Abstract: Host diet and environmental factors are key drivers shaping the gut microbiota. Although the gut microbiota structure of plateau pikas varies with altitude, the independent role of hypoxia remains to be clarified through controlled experiments, given that the plateau environment involves both cold and hypoxic stresses. Therefore, under strictly controlled temperature conditions, experiments on hypoxic stress were conducted, and metagenomic sequencing technology was used to compare the structural composition of the gut microbiota of plateau pikas at 2100 m altitude （PL） and those maintained at 6000 m altitude （PH）. The results showed that hypoxia did not cause significant changes in the diversity of the gut microbiota. Stochastic processes still dominated the community assembly mechanism, but this role was significantly reduced due to the weakening of dispersal limitation. The gut microbiota could be divided into two distinct community types, withRikenellaandAkkermansiabeing differentially abundant genera, among which the abundance of Akkermansiaceae was significantly reduced. Compared with that of the PL group, the co-occurrence network of the PH group showed higher structural stability. This study revealed the impact of hypoxia on the gut microbiota structural composition in plateau pikas, providing new insights into the adaptation to hypoxia in animals on the plateau.

Key words: environmental stress, hypoxia, gut microbiota, metagenome, plateau pika