微生物群落，但在不同品种个体的相同肠段中显示出相似且相对固定的细菌丰度。我们还发现只有少数细菌种类（但在来自不同品种的个体的相同肠段中显示出相似且相对固定的细菌丰度。我们还发现只有少数细菌种类（但在来自不同品种的个体的相同肠段中显示出相似且相对固定的细菌丰度。我们还发现只有少数细菌种类（毛螺，Akkermansia）来区分小尾寒羊（STH）和大尾寒羊（LTH），它们的代谢过程可能会影响绵羊脂肪型大尾表型的形成。功能谱分析表明，所有样品都富含环境信息处理、遗传信息处理和代谢途径。肠道微生物群的主要功能作用是氨基酸代谢、复制和修复、碳水化合物代谢和膜转运。最后，我们的研究结果表明，STH 和 LTH 之间的不同肠道物种具有相对固定性，肠道微生物与绵羊大尾表型性状形成之间存在潜在的相关性，