State Key Laboratory of Barley and Yak Germplasm Resources and Genetic Improvement, Tibet Academy of Agricultural and Animal Husbandry Sciences (TAA AS)), Lhasa, China.
School of Public Health, Lanzhou University, Lanzhou, China.
J Appl Microbiol. 2022 Mar;132(3):1652-1665. doi: 10.1111/jam.15322. Epub 2021 Oct 20.
Yak is a dominant ruminant, well adapted to grazing on pasture year around in the harsh climate of the 3000-meter-high Qinghai-Tibetan Plateau. The complex microbial community that resides within the yak rumen is responsible for fermentation and contributes to its climatic adaptation. This study aimed to characterize the rumen microbiota responses to wide seasonal variations, especially those necessary for survival in the cold seasons.
In the present study, we performed 16s rRNA gene sequencing to investigate the seasonal variations in microbiota composition, diversity and associated volatile fatty acids (VFAs) in yak rumen. The results showed that rumen microbiota were dominated by Bacteroides (72.13%-78.54%) and Firmicutes; the relative abundance of Firmicutes was higher in summer (17.44%) than in winter (10.67%; p < 0.05). The distribution of taxa differed among spring, summer and winter rumen communities (PERMANOVA, p = 0.001), whereas other taxa (e.g., Fibrobacter, Verrucomicrobia, Anaerostipes and Paludibacter), which could potentially help overcome harsh climate conditions were observed in higher abundance during the cold spring and winter seasons. The highest total VFA concentration in the yak rumen was obtained in summer (p < 0.05), followed by spring and winter, and both positive and negative correlations between VFAs and specific genera were revealed.
Microbiota in yak rumen appear to be highly responsive to seasonal variations. Considering environmental factors, we suggest that seasonal adaptation by microbial communities in rumen enables their hosts to survive seasonal scarcity and cold stress in the spring and winter.
The present study furthers our understanding of how microbial adaptation to seasonal variations in nutrient availability and climate may function in high plateau ruminants, providing insights into the tripartite relationship between the environment, host and microbiota.
牦牛是一种适应能力很强的反刍动物，能够在海拔 3000 米的青藏高原恶劣气候条件下常年放牧。栖息在牦牛瘤胃中的复杂微生物群落负责发酵，并有助于其适应气候。本研究旨在描述瘤胃微生物群对广泛季节性变化的反应，特别是那些在寒冷季节生存所必需的反应。
本研究通过 16s rRNA 基因测序，研究了牦牛瘤胃微生物群落组成、多样性和相关挥发性脂肪酸（VFAs）在季节变化中的变化。结果表明，瘤胃微生物群以拟杆菌（72.13%-78.54%）和厚壁菌门为主；夏季（17.44%）的厚壁菌门相对丰度高于冬季（10.67%；p<0.05）。春季、夏季和冬季瘤胃群落之间的分类群分布不同（PERMANOVA，p=0.001），而在寒冷的春季和冬季，观察到其他分类群（如纤维杆菌属、疣微菌门、厌氧棒菌属和沼泽红假单胞菌）的丰度更高，这些分类群可能有助于克服恶劣的气候条件。牦牛瘤胃中总 VFA 浓度最高的是夏季（p<0.05），其次是春季和冬季，并且 VFA 与特定属之间存在正相关和负相关。
牦牛瘤胃中的微生物群似乎对季节性变化高度敏感。考虑到环境因素，我们认为微生物群落对瘤胃中季节性变化的适应使它们的宿主能够在春季和冬季适应季节性资源匮乏和寒冷应激。
本研究增进了我们对微生物如何适应高原反刍动物营养可用性和气候季节性变化的理解，为环境、宿主和微生物群落之间的三方关系提供了新的见解。
