The yak (Poephagus grunniens) has evolved unique adaptations to survive the harsh environment of the Qinghai–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, promoting interspecies coexistence. Using the yak as a model animal, this paper discusses 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 microbiota, this review offers new insights into the adaptation of yaks and their ecological niche on the Qinghai–Tibetan plateau.

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 investigates the effect of altitude on the fatty acid composition of pasture grass, yak milk, and yak ghee on the Qinghai–Tibet Plateau, aiming to understand how environmental factors influence the nutritional quality of these products. Samples were collected from four different altitudes and analyzed for fatty acid profiles using gas chromatography. The analysis reveals that higher altitudes are associated with an increased prevalence of beneficial unsaturated fatty acids, such as oleic acid (C18:1) and linoleic acid (C18:2n6c). These findings highlight the significant influence of altitude on yak lipid metabolism, ultimately enhancing the nutritional value of dairy products. This adaptation not only supports the health and resilience of yaks, but also provides vital nutritional benefits to residents in high-altitude regions. The research underscores the importance of further investigations to optimize dairy production practices, ensuring improved food security and health outcomes for residents of the plateau.

Objective: This study aimed to elucidate the mechanisms underlying milk composition divergence between naks (female yaks) and Simmental cows (S-cows) by integrating longitudinal multi-omics analyses of gut microbiota and metabolomes.Methods: We determined the gut microbiota and metabolites of both species over a 54-day period (day 26 to 80 of lactation) of ten naks and ten S-cows. Gut microbiota dynamics were assessed via 16S rRNA sequencing, while serum and fecal metabolomes were profiled using ultra-high performance liquid chromatography–tandem mass spectrometry. Statistical analyses included Wilcoxon rank-sum tests, linear discriminant analysis effect size (linear discriminant analysis>2, p0.70).Results: Milk yield was lesser (0.53–0.91 vs. 2.07–3.88 kg/d) but concentrations of fat (5.63%–6.30% vs. 3.30%–3.74%), protein (5.66%–6.30% vs. 3.39%–3.74%), and conjugated linoleic acid (CLA) (1.74%–2.35% vs. 1.40%–1.75%) were greater (p<0.001) in nak than Scow milk. Species-specific microbial signatures emerged. In naks, the g-Family-XIIIAD3011-group and g-norank-Ruminococcaceae were correlated with bile acid metabolism and CLA synthesis via 13-hydroxyoctadecadienoic acid transport. Additionally, the naks gut had a greater concentration of 13-hydroxyoctadecadienoic acid, a precursor of CLA, which may be transported to mammary cells via phosphatidylcholine and converted to CLA under the catalysis of fatty acid desaturase2. S-cows harbored g-Succinivibrio and g-Eubacterium-ruminantium-group, which are linked to galactose utilization and mTORmediated amino acid allocation. Metabolomics revealed naks-enriched steroid biosynthesis and taurine pathways (false discovery rate<0.05), while S-cows exhibited a lactating network associated with greater milk yield.Conclusion: Host-specific gut microbiota mediated nutrient allocation trade-offs. Naks optimized lipid-rich milk through bile acid and CLA metabolic networks, whereas S-cows enhanced yield via microbial-galactose synergies. This research underscores the pivotal role of the gut microbiome in mediating milk composition and suggests that microbiome manipulation could be a promising strategy to enhance milk quality in ruminants.

This study investigates the effect of altitude on the fatty acid composition of grass, yak milk, and yak ghee on the Qinghai-Tibet Plateau, aiming to understand how environmental factors influence the nutritional quality of these products. Samples were collected from four different altitudes and analyzed for fatty acid profiles using gas chromatography. The findings reveal significant differences in fatty acid profiles, with notably higher concentrations of lauric acid (C12:0) and myristic acid (C14:0) at altitude A2 compared to others (p＜ 0.001). Furthermore, the fatty acid composition in yak milk and ghee is influenced by the grass consumed and the metabolism of rumen microorganisms. The results indicate that yaks adapt their lipid biosynthesis to high-altitude conditions, as evidenced by a significant increase in stearic acid (C18:0) levels at higher altitudes, which subsequently affects the nutritional value of their milk and ghee. These insights are crucial for improving yak breeding and dairy production practices, ultimately enhancing food security and nutritional health for local communities residing in high-altitude areas. The study underscores the necessity for further research on optimizing these natural resources for better health outcomes.