In recent years, yak milk has received widespread attention due to its high nutrition, green and pollution-free characteristics, but the source of yak milk flavor is still unclear. In this study, fresh yak manure collected from Lhasa, Nagqu, Qamdo, Yushu, and Qinghai Lake were sequenced by 16S rRNA gene high-throughput sequencing technology. The correlation between intestinal microbiota and yak milk quality combined with the local environmental factors was evaluated for the first time. The enterotype of yaks from Lhasa, Nagqu, and Qinghai Lake was classified as enterotype of norank_f_Oscillospirales_UCG-010 and Rikenellaceae_RC9_gut_group, and the enterotype of yaks from Qamdo and Yushu was classified as enterotype of Oscillospiraceae UCG-005. Procrustes analysis showed that there was a close relationship between yak milk composition and intestinal microbiota. Metabolic pathway analysis found that different genera and key enzymes of methane and short-chain fatty acid metabolic pathways differed in their responses to environmental factors. Based on the above analysis, a model about environmental factors, intestinal bacteria and the flavor of yak milk was developed. The results provided a reference for the study of flavor substances in yak milk and a new direction for the improvement of dairy products and their derivatives.

近年来，牦牛奶以其高营养、绿色无公害的特点受到广泛关注，但牦牛奶风味的来源仍不清楚。本研究采用16S rRNA基因高通量测序技术对拉萨、那曲、昌都、玉树和青海湖采集的新鲜牦牛粪便进行测序。首次结合当地环境因素评价肠道菌群与牦牛奶品质的相关性。拉萨、那曲、青海湖牦牛肠型为norank_f_Oscillospirales_UCG-010和Rikenellaceae_RC9_gut_group肠型，昌都、玉树牦牛肠型为Oscillospiraceae UCG-005肠型. Procrustes 分析表明，牦牛乳成分与肠道微生物群之间存在密切关系。代谢途径分析发现，甲烷和短链脂肪酸代谢途径的不同属和关键酶对环境因素的反应不同。基于上述分析，建立了环境因素、肠道细菌和牦牛奶风味的模型。研究结果为牦牛奶中风味物质的研究提供了参考，为乳制品及其衍生物的改良提供了新的方向。