Yak milk is superior to common cow milk in nutrients including protein, fat and calories. However, the milk yield of the yak is very much lower compared with other dairy bovines. To understand the molecular mechanisms of lactogenesis, lactation and mammary gland development, mammary tissue samples were taken from five yaks during a dry period (DP, n = 3) and lactation period (LP, n = 2). Two types of cDNA sequence libraries that reflected the different physiological states of the mammary gland were constructed using RNA sequencing technology. After removing reads containing adapters, reads containing poly-N and low-quality reads from the raw data, 45,423,478 to 53,274,976 clean reads were obtained from these libraries. A total of 74.72% to 80.65% of the high-quality sequence reads were uniquely aligned to the BosGru v2.0 yak reference genome. Using the DESeq R package, 360 differentially expressed genes were detected between the two groups when the adjusted P value (padj < 0.05) was used as the cutoff value; this included 192 upregulated and 168 downregulated genes in the yak mammary gland tissue of the DP compared to the LP. A gene ontology analysis revealed that the most enriched GO terms were protein binding, multi-organism process, immune system and others. KEGG pathway analysis indicated that the differentially expressed genes were mostly enriched in Hippo signaling, insulin signaling, steroid biosynthesis and others. The analysis of the up- and downregulated genes provides important insights into the molecular events involved in lactogenesis, lactation and mammary gland development and will guide further research to enhance milk yield and optimize the constituents of yak milk.

Fumonisin B1 (FB1), a mycotoxin produced by Fusarium species, is prevalent in crops and animal feed, posing significant health risks to livestock and humans. FB1 induces oxidative stress in Sertoli cells, destroys testicular structure, and affects spermatogenesis. However, methods to mitigate the reproductive toxicity of FB1 in testes remain unknown. Quercetin, a natural flavonoid antioxidant, may offer protective benefits. This study investigated the protective effects and mechanisms of quercetin against FB1-induced reproductive toxicity in TM4 cells (a Sertoli cell line). The results indicated that 40 μM quercetin improved cell viability, reduced apoptosis, and preserved cell functions. Quercetin also decreased reactive oxygen species (ROS) levels in TM4 cells exposed to FB1, enhanced the expression of antioxidant genes, and improved mitochondrial membrane potential. Compared with FB1 alone, the combination of quercetin and FB1 increased ATP levels, as well as pyruvate and lactic acid, the key glycolysis products. Furthermore, this combination elevated the mRNA and protein expression of glycolysis-related genes, including glucose-6-phosphate isomerase 1 (Gpi1), hexokinase 2 (Hk2), aldolase (Aldoa), pyruvate kinase, muscle (Pkm), lactate dehydrogenase A (Ldha) and phosphofructokinase, liver, B-type (Pfkl). Quercetin also boosted the activity of PKM and LDHA, two crucial glycolytic enzymes. In summary, quercetin mitigates FB1-induced toxicity in TM4 cells by reducing ROS levels and enhancing glycolysis. This study offers new insights into preventing and treating FB1-induced toxic damage to the male reproductive system and highlights the potential application of quercetin.

Background: Growing oocytes acquire the ability to mature through two-way communication between gametes and surrounding somatic cumulus cells (CCs). Granulosa cells (GCs) support oocyte growth, regulate meiosis progression, and modulate global oocyte transcription activity. However, the proliferation and differentiation of the yak ovary in GCs and CCs remain unclear. To characterize the important roles of long non-coding RNA, (lncRNA), microRNA (miRNA), and messenger RNA (mRNA), whole-transcriptome analysis was performed. Real-time quantitative fluorescence PCR was performed to verify the selected RNA sequences. Results: Important gene ontology terms and Kyoto Encyclopedia of Genes and Genomes pathways related to differentiation and oocyte development were identified for the target genes of differentially expressed lncRNAs, miRNAs, and mRNAs. In total,6223 mRNAs (2197 upregulated, 4026 downregulated), 643 lncRNAs (204 upregulated, 479 downregulated), and 559 miRNAs (311 upregulated, 248 downregulated) were significantly altered between the two groups. Target genes involved in cell adhesion, cell differentiation, regulation of developmental processes, cell proliferation, embryo development, signal transduction, apoptosis, and aromatic compound biosynthetic processes were significantly enriched. These RNAs were involved in ECM-receptor interaction, MAPK signaling, Hippo signaling, PI3K-Akt signaling, cell cycle, cell adhesion, leukocyte trans-endothelial migration, and actin cytoskeleton regulation. Conclusions: A comprehensive analysis of the co-expression network of competing endogenous RNAs (ceRNAs) will facilitate the understanding of the process of granulosa cell proliferation and differentiation and offer a theoretical basis for the development of oocytes.

Introduction: The CDO1 gene is an important gene in the taurine synthesis pathway and has been observed to have high expression in ovaries of female mammals. This study aims to explore the conservation of CDO1 gene in domestic yaks, as well as to examine the fundamental characteristics of CDO1 gene and its expression in female yaks.Methods: Ovarian samples were collected from yaks in the follicular phase, luteal phase and gestation period in this experiment, and their total RNA and protein were extracted. Then Polymerase Chain Reaction (PCR) and bioinformatics online software were used to clone and analyze the CDO1 gene. The relative expression of CDO1 in yak ovaries was detected by Quantitative Real-time PCR (RT-qPCR) and Western blotting. The distribution and localization of CDO1 protein in ovary were detected by immunohistochemistry.Results: We have successfully cloned the coding region of CDO1 gene in yak. The results showed that the CDS region of CDO1 gene was 603 bp, encoding 200 amino acids, and was a relatively stable hydrophilic protein. CDO1 is relatively conservative in species evolution. The protein encoded by CDO1 gene does not have a signaling peptide or a transmembrane structure. It is a protein that is not involved in transmembrane transport and is mainly located in the cytoplasm. The secondary structure of the protein is dominated by the random coil. CDO1 is estimated to interact with 10 proteins. The results of RT-qPCR and Western blotting showed that the CDO1 gene exhibited the highest expression in the ovary during the luteal phase and the lowest expression in the ovary during the follicular phase (P < 0.01). The results of immunohistochemistry showed that CDO1 was mainly expressed in granular cells, theca cells and lutein cells of ovarian tissue.Conclusion: These results suggest that the CDO1 gene has undergone minimal evolutionary changes during the course of animal evolution. The results provide a reference for further investigation of the function of CDO1 gene in reproduction and production in yaks.

Arginine (Arg), a safe basic amino acid, modulates interprotein interactions and impacts the processing characteristics of myofibrillar proteins (MP) in meat products, as numerous studies have demonstrated. This study aimed to explore the effects of varying concentrations of Arg (0.025, 0.050, 0.100, 0.200 %) on the physicochemical properties and gel behavior of yak MP. Utilizing yak MP as the substrate, we assessed and analyzed the physicochemical attributes and gel performance of the MP-Arg composite system. The findings revealed that Arg facilitates MP unfolding and internal group exposure, effectively mitigating oxidative tertiary structure alterations. Arg exerts potent antioxidant activity on MP, augmenting their water-holding capacity, which ameliorates gel properties. In this experiment, 0.05 % Arg maximally inhibited oxidative damage to MP, with protection being concentration-dependent. Collectively, these findings suggest that Arg effectively inhibits the oxidative degradation of MP structure and promotes the formation of enhanced gel characteristics.