Diversity, stability and variability of pika gut microbiota

Here, we investigated the gut microbial composition, short chain fatty acid (SCFA) profile and cellulase activity from two common pika species in China, including plateau pikas from Qinghai-Tibet Plateau and Daurian pikas from Inner Mongolia Grassland. Similar to other mammals, pika gut microbiota were dominated by the phyla Firmicutes, Bacteroidetes, Proteobacteria and Spirochaetes. At genus level, four predominant bacterial genera, including Prevotella, Oscillospira, Ruminococcus and Treponema were widespread and positively correlated with SCFAs and cellulase activity. The gut microbial community of pikas showed higher diversity and metabolic activity in summer or high-altitude regions or wild environments when compared to in winter or low-altitude regions or lab-reared environments. Notably, the gut microbiota structure exhibited greater variations but smaller fluctuations than that of SCFA functional profile in response to seasons, altitude, habitats and host species. Among these various factors, the divergence of gut microbiota and SCFA profile were mainly influenced by habitats, followed by altitude, seasons and animal species. Our results suggested the space factors play a major role in shaping the variations in gut microbial structure and function, implicating that geographical isolation is the main reason for the evolution of gut microbiota as well as animal populations.