Search Results (94)

The yak (Bos grunniens) is a key species in high-altitude rangelands of Asia. Despite their ecological and economic importance, yak production faces persistent challenges, including low milk yields, vulnerability to climate changes, emerging diseases, and a lack of systematic breeding programs. This review presents the genomic, physiological, and environmental dimensions of yak biology and husbandry. Genes such as EPAS1, which encodes hypoxia-inducible transcription factors, underpin physiological adaptations, including enlarged cardiopulmonary structures, elevated erythrocyte concentrations, and specialized thermoregulatory mechanisms that enable their survival at elevations of 3000 m and above. Copy number variations (CNVs) and single nucleotide polymorphisms (SNPs) present promising markers for improving milk and meat production, disease resistance, and metabolic efficiency. F1 and F2 generations of yak–cattle hybrids show superior growth and milk yields, but reproductive barriers, such as natural mating or artificial insemination, and environmental factors limit the success of these hybrids beyond second generation. Infectious diseases, such as bovine viral diarrhea and antimicrobial-resistant and biofilm-forming Enterococcus and E. coli, pose risks to herd health and food safety. Rising ambient temperatures, declining forage biomass, and increased disease prevalence due to climate changes risk yak economic performance and welfare. Addressing these challenges by nutritional, environmental, and genetic interventions will safeguard yak pastoralism. This review describes the genes associated with different yak traits and provides an overview of the genetic adaptations of yaks (Bos grunniens) to environmental stresses at high altitudes and emphasizes the need for conservation and improvement strategies for sustainable husbandry of these yaks. Full article

In order to investigate the infection status of Cryptosporidium in O. curzoniae and B. grunniens in Zoige County, Sichuan Province, fecal samples from B. grunniens and gastrointestinal contents from captured O. curzoniae were collected between March and December 2023 from five townships (Dazhasi, Axi, Hongxing, Tangke, and Maixi). Genomic DNA was extracted, and nested PCR targeting the small subunit (SSU) rRNA gene of Cryptosporidium was performed. PCR-positive products were sequenced, trimmed, aligned, and subjected to phylogenetic analysis to determine species and genotypes. A total of 242 samples were obtained, of which 20 were Cryptosporidium SSU rRNA-positive, yielding an overall detection rate of 8.3% (20/242). The detection rates of O. curzoniae and B. grunniens were 7.0% (8/114) and 9.4% (12/128), respectively. Among the five sampling sites, Maixi town exhibited the highest detection rate (32.4%, 11/44), followed by Hongxing town (15.2%, 7/46) and Tangke town (4.6%, 2/44). Phylogenetic analysis detected an unidentified Cryptosporidium sp. in O. curzoniae, while C. bovis (n = 10) and C. ryanae (n = 2) were detected in B. grunniens. These findings demonstrate that Cryptosporidium infections are present in both O. curzoniae and B. grunniens in Zoige County, with notable differences in infection rates and species composition. Continued surveillance of Cryptosporidium in local livestock and wildlife is warranted to provide critical data for regional public health management. Full article

The yak (Bos grunniens) has exceptional hypoxia resilience, making it an ideal model for studying high-altitude adaptation. Here, we investigated the effects of oxygen concentration on yak cardiac fibroblast proliferation and the underlying molecular regulatory pathways using RNA sequencing (RNA-seq) and metabolic analyses. Decreased oxygen levels significantly inhibited cardiac fibroblast proliferation and activity. Intriguingly, while the mitochondrial DNA (mtDNA) content remained stable, we observed coordinated upregulation of mtDNA-encoded oxidative phosphorylation components. Live-cell metabolic assessment further demonstrated that hypoxia led to mitochondrial respiratory inhibition and enhanced glycolysis. RNA-seq analysis identified key hypoxia adaptation genes, including glycolysis regulators (e.g., HK2, TPI1), and hypoxia-inducible factor 1-alpha (HIF-1α), with Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses highlighting their involvement in metabolic regulation. The protein–protein interaction network identified three consensus hub genes across five topological algorithms (CCNA2, PLK1, and TP53) that may be involved in hypoxia adaptation. These findings highlight the importance of metabolic reprogramming underlying yak adaptation to hypoxia, providing valuable molecular insights into the mechanisms underlying high-altitude survival. Full article

Yak (Bos grunniens) meat is popular with a unique flavor and high nutritional value. This study investigated the effects of dietary supplementation with rumen-protected methionine (RPM) on meat quality, fatty acid composition, volatile flavor compounds, and transcriptomics of Longissimus lumborum of yak. Twenty-four male Maiwa yaks were selected and assigned to four groups: basal diet (CON), or supplementation of 5 g/d (RPM5), 10 g/d (RPM10), and 15 g/d (RPM15) RPM. The dose-dependent effects of RPM levels were evaluated through linear or quadratic trend analysis. The results showed that diet supplementation with RPM increased the intramuscular fat contents, improved composition of volatile flavor compounds and the ratio of monounsaturated fatty acids to saturated fatty acids. Compared to the CON group, there were 36, 84 and 23 up-regulated genes, and 85, 94 and 70 down-regulated genes in the RPM5, RPM10 and RPM15 groups, respectively. Gene ontology enrichment analysis revealed significant differentially expressed genes enrichment in biological processes, cellular components, and molecular functions across RPM5, RPM10, and RPM15 groups compared to the CON. KEGG pathway analysis revealed 99, 169, and 104 enriched pathways in RPM5, RPM10, and RPM15 groups, respectively. In summary, the addition of RPM to diets may provide new ideas and methods to improve meat quality of yaks. Full article

Cryptosporidium spp. and Giardia intestinalis are important zoonotic protozoa that are closely related to diarrhea and cause considerable economic losses in the livestock breeding industry. Ganzi is one of the main production areas for yaks in China, but there have been few reports on the occurrence of Cryptosporidium spp. and G. intestinalis in yaks. This study used PCR-based sequencing techniques to survey the prevalence and species/genotypes of Cryptosporidium spp. and G. intestinalis in faecal samples from 223 yaks in Ganzi, Sichuan Province. The positive rate of Cryptosporidium spp. was 7.2% (16/223), with the highest positive rate of yaks found in Yajiang (37%, 10/27), which was significantly higher than that in Litang (3.1%, 4/130) and Seda (3%, 2/66). The positive rate of Cryptosporidium spp. in young animals aged <6 months (20.5%, 8/39) was significantly higher than that in older animals aged 12–23 months (0; 0/43) and >24 months (3.3%, 3/90). Three Cryptosporidium species were found by sequence analysis of 18S rRNA locus, namely C. andersoni, C. ryanae, and C. bovis. The total positive rate of G. intestinalis was 15.7% (35/223), with significant differences identified between Yajiang (40.7%, 11/27), Litang (17.7%, 23/130), and Seda (1.5%, 1/66). One genotype (assemblage E) was found by analyzing the sequence of gdh, bg, and tpi loci. Meanwhile, co-infection of Cryptosporidium spp. and Giardia intestinalis was identified in five samples. The present study explores the infection of Cryptosporidium spp. and G. intestinalis from yaks in Ganzi, aiming to enrich our understanding of the occurrence of these protozoa in livestock. Full article

The yak (Bos grunniens), prevalent at an altitude between 3000 and 5000 m above sea level, provides the local inhabitants with meat, milk, leather, fuel (dung), and transport. However, intestinal zoonotic parasites seriously endanger its holistic well-being. The prime concern of this study is to investigate the prevalence of four globally ubiquitous zoonotic enteric protozoans, namely Cryptosporidium spp., G. intestinalis, Blastocystis spp., and E. bieneusi in yaks from different areas of Lhasa, Xizang. In the given study, 377 yak fecal samples from various regions in Lhasa were obtained, including 161 samples from Linzhou County, 66 samples from Dangxiong County, and 150 samples from the Nimu County cattle farms. Molecular identification of these protozoans was done after amplification using PCR and sequencing of PCR-positive samples, and further phylogenetic analysis was performed. The results indicated that the prevalence of Cryptosporidium spp., G. intestinalis, E. bieneusi, and Blastocystis spp. in yak farms in Linzhou County was 48.5, 22.9, 47.8, and 90.7%; 65.2, 13.6, 72.7, and 87.9% in Dangxiong County; and 56.0, 29.3, 58.0, and 80.0%, respectively, in Nimu County. The results of this study provide a basic reference for preventing and controlling intestinal parasites in yaks in Lhasa, Xizang. Full article

The yak (Bos grunniens), the only large domesticated species endemic to the Qinghai–Tibet Plateau, is a vital resource for local livelihoods and regional economic sustainability. However, yak breeding faces significant challenges, including limited understanding of the genetic architecture underlying quantitative traits, inadequate advanced breeding strategies, and the sterility of hybrid offspring from yak–cattle crosses. These constraints have hindered genetic progress in key production traits. To address these issues, integrating modern genomic tools into yak breeding programs is imperative. This review explores the application and potential of molecular marker-assisted selection (MAS) and genomic prediction (GP) in yak genetic improvement. We systematically evaluate critical components of genomic breeding pipelines, including: (1) phenotypic trait assessment, (2) sample collection strategies, (3) reference population design, (4) high-throughput genotyping (via genome sequencing and SNP arrays), (5) predictive model development, and (6) heritability estimation. By synthesizing current advances and methodologies, this work aims to provide a framework for leveraging genomic technologies to enhance breeding efficiency, preserve genetic diversity, and accelerate genetic gains in yak populations. Full article

Differences in skin and hair phenotypes between the scapular and ventral regions of yaks (Bos grunniens) are obvious and become more prominent with age. However, the genetic mechanism that causes differences in yak skin at different ages has not been reported. In this study, we investigated the transcriptomic profile of yak skin across different ages (0.5 years, 2.5 years, and 4.5 years) and body sites (scapular and ventral regions). Differential gene expression analysis was initially conducted to explore the transcriptomic differences in skin at different ages and different body sites. Subsequently, weighted gene co-expression network analysis (WGCNA) was employed to analyze the transcriptomic data comprehensively. The results showed that, among all comparison groups, the Y2.5_S vs. Y2.5_V group (regional comparison) exhibited the highest number of DEGs, with 491 genes (179 upregulated and 312 downregulated), followed by the Y2.5_V vs. Y0.5_V group (age comparison), which had 370 DEGs (103 upregulated and 267 downregulated). DEGs such as IGF2BP3, ADCY8, FOSL1, and S100A8 were found in all comparison groups of different ages, and multiple members of the HOX gene family including HOXC10, HOXA9, HOXA6, HOXB9, and HOXB6 were differentially expressed in comparison groups at different sites. Functional enrichment analysis showed that there were more obvious differences in immune function between different ages of skin and more obvious differences in endocrine function between different parts of skin. WGCNA revealed that genes related with immunity such as GLYATL2, ACSL5, and SPDEF were the core genes of the co-expression module associated with the scapula region, and multiple genes related to hair follicle development such as FOXN1, OVOL1, DLX3, HOXC13, and TCHH were found to be the hub genes of the co-expression module associated with the ventral region. Overall, our study provides valuable insights into the transcriptomic complexity of yak skin across different ages and body sites. The differential gene expression patterns and co-expression network modules identified in this study lay the foundation for further research on skin biology and adaptation mechanisms in yaks. Full article

Yak (Bos grunniens) is the main economic animal growing in the Qinghai–Tibet Plateau. Because of its poor growing environment, copper deficiency is common. Studies have shown that appropriate copper supplementation can improve the reproductive performance of heifers. In this study, the primary granulosa cells of yak were isolated, and different copper levels were established by adding copper chelator and copper sulfate. Biochemical, Western blot and transcriptome methods were used to reveal the mechanism of copper on the hormone secretion function of granulosa cells. The results showed that copper promoted hormone secretion by regulating the expression of steroid synthase such as StAR, CYP19A1 and CYP11A1. Transcriptome analysis showed that copper ion levels significantly affected the function of cells, and changes in copper ion level affected genes related to protein phosphorylation, lipid metabolism, lipid biosynthesis, steroid hormone synthesis and the MAPK pathway. In conclusion, copper can promote steroid hormone synthesis in the granulosa cells of yak follicles, and the MAPK signaling pathway may be involved. Full article

The Yushu yak is one of China’s distinctive yak breeds, primarily distributed in the Yushu Tibetan Autonomous Prefecture of Qinghai Province and its surrounding areas. Yushu yaks are not only economically and culturally significant but also play a crucial role in protecting the ecosystem of the Qinghai-Tibet Plateau and promoting sustainable development. However, there are no clear records regarding the ancestry, population structure, and unique traits of Yushu yaks. Therefore, this study conducted an analysis of genetic diversity, population structure, and selection signals in Yushu yak populations, aiming to provide references for the conservation and utilization of the breed genetic resources. The results of the analysis showed that the Yushu yak population has high genetic diversity and low inbreeding coefficients, indicating a stable genetic structure. Population structure analysis revealed that the Yushu yak lineage is unique, with limited gene flow between domestic and wild yaks. Functional enrichment analysis of positively selected genes in Yushu yaks indicated prominent selection features related to growth and development as well as energy metabolism. Additionally, we classified the Yushu yak breeding bulls into family lineages based on kinship, which is essential for improving the efficiency of utilizing genetic resources and scientifically managing the population. Full article

Variations in salinity levels in aquaculture significantly influence fish physiology, impacting population dynamics and industry viability. This study aimed to examine the physiological response of the freshwater drum (Aplodinotus grunniens) to differing salinity conditions, assessing its potential for cultivation in brackish water environments. Fish averaging 45 ± 0.1 g were subjected to acute salinity tests across three groups: a control group at 0‰ and experimental groups at 7.5‰ and 15‰ over four days. The initial findings indicated that A. grunniens could tolerate salinity levels up to 15‰ without adverse effects. Key biochemical markers, such as aspartate aminotransferase and alanine aminotransferase, exhibited significant fluctuations but decreased over time. Antioxidant enzyme activity increased relative to the control, while malondialdehyde levels declined, indicating effective oxidative stress management. Additionally, digestive enzymes like amylase and lipase demonstrated adaptability to changing salinity. The expression of heat shock proteins 70 and 90 in the gills and livers varied initially but showed no sustained changes. Overall, the results suggest that A. grunniens possesses notable resilience to salinity variations, indicating its suitability for brackish water aquaculture and highlighting the optimal salinity ranges for promoting growth. Full article

This study investigated tick species and spotted fever group rickettsiae (SFGR) infection rates in ticks from yaks in Jiulong County, Sichuan Province, China. Firstly, ticks collected from yaks were meticulously classified through morphological identification. Subsequently, the total DNA of ticks was extracted, and specific partial sequences of their ITS-2 region, as well as the ompA and ompB genes of SFGR, were amplified using PCR. The positive PCR products were sequenced and compared thoroughly against the NCBI database. A phylogenetic analysis was conducted for ITS-2, ompA, and ompB to determine the species of tick and the SFGR. The results revealed that a total of 585 ticks were collected, with the most abundant species being R. microplus, which accounted for 52.65% (308/585) of the total and was followed by I. ovatus (32.99%, 193/585), I. acutitarsus (8.89%, 52/585), and D. everestianus (5.50%, 32/585). Furthermore, SFGR was detected in 63.93% (374/585) of the ticks. Notably, the infection rate of SFGR in semi-agricultural and pastoral areas was significantly higher at 70.60%, compared to 45.10% in pastoral areas (p < 0.01). Overall, this study marks the first investigation into the prevalence of SFGR in Jiulong County and highlights the high infection rate of SFGR in ticks, with R. raoultii being the predominant species. Full article

Bos frontalis (Mithun) and Bos grunniens (yak) are crucial to the culture, food security, and economy of Southeast Asia, especially in India and China, respectively. Their genetic closeness to Bos indicus (indicine cattle) and Bos taurus (taurine cattle) necessitates precise methods for meat origin authentication. This study introduces a DNA-based technique to distinguish Mithun and yak species using the alkaline lysis (AL) protocol for DNA extraction, followed by species-specific polymerase chain reaction (PCR) to amplify unique mitochondrial D-loop regions, yielding 489 bp and 422 bp amplicons, respectively. The AL-PCR method showed high specificity for both species, with no cross-amplification with other related species. The method’s effectiveness was validated across various sample preparations, including raw, cooked, autoclaved, microwaved, and fried samples. The AL-PCR assay is highly sensitive, detecting as little as 1 pg of Mithun DNA and 100 pg of yak DNA, and can identify down to 0.1% of these species in binary mixtures. This approach is rapid and cost-effective, offering significant benefits for consumer protection, promoting Mithun and yak farming, and addressing food safety and traceability issues. Full article

High-quality oocyte production strategies play an important role in animal-assisted reproductive biotechnologies, and rapamycin (Rap) has been commonly used to increase the development potential of mammalian oocytes. The purpose of this study is to evaluate the effects and possible molecular mechanisms of rap on the maturation of yak oocytes. Different concentrations of Rap were supplemented during in vitro maturation (IVM) of yak oocytes. The maturation rates of oocytes and development rates of parthenogenetically activated embryos were assessed. The levels of 17β-estradiol (E2) were detected via ELISA, and the expression of autophagy-related factors, steroidogenic enzymes, and HIF-1α was detected via qRT-PCR, western blotting, and fluorescence microscopy, respectively. In addition, the impacts of E2 and HIF-1α on Rap-mediated oocyte autophagy were investigated by investigating the activities of E2 and HIF-1α. Our results showed that 0.1 nM Rap substantially enhanced the developmental ability of yak oocytes. In this group, the levels of E2, CYP19A1, CYP17A1, and autophagy-related factors were also significantly increased, and the expression of ATG5 and BECN1 in subsequent embryos was also increased. Further analysis revealed that Rap tends to enhance the development competence of yak oocytes and that the levels of autophagy-related factors are reduced when the activity of E2 or HIF-1α is inhibited. Furthermore, the levels of E2, CYP19A1, and CYP17A1 were downregulated when the activity of HIF-1α was inhibited, and the levels of HIF-1α were also significantly reduced by the estrogen receptor antagonist G15. Nevertheless, the levels of CYP11A1 mRNA in mature yak COCs were not significantly different among these groups, a phenomenon which implies that the levels of E2 were not correlated with the CYP11A1 content in yak COCs. There was an increasing tendency for the development competence of yak oocytes at the optimum concentration of Rap during IVM. The potential underlying mechanism is that Rap can activate autophagy and upregulate the levels of E2 and HIF-1α in mature oocytes. Additionally, the levels of both E2 and HIF-1α are regulated by each other and involve Rap-regulated autophagy in oocytes. Full article