Compositional and functional variations of pika gut microbiota respond to season and host species

The gut microbiota in mammals plays a key role in host nutrition. However, relatively little is known regarding those factors that influence gut microbiota composition and functions. Here, we investigated the diet, gut microbiota, short chain fatty acid (SCFA) profiles and cellulolytic activity from two common pika (Ochotona spp.) species in China, including Plateau pikas (O. curzoniae) from the Qinghai-Tibet Plateau and Daurian pikas (O. daurica) from the 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 genera included Prevotella, Oscillospira, Ruminococcus and Treponema. Microbial diversity, SCFA profiles and cellulolytic activity in pika gut were affected by both season and host species. Pika gut microbial communities were segregated structurally between seasons or host species. The gut microbiota also co-varied with SCFA profile and cellulolytic activity. The Plateau pikas harbored lower diet diversity but higher microbial diversity, SCFA concentration and cellulolytic activity than Daurian pikas. Our results suggested that pika gut microbiota composition and function co-vary in response to environmental and host factors. Specifically, Plateau pikas had a stronger ability for the utilization of plant-based diets by the gut bacterial fermentation compared with Daurian pikas.