The experiment was to compare the effects of switching all-concentrate to all-roughage diets on rumen microflora and functional metabolism of yak, cattle-yak, Tibetan yellow cattle and yellow cattle living in different altitudes. A total of 24 yaks, cattle-yaks, Tibetan yellow cattle and yellow cattle with a similar weight and good body condition aged 3.5 years were selected and divided into four groups according to species. They were fed a concentrate diet with 40% soybean meal and 60% corn meal for the first month (C group) and a roughage diet with dry corn stalks (100%) for the second month (R group); the formal experimental period was 60 d. These results showed that the conversion had a significant effect on the rumen microflora structure of the four herds, and the biggest difference between concentrate and roughage diets was yak and cattle-yak, followed by Tibetan yellow cattle and yellow cattle. At the phylum level, Bacteroidetes and Firmicutes still predominate in all groups. Compared with the C groups, the relative abundance of Lentisphaerae and Kiritimatiellaeota increased in all R groups, and Lentisphaerae was significantly increased in yak and cattle-yak (p < 0.05). At the genus and species levels, Prevotella had the highest abundance, and the relative abundances of Prevotella, Ruminococcus, Sarcina and Ruminobacter in R groups were lower, while the abundances of other differential genera, including Methanobrevibacter, Fibrobacter, Treponema, Eubacterium, Butyrivibrio, Succinivibrio and Succinimonas, were all higher. Roughage diets increased the number of unique genes and functional genes encoding different CAZymes in rumen microorganisms in all four herds. In the functional contribution analysis, with the exception of ABC transporters and methane metabolism, Prevotella was the main contributor to almost all of these functions. In methane metabolism, Methanobrevibacter had the highest relative abundance, followed by Prevotella, Clostridia and Bacteroidales in all groups. Compared with Tibetan yellow cattle and yellow cattle, yaks and cattle-yaks have better adaptability to roughage, and its utilization rate can be fully improved to reduce methane emission. The study indicates that when four herds are converted to high roughage at the later stage of feeding, the growth and reproduction of rumen microorganisms are affected, and the abundance and diversity of rumen microorganisms are increased to varying degrees. The transformation of concentrate to roughage diet can change the metabolic pathways of rumen microorganisms in yaks and finally affect the fermentation mode of rumen. The above results provide a theoretical basis for the research and development of fattening feeds for yaks, cattle-yaks, Tibetan yellow cattle and yellow cattle and the intensive feeding of livestock on the plateau.

Yaks are the main pillar of plateau animal husbandry and the material basis of local herdsmen’s survival. The level of mineral elements in the body is closely related to the production performance of yaks. In this study, we performed a comprehensive analysis of rumen epithelial morphology, transcriptomics and metagenomics to explore the dynamics of rumen functions, microbial colonization and functional interactions in yaks from birth to adulthood. Bacteria, eukaryotes, archaea and viruses colonized the rumen of yaks from birth to adulthood, with bacteria being the majority. Bacteroidetes and Firmicutes were the dominant phyla in five developmental stages, and the abundance of genus Lactobacillus and Fusobacterium significantly decreased with age. Glycoside hydrolase (GH) genes were the most highly represented in five different developmental stages, followed by glycosyltransferases (GTs) and carbohydrate-binding modules (CBMs), where the proportion of genes coding for CBMs increased with age. Integrating host transcriptome and microbial metagenome revealed 30 gene modules related to age, muscle layer thickness, nipple length and width of yaks. Among these, the MEmagenta and MEturquoise were positively correlated with these phenotypic traits. Twenty-two host genes involved in transcriptional regulation related to metal ion binding (including potassium, sodium, calcium, zinc, iron) were positively correlated with a rumen bacterial cluster 1 composed of Alloprevotella, Paludibacter, Arcobacter, Lactobacillus, Bilophila, etc. Therefore, these studies help us to understand the interaction between rumen host and microorganisms in yaks at different ages, and further provide a reliable theoretical basis for the development of feed and mineral element supplementation for yaks at different ages.

The yak (Bos grunniens) was domesticated in the high-altitude QTP. Research about their genetic diversity and population structure is limited. In this study, we resequenced the genome of 494 domestic yaks using Specific-Locus Amplified Fragment Sequencing (SLAF-seq). The survey was conducted on six populations sampled from isolated locations in China in order to analyze their structure and genetic diversity. These six domestic populations were clearly grouped into two independent clusters, with Jinchuan, Changtai, and Jiulong showing a tight genetic relationship with the wild yak. Nerve development pathways were enriched with GO enrichment analysis of 334 domesticated genes. Major genomic regions associated with the differentiation of domestic yaks were detected. These findings provide preliminary information on the yak genome variability, useful to understand the genomic characteristics of different populations in QTP.

Introduction: Mastitis, a disease affecting milk production and quality, poses a significant challenge to agricultural practitioners. Conventional antibiotic treatments present potential issues such as drug resistance, disruption of animal intestinal microbiota, and milk safety issues, necessitating the development of novel alternative therapies for bovine mastitis. Yak β-defensin 127 ( DEFB127 ), a natural antimicrobial peptide, represents a promising candidate for alternative to antibiotics, yet remains underexplored as a therapy for mastitis. Results: In MAC-T cell, qRT-PCR analysis revealed that expression of IL-6 and IL-1β in the pLF- DEFB127 treatment group were significantly lower than the infection group ( P < 0.01). In vivo , histopathological examination showed that degree of inflammatory cell infiltration in the mammary gland tissue of the treatment group was significantly reduced compared to the infection group, accompanied by marked alleviation of alveolar dilation and epithelial cell necrosis. ELISA and qRT-PCR results demonstrated that the expression of TNF- α, IL-6 , and IL-1 β in the mammary gland tissue of mice from the pLF- DEFB127 treatment group were significantly downregulated than those in the infection group ( P < 0.01). Furthermore, 16S rRNA gene sequencing revealed that pLF- DEFB127 treatment altered the structure of the mouse intestinal microbiota, increasing the relative abundance of Bacteroidia and Bacilli, while decreasing that of Gammaproteobacteria. Finally, functional prediction of the intestinal microbiota based on 16S rRNA correlation analysis indicated that yak DEFB127 might exert anti-inflammatory effects by mechanisms involving glycosphingolipid biosynthesis and immune signaling, though this requires experimental validation.

Objective: Non-conventional peptides play a key role fundamental biological processes in basic plants and animals. This study investigates adaptive molecular genetic mechanisms of yaks from the perspective of non-coding peptides (NCPs).Methods: We established an integrated peptidogenomic pipeline, featuring a customized six-frame translation database using high-throughput mass spectrometry, which was utilized for the large-scale identification of NCPs in several vital organs/tissues of yaks.Results: In contrast to conventional peptides, these NCPs exhibit unique properties derived from introns, untranslated regions (UTRs), out-of-frame exons, and intergenic regions. Additionally, our findings indicate that translation events are more prevalent in unannotated transcripts than previously understood. Through transcriptome analysis and ribosome mapping analysis, 727 NCPs were identified as derived from long non-coding RNA and 944 NCPs were from circular RNA. Interestingly, the number of hydrophobic amino acids in NCPs was found to exceed that of hydrophilic amino acids in almost all tissues; in contrast to the findings for CPs, where the reverse was observed. The findings suggest a potential role in the maintenance of protein stability and minimizing the effects of oxidative stress. Furthermore, the in vitro antioxidant activity of the 38 candidate peptides further confirmed their physiological functions; however, specific physiological mechanisms require further investigation.Conclusion: In conclusion, this study demonstrates that a substantial portion of the yak genome can be translated into biologically functional molecules, which is crucial for functional genome research. These unique molecules will serve as basic data for future biomedical development and treatment of plateau diseases.