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Introduction: There are few studies on the effect of rumen fluid transplantation on the fecal flora of yaks. Yak fecal flora is closely related to their health. This study aimed to evaluate the effects of rumen fluid transplantation on growth performance and fecal flora indicators. Methods: Twenty 6-month healthy male yaks (weight: 57.20 ± 7.80 kg) were selected from grazing yaks in an alpine meadow pasture at an altitude of approximately 3,400 m. They were then transferred to a farm and randomly divided into a control group (CON; n = 10) and a rumen fluid transplantation group (RT; n = 10). Separate single-pen rearing was performed in two pens using the same rearing environment and feeding method, and all yaks were earmarked for identification. In addition, 10 yaks that had been adapted to stall fattening feed in 1 month were selected as the rumen fluid donor group to provide fresh rumen fluid. Ruminal fluid transplantation trials were conducted on the 1st, 3rd, and 5th weeks. Overall, 1 L of ruminal fluid was transplanted to each yak in the RT and CON groups. The formal trial then began with both groups fed the same diet. After this, yak feed intake was recorded daily; yaks were weighed on days 1, 30, and 60 of the formal trial; and yak feces were collected directly from the ground on days 1, 4, 7, 14, 30, and 60 to compare the microbial composition of the feces using 16S rRNA sequencing data. Results: The results showed that rumen fluid transplantation significantly increased the alpha diversity of fecal microflora (P < 0.05), and on day 30 of the experiment, both the operational taxonomic unit (OTU) and Shannon index were significantly higher in the RT group than the CON group (P < 0.05). In the principal coordinate analysis (PCoA) plot, the intestinal flora of the RT group was significantly different (P < 0.05) on days 1–7 but not significantly different after day 14. In contrast, the intestinal flora of the CON group was significantly different (P < 0.05) on days 1–14 but not significantly different after day 30. Compared with the CON group, the relative abundance of Firmicutes in the RT group was significantly lower on days 1, 4, 7, and 14 (P < 0.05); the relative abundance of Bacteroidetes in the RT group was significantly higher on days 1, 4, 14, and 30 and significantly lower on day 7 (P < 0.05); the relative abundance of Tenericutes in the RT group was significantly higher on day 30 (P < 0.05); the relative abundance of Actinobacteria in the RT group was significantly higher on day 60 (P < 0.05); the relative abundance of Ruminococcaceae_UCG-005 in the RT group was significantly lower on days 4, 7, 14, and 60 (P < 0.05); the relative abundance of Unidentified in the RT group was significantly higher on days 1, 4, and 7 days (P < 0.05); and the relative abundance of Rikenellaceae_RC9_gut_group , Bacteroides , and Christensenellaceae_R-7_group in the RT group was significantly higher on day 1 (P < 0.05). Moreover, Actinobacteria was positively correlated with ADG and negatively correlated with DMI; Tenericutes was positively correlated with weight and negatively correlated with F/G. Metabolism of terpenes and polyketones, metabolism of other amino acids, and energy metabolism were higher in the RT group than in the CON group. LEfSe analysis showed that 32 species were more abundant in the RT group and 11 in the CON group. In conclusion, our findings suggest that rumen fluid transplantation improved the stability of the intestinal tract of yaks, improved the immunity of yaks, and reduced the occurrence of intestinal diseases; rumen fluid transplantation remodeled the structure of the intestinal flora, shortened the time of remodeling the intestinal flora of yaks during the transition period, and accelerated yak adaptation to digest housed rations, reducing the DMI. The findings of this study provide new insights into yak microbial community transplantation and a reference for improving feed efficiency in the yak industry. [ABSTRACT FROM AUTHOR]

Simple Summary: The purpose of this study is to investigate the effect of Rap on yak oocyte maturation and its underlying molecular mechanisms. During in vitro maturation (IVM), different concentrations of Rap were administered to evaluate both the maturation rate and embryo development rate. The levels of E2 were measured using ELISA, while the expression of autophagy factors, steroidogenic enzymes, and HIF-1α was analyzed through qRT-PCR, western blot, and immunofluorescence techniques. It was found that 0.1 nM Rap significantly enhanced the developmental capacity of yak oocytes and increased the levels of E2, aromatase, CYP17A1, and various autophagy factors. Inhibition of E2 or HIF-1α diminished the effects of Rap. Furthermore, the inhibition of HIF-1α resulted in decreased levels of E2, aromatase, and CYP17A1, while estrogen receptor antagonists were observed to reduce HIF-1α levels. These results indicate that appropriate concentrations of Rap can promote autophagy by upregulating 17β-estradiol and HIF-1α, thereby improving the developmental potential of yak oocytes. Additionally, E2 and HIF-1α appear to mutually regulate each other in the context of Rap-induced autophagy. 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. [ABSTRACT FROM AUTHOR]

Indian yaks (Bos grunniens) have experienced a significant decline in their population in recent years, primarily due to reduced economic returns from bovid products and the lack of mainstream markets for yak milk and meat. This decline has led to a decreased interest among younger generations in continuing the tradition of nomadic yak herding. To establish effective conservation strategies and improvement plans, it is imperative to conduct in-depth studies on these animals, uncovering their genetic intricacies and identifying key genomic variants associated with adaptive traits. The present study focuses on whole-genome sequencing data from diverse Indian yak populations to elucidate the genomic adaptations associated with high-altitude hypoxia tolerance, physiological resilience, coat color variations, and skeletal modifications. Despite the critical role of yaks in these regions, the comprehensive genetic structure and evolutionary dynamics of these animals remain largely unexplored. Through comparative analyses using interpopulation statistical methodologies, including Fixation Index (FST) and Nucleotide Diversity Ratio (θπ), we examined the genetic makeup of Arunachali, Himachali, and Ladakhi yak populations alongside the Chinese Jinchuan yak. This analysis identified genomic loci subjected to selective pressures, revealing a suite of candidate genes indicative of adaptation to distinct environmental niches. Our integration of FST and θπ analyses highlighted substantial genetic signatures of selection, particularly in the Ladakhi yak, which exhibits enhanced adaptation to high-altitude environments. Notably, Ladakhi yaks demonstrated enriched pathways associated with altitude adaptation, underscoring their superior resilience compared to other Indian yak breeds. Comparative analyses between Indian and Chinese yaks unveiled distinctive genetic profiles, with Chinese yaks showing enrichment in pathways associated with tameness and domestication. These findings provide valuable insights into the molecular underpinnings of high-altitude adaptation and the diverse selective forces shaping the genomes of yak populations. Our study will contribute crucial knowledge on the genetic relationships between Indian yak populations, which is essential for the conservation of this native germplasm. [ABSTRACT FROM AUTHOR]

BACKGROUND: This study aimed to explore how interactions between reactive oxygen species (ROS) and reactive nitrogen species (RNS) affect oxidative properties, nitrosative properties, and myofibrillar protein degradation during postmortem aging of yak meat. RESULTS: Yak longissimus dorsi was incubated with saline, ROS activator (H2O2)/inhibitor N‐Acetyl‐L‐cysteine (NAC) and RNS activator S‐Nitrosoglutathione (GSNO)/inhibitor L‐NAME hydrochloride (L‐NAME) combined treatments at 4 °C for 12, 24, 72, 120, and 168 h. The results indicated that regardless of whether RNS was activated or inhibited, activated ROS played a dominant role in myofibrillar protein degradation by oxidative modification to increase carbonyl content, disulfide bonds, surface hydrophobicity, and dimerized tyrosine while decreasing sulfhydryl content, thereby degrading nebulin, titin, troponin‐t and desmin. Notably, the Warner–Bratzler shear force (WBSF) of the H2O2 + L‐NAME group was the smallest, whereas that of the NAC + GSNO group was smaller than that of the NAC + L‐NAME group. CONCLUSION: These findings provide new insights into meat tenderization patterns through the interaction between ROS and RNS. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Introduction: Chinese herbal medicines are relatively inexpensive and have fewer side effects, making them an effective option for improving health and treating diseases. As a result, they have gained more attention in recent years. The weaning period is a critical stage in the life of yaks, often inducing stress in calves. Weaning stress, along with dietary changes, can lead to a decline in physical fitness and immune function, making yaks more susceptible to diarrhea and resulting in high mortality rates during this period. Therefore, our study aimed to address this issue by incorporating traditional Chinese medicine (TCM) formulas into the diet of yaks during the weaning period. Methods: Following a dialectical analysis, three TCM formulas, mainly composed of Paeonia lactiflora, Coptis chinensis , and Dandelion , were identified for their anti-inflammatory, antioxidant, and immune enhancing potentials. We explored the possible molecular mechanisms of these TCM formulas using network pharmacology analysis and investigated their effects on the physiology of yaks through metabolomics. Results: Network pharmacology analysis revealed several key target proteins in the protein–protein interaction (PPI) network between three formulas and immune-related genes, including PIK3R1 , PIK3CA , JAK2 , PTK2, and PYPN11. The key target proteins in the PPI network associated with metabolism-related genes included ENPP1 , CYP1A1 , PTGS1 , members of the CYP1 family, and EPHX2. GO analysis of co-targets revealed highly enriched pathways such as protein phosphorylation, plasma membrane, and one-carbon metabolic processes. Metabolomics revealed significant changes in the abundance of metabolites including dimethyl sulfoxide, tyrphostin A25, and thromboxane A2 in the intestines of weaned yaks supplemented with these Chinese herbal compounds. Significant changes were also observed in pathways such as vitamin A metabolism, chloroalkane, and chloroalkene degradation. Discussion: Based on these findings, it can be inferred that TCM formulas improve the physical fitness of weaned yaks by enhancing antioxidant capacity, boosting immunity, and reducing intestinal inflammation. This study preliminarily elucidates the pharmacological mechanisms by which TCM formulas prevent diarrhea and improve physical fitness in weaned yaks through metabolomics and network pharmacology, paving the way for further evaluation of the effectiveness of these three formulas. [ABSTRACT FROM AUTHOR]

Introduction: Bovine coronavirus (BCoV) is an important pathogen of enteric and respiratory disease in cattle, resulting in huge economic losses to the beef and dairy industries worldwide. A specific and sensitive detection assay for BCoV is critical to the early-stage disease prevention and control. Methods: We established a specific, sensitive, and stable assay for BCoV nucleic acid detection based on CRISPR/Cas13a combined with reverse transcription recombinase-aided amplification (RT-RAA) technology. The specific primers for RT-RAA and CRISPR RNA (crRNA) were designed in the conserved region of the BCoV nucleocapsid (N) gene. Results: The detection limit of the RT-RAA CRISPR/Cas13a assays for BCoV detection was 1.72 copies/μl, and there were no cross-reactions with the other 10 common bovine enteric and respiratory disease-associated pathogens. The coefficient of variations (CVs) of within and between batches were less than 4.98 and 4.58%, respectively. The RT-RAA-CRISPR/Cas13a assays work well in clinical samples of cattle and yak, the BCoV positive rate of 84 clinical samples detected by RT-RAA-CRISPR/Cas13a assays was 58.3% (49/84), it was notably higher than that of RT-qPCR (2.4%, 2/84; p < 0.001). The 49 positive samples detected by RT-RAA-CRISPR/Cas13a assays were further confirmed as BCoV by Sanger sequencing. Discussion: A specific, sensitive, and stable assay based on RT-RAA-CRISPR/Cas13a assays for BCoV was developed, providing new technical support for the clinical detection and epidemiological monitoring of BCoV. [ABSTRACT FROM AUTHOR]

Simple Summary: Methionine is an essential amino acid for animal growth and development. In this study, we added four different doses of methionine to the yak basal diet to explore the impact of adding methionine on RNA editing sites in yak muscle tissue. After filtering, we detected a total of 1116 RNA editing sites, the main types of which are T-to-C and A-to-G. Most of them were enriched in muscle development pathways, such as extracellular matrix (ECM) interactions and thyroid hormone synthesis. The two significant RNA editing sites present high-risk editing types. This provides further understanding of the mechanism of yak muscle tissue and regulation of gene expression after the addition of methionine to daily rations. Methionine is an amino acid necessary for the growth and development of all animals. Glutathione produced during methionine metabolism can reduce damage to cells caused by oxidative stress. Supplementing restricted amino acids in animals by scientific means will be beneficial to protein synthesis, which will affect the growth and development of animals and will bring huge economic benefits when applied to actual production and life. In this study, we collected three muscle tissues from 24 male Maiwa yaks, which were fattened for three months with different methionine concentrations in their diet. RNA-seq was performed to obtain expression reads. A total of 1116 editing sites were identified by at least two software; the editing site types were mainly T-to-C and A-to-G mutations. We found two significant RNA editing sites presenting high-risk editing types. One was located on the MSRA gene that regulates the reduction of methionine, and the other can make changes to the properties of encoded proteins. This provides further understanding of the mechanism of yak muscle tissue and regulation of gene expression after the addition of methionine to daily rations. [ABSTRACT FROM AUTHOR]

Simple Summary: Circular RNA (circRNA), a non-coding RNA that regulates gene expression, plays significant biological roles. Understanding the role of yak lactation and mammary gland development is crucial. This study conducted Circular RNA sequencing (circRNA-Seq) analysis of yak mammary tissues during the lactation (LP) and dry period (DP) stages. A total of 18,905 circRNAs were identified in yak mammary tissues, and the differentially expressed circRNAs (DECs) may contribute to milk synthesis and composition regulation. This study provides a valuable resource for enhancing yak circRNA databases, marking its particular significance. Lactation is a complex physiological process regulated by numerous genes and factors. Circular RNA (circRNA), a non-coding RNA, acts as a molecular sponge that sequesters microRNAs (miRNAs) to regulate target gene expression. Although circRNA has been linked to mammary gland lactation, its specific role in yaks remains underexplored. This study employed circular RNA sequencing (circRNA-seq) to examine the differential expression of circRNAs in yak mammary tissues during lactation and the dry period. Additionally, an enrichment analysis of the differentially expressed circRNAs (DECs) was performed. A competing endogenous RNA (ceRNA) network was then constructed to explore the potential of their roles in lactation and mammary gland development. We detected 18,905 circRNAs in yak mammary tissue, among which 302 showed differential expression. The host genes of these DECs were enriched in functions and pathways associated with yak milk synthesis and composition. Through the construction of a ceRNA network and the enrichment analysis of associated mRNAs, this study identified ceRNAs potentially involved in regulating lactation and mammary gland development. In conclusion, circRNAs in yak mammary tissues were identified and analyzed across lactation and dry periods, establishing a ceRNA network related to lactation regulation. These findings provide novel insights into the regulatory mechanisms governing lactation in yaks (Bos grunniens). [ABSTRACT FROM AUTHOR]

Simple Summary: This study utilized small RNA sequencing to explore how the expression of miRNAs differs in milk-derived exosomes from yaks living at different altitudes. The analysis revealed distinct miRNAs associated with yak adaptations to environmental pressures such as mastitis, viral infections, and heat stress. These findings suggest that miRNAs carried by yak milk-derived exosomes play a crucial role in yak resilience, disease resistance, and immune regulation, offering valuable insights for a deeper understanding of yak adaptation. Yaks are a rare and unique animal species inhabiting the Qinghai–Tibet Plateau; they are renowned for their remarkable ability to thrive in harsh environments. Milk-derived exosomes, tiny vesicles containing various biological molecules, play crucial roles in numerous pathological and physiological processes, including cell growth, development, and immune regulation. This study delved into the microRNA expression profiles of yak milk-derived exosomes collected from both high- and low-altitude populations using small RNA sequencing. These miRNAs were found to be implicated in pathways associated with mammary gland inflammation, virus infection regulation, and heat stress response. Functional enrichment analyses, utilizing GO and KEGG databases, revealed that the target genes of these differentially expressed miRNAs are enriched in signaling pathways crucial for Th17 cell differentiation and the Ras-MAPK signaling pathway. In conclusion, this research illuminates the adaptive mechanisms of yaks through the differential expression of miRNAs in their milk-derived exosomes across varying environmental conditions. These findings provide a valuable foundation for future investigations into yak resilience and the potential of milk-derived exosomes as tools for disease management and immune modulation. [ABSTRACT FROM AUTHOR]

Cumulus granulosa cells (CGCs) are somatic cells surrounding the oocyte that play an important role in oocyte growth, meiotic maturation, ovulation, and fertilization in mammals. Therefore, revealing the molecular mechanisms related to the development and function of CGCs is essential for further understanding the regulatory network in female reproduction. MSX2 belongs to the highly conserved msh homeobox gene family and plays diverse roles in different biological processes. This study cloned the coding sequence (CDS) of the yak MSX2 gene and detected the abundance and localization of MSX2 in the major female reproductive organs. The results indicated that the CDS of this gene included 747 base pairs and encoded 248 amino acids. The abundance of MSX2 mRNA was highly expressed in the luteal phase of the yak ovary during the estrous cycle, and MSX2 protein was widely expressed in different female reproductive organs, including the ovary, corpus luteum, uterus, and oviduct. Repressing MSX2 abundance in yak CGCs declined the cell viability and defective steroidogenesis. Several genes abundances related to cell proliferation, apoptosis, and sterogenesis also changed after MSX2 knockdown. MSX2 overexpression had the opposite effect on cell viability in yak CGCs. These results reveal the specific mechanism by which MSX2 regulates the development and function of yak CGCs and give novel and valuable insights into the mechanisms involved in yak reproduction. • Detecting MSX2 expression in yak reproductive organs. • MSX2 is crucial for steroidogenesis in yak cumulus granulosa cells. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. Hybrids between closely related but genetically incompatible species are often inviable or sterile. Cattle-yak, an interspecific hybrid of yak and cattle, exhibits male-specific sterility, which limits the fixation of its desired traits and prevents genetic improvement in yak through crossbreeding. Transcriptome profiles of testicular tissues have been generated in cattle, yak, and cattle-yak; however, the genetic variations underlying differential gene expression associated with hybrid sterility have yet to be elucidated. We detected differences in the cellular composition and gene expression of testes from yak and cattle-yak at 3 mo of age, 10 mo of age, and adulthood. Histological analysis revealed that the most advanced germ cells were gonocytes (prospermatogonia) at 3 mo and spermatocytes at 10 mo. Complete spermatogenesis occurred in the seminiferous tubules of adult yak, whereas only spermatogonia and a limited number of spermatocytes were detected in the testis of adult cattle-yak. Transcriptome analysis revealed 180, 6,310, and 6,112 differentially expressed genes (DEG) in yak and cattle-yak at each stage, respectively. Next, we examined the spermatogenic cell types in the backcross generation (BC1) and detected the appearance of round spermatids, indicating the partial recovery of spermatogenesis in these animals. Compared with those in cattle-yak, 272 DEG were identified in the testes of BC1 animals. Notably, we discovered that the expression of X chromosome–linked genes was upregulated in the testis of cattle-yak compared with yak, suggesting a possible abnormality in the process of meiotic sex chromosome inactivation in hybrid animals. We next screened DEG harboring structural variations (SV) and identified a list of SV genes associated with spermatogonial development, meiotic recombination, and double-strand break repair. Furthermore, we found that the SV genes ESCO2 (establishment of sister chromatid cohesion N-acetyltransferase 2) and BRDT (bromodomain testis associated) may be involved in meiotic arrest of cattle-yak spermatocytes. Overall, our research provides a valuable database for identifying structural variant loci that contribute to hybrid sterility. [ABSTRACT FROM AUTHOR]

Yak breeding plays a crucial role in sustaining livestock production and ensuring the livelihoods of communities in the mountainous regions of China. With the aim of improving production traits in yaks, this study explores the potential of harnessing genetic diversity and marker-assisted selection (MAS) techniques. The genetic diversity of yak populations is a valuable resource that can be tapped into to enhance desirable traits such as meat quality, milk yield, disease resistance, and adaptability to harsh environments. This study emphasizes the importance of conducting comprehensive genetic characterization of yak populations across different regions in China to identify unique genetic variations and breed-specific traits. Furthermore, the integration of MAS techniques can facilitate the selection of superior individuals for breeding programs. By identifying and utilizing genetic markers associated with desired traits, breeding strategies can be optimized, resulting in accelerated genetic improvement. Various molecular markers, such as single nucleotide polymorphisms (SNPs), microsatellites, and candidate genes, can aid in the identification of economically important traits in yaks. The availability of high-throughput genotyping technologies and advanced statistical models further support the efficient implementation of MAS in yak breeding programs. [ABSTRACT FROM AUTHOR]

Comparative analysis of divergence in serum chemical derivatives among yaks living in ecological habitats at different altitudes was performed to determine the physiological adaptation basis in blood metabolites of yaks at extreme high altitudes due to long-term natural selection of plateau ecological environment. Twenty serum samples from yaks were collected, including 10 from those living on the Qinghai-Tibet Plateau at altitudes above 5000 m for a long time and 10 from those living in ecological regions at altitudes of ~4000m. Results revealed 592 metabolites in all samples, of which the highest proportion was attributed to amino acids and their metabolites (18.58%), followed by organic acids and their derivatives (16.20%). Meanwhile, 89 significantly different metabolites (SDMs) were identified between groups, of which 55 were significantly upregulated (e.g., 3-methylcrotonyl glycine, 2-hydroxy-3, and 5-dinitrobenzoic acid, etc.) in the yaks living at extremely high altitude. In addition, 28 metabolites (fumaric acid, serotonin, glycochenodeoxycholic acid, and all trans-retinal) were enriched in 55 KEGG signaling pathways and mainly attributed to organismal systems and metabolism. This work further clarified that long-term natural selection at extremely high altitude prompts animals to have visible physiological adaptations in serum. In addition, the serum of yak living at high altitudes is rich in a series of metabolites (e.g., lysophosphatidylethanolamine, γ-linolenic acid, and 12-hydrox) that are helpful for the treatment of cerebrovascular diseases and respiratory diseases and could contribute to the drug development of anti-plateau in the future. [ABSTRACT FROM AUTHOR]

Understanding the change in the habitat distributions and abundance of wildlife in space and time is critical for the conservation of biodiversity and mitigate human–wildlife conflicts (HWCs). Tibetan antelope or chiru (Pantholops hodgsonii), Tibetan gazelle or goa (Procapra picticaudata), Tibetan wild ass or kiang (Equus kiang), and Wild yak (Bos mutus) have been sympatric on the Qinghai–Tibetan plateau (QTP) for numerous generations. However, reviews on the habitat distributions and abundance of these four wild herbivores (WHs), as well as the methods examining the changes in these aspects, are still lacking. Here, we firstly review the distributions and abundance of four major WHs on the QTP across different periods, examining the underlying causes of changes and HWCs. Furthermore, we critically compare three aspects of methods: transect surveys, machine learning (ML), and deep learning (DL) methods of studying WHs. The results show that since the 1990s, the distributions and abundance of WHs have exhibited a trend of initial decline followed by recovery, largely attributed to global climate warming and a decrease in illegal hunting. However, in recent years, the primary challenge has shifted from wildlife protection to balancing the human and wildlife interests within the constraints of limited resources. In the future, we should focus on enhancing the ecological functions of habitats to achieve harmonious coexistence between humans and nature, as well as establishing a scientific compensation mechanism to mitigate human–wildlife conflicts. In order to accurately calculate the changes, we should select appropriate models to analyze the habitats of wildlife based on their specific characteristics and the environmental conditions. Additionally, with the advancement of large models, AI (artificial intelligence) should be utilized for precise and rapid wildlife conservation. The findings of this study also provide guidance and reference for addressing the issues related to wildlife habitats and abundance in other regions globally. [ABSTRACT FROM AUTHOR]

The transition period is a crucial stage in the reproductive cycle for dams and is linked closely with postpartum recovery, reproduction performance, and health. The confronting problem in the yak industry is that transition yaks under a conventional grazing feeding regime endure nutritional deficiency since this period is in late winter and early spring of the Qinghai-Tibet Plateau with the lack of grass on natural pasture. Therefore, this study aimed to investigate the effects of perinatal nutritional supplementation and early weaning on serum biochemistry, reproductive performance, and metabolomics in transition yaks. Eighteen healthy yaks in late pregnancy (233.9 ± 18.3 kg, 2–4 parity) were randomly assigned to three groups: conventional grazing feeding (GF, n = 6), additional nutrition supplementation (SF, n = 6), and additional nutrition supplementation with early weaning (SW, n = 6). Yaks in the GF, SF, and SW groups were free grazing on the same pasture in the daytime from −30 to 90 d relative to parturition. Yaks in SF and SW groups received total mixed ration supplementation in the barn during the night throughout the trial. Calves in the SW group were early weaned and separated from the dam at 60 d postpartum. Maternal body weight was measured at −30 and 90 d, and serum samples were collected to analyze serum biochemistry, hormones, and metabolomics at −15, 30, and 90 d relative to calving. In the SF and SW groups, yaks showed significantly higher body weight gain, serum glucose, globulin, and total protein concentrations. Lipid transportation molecules apolipoprotein B100 and very low-density lipoprotein of SF and SW yaks were significantly increased along with the decreased lipid mobilization products non-esterified fatty acid and β-hydroxybutyric acid when compared to GF yaks at −15 and 30 d. At 90 d, serum non-esterified fatty acid and β-hydroxybutyric acid levels were significantly lower in SW yaks than in SF ones, while apolipoprotein B100 and very low-density lipoprotein levels were significantly higher in SW yaks than in GF yaks. The serum levels of metabolic regulatory hormones, including insulin, leptin, and insulin-like growth factor I were significantly increased, and glucagon was significantly reduced in the SF and SW groups than in the GF group at −15 and 30 d. Among serum reproductive hormones, SF and SW yaks had significantly higher estradiol and progesterone concentrations than GF ones at −15 and 30 d. Follicle-stimulating and luteinizing hormone levels were increased in SW group than in SF and GF ones at 90 d. The calving rates in the following year were 0% (GF), 16.7% (SF), and 83.3% (SW), respectively. The serum metabolomics analysis revealed 848 metabolites in positive mode and 350 in negative mode. With the perinatal nutritional supplementation, the lipid and energy metabolism of transition yaks were improved, meanwhile, lipid mobilization and estrogen production-related pathways were down-regulated. These data suggest that perinatal nutrition supplementation reduces body weight loss, improves glucose and lipid metabolic adaptation to the transition period, and improves yaks' reproductive performance. Additionally, the combination of early weaning and nutritional supplementation results in lower lipid mobilization and up-regulation of lipid transportation and reproductive hormone secretion, which may further contribute to postpartum recovery and acceleration of the reproductive cycle. [ABSTRACT FROM AUTHOR]

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Yak (Bos grunniens) is a large ruminant endemic to the Tibetan plateau. The addition of enzyme complexes to feed can significantly improve their growth performance. Therefore, studying the effects of ruminant compound enzyme preparations dosage on yak rumen microorganisms and production performance is crucial to promoting the development of the yak industry. This study aimed to determine the effects of feeding yaks with different doses of ruminant enzyme compounds on the performance, meat quality, and rumen microorganisms of yaks. Three kinds of experimental diets with doses of 0.5 g/kg (LE group), 1 g/kg (ME group), and 2 g/kg (HE group) were selected to determine the growth index, meat quality, serum biochemical indexes, rumen fluid pH and other indexes of the three experimental groups. Metagenomics studies were used to investigate the differences in rumen microbial composition and function among yak groups, and transcriptome sequencing of the longest dorsal muscle was performed to reveal the expression of differential genes among different groups. It was determined that the levels of dietary enzyme complexes significantly affected growth performance, rumen fluid pH, and serum biochemical indices. At the phylum level, the dominant phylum in all three treatment groups was Bacteroidota, Bacillota, Kiritimatiellota, and Pseudomonadota. At the genus level, Prevotella, Methanobrevibacter, Oscillibacter. Fibrobacter showed statistically significant differences in abundance (p < 0.05). CAZymes family analysis revealed significant differences in GHs, CTs, and CEs among the three groups. Genome-wide differential gene expression in the longest muscle of the yak back was analyzed by RNA-seq between the three experimental groups. Some DEGs were found to be enriched in the ECM, PI3K-Akt, PPAR, and protein digestion and absorption receptor pathways. Combined metagenomics and transcriptomics analyses revealed that some microorganisms were significantly associated with the genes COL11A1, POSTN, and PTHLH, which are involved in growth metabolism. In summary, this study investigated the effects and interrelationships of ruminant complex enzymes on yak performance, meat quality, and rumen environment. The results of this study provide a scientific basis for adding ruminant enzymes to yaks. [ABSTRACT FROM AUTHOR]

Antioxidant peptides could interact with free radicals and excess reactive oxygen species to avoid the organism from oxidative harm; at the same time, antioxidant peptides have the characteristics of high safety, good stability, and wide application. In this study, a strain named XBMU‐SK‐01 with high proteinase activity was isolated and identified from fermented bean curd. The results showed that the strain (XBMU‐SK‐01) with protease activity of 96.2 ± 1.3 U/mL was identified as Bacillus cereus based on 16S rDNA gene sequencing. The yak casein antioxidant peptide was prepared through fermentation using Bacillus cereus (XBMU‐SK‐01), and the fermentation conditions were optimized by response surface methodology (RSM) based on the Box–Behnken design, using 1,1‐diphenyl‐2‐trinitrophenylhydrazine (DPPH) radical scavenging rate and the degree of hydrolysis (DH) as indicators. It was found that the optimal fermentation conditions for the preparation of antioxidant peptides from yak casein by Bacillus cereus (XBMU‐SK‐01) were as follows: pH of 7.96, temperature of 32.5°C, and inoculation amount of 6.99%. Under these conditions, the DPPH free radical scavenging rate could reach 78.19% ± 0.21%, and DH is 19.8% ± 0.15%. Following the sequence analysis of antioxidant peptides, 11 distinct polypeptide sequences were identified: FPP, AFK, GILF, PAAP, VIGP, TIPT, IEQI, FPFF, IPLLP, KPWIQP, and EAGPPGP. This study is aimed at establishing a preparation pathway for peptides with high antioxidant activity and proposes a novel method for producing high‐value products from yak milk. [ABSTRACT FROM AUTHOR]

The aim of the experiment was to study the effects of low protein concentrate supplementation with per rumen lysine and per rumen methionine on serum immunity indexes, lactation hormones and ru‐ men fermentation parameters of lactating grazing yaks. Twenty-four lactating grazing yaks in good condi‐ tion and similar body weight were selected as test animals and randomly divided into three groups with eight replicates in each group. The high protein group (HP group) was fed concentrate supplement with 16.66% crude protein level, the medium protein group (MP group) was fed concentrate supplement with 15.05% crude protein level and additional 0.23% per rumen lysine and 0.03% per rumen methio‐ nine, and the low protein group (LP group) was fed concentrate supplement with 13.57% crude protein level and additional 0.46% per rumen ly‐ sine and 0.07% per rumen methionine. The pretest period was 8 days and the formal test was conducted for 40 days. The results showed that, ① there were no significant differences (P>0.05) in growth performance indicators among the three lactation yak groups; ② there were no significant differences (P>0.05) in rumen fermentation parameters among the three lactation yak groups, and there was a tendency to increase the concentration of acetic and propi‐ onic acids (0.05≤P<0.10); ③ there was no significant difference in blood immunity indexes among the three groups of lactating yaks (P>0.05), and immunoglobulin G tended to increase (0.05≤P<0.10); ④ there was no significant difference (P>0.05) between the blood immunity indexes of lactating yaks in the three groups. In conclusion, it can be seen that reducing the crude protein level in the concentrate supplement of lactating yaks by 1.5%-3.0% and supplementing the corresponding per rumen amino ac‐ ids did not affect the rumen fermentation of lactating yaks, nor did it affect the immune indexes and the secretion of lactation hormones of lactating yaks. [ABSTRACT FROM AUTHOR]

Long noncoding RNAs (LncRNAs) play essential roles in numerous biological processes in mammals, such as reproductive physiology and endocrinology. Cryptorchidism is a common male reproductive disease. Circadian rhythms are actively expressed in the reproductive system. In this study, a total of 191 LncRNAs were obtained from yak testes and cryptorchids. Then, we identified NTRK2's relationship to circadian rhythm and behavioral processes. Meanwhile, the ceRNA (LncRNA-MSTRG.19083.1/miR-429-y/NTRK2) network was constructed, and its influence on circadian rhythm was revealed. The results showed that NTRK2 and LncRNA-MSTRG.19083.1 were significantly upregulated, and miR-429-y was obviously decreased in cryptorchid tissue; NTRK2 protein was mainly distributed in the Leydig cells of the testis. In addition, the upregulation of the expression level of miR-429-y resulted in the significant downregulation of LncRNA and NTRK2 levels, while the mRNA and protein levels of CREB, CLOCK, and BMAL1 were significantly upregulated; the knockdown of miR-429-y resulted in the opposite changes. Our findings suggested that LncRNA-MSTRG.19083.1 competitively binds to miR-429-y to target NTRK2 to regulate circadian rhythm through the cAMP pathway. Taken together, the results of our study provide a comprehensive understanding of how the LncRNA-miRNA-mRNA networks operate when yak cryptorchidism occurs. Knowledge of circadian-rhythm-associated mRNAs and LncRNAs could be useful for better understanding the relationship between circadian rhythm and reproduction. [ABSTRACT FROM AUTHOR]

Simple Summary: In order to increase the economic benefits of breeding, local people often use a high-concentrate diet to feed yaks. The appropriate concentrate ratio can improve rumen fermentation and production performance. However, long-term feeding with a high-concentrate diet can induce a series of nutritional metabolic diseases. At present, there are limited reports on the effects of a high-concentrate diet on growth performance, serum biochemistry, and rumen flora in yaks. This study suggested that high-concentrate diets raised the average daily feed intake (ADFI), average daily gain (ADG), and albumin (ALB) concentration. The relative abundance of Firmicutes, Christensenellaceae_R-7_group, and NK4A214_group was greater in the HC group, while the levels of glycosaminoglycan degradation, apoptosis, and ECM–receptor interactions were greater in the LC group. These results provide a basis for the utilization of diets containing high concentrate levels in yak fattening and production. The aim of this study is to determine the effects of a high-concentrate diet on growth performance, serum biochemical indexes, and rumen microbiota in house-fed yaks. Sixteen male yaks (body weight, 151.73 ± 14.11 kg; 18 months) were randomly allocated into two dietary treatments: a group with a low level of concentrate (n = 8, LC, concentrate–forage = 40:60) and a group with a high level of concentrate (n = 8, HC, concentrate–forage = 60:40). We found that compared with the LC group, the average daily feed intake (ADFI), the average daily gain (ADG), and the serum albumin (ALB) concentration in the HC group were significantly increased (p < 0.05). The rumen bacterial compositions also differed significantly between the groups, as indicated by principal coordinate analysis (p < 0.05). Firmicutes and Bacteroidota were the main dominant phyla of rumen bacteria in yaks. Compared with the LC group, the relative abundance of Firmicutes in the HC group was significantly increased (p < 0.05) and the relative abundance of Bacteroidota was significantly decreased (p < 0.05). At the genus level, Rikenellaceae_RC9_gut_group, Succiniclasticum, Prevotella, Christensenellaceae_R-7_group, and NK4A214_group had the highest relative abundance. The relative abundance of Christensenellaceae_R-7_group in the HC group was significantly higher than that in the LC group (p < 0.05). The PICRUSt 2 results showed a significant enrichment in glycosaminoglycan degradation, apoptosis, and ECM–receptor interaction in HC relative to LC (p < 0.05). In conclusion, high-concentrate diets can enhance growth performance and alter the compositions and functions of ruminal bacterial communities in yaks. [ABSTRACT FROM AUTHOR]

In order to explore the differences in subcutaneous fat metabolism and pathway information in yaks under different feeding conditions, this experiment used Illumina high-throughput sequencing technology to sequence the transcriptome of subcutaneous fat tissues of yaks under different feeding conditions and analyzed them bioinformatically. 9 naturally grazed yaks at 18 months of age were randomly divided into 3 groups, one group (G18_SF) was slaughtered, one group (G24_SF) continued to graze until 24 months of age was slaughtered, and one group (F24_SF) was housed until 24 months of age was slaughtered, and subcutaneous fat tissue was collected from the back of the yaks. A total of 15,261 expressed genes were identified in the nine samples, with 13,959 coexpressed genes and 533 differential expressed genes (DEGs), G18_SF vs F24_SF 133 DEGs, G18_SF vs G24_SF 469 DEGs, F24_SF vs G24_SF 5 DEGs. GO functional annotation analysis found that DEGs were mainly annotated in BP and CC, which included biological regulation, metabolic processes and cellular processes. KEGG revealed that the DEGs are mainly enriched for PPAR signaling pathway, AMPK signaling pathway and other pathways related to lipid metabolism. This study provides a scientific basis for further research on the effects of mRNA on subcutaneous fat in yaks under different feeding conditions. [ABSTRACT FROM AUTHOR]

Rumen-protected glucose (RPG) and taurine (TAU) are crucial for the nutrition and physiology of ruminants, enhancing production performance and mitigating negative energy balance. This study aimed to assess the impact of RPG levels and TAU supplementation on the body weight, antioxidant capacity, immune function and stress responses in yaks before and after transport. Thirty-two healthy male yaks, aged 3 years and weighing 172.5 ± 10.2 kg, were randomly assigned to one of four dietary treatments: (1) low RPG and low TAU (LRLT), with 1% RPG and 5 g/d TAU; (2) low RPG and high TAU (LRHT), with 1% RPG and 15 g/d TAU; (3) high RPG and low TAU (HRLT), with 3% RPG and 5 g/d TAU; and (4) high RPG and high TAU (HRHT), with 3% RPG and 15 g/d TAU. The yaks were treated with the corresponding diet for 7 days, then received 9 h of transportation, and finally fed the same diet at their destination for 30 days. The weight was measured before and on days 0 and 30 after transport, and the plasma was collected before and on day 0, 10, and 30 after transport for analysis of biochemical, antioxidant, immune, and stress response indicators. We observed that transport increased plasma concentrations of total cholesterol, total protein, lactate dehydrogenase, creatine kinase, malondialdehyde, cortisol and lipopolysaccharides of yaks among treatments, while decreased their BW and plasma IL-10 concentration. Increasing TAU supplementation reduced weight loss (8.42 vs. 11.9 kg) and weight loss percent (4.83% vs. 6.87%) in yaks after transport. The concentration of MDA in plasma was lower in HRHT than in LRLT at day 0 after transport (p = 0.03). The activity of GSH-PX was higher in HRHT than in LRLT at day 10 after transport (p = 0.04). Concentrations of IL-10 at day 0 and 10 after transport was higher in HRHT than in LRLT and HRLT (p = 0.02, p = 0.01, respectively). With the increase of TAU supplementation, concentrations of IL-1β at day 30 after transport (p = 0.02), TNF- α at day 0 after transport (p = 0.02), COR at day 10 (p = 0.03) and 30 (p = 0.05) after transport as well as LPS at day 0 after transport (p = 0.04) decreased. In addition, concentrations of COR at day 0 after transport was lower in LRHT and HRHT than in LRLT (p = 0.03). Based on all the results, we demonstrated that increasing TAU supplementation levels reduced post-transport weight loss in yaks, improved their antioxidant capacity and immune function, and alleviated stress responses. Considering the effect of resistance to transport stress and costs, the optimal treatment identified in this study involved a diet containing 1% RPG and supplemented with 15 g/d TAU. [ABSTRACT FROM AUTHOR]

Yaks are crucial to local herders' economy and agriculture. However, several diseases pose a significant threat to the health of yaks and cause substantial economic losses for herders. Therefore, studying the immune indicators and breeding of yaks has become an important task. This study aimed to investigate the association between single nucleotide polymorphisms (SNPs) of the G protein-activated inwardly rectifying K+ channel 2 (KCNJ6, GIRK2) gene and yak immune indicators, with the goal of identifying potential candidate molecular markers for yak breeding. In this study, we genotyped 192 healthy adult yaks and detected three SNPs (g163684421 C > T, g163688148 C > T, and g163690745 T > C) in the yak KCNJ6 gene. These SNPs were found to be distributed in the yak population. Subsequently, we performed a linkage disequilibrium analysis and found that the linkage disequilibrium levels of g163684421 C > T and g163690745 T > C were relatively high. Through a correlation analysis of yak KCNJ6 gene SNPs and immune indicators, we found that g163684421 C > T and g163690745 T > C were significantly associated with IgA, IgG, IgM, CRP, HP, IL-2, IL-4, IFN-γ, and TNF-α (p < 0.05), and the mutation of these SNPs leads to a decrease in yak immune indicators. On the other hand, g163688148 C > T was significantly associated with IgG, IL-4, IFN-γ, TNF-α, IgA, CRP, and HP (p < 0.05), and the mutation of this SNP leads to an increase in yak immune indicators. In conclusion, we identified SNPs associated with yak immune indicators and found that KCNJ6 gene polymorphisms can serve as candidate molecular markers for yak immune indicators. This study provides valuable genetic resources for marker-assisted selection in yak breeding. The results of this study are of great importance for the research on yak immune indicators and marker-assisted selection in yak breeding. [ABSTRACT FROM AUTHOR]

Simple Summary: Yaks, which are ruminant animals primarily distributed in the Qinghai–Tibet Plateau, have an unclear skeletal muscle development process. This paper investigates the changes of muscle satellite cells and their epigenetic modifications in yak skeletal muscles during the developmental process. These data provide a theoretical basis for the growth and development of yak skeletal muscles. To investigate prenatal muscle satellite cell (MuSC) development and the associated epigenetic modifications in yak. Here, we conducted morphological and protein co-localization analyses of fetal longissimus dorsi muscle at various developmental stages using histology and immunofluorescence staining methods. Our study observed that primary muscle fibers began forming at 40 days of gestation, fully developed by 11 weeks, and secondary muscle fibers were predominantly formed by around 105 days. Throughout development, MuSCs were mainly located between the muscle fiber membrane and the basement membrane, acting as a reserve for the stem cell pool. MuSCs appeared within myotubes only during critical phases of primary and secondary muscle fiber formation. The proliferation of MuSCs gradually decreases until birth. MuSCs with 5mC modification show a trend of increasing first and then decreasing. MuSCs with 5hmC modification also present a dynamic change trend. The 41st day and 11th week are the critical periods for the changes of both. From the 11th week to around the 110th day of gestation, the modification effect of histone H3K4me3 is crucial for MuSCs during the development of the fetal longissimus dorsi muscle. Combined, our data identify key time points for yak fetal skeletal muscle growth and development and demonstrate that DNA methylation and histone modifications in MuSCs are closely related to this process, offering a valuable basis for future research into the molecular mechanisms underlying yak muscle development. [ABSTRACT FROM AUTHOR]

The effects of C-type natriuretic peptide (CNP) pre-treatment on the in vitro maturation (IVM) and developmental competence of yak (Bos grunniens) oocytes were evaluated. The results showed that 100 nM CNP could effectively maintain meiotic arrest of yak oocytes in vitro within 6 h. Yak oocytes matured in two-step IVM (pre-IVM with 100 nM CNP for 6 h followed by conventional IVM for 28 h) yielded a significantly (P <.05) increased cleavage rate, blastocyst rate after in vitro fertilization with cattle spermatozoa compared to the conventional one-step IVM method. The density of transzonal projections (TZPs) decreased after 6 h standard IVM (P <.05), whereas, COCs pre-IVM with 100 nM CNP for 6 h maintained the same density of TZPs compared to the fresh COCs. This pre-IVM resulted in lesser reactive oxygen species level (P <.05). Two-step IVM resulted in the increased glutathione levels, mRNA expression levels of BCL2, BMP15, and GDF9 (P <.05) in oocytes. In conclusion, these results indicate that CNP treatment (100 nM, 6 h) before IVM could enhance the maturation of yak oocytes and developmental competence of their crossbred embryos. This may have important applications in in vitro production of yak crossbred embryos. [ABSTRACT FROM AUTHOR]

Ungulates are essential for maintaining the health of grassland ecosystems on the Tibetan plateau. Increased livestock grazing has caused competition for food resources, threatening ungulates' survival. The survival risk of food resources for ungulates can be quantified by the grazing pressure index, which requires accurate grassland carrying capacity. Previous research on the grazing pressure index has rarely taken into account the influence of wild ungulates, mainly due to the lack of precise spatial data on their quantity. In this study, we conducted field investigations to construct high-resolution spatial distributions for the four endemic ungulates on the Tibetan plateau. By factoring in the grazing consumption of these ungulates, we recalculated the grassland carrying capacity to obtain the grazing pressure index, which allowed us to assess the survival risks for each species. The results show: (1) Quantity estimates for Tibetan antelope (Pantholops hodgsonii), Tibetan wild donkey (Equus kiang), Tibetan gazelle (Procapra picticaudata), and wild yak (Bos mutus) of the Tibetan plateau are 24.57 × 104, 17.93 × 104, 7.16 × 104, and 1.88 × 104, respectively; they mainly distributed in the northern and western regions of the Tibetan plateau. (2) The grassland carrying capacity of the Tibetan plateau is 69.98 million sheep units, with ungulate grazing accounting for 5% of forage utilization. Alpine meadow and alpine steppe exhibit the highest grassland carrying capacity. (3) The grazing pressure index on the Tibetan plateau grasslands is 2.23, indicating a heightened grazing pressure in the southern and eastern regions. (4) The habitat survival risk analysis indicates that the high survival risk (the grazing pressure index exceeds 1.2) areas for the four ungulate species account for the following proportions of their total habitat areas: Tibetan wild donkeys (49.76%), Tibetan gazelles (47.00%), Tibetan antelopes (40.76%), and wild yaks (34.83%). These high-risk areas are primarily located within alpine meadow and temperate desert steppe. This study provides a quantitative assessment of survival risks for these four ungulate species on the Tibetan plateau grasslands and serves as a valuable reference for ungulate conservation and grassland ecosystem management. [ABSTRACT FROM AUTHOR]

Different percentages of jujube yrup (0%, 3%, 6% and 9%) were incorporated into yak milk and fermented using the fermenting agent YF‐L922. The quality characteristics and antioxidant activity of the resulting yogurt were evaluated at days 0, 7, 14, 21 and 28. The results indicated that the pH and acidity of the yogurt were not significantly influenced by the varying additions of jujube syrup during storage (p > 0.05). However, the addition of jujube syrup significantly reduced the water‐holding capacity of the yogurt (p < 0.05). Furthermore, the levels of jujube syrup were significantly and positively correlated with both antioxidant activity and free radical scavenging ability (p < 0.05). The live bacterial count of the yogurt decreased significantly by day 28, although the count of live lactic acid bacteria remained above 106 CFU/mL. Notably, yak yogurt with a 3% addition of jujube syrup achieved a favorable sensory score. The incorporation of jujube syrup resulted in a firmer texture and a more porous microstructure, demonstrating a higher degree of syneresis. Additionally, the inclusion of jujube syrup substantially diminished the animalic odor associated with yak milk, improved flavor acceptability and enhanced the antioxidative properties of yak yogurt. Therefore, yak yogurt augmented with jujube syrup represents a novel product with high nutritional value. [ABSTRACT FROM AUTHOR]

Yaks (Bos grunniens) are the most economically important mammals on the Xizang Plateau, providing milk, meat and income for people. The molecule CaMKII is key to the cellular Ca2+ signalling pathway, which can regulate intracellular environmental homeostasis and bind to a variety of proteins to regulate the location, activity and function of proteins. Calcium as Ca2+ controls the maturation process of oocytes, maintains fertilisation and initiates embryonic development. In this study, immunohistochemistry was used to detect the location and expression of CaMKII at different stages of follicular development. The activator as Ca2+ at 0.20, 0.22 and 0.24 mM and the inhibitor KN-93 at 0.5, 1.0 and 1.5 μM were added to compare maturation rate of oocytes in vitro. Immunofluorescence staining analysed the antioxidant levels of reactive oxygen species (ROS) and glutathione (GSH) and the expression of CaMKII in the mature oocytes.The growth related genes c-fos, epidermal growth factors EGF and EGFR and apoptotic genes BAX, BCL-2, were detected in mature oocytes after 24 h of culture using a real-time quantitative polymerase chain reaction. The results showed that CaMKII was widely distributed in follicular tissues. The GSH level of mature oocytes reached the highest value in 0.24 mM Ca2+ group. The ROS level of mature oocytes reached the highest level in 1.5 μM KN-93 group, and the expression of BCL-2, EGF, EGFR and c-fos mRNA was increased by adding Ca2+.The KN-93 decreased the expression of BCL-2, EGF, EGFR and c-fos genes. The study showed that Ca2+ could regulate the levels of GSH and ROS by activating CaMKII, activity and it improved the maturation rate of oocytes in vitro. HIGHLIGHTS: 1. Ca2+ promotes the biological function by CaMKII of oocytes cells. 2. Ca2+ activates CaMKII activity, regulates GSH and ROS levels, and improves the in vitro maturation rate of yak oocytes. 3. CaMKII is widely distributed in follicular tissues and is most abundantly expressed in oocytes. [ABSTRACT FROM AUTHOR]

Simple Summary: Yaks are indispensable economic animals in pastoral areas, providing local herdsmen with abundant necessities of life. Their meat is of excellent quality and highly favored by the market. As a newly cultivated breed, the Ashidan yak has been under continuous selection and breeding to improve its production performance, which is a long-term goal. The growth traits of yaks are crucial indicators of their economic benefits. Therefore, through the use of SNP molecular marker-assisted selection technology, the early and precise selection of yak growth traits can be achieved. This technology effectively accelerates the pace of genetic improvement and enhances breeding efficiency. The tyrosine protein kinase (TXK) gene, as a member of the non-receptor tyrosine kinase Tec family, plays a vital role in signal transduction mediation. Phospholipase C epsilon 1 (PLCE1), a membrane-associated enzyme, is of paramount importance for the differentiation of myoblasts and the normal functioning of muscle tissue. In recent years, both of these genes have been reported to be associated with the economic traits of animals. This study aimed to investigate the relationship between single nucleotide polymorphisms (SNPs) in the TXK and PLCE1 genes and growth traits in Ashidan yaks and to search for potential molecular marker loci that can influence Ashidan yak breeding. A cGPS liquid microarray was utilized to genotype 232 Ashidan yaks and to analyze correlations between two SNP loci in the TXK and PLCE1 genes and yak body weight, body height, body length, and chest circumference at different periods. The results indicated that the g.55,999,531C>T locus of the TXK gene and the g.342,350T>G locus of the PLCE1 gene were significantly correlated with the growth traits of Ashidan yaks. Among these, individuals with the CC genotype at the g.55,999,531C>T locus showed a significantly higher body length at 6 months old compared to TT individuals, and those with the CT genotype at 12 months old had a significantly higher chest circumference than TT individuals. At the g.342,350T>G locus, the body height of GG genotype individuals at 18 months of age was significantly higher than that of TT genotype individuals and TG genotype individuals. The above findings can be used as theoretical support for the subsequent improvement of Ashidan yak breeding. [ABSTRACT FROM AUTHOR]

Sarcocystosis is an emerging disease in yaks, and Sarcocystis infection creates a health threat to humans and animals. During a recent study, Sarcocystis infection was detected in yaks by means of morphological observation using hematoxylin and eosin, Giemsa, and acridine orange staining. The species of Sarcocystis isolated from yaks were analyzed and identified phylogenetically. To establish the best model for culturing sarcocystosis isolated from yaks in vitro, four different cell lines—PAMs, Pk15, HeLa, and Vero cells—were used. The effects of sarcocystosis isolated from yaks on the MAPK signaling pathway in Vero cells were detected using Wes automatic Western blot and RT-qPCR. The results from the phylogenetic tree indicate that the sequences of Sarcocystis obtained from yaks in this study were grouped within the Sarcocystis cruzi clade. Results also have shown that S. cruzi had a higher proliferation rate in Vero cells, suggesting that Vero cells are more suitable for the long-term culturing of S. cruzi in vitro. Results also indicate that S. cruzi infecting Vero cells could cause the activation of ERK1/2 pathway, while inhibiting the ERK1/2 pathway could suppress S. cruzi infection in Vero cells. Therefore, the study and exploration of Sarcocystis-host relationships can effectively provide certain theoretical knowledge and the basis for the treatment of clinical diseases and the development of Sarcocystis drugs. [ABSTRACT FROM AUTHOR]

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[Objective] This study explored the molecular mechanism behind the differences in muscle quality among three parts of yak. [Method] Muscle samples from shoulder (Sh), striploin (St),and silver-side (Si) of yak were collected and subjected to high-throughput sequencing to analyze transcriptomes. The data were filtered and differentially expressed genes (DEGs) between Sh/Si, St/Si and St/Sh were selected using FPKM for GO functional clustering analysis and KEGG pathway analysis. Four DEGs, including two upregulated genes (BARX2 and HOXA 13) and two downregulated genes (HOXC8 and LOCI 1 2441 511 ), were randomly selected for validation of expression levels using real-time quantitative PCR (RT-qPCR). [Result] Post-sequencing data quality analysis confirmed the reliability of sequencing data. Differential expression analysis revealed that there were 607 DEGs between Sh/Si, with 419 upregulated and 188 down-regulated. There were 713 DEGs between St/Si>with 445 upregulated and 268 downregulated, and there were 295 DEGs between St/Sh, with 132 upregulated and 163 downregulated. GO annotation and KEGG pathway enrichment analyses showed that main functions of DEGs in the three parts related to ion transport, transmembrane ion transport, nuclear functions, actin filament-based process and anion transport, and major enrichment pathways included oxidative phosphorylation, nitrogen metabolism and MAPK signaling pathway. The RT-qPCR results confirmed the reliability of RNA-Seq data. [Conclusion] NADH dehydro-genase (ubiquinone) Fe-S protein (NDUFS6), NADH dehydrogenase (ubiquinone) 1-subcomplex subunit 8 (NDUFB8),fibroblast growth factor-7 (FGF7),thin filament protein C (FLNC), carbonic anhydrase 14 precursor (CAT 4) and carbonic anhydrase 3 (CA3) may be characteristic genes for regulation of yak meat quality. [ABSTRACT FROM AUTHOR]

Simple Summary: Yak is a unique species of highland cattle that inhabits cold regions year-round. Poor soil conditions lead to low nutrient content in forage, making yaks susceptible to trace element deficiencies. This deficiency results in reduced reproductive rates and overall productivity in yaks. Hormones synthesized by the granulosa cells of yak follicles play a crucial role in yak reproduction. In this study, the changes in cell viability, hormone secretion, and hormone synthesis-related genes were observed by adding metal trace elements and vitamins to the culture medium of cultured granulosa cells of yak follicles in vitro. The results showed that the addition of certain trace elements and vitamins had a positive effect on the activity and hormone secretion of granulosa cells in yak follicles. These findings offer a potential solution for enhancing the reproductive performance of female yaks affected by trace element deficiencies. Yak (Bos grunniens), a special breed of cattle on the Qinghai–Tibet Plateau, has low fertility due to nutritional deficiency, especially the trace elements. The steroid hormones estradiol (E2) and progesterone (P4) synthesized by yak follicular granulosa cells (BGCs) are involved in the entire reproductive process. In the present study, we investigated the effects of trace elements and vitamins on yak follicular GCs, including the cellular activity, the synthesis of E2 and P4, and the expression of genes related to steroid hormone synthesis. The results showed that moderate supplementation of vitamin D3 (VD3), strontium (Sr), manganese (Mn), and selenium (Se) enhanced granulosa cell activity. Within the safe dose range, the addition of vitamin A (VA), VD3, cobalt (Co), Sr, copper (Cu), Mn, Se, and chromium (Cr) significantly increased the synthesis of E2 by GCs, while the addition of VA, vitamin C (VC), VE, zinc (Zn), Sr, Cu, and Cr enhanced the production of P4 in GCs. The changes in steroid synthesizing genes were consistent with the changes in hormone synthesis. This study provides an experimental basis for the addition of trace elements to improve the production performance of yaks. [ABSTRACT FROM AUTHOR]

Background: The identification of novel bacterial species from the intestines of yaks residing on the Qinghai–Tibet Plateau is pivotal in advancing our understanding of host–microbiome interactions and represents a promising avenue for microbial drug discovery. Methods: In this study, we conducted a polyphasic taxonomic analysis and bioactive assays on a Bacillus strain, designated Bos-x6-28, isolated from yak feces. Results: The findings revealed that strain Bos-x6-28 shares a high 16S rRNA gene sequence similarity (98.91%) with B. xiamenensis HYC-10T and B. zhangzhouensis DW5-4T, suggesting close phylogenetic affinity. Physiological and biochemical characterizations demonstrated that Bos-x6-28 could utilize nine carbon sources, including D-galactose, inositol, and fructose, alongside nine nitrogen sources, such as threonine, alanine, and proline. Analysis of biochemical markers indicated that Bos-x6-28's cell wall hydrolysates contained mannose, glucose, and meso-2,6-diaminopimelic acid, while menaquinone-7 (MK-7), phosphatidylethanolamine (PE), phosphatidylcholine (PC), and phosphatidylglycerol (DPG) were found in the cell membrane. The primary cellular fatty acids included C16:0 (28.00%), cyclo-C17:0 (19.97%), C14:0 (8.75%), cyclo-C19:0 (8.52%), iso-C15:0 (5.49%), anteiso-C15:0 (4.61%), and C12:0 (3.15%). Whole-genome sequencing identified a genome size of 3.33 Mbp with 3353 coding genes. Digital DNA–DNA hybridization (dDDH) and average nucleotide identity (ANI) analyses confirmed Bos-x6-28 as a novel species, hereby named B. maqinnsis Bos-x6-28 (MCCC 1K09379). Further genomic analysis unveiled biosynthetic gene clusters encoding bioactive natural compounds, including β-lactones, sactipeptides, fengycin, and lichenysin analogs. Additionally, in vitro assays demonstrated that this strain exhibits antibacterial and cytotoxic activities. Conclusions: These findings collectively indicate the novel Bacillus species B. maqinnsis Bos-x6-28 as a promising source for novel antibiotic and antitumor agents. [ABSTRACT FROM AUTHOR]