Differences in Bacterial diversity across indigenous and introduced ruminants in the Qinghai Tibetan plateau

Context: The Qinghai Tibetan plateau (QTP) is characterized as a harsh high-altitude environment inhabited by a large numbers of ruminants. Rumen microorganisms potentially play a vital role in the adaptation of indigenous ruminants to this harsh environments.Aims:The present study aims to investigated the diversity of rumen bacteria in ruminants (yak and Tibetan sheep) indigenous to the QTP and introduced species (cattle and crossbred sheep) Methods: Bacteria composition and alpha & beta diversity were analyzed based on 16s rDNA sequence data obtained from 454 pyrosequencing.Key results: The majority of the sequences from all animals were affiliated with phylum Bacteroidetes (67.6%–84.0%) followed by Firmicutes (11.6%–21.0%). The ß-diversity (Bray–Curtis and weighted-Unifrac distance matrices) of bacteria was significantly different between ruminant species [yak (Bos grunniens), cattle (Bos taurus), and sheep (Ovis aries) but there were no differences between the indigenous and introduced sheep breeds. At the genus level; Fibrobacter, Lachnospira, and Pseudobutyrivibrio were more abundant (P < 0.05) in the rumen of yak while Prevotella was significantly more abundant (P < 0.05) in cattle compared with the other ruminants;. Enterotypes affiliated with the Ruminococcaceae and Prevotella were more dominant in the indigenous and introduced ruminants respectivelyConclusion: Ruminant species was the main factor differentiating the bacterial diversity in the microbiota of ruminants grazing on the QTP although there were differences in discrete populations of bacteria between indigenous and introduced ruminants. It appears that yak which have evolved as a distinctive species with specialized physiological and anatomical adaptations results in a rumen bacterial population that favours their survival in this extreme environment.Implication: This work extends the findings of previous studies comparing microbiota from different ruminants in Qing hai Tibetan Plateau, and provides a basis for exploration of the interactions governing the tri-partite relationship between host, rumen microbiota, and the harsh environment and indicates the potential of rumen microbiota in assisting the adaptation of host to the harsh environment.