Environmental filtering increases with elevation for the assembly of gut microbiota in wild pikas

Abstract

Summary Despite their important roles in host nutrition, metabolism and adaptability, the knowledge on how the mammalian gut microbial community assemble is relatively scanty, especially regarding the ecological mechanisms that govern microbiota along environmental gradients. To address this, we surveyed the diversity, function and ecological processes of gut microbiota in the wild plateau pika, Ochotona curzoniae, along the elevational gradient from 3106 to 4331 m on ‘the Roof of the World’—Qinghai‐Tibet Plateau. The results indicated that the alpha, beta and functional diversity of gut microbiota significantly increased with elevation, and elevation significantly explained the variations in the gut microbial communities, even after controlling for geographical distance, host sex and body weight. Some gene functions (e.g. nitrogen metabolism and protein kinases) associated with metabolism were enriched in the high‐altitude pikas. Null model and phylogenetic analysis suggest that the relative contributions of environmental filtering responsible for local gut communities increased with elevation. In addition, deterministic processes dominated gut microbial communities in the high‐altitude (more than 3694 m) pikas, while the percentages of stochastic and deterministic processes were very close in the low‐altitude (3106 and 3580 m) pikas. The observed mechanisms that influence pika gut microbiota assembly and function seemed to be mainly mediated by the internal gut environment and by the external environmental pressure (i.e. lower temperature) in the harsh high‐altitude environment. These findings enhance our understanding of gut microbiota assembly patterns and function in wild mammals from extreme harsh environments.

Altitude influences microbial diversity and herbage fermentation in the rumen of yaks

“…This study revealed that the phyla Firmicutes and Bacteroidetes were the predominant bacteria in the rumen of yaks. The two phyla in the current study were also found to be abundant in the GIT of yaks [1,2,4], sheep [19], goats [20], bovine animals [21], and pikas [11], indicating an ecological and functional role of Firmicutes and Bacteroidetes in the mammalian GIT. Huang and Li (2017) [22] reported that the relative abundance of Firmicutes in yaks was higher than that of Bacteroidetes during grazing.…”

“…These unique characteristics result in an attractive system explore the adaptation process of yaks to altitudinal gradients. First, because the main characteristics of high altitude areas are low pressure, low oxygen, low temperature, high sunlight, and climate dynamics [ 11 ], the ecological mechanisms associated with rumen microbiota consortium could respond in a different manner compared with those of low altitude yaks. Second, yaks have adapted well to high altitude environments through long-term evolution [ 9 ].…”

Rumen Microbiome and Metabolome of Tibetan Sheep (Ovis aries) Reflect Animal Age and Nutritional Requirement

“…Microbiome data analysis was mainly performed using QIIME Pipeline-Version 1.9.0 ( http://qiime.org/scripts/index.html ) from our Microbiome and Bioinformatics Platform in School of Public Health, Lanzhou University. The detailed analysis methods and procedures were described in our previous reports with slight modification ( 14 – 17 ). In brief, the original paired-end reads produced by MiSeq sequencer were assembled using the FLASH-1.2.8 software ( 18 ).…”

Alterations in Rumen Bacterial Community and Metabolome Characteristics of Cashmere Goats in Response to Dietary Nutrient Density

“…Among the microbiota, bacteria are the most abundant, diverse, and metabolically active species in the rumen [ 7 , 8 ]. The bacterial community in the rumen are linked to various factors, such as animal diet, breed, age health and geographic region [ 9 , 10 ]. Diet is the major determinant of the microbial composition in the rumen [ 11 ].…”