Rumen microbiota of indigenous and introduced ruminants and their adaptation to the Qinghai–Tibetan plateau

Abstract

The grassland in the Qinghai–Tibetan plateau provide habitat for many indigenous and introduced ruminants which perform important ecological functions that impact the whole Qinghai–Tibetan plateau ecosystem. These indigenous Tibetan ruminants have evolved several adaptive traits to withstand the severe environmental conditions, especially cold, low oxygen partial pressure, high altitude, strong UV radiation, and poor forage availability on the alpine rangelands. Despite the challenges to husbandry associated with the need for enhanced adaptation, several domesticated ruminants have also been successfully introduced to the alpine pasture regions to survive in the harsh environment. For ruminants, these challenging conditions affect not only the host, but also their commensal microbiota, especially the diversity and composition of the rumen microbiota; multiple studies have described tripartite interactions among host-environment-rumen microbiota. Thus, there are significant benefits to understanding the role of rumen microbiota in the indigenous and introduced ruminants of the Qinghai–Tibetan plateau, which has co-evolved with the host to ensure the availability of specific metabolic functions required for host survival, health, growth, and development. In this report, we systemically reviewed the dynamics of rumen microbiota in both indigenous and introduced ruminants (including gut microbiota of wild ruminants) as well as their structure, functions, and interactions with changing environmental conditions, especially low food availability, that enable survival at high altitudes. We summarized that three predominant driving factors including increased VFA production, enhanced fiber degradation, and lower methane production as indicators of higher efficiency energy harvest and nutrient utilization by microbiota that can sustain the host during nutrient deficit. These cumulative studies suggested alteration of rumen microbiota structure and functional taxa with genes that encode cellulolytic enzymes to potentially enhance nutrient and energy harvesting in response to low quality and quantity forage and cold environment. Future progress toward understanding ruminant adaptation to high altitudes will require the integration of phenotypic data with multi-omics analyses to identify host-microbiota co-evolutionary adaptations enabling survival on the Qinghai–Tibetan plateau.

“Get the best out of what comes in” – adaptation of the microbiota of chamois (Rupicapra rupicapra) to seasonal forage availability in the Bavarian Alps

“…However, the adaptations to the changing environment over the seasons are not only reflected in migratory movements and ingested food. It is well known that forage plays a vital role in the composition of the microbial community of wild ruminants, and this adapts accordingly ( Henderson et al, 2015 ; Ricci et al, 2019 ; Li et al, 2022 ).…”

“…For a few species, such as reindeer, there are now more studies available that have been carried out using genetic sequencing methods. In addition, some studies are currently known on ruminants from the Qinghai-Tibetian Plateau, which can be compared with the alpine chamois ( Li et al, 2022 ). Comparability is also often problematic, as the number of samples is often minimal, or sample material originates from fecal or rumen samples with the limitation of fecal samples to improperly reflect the rumen bacterial populations.…”

“…A significantly increased proportion of ruminococci in summer, as found in chamois, is also known from Tibetan sheep ( Fan et al, 2021 ). Highland ruminants have been shown to have a more diverse microbiota than related lowland species ( Wu et al, 2020 ; Li et al, 2022 ). Unfortunately, a closely related species from the alpine region is not available for comparison.…”

“…The average total VFA content is also significantly higher in the chamois, with an average of 10.5 mg/mL, compared to the roe deer with 6.7 mg/mL (Dahl et al, 27 April 2023, PREPRINT available at Research Square). 1 The increased VFA content, which indicates increased microbial activity, is known from various species from the highlands ( Zhang et al, 2016 ; Li et al, 2022 ). Generally, a strong influencing factor for the inhabitants of high altitudes is their exposure to strongly pronounced seasonal differences.…”

Influence of Varied Environment Conditions on the Gut Microbiota of Yaks

“…Nyêmo county is located at east longitude 90.1° and northern latitude 29.4°, at an altitude above 3800 m; this region experiences an annual average temperature of 6.7 °C, with temperatures reaching −40 °C in January and 15.0 °C in July. The annual precipitation of Nyêmo county is 295.3 mm, the frost-free period extends for 100 days, and the average amount of sunshine is 2947.8 h. Yaks in Tibet achieve adaptation to high-altitude environments by establishing a sophisticated oxygen delivery system participating in three physiological processes: oxygen intake, transportation, and utilization [ 17 , 18 ]. Moreover, at the genomic level, yaks harbor positively selected genes involved in hypoxic response and energy metabolism [ 19 , 20 ].…”