Meat quality has a close relationship with fat and connective tissue; therefore, screening and identifying functional genes related to lipid metabolism is essential for the production of high-grade beef. The transcriptomes of the Longissimus dorsi muscle in Wagyu and Chinese Red Steppe cattle, breeds with significant differences in meat quality and intramuscular fat deposition, were analyzed using RNA-seq to screen for candidate genes associated with beef quality traits. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that the 388 differentially expressed genes (DEGs) were involved in biological processes such as short-chain fatty acid metabolism, regulation of fatty acid transport and the peroxisome proliferator-activated receptor (PPAR) signaling pathway. In addition, crystallin alpha B (CRYAB), ankyrin repeat domain 2 (ANKRD2), aldehyde dehydrogenase 9 family member A1 (ALDH9A1) and enoyl-CoA hydratase and 3-hydroxyacyl CoA dehydrogenase (EHHADH) were investigated for their effects on intracellular triglyceride and fatty acid content and their regulatory effects on genes in lipogenesis and fatty acid metabolism pathways. This study generated a dataset from transcriptome profiling of two cattle breeds, with differing capacities for fat-deposition in the muscle, and revealed molecular evidence that CRYAB, ANKRD2, ALDH9A1 and EHHADH are related to fat metabolism in bovine fetal fibroblasts (BFFs). The results provide potential functional genes for maker-assisted selection and molecular breeding to improve meat quality traits in beef cattle.

This study aims to screen potential regulators and regulate fecundity networks between microRNAs (miRNAs) and target genes. The bovine testes of immature and mature Chinese Red Steppes were performed by genome-wide analysis of mRNAs and miRNAs. Compared with testicular tissues of newborns, 6051 upregulated genes and 7104 downregulated genes in adult cattle were identified as differentially expressed genes (DEGs). The DEGs were significantly enriched in 808 GO terms (p < 0.05) including male gonad development, male genitalia development, spermatogenesis, and sperm motility. Moreover, DEGs were also significantly enriched in 105 KEGG pathways (p < 0.05), including cGMP-PKG signaling pathway and calcium signaling pathway. To explore the expression of miRNA-regulated gene expression, 896 differentially expressed target genes negatively regulated with the expression levels of 31 differentially expressed miRNAs (DERs) were predicted and analyzed, and a network-integrated analysis was constructed. Furthermore, real-time PCR was performed to verify the expression levels of DEGs and DERs. Our results identified novel candidate DEGs and DERs correlated with male reproduction and intricate regulating networks between miRNAs and genes, which will be valuable for future genetic and epigenetic studies of sperm development and maturity, as well as providing valuable insights into the molecular mechanisms of male fertility and spermatogenesis in cattle.

In this study, we successfully isolated and cultured bovine skeletal muscle satellite cells (bSMSCs) and induced muscle cell formation in vitro . Skeletal muscle satellite cells (SMSCs) were isolated from the deep tissues of foetal bovine hind limbs and differentiated with 2% horse serum in vitro . The transcriptome sequencing results revealed a total of 1030 differentially expressed genes (DEGs) in the middle stage of differentiation (day 3) compared with the predifferentiation stage (day 0). A total of 374 DEGs were identified in the postdifferentiation stage (day 7) compared with the middle differentiation stage (day 3). We further investigated the regulatory effects of the DEG nerve growth factor (NGF) on the proliferation and myogenic differentiation of bSMSCs. The overexpression of NGF increased the mRNA and protein expression levels of myosin heavy chain (MyHC) and myogenin (MyoG), which are myoblast development markers, whereas NGF knockdown had the opposite effect; however, NGF did not affect the expression of the proliferation marker paired box gene 7 (Pax7) in bSMSCs. In addition, functional enrichment analysis of the DEGs revealed that the PI3K/Akt signalling pathway was significantly enriched in the DEGs and that NGF regulates myogenesis through the activation of the PI3K/Akt signalling pathway. Our results revealed that NGF was shown to be a putative regulator that controls myogenesis by activating the PI3K/Akt signalling pathway. The study provided a reference for further studies on the molecular mechanism of myogenic differentiation, regulatory network establishment, and beef quality improvement.

Breed is a major source of variation in beef quality, yet how differences in rumen microbial communities relate to metabolic profiles and meat quality across breeds remains unclear. This study compared growth performance, meat quality traits, rumen microbiota, and rumen metabolomic profiles of Chinese steppe red cattle (CR), Yanhuang cattle (YH), and Simmental hybrid cattle (SH). The results showed that SH cattle had better performance in some growth-related traits. In contrast, YH and CR cattle exhibited better meat quality, with higher marbling scores, lower drip loss and shear force, and higher levels of several unsaturated fatty acids. Significant differences in individual amino acid contents were also observed among breeds, and SH cattle showed higher levels of some amino acids. Microbial analysis showed that CR and YH cattle had higher rumen microbial richness and diversity than SH cattle, with differences in microbial community composition among breeds. A total of 2425 metabolites were annotated by metabolomic analysis. The differential metabolites were mainly involved in lipid metabolism, amino acid metabolism, carbon metabolism, and energy metabolism pathways. Correlation analysis further revealed relationships between specific rumen microorganisms and metabolites related to meat quality traits.