The rumen microbiota—a symbiont to its host and consists of critical functional substances—plays a vital role in the animal body and represents a new perspective in the study of adaptive evolution in animals. This study used Slide Viewer slicing analysis system, gas chromatography, RT-qPCR and other technologies, as well as 16S and metabolomics determination methods, to measure and analyze the microstructure of rumen epithelium, rumen fermentation parameters, rumen transport genes, rumen microbiota and metabolites in Tibetan sheep and Hu sheep. The results indicate that the rumen nipple height and cuticle thickness of Tibetan sheep are significantly greater than those of Hu sheep (p < 0.01) and that the digestion and absorption of forage are greater. The levels of carbohydrate metabolism, lipid metabolism, and protein turnover were increased in Tibetan sheep, which enabled them to ferment efficiently, utilize forage, and absorb metabolic volatile fatty acids (VFAs). Tibetan sheep rumen metabolites are related to immune function and energy metabolism, which regulate rumen growth and development and gastrointestinal homeostasis. Thus, compared with Hu sheep, Tibetan sheep have more rumen papilla and cuticle corneum, and the synergistic effect of the microbiota and its metabolites is a characteristic and strategy for adapting to high-altitude environments.

The gut microbiota in Tibetan sheep's ruminant stomach varies across phenological phases, influencing nutrient absorption and adaptation. During the green grass period, acetic, propionic, and butyric acid concentrations in the rumen were higher than in the regreening and withered grass periods (P < 0.05). MCT1 expression peaked during regreening. Bacteroidetes dominated during the withered grass period (P < 0.01), with Rikenellaceae_RC9_gut_group and Prevotella most abundant in the rumen. Spatially, rumen VFA concentrations and MCT1 expression were significantly higher than in other stomachs (P < 0.05). Bacteroidetes, Prevotella and Rikenellaceae_RC9_gut_group were dominant across the ruminant stomach. Correlations between microbiota, VFAs, and transport genes highlight the interplay of fermentation, flora, and gene expression, crucial for Tibetan sheep's adaptation to the plateau environment.

Astragalus polysaccharide (APS) has become a natural feed additive that has attracted much attention in animal husbandry due to its significant immunomodul

Microbiota density plays an important role in maintaining host metabolism, immune function, and health, and age has a specific effect on the composition of intestinal microbiota. Therefore, the age-specific effects of age differences on the structure and function of the ileum microbiota in Tibetan sheep were investigated by determining the density of the ileum microbiota, the content of VFAs, and the expression levels of their transporter-related genes at different ages. The results showed that the contents of acetic acid and propionic acid in the ileum of Tibetan sheep in the 1.5-year-old group were significantly higher (p < 0.05) than those in other age groups, and that the contents of total VFAs were also significantly higher (p < 0.05) than those in other age groups. The relative densities of ileum Rf, Ra, and Fs were significantly higher in the 1.5-year-old group than in the other age groups (p < 0.05). The ileum epithelial VFAs transport-related genes AE2, MCT-4, and NHE1 had the highest expression in the 1.5-year-old group, and the expression of DRA was significantly lower in the 1.5-year-old group than in the 6-year-old group (p < 0.05). Correlation analysis showed that Cb, Sr, and Tb were significantly positively correlated with butyric acid concentration (p < 0.05) and negatively correlated with acetic acid, but the difference was not significant (p > 0.05); MCT-1, MCT-4, and AE2 were significantly positively correlated (p < 0.05) with acetic, propionic, and isobutyric acid concentrations; NHE1, NHE2, and MCT-4 were highly significantly positively correlated (p < 0.01) with Romboutsia and unclassified_Peptostreptococcaceae, while acetic acid was significantly positively correlated (p < 0.05) with NK4A214_group; Romboutsia, and unclassified_Peptostreptococcaceae were significantly positively correlated (p < 0.05). Therefore, compared with other ages, the 1.5-year-old Tibetan sheep had a stronger fermentation and metabolic capacity in the ileum under traditional grazing conditions on the plateau, which could provide more energy for Tibetan sheep during plateau acclimatization.

Hexi cattle are a local cattle population endemic to the Hexi Corridor in Gansu Province, China, and exhibit strong adaptability to the region’s arid continental environment. However, comprehensive genomic investigations of this population are still lacking. In the present study, we integrated population genomic analyses with a genome-wide association study (GWAS) to dissect the genetic architecture of Hexi cattle. Whole-genome resequencing data were generated for 264 Hexi cattle, and public genomic datasets from six representative cattle breeds were obtained from the NCBI database for comparative analysis. Multiple analytical approaches—including principal component analysis (PCA), linkage disequilibrium (LD) decay analysis, neighbor-joining (NJ) phylogenetic tree construction, and ADMIXTURE analysis—were adopted to evaluate population structure and evolutionary relationships. A mixed linear model was then used to identify significant SNPs associated with five major body conformation traits in six-month-old cattle: body weight (BW), withers height (WH), hip height (HH), heart girth (HG), and abdominal girth (AG). Our results confirm the admixed nature of Hexi cattle, whose genome is derived primarily from Simmental cattle and secondarily from Mongolian cattle. A total of 69 trait-associated significant SNPs were identified and functionally annotated. Specifically, TBC1D31, DERL1 and MCPH1 were linked to BW; FSCN3 and PLBD1 to WH; MCPH1 to HH; NPAS3, TBC1D31, DERL1 and MCPH1 to HG; and SOX5, NTAQ1, FAM83A, TBC1D31, DERL1, CDH11, CPLX4 and ADAM18 to AG. This study deepens our understanding of the genetic basis of growth traits in Hexi cattle and offers valuable molecular resources for future selective breeding, genetic improvement, and long-term conservation of this indigenous cattle population.

Introduction: The Jersey-yak, a hybrid offspring of Jersey cattle and yak, exhibits characteristics such as strong adaptability, rapid growth and development, and outstanding production performance. Therefore, Jersey-yaks were fed diets with different crude protein (CP) levels (0%, 15.16%, and 17.90% CP, respectively), and the regulatory mechanisms underlying their growth and development were elucidated. Methods: In this study, we generated transcriptomic profiles of lncRNAs, circRNAs, miRNAs, and mRNAs from the skeletal muscle tissues of Jersey-yaks, and constructed a ceRNA network using differentially expressed RNAs. Results: We identified 429, 298, and 84 differentially expressed mRNAs, 394, 356, and 302 differentially expressed lncRNAs, 212, 234, and 20 differentially expressed circRNAs, and 6, 7, and 6 differentially expressed miRNAs in LP vs. MP, LP vs. HP, and MP vs. HP, respectively. These genes were found to be involved in signaling pathways related to skeletal muscle development, cell proliferation, and differentiation, such as the PI3K-Akt, MAPK, HIF-1, Wnt, and Notch signaling pathways. The ceRNA network mainly comprised 6 miRNAs, 6 circRNAs, 8 mRNAs, and multiple lncRNAs. These interactions may affect specific biological processes involved in the growth and development of Jersey-yaks. In addition, association analysis identified genes such as LASP1 , DUSP29 , and PDLIM7 . Discussion: These findings provide new insights into the molecular mechanisms underlying muscle development in yak and their hybrids.