The yak (Poephagus grunniens) has evolved unique adaptations to survive the harsh environment of the Tibetan Plateau, while their gut microorganisms play a crucial role in maintaining the health of the animal. Gut microbes spread through the animal population not only by horizontal transmission but also vertically, which enhances microbial stability and inheritance between generations of the population. Homogenization of gut microbes in different animal species occurs in the same habitat enhancing interspecies coexistence. Using the yak as a model animal, this paper reviews the adaptive strategies under extreme environments and how the gut microbes of the yak circulate throughout the Tibetan Plateau system, which not only affects other plateau animals such as plateau pikas, but can also have a profound impact on the health of people. By examining the relationships between yaks and their gut microbes, this review provides new perspectives in understanding the adaptations of plateau animals and the stability of the ecosystem.

This study compared growth performance, serum biochemical indicators, rumen fermentation parameters, rumen bacterial structure, and fecal bacterial structure of cattle and yaks, fed for two months, given a feed containing concentrate to roughage ratio of 7: 3 on dry matter basis. Compared with cattle, yak showed better growth performance. The serum biochemical results showed that the albumin: globulin ratio in yaks serum was significantly higher than that in cattle. Aspartate aminotransferase, indirect bilirubin, creatine kinase, lactate dehydrogenase and total cholesterol were significantly lower in yaks than that in cattle. Rumen pH, acetate to propionate ratio, and acetate were lower in yaks than in cattle while the lactate in yaks was higher than in cattle. There were significant differences in the structure of ruminal as well as fecal bacteria between cattle and yaks. The prediction of rumen bacterial function showed that there was metabolic difference between cattle and yaks. In general, the metabolic pathway of cattle was mainly riched in de novo synthesis of nucleotides, while that of yaks was mainly riched in the metabolic utilization of nutrients. This study provides a basis for understanding the rumen ecology under the condition of high concentrate diet.