Intramuscular fat (IMF) deposition significantly impacts beef quality, yet microRNA (miRNA)-mediated mechanisms regulating bovine intramuscular preadipocyte development are not fully understood. This study aimed to elucidate the role of bta-miR-380-3p in preadipocyte proliferation, apoptosis, and adipogenic differentiation, identifying sterol O-acyltransferase 1 (SOAT1) as its functional target. Bta-miR-380-3p exhibited dynamic expression during adipogenesis and was highly expressed in adult bovine IMF. Gain- and loss-of-function assays showed that bta-miR-380-3p promoted DNA synthesis, cell viability, and cell-cycle progression, and reduced apoptosis-related signaling. Consistently, western blot analysis confirmed increased PCNA and CDK1 and reduced P21 after bta-miR-380-3p overexpression, whereas inhibition produced the opposite pattern. Bta-miR-380-3p also enhanced lipid droplet accumulation and upregulated adipogenic markers, with western blotting confirming increased PPARγ, FABP4, and SREBP1 protein abundance. Bioinformatics prediction, expression validation, and dual-luciferase reporter assays demonstrated that bta-miR-380-3p directly targets the SOAT1 3'UTR and negatively regulates SOAT1 expression. Functional manipulation of SOAT1 further revealed its involvement in triglyceride accumulation, adipogenic marker regulation, and proliferation-associated remodeling. Collectively, these findings reveal a bta-miR-380-3p-SOAT1 regulatory axis linking post-transcriptional control with cholesterol metabolism, preadipocyte expansion, and IMF deposition. These results provide mechanistic insight and a potential molecular target for improving marbling and meat quality traits in cattle breeding programs.

Long non-coding RNAs (lncRNAs) are non-coding transcripts longer than 200 nucleotides with diverse regulatory roles. LncRNAs are being increasingly recognized for their roles in milk fat synthesis. LOC112442979 is a novel uncharacterized lncRNA located on bovine chromosome 20. The expression level of LOC112442979 in the mammary gland tissue of dairy cows was significantly higher during middle lactation than in the dry period, suggesting its potential regulatory role in lactation. Subsequently, we renamed the LOC112442979 as Mammary Lipid Synthesis-associated Transcript (MLST). In this study, we find that MLST promotes lipid droplet accumulation and triacylglycerol (TAG) synthesis in bovine mammary epithelial cells (BMECs). Bioinformatics analysis predicted that MLST acts as a molecular sponge for miR-7 and that mTOR is a target gene of miR-7. Overexpression of MLST significantly increases the expression of mTOR both at the mRNA and protein levels, whereas knockdown of MLST has the opposite effect. MLST also significantly promotes the expression of key milk fat metabolism-related genes both at mRNA and protein levels, including PPARγ, SREBP1, FASN, CEBPα, CEBPβ, and ACCα, as well as the protein level of phosphorylated mTOR (p-mTOR) in the mTOR signaling pathway. Furthermore, the inhibitory effect of MLST silencing on milk fat synthesis is reversed by the mTOR activator, MHY1485. These results demonstrate that MLST regulates the mTOR signaling pathway by sponging miR-7, thereby promoting milk fat synthesis. Our findings provide valuable insights into the molecular mechanisms underlying milk quality improvement from the perspective of lncRNA-miRNA-mRNA regulatory network.

Meat quality characteristics such as juiciness, tenderness, and flavor are greatly enhanced by intramuscular fat (IMF). Improving intramuscular adipose tissue accumulation while maintaining stable lipid levels in fat depots has become a critical priority in the beef sector. Understanding the molecular mechanisms driving intramuscular fat deposition is critical because it can enable the utilization of genetic selection to produce high-quality beef. Emerging research suggests that miRNAs play essential roles in regulating IMF deposition, particularly through regulating preadipocyte dynamics such as proliferation and differentiation. Our study aimed to screen and explore the function of potential miRNA in bovine intramuscular preadipocytes and to delineate the underlying molecular mechanisms governing cell proliferation and differentiation. Through time series cluster analysis following by experimental validation by qPCR and Agarose gel PCR identified that bta-miR-380-3p was potential miRNA that highly related with intramuscular preadipocyes differentiation in beef cattle. Bta-miR-380-3p enhanced the proliferation of intramuscular pre-adipocytes by increasing the cell cycle progression and show dynamic time dependent regulation during proliferation and differentiation. It also boosted the formation of lipid droplets in intramuscular pre-adipocytes. The qPCR results revealed that bta-miR-380-3p mimic boosted the expression of PPARγ, FASN, FABP4, SREBP1, and DGAT2 differentiation marker genes. These results provide new insight on the regulatory processes of intramuscular adipogenesis and identify bta-miR-380-3p as a potential target for increasing beef quality through directional selection and molecular breeding. This finding provides a theoretical framework and molecular targets for increasing IMF content

Intramuscular fat (IMF) is a key determinant of beef quality, particularly with respect to tenderness, flavor, and juiciness. Increasing evidence indicates that microRNAs (miRNAs) function as important post-transcriptional regulators in adipogenesis. In this study, microRNA sequencing was performed on IMF tissue obtained from beef samples with distinct marbling scores to characterize miRNA expression profiles. Among the differentially expressed miRNAs, miR-222 was also significantly regulated during bovine intramuscular preadipocyte differentiation and was therefore selected for further functional and mechanistic investigation. Functional analyses demonstrated that miR-222 promotes lipid droplet accumulation and triacylglycerol (TAG) synthesis. Moreover, miR-222 increased the mRNA and protein expression levels of adipogenic marker genes, including fatty acid synthase (FASN) and peroxisome proliferator-activated receptor gamma (PPAR gamma). DNA damage induced transcript 4 (DDIT4) was identified as a direct target of miR-222. Knockdown of DDIT4 significantly enhanced lipid droplet accumulation and TAG synthesis. Notably, the inhibitory effect of miR-222 knockdown on adipogenic differentiation was reversed by treatment with the mammalian target of rapamycin complex 1 (mTORC1) agonist MHY1485. In summary, our findings demonstrate that miR-222 promotes bovine intramuscular adipogenesis by directly targeting DDIT4, thereby activating mTORC1-mediated lipid synthesis. These results provide new insights into the molecular mechanisms underlying IMF deposition in beef cattle and offer a theoretical basis for genetic improvement strategies.

This study investigates circDCAF6 in Qinchuan cattle muscle development. Firstly, circDCAF6 was screened and identified, and it was found that this circular RNA was highly expressed in muscle tissue and more stable than linear RNA. By designing interference RNA and overexpression recombinant vectors based on circDCAF6, functional studies have shown that circDCAF6 can significantly promote the proliferation of myoblasts and inhibit their apoptosis process. Through targeted regulation analysis, we found that circDCAF6 can interact with miR-181d and regulate the expression of downstream target gene CCNB1 through miR-181d, thereby affecting the proliferation and apoptosis of myoblasts. In addition, interference experiments have shown that inhibiting CCNB1 can significantly reduce the proportion of cells in the S phase of the cell cycle and increase the proportion of early apoptotic cells. This effect can be partially rescued by co-transfection with circDCAF6. In summary, this study suggests that circDCAF6 plays a critical role in the proliferation and apoptosis of Qinchuan cattle myoblasts by targeting miR-181d to regulate the expression of CCNB1. These findings provide a new perspective for a deeper understanding of the molecular mechanisms underlying muscle development and may offer new molecular targets for genetic improvement in beef cattle.

Beef quality traits, such as intramuscular fat deposition, water-holding capacity, and tenderness, vary among breeds, yet their molecular basis remains unclear. In this study, we hypothesized that the regulation of muscle energy metabolism and lipid deposition is associated with differences in beef quality between Qinchuan and Nanyang cattle. To this end, we measured meat quality traits in the longissimus dorsi muscle of females from the two breeds (n = 5 per group) and conducted integrative analyses using transcriptomic, proteomic, and metabolomic data. The results showed that Qinchuan cattle exhibited higher intramuscular fat content, marbling score, and better tenderness and water-holding capacity. Multi-omics analysis identified 1011 differentially expressed genes, 895 differentially expressed proteins, and 12 differential metabolites, with some molecules showing consistent changes at both the transcriptional and protein levels. Pathway analysis revealed that glycolysis and energy metabolism pathways were enhanced in Nanyang cattle, whereas the PPAR signaling pathway was activated in Qinchuan cattle. Correlation network analysis indicated that energy metabolism-related molecules were positively correlated with shear force and water loss, while PPAR signaling pathway-related molecules were positively correlated with intramuscular fat content and marbling score. L-serine was associated with PPARrelated molecules and intramuscular fat content, and promoted adipogenic differentiation of intramuscular preadipocytes in vitro by upregulating PPAR-related genes. This study reveals that the regulation of energy metabolism and lipid deposition is associated with breed-specific differences in meat quality, providing candidate molecular targets and metabolic biomarkers for improving meat quality in local cattle breeds.

Intramuscular fat (IMF) content is a critical factor determining beef quality, influenced by various factors including breed and age. However, the regulatory role of long non-coding RNAs (lncRNAs) in IMF deposition remains unclear. This study investigated IMF deposition in the longissimus dorsi muscle of one- and two-year-old Qinchuan and Wagyu cattle through histological examination and fat content measurement. Based on transcriptome sequencing data of intramuscular fat tissue, differential expression analysis and weighted gene co-expression network analysis (WGCNA) were performed to identify lncRNAs associated with IMF deposition. The effects of a key candidate lncRNA on the adipogenic differentiation of cattle intramuscular preadipocytes were further examined. Results showed that Wagyu cattle exhibited stronger IMF deposition capacity than Qinchuan cattle across all age groups, with IMF content increasing with age in both breeds. We identified 7,910 lncRNAs from intramuscular fat tissue transcriptome data, including 6,455 novel lncRNAs. Through integrated differential expression analysis and WGCNA, 88 lncRNAs closely associated with IMF deposition were screened from two-year-old Qinchuan and Wagyu cattle. Notably, lnc11599 was significantly upregulated in Qinchuan cattle intramuscular fat tissue, but its expression decreased during intramuscular preadipocyte differentiation. Functional experiments demonstrated that lnc11599 knockdown enhanced adipogenic differentiation capacity, manifested as a highly significant increase in lipid accumulation, upregulation of key adipogenic genes at the mRNA level, together with increases in total fatty acid content and unsaturated fatty acid proportion. This study established the lncRNA expression profiles in intramuscular fat tissue of Qinchuan and Wagyu cattle across different developmental stages, and demonstrated that lnc11599 acts as a negative regulator of intramuscular fat deposition. These findings provide new directions for elucidating the mechanisms of cattle IMF deposition and offer potential targets for genetic improvement of beef quality.

Lycopene (LYC) is a natural carotenoid with antioxidant and anti-inflammatory properties, but its effects on rumen fermentation, microbiota, and metabolite profiles in beef cattle remain insufficiently characterized. This study evaluated the effects of dietary LYC supplementation on growth performance, nutrient digestibility, serum antioxidant and immune-inflammatory status, ruminal fermentation, and rumen microbiota-metabolome profiles in Qinchuan beef cattle. Twenty healthy female cattle (12-13 months; 234.50 ± 12.19 kg) were randomly assigned to four treatments and fed a basal diet supplemented with 0 (Con), 15 (L15), 30 (L30), or 45 (L45) mg/kg initial body weight per day LYC. Compared with the Con, L30 group increased average daily gain and crude protein digestibility and decreased feed conversion ratio (P < 0.05), without affecting dry matter intake. LYC supplementation decreased serum low-density lipoprotein and malondialdehyde concentrations and increased total antioxidant capacity, glutathione peroxidase, and superoxide dismutase activities (P < 0.05). The L30 group reduced serum IL-1β, IL-6, and TNF-α and increased IL-10 (P < 0.05). In the rumen, L30 and L45 groups decreased NH3-N concentration, increased propionate proportion, and reduced the acetate-to-propionate ratio (P < 0.05). Comparison of the Con and L30 groups identified selective shifts in rumen bacterial taxa and 133 differential metabolites, mainly including lipid-like, phenolic/aromatic, and nitrogen-containing compounds. Overall, dietary LYC improved feed efficiency, antioxidant defense, immune-inflammatory balance, and ruminal fermentation, with L30 group showing the most consistent benefit.

Body condition score (BCS) is a cornerstone indicator for beef cattle reproduction and nutritional management, but conventional visual scoring is subjective and lacks quantitative standards. This study aimed to develop a low-cost, objective BCS evaluation system for Qinchuan beef cattle using routine body measurements and machine-learning models. A total of 321 qinchuan breeding cows aged 24–36 months were scored for BCS (4–8) by two trained evaluators following the Chinese national standard, and seven conventional traits (withers height, body length, hip height, heart girth, abdominal girth, rump width, and body weight) were recorded. One-way ANOVA and Pearson correlation analyses were used to test the biological consistency of subjective scores and to identify informative traits. Six composite body condition indices were constructed to standardize frame size, and seven machine-learning algorithms were compared under nested cross-validation using quadratic weighted kappa (QWK) as the primary metric. All measured traits increased significantly across BCS classes, and heart girth, abdominal girth, and body weight showed the strongest correlations with BCS ( r ≥ 0.80 , P < 0.001 ). A composite morphometric index (CMI) provided the best trade-off between correlation and classification performance. The best model, k-nearest neighbors using six key traits, achieved a QWK of 0.89 and 95.5 ± 1 BCS unit. This study demonstrates that conventional body measurements, combined with composite indices and machine-learning models, can provide a practical, scalable tool for objective BCS evaluation in Qinchuan beef cattle and support precision livestock farming.

This study evaluated the effects of maternal dietary protein levels from gestation through lactation on post-weaning feed efficiency, apparent nutrient digestibility, rumen fermentation, and rumen microbiota in Qinchuan calves. Eighteen mid-gestation cows were assigned to low (LCP = 8.08% CP), medium (MCP = 10.01% CP), or high (HCP = 12.04% CP) protein diets (n = 6 per group) from mid-gestation to weaning at 90 d. Calves were allowed to suckle freely from birth to 90 d and were then fed the same diet ad libitum from 90 to 180 d. Calves in the MCP group had higher body weight than those in the LCP and HCP groups at birth and 15 d (P < 0.05), whereas both MCP and HCP calves had greater body weight than LCP calves from 45 to 180 d (P < 0.05). During the post-weaning period, dry matter intake did not differ among treatments, but the feed-to-gain ratio was lower in the HCP group than in the LCP group (P < 0.05). Apparent nutrient digestibility was affected by maternal dietary protein level, with higher ADF and EE digestibility in the HCP group and higher CP digestibility in both MCP and HCP groups than in the LCP group (P < 0.05). At 90 d, ruminal ammonia nitrogen and valerate concentrations were higher in the MCP and HCP groups (P < 0.05). At 180 d, ruminal ammonia nitrogen, acetate, isobutyrate, and total volatile fatty acid concentrations were higher in the MCP and HCP groups than in the LCP group, while the HCP group also showed higher propionate concentration and a lower acetate-to-propionate ratio (P < 0.05). Maternal dietary protein level did not markedly alter the core rumen microbiota, but influenced microbial richness and the abundance of functionally relevant taxa. At 180 d, Prevotella was enriched in the MCP and HCP groups, and Succiniclasticum was enriched in the HCP group. These results indicate that maternal dietary protein level during gestation and lactation has lasting effects on post-weaning feed efficiency, nutrient digestibility, rumen fermentation, and microbial functional maturation in Qinchuan calves.

Beef quality traits significantly varies among cattle breeds. These differences cannot be fully explained using traditional omics techniques as they lack cell-level detail. To address this gap, we integrated phenotypic data, histological analyses, and single-nucleus RNA sequencing (snRNA-seq) of the longissimus dorsi muscle to uncover the cellular and molecular mechanisms underlying breed-specific variation. Histology and molecular markers indicated that Wagyu (WY) had the highest intramuscular fat(IMF) and the lowest shear force followed by Angus (AN) with the intermediate while Qinchuan cattle (QC) showed the lowest levels. SnRNA-seq resolved 12 cell types, revealing breed-specific cellular compositions. Pseudotime analysis revealed myoblast differentiation through hybrid states to type IIX (IIX), type IIA (IIA), and type I (I) myofibers, with lineage-specific remodeling of glycolysis, oxidative phosphorylation, and Ca²⁺ handling directing QC toward IIX fibers and WY toward Type I fibers. Reclustering of PDGFRα⁺ fibro-adipogenic progenitors (FAPs) revealed a bifurcation between adipogenic and fibrogenic fates, with WY favoring lipid-metabolism and adipogenesis-enriched FAPs alongside stronger FGF/ANGPTL–integrin signaling, while QC showed extracellular matrix (ECM)–integrin and TGF-β/TNFα–NF-κB pathways. Ligand–receptor analysis indicated that, in contrast to QC’s adhesion-centric ECM axis, WY-specific laminin/collagen–integrin and IGF/ANGPT inputs enhance metabolic–mechanical coupling. These results suggested that breed-dependent phenotypes arise from coordinated shifts in FAP fate, myofiber metabolism, and ECM–vascular signaling. Beef-quality variation reflects coordinated reprogramming along three axes: myofiber metabolic programs, FAP fate specification, and basement-membrane/integrin–vascular coupling, forming a phenotypic gradient from WY, which is pro-adipogenic and anti-fibrotic, through AN, which is intermediate, to QC, which is pro-fibrotic with high stiffness.

Qinchuan cattle, renowned for their distinctive meat quality, flavor, and exceptional environmental adaptability, represent a highly valuable genetic resource in beef cattle breeding. However, the molecular mechanisms underlying the formation of its meat quality traits, especially the genetic regulatory network of the core indicator of tenderness that affects consumer experience, are not yet clear. This study aims to employ transcriptomic techniques to identify candidate genes associated with tenderness in Qinchuan cattle, thereby providing a theoretical foundation for molecular breeding in beef cattle. Phenotypic analysis of meat quality revealed that the average shear force of the longissimus dorsi muscle (LDM) from 20 Qinchuan cattle was 115.43 ± 20.25 N, with significant differences among individuals (P < 0.01). Based on extreme tenderness differences, high shear force groups (HSF, n = 3) and low shear force groups (LSF, n = 3) were selected for transcriptome sequencing. A total of 286 differentially expressed genes (DEGs) were identified. Compared with the low shear force group, 247 genes were up-regulated and 39 genes were down-regulated in the HSF. GO and KEGG enrichment analyses indicated that these genes were significantly enriched in processes such as collagen binding, collagen trimer assembly, PI3K-Akt signaling pathway, and regulation of the actin cytoskeleton. Further protein-protein interaction (PPI) network analysis identified 5 hub genes associated with tenderness: POSTN, BGN, COL5A2, COL6A1 and COL6A2. Functional validation in cells showed that knockdown of POSTN expression significantly promoted bovine myoblast differentiation (up-regulation of MRF4, MYOG, and MYH3 expression, increase in MYH3 and MRF4 proteins), while inhibiting the expression of collagen deposition-related genes (CCN2 and LOX). Through transcriptomic and bioinformatic analyses, this study identified 5 core genes closely associated with meat tenderness in Qinchuan cattle and demonstrated that POSTN modulates tenderness formation through its dual role in regulating myogenic differentiation and collagen metabolism. These findings provide critical molecular targets for meat quality improvement in Qinchuan cattle and establish a theoretical foundation for molecular breeding of high-quality beef cattle.

As a fundamental mechanism of post-transcriptional epigenetic regulation, RNA modifications have attracted increasing research interest in recent years. N6-methyladenosine (m6A), the most abundant internal RNA modification, plays a crucial role in regulating multiple stages of mRNA metabolism including processing, transport, translation, and degradation. The differentiation of bovine preadipocytes into mature adipocytes is regulated at multiple levels including transcriptional, post-transcription, translation, and post-translation levels. However, the precise regulatory mechanism of m6A modification during bovine adipogenesis remains poorly understood. In this study, we conducted MeRIP-seq and RNA-seq analyses across three stages of bovine preadipocyte differentiation—pre-differentiation (day 0, D0), early differentiation (day 2, D2), and late differentiation (day 8, D8)—to characterize the dynamic landscape of m⁶A methylation during adipogenesis. The analysis identified 400 genes exhibiting significant changes in both m⁶A modification levels and mRNA expression during the differentiation phase (D0–D2), while 592 genes exhibited such changes during the lipid accumulation phase (D2–D8). These results indicate that m⁶A modification likely contributes to adipogenesis by modulating the expression of these genes. To further investigate the functional relevance of the m⁶A machinery, we knocked down the m⁶A writer METTL14, a core component of the methyltransferase complex, and performed RNA-seq analysis. Integrative analysis of the differentially expressed genes (DEGs) with the stage-specific expression profile revealed a set of candidate genes potentially regulated by METTL14 that participate in early preadipocyte differentiation and late-stage lipid accumulation. These findings provide new evidence for the molecular mechanisms underlying m⁶A modification during bovine adipogenesis and highlight a functional contribution of the m⁶A writer METTL14.

This study aimed to evaluate the effects of dietary cold-pressed linseed cake supplementation on growth performance, carcass traits, meat quality, and nutritional composition in Qinchuan beef cattle. Eighteen healthy 18-month-old cattle (282 ± 10 kg) were randomly assigned to three dietary treatments (n = 6): a control diet (CON), a diet supplemented with 12% cold-pressed linseed cake (CLC), and a diet supplemented with 12% crushed linseed (CLS). The trial consisted of a 15-day adaptation period and a 100-day feeding period.Compared with the CON group, dietary linseed supplementation increased dry matter intake and average daily gain (P < 0.05), whereas no significant differences were detected between the CLC and CLS groups (P > 0.05). The CLC group had a lower feed-to-gain ratio and lower feed cost per unit of gain. Carcass weight, net meat yield, and meat-to-bone ratio were improved in the linseed-supplemented groups (P < 0.05). Shear force decreased during postmortem ageing, indicating improved tenderness. In addition, dietary linseed supplementation increased the contents of α-linolenic acid (C18:3 n-3) and total amino acids in beef (P < 0.05).The results indicate that cold-pressed linseed cake can improve growth performance, feed efficiency, carcass characteristics, and beef nutritional quality in Qinchuan beef cattle, and may be used as a cost-effective feed ingredient in beef cattle production.

Intramuscular fat (IMF) content is a critical determinant of beef quality, yet the regulatory mechanisms within the skeletal muscle microenvironment remain largely undefined. This study established a co-culture system comprising bovine skeletal muscle cells (BSMCs) and bovine intramuscular preadipocytes (BIPs) to investigate the cellular crosstalk regulating IMF deposition. Flow cytometry, lipid staining, and multi-omics analyses were employed to investigate BSMCs-mediated regulation of IMF deposition. Co-culture with BSMCs inhibited BIPs proliferation, evidenced by G1 phase arrest and reduced expression of proliferation markers. BIPs exhibited decreased lipid droplet numbers and TG content. Transcriptome analysis of BIPs in co-culture with BSMCs versus monoculture identified 742 DEGs and 139 microRNAs, including 82 lipidogenesis-associated genes. Metabolomics revealed 120 and 139 DEMs in negative and positive ion modes, respectively. Integrated miRNA–mRNA and exosomal analyses revealed BSMCs-derived exosomal bta-miR-1246 as a key mediator suppressing BIPs differentiation via ATOH8 targeting, validated by dual-luciferase assays. These findings highlight a molecular mechanism through which BSMCs suppress bovine IMF deposition via exosomal miRNA-mediated regulation of target gene expression, providing novel targets for molecular breeding strategies to enhance beef quality traits.

As one of the five major indigenous yellow cattle breeds in China, Qinchuan cattle are characterized by stable genetic performance and desirable meat quality. However, compared with imported commercial breeds, Qinchuan cattle have a relatively slow growth rate. Therefore, improving the growth rate of Qinchuan cattle has become a top priority in Qinchuan cattle breeding. The CDC10 (Septin 7) gene, an important member of the Septin family, participates in various cellular physiological processes including intracellular substance transport, cell division, cell cycle regulation, and apoptosis. Studies have repeatedly mapped the CDC10 gene to quantitative trait loci influencing growth-related traits, such as body weight and carcass weight in many beef cattle breeds. Previous study has also demonstrated the high expression of CDC10 in JB cattle with high performance for carcass weight, however, the association between CDC10 and growth-related traits in Qinchuan cattle remain unclear. Therefore, in this study, we selected five individuals each from Chinese Simmental, Mongolian cattle, Luxi cattle, and Qinchuan cattle for direct sequencing, aiming to identify mutations within the CDC10 gene of native Chinese yellow cattle. Subsequently, we performed genotyping of 367 Qinchuan cattle using the MassARRAY technology, followed by genetic diversity analysis of the identified mutations and association analysis between these sites and growth-related traits of Qinchuan cattle. This study demonstrated high expression of the CDC10 gene in Qinchuan cattle with high performance for carcass weight. Furthermore, we identified the g.61303052G>C and c.225A>G SNPs in the promoter and exon regions, respectively, as being significantly associated with multiple growth-related traits in Qinchuan cattle. The c.225A>G SNP was also found to alter the secondary structure of the CDC10 protein. These findings provide reliable molecular markers for enhancing the growth rate of Qinchuan cattle and establish a solid theoretical foundation for the development of the beef cattle industry.

The presence of carcinogenic substances in beef poses a significant risk to public health, with far-reaching implications for consumer safety and the meat production industry. Despite advancements in food safety measures, traditional breeding methods have proven inadequate in addressing these risks, revealing a substantial gap in knowledge. This review aims to fill this gap by evaluating the potential of healthy breeding techniques to significantly reduce the levels of carcinogenic compounds in beef. We focus on elucidating the molecular pathways that contribute to the formation of key carcinogens, such as heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs), while exploring the transformative capabilities of advanced genomic technologies. These technologies include genomic selection, CRISPR/Cas9, base editing, prime editing, and artificial intelligence-driven predictive models. Additionally, we examine multi-omics approaches to gain new insights into the genetic and environmental factors influencing carcinogen formation. Our findings suggest that healthy breeding strategies could markedly enhance meat quality, thereby offering a unique opportunity to improve public health outcomes. The integration of these innovative technologies into breeding programs not only provides a pathway to safer beef production but also fosters sustainable livestock management practices. The improvement of these strategies, along with careful consideration of ethical and regulatory challenges, will be crucial for their effective implementation and broader impact.

Vegetable oil, a widely used energy source, is frequently added to livestock and poultry feed to enhance energy density. However, its effects on cattle production have been inconsistent across various studies. Therefore, this study aimed to evaluate the impact of vegetable oils on cattle traits using meta-analysis and sub-group analysis, quantify these effects through meta-regression, and develop dosage-response models linking cattle traits to vegetable oil supplementation. Data from 146 articles were included in this study following strict selection criteria. The results showed that vegetable oils reduced TDMI by 0.649 kg/d, OM intake by 0.748 kg DM/d, CP intake by 0.176 kg DM/d, NDF intake by 0.272 kg DM/d, DM digestibility by 1.091 %, NDF digestibility by 1.619 %, total VFAs by 3.864 mmol/L, the concentration of N-NH3 by 0.734 mg/100 mL, acetate by 1.080 mol/100 mol, butyrate by 0.397 mol/100 mol, acetate/propionate by 0.277, milk protein concentration by 0.042 %, milk fat concentration by 0.365 %, fat yield by 88.961 g/d, and the concentrations of C4:0, C6:0, C8:0, C10:0, C12:0, C14:0, C14:1, C15:0, C16:0, C16:1, C17:0, and C18:3 in milk. They also increased in EE intake by 0.303 kg DM/d, CP digestibility by 1.379 %, EE digestibility by 8.011 %, rumen pH by 0.039, propionate concentration by 1.248 mol/100 mol, milk yield by 0.413 kg/d, lactose yield by 24.329 g/d, and the concentrations of C18:0, C18:1, C18:2 and C20:0. Sub-group analysis of cattle categories revealed that vegetable oil supplementing in lactating cattle diets resulted in increases in body weight by 9.384 kg, CP digestibility by 0.850 %, and ruminal pH by 0.036. However, vegetable oils supplementing in non-lactating cattle diets led to an increase in isovalerate concentration by 0.051 mol/100 mol and decreases in N-NH3 concentration by 1.469 mg/100 mL and digestibility of DM, OM, and NDF by 2.292 %, 1.964 %, and 3.406 %, respectively. The regression analysis indicated the linear or quadratic response of cattle traits to the supplemental amount of vegetable oils. Total dry matter intake, OM intake, total VFAs, acetate, butyrate, milk protein, milk fat, and fat yield exhibited quadratic relationships with the dosage of some kinds of vegetable oils. Additionally, several traits had linear relationships with some vegetable oils. For instance, a 1 % increase of linseed oil resulted in a 0.120 kg/d decrease in CP intake; a 1 % increase of soybean oil led to a 0.133 kg/d decrease in NDF intake; a 1 % increase in safflower oil led to a 0.145 % decrease in milk fat; a 1 % increase of safflower oil resulted in a 61.050 g/d decrease in fat yield. In summary, supplemental vegetable oils can significantly alter intake and growth, rumen fermentation, nutrient digestibility, lactation performance, and milk fatty acid composition in cattle. However, the magnitude of these effects depends on cattle categories, the type of vegetable oils, and the supplemental amount. These findings offer crucial information for refining feed strategies to improve cattle performance and milk quality.

OBJECTIVE:Our study aimed to investigate the gender and age-related variations in rumen fermentation, serum metabolites, and microbiota in Qinchuan cattle. METHODS:A total of 38 Qinchuan beef cattle were selected and maintained on a uniform diet for three months. Rumen fluid and blood samples were collected to determine rumen fermentation, serum metabolites, and microbial 16S rRNA sequencing. RESULTS:The results revealed that the concentration of rumen butyrate in female Qinchuan cattle was significantly higher than in males (p<0.05). Isobutyrate, butyrate, and isovalerate exhibited significant age-related differences. Females exhibited lower serum glucose (GLU) and higher triglycerides (TG), nonesterifiedfatty acid (NEFA) levels compared to males (p<0.05). Serum albumin (ALB) and urea (UA) levels increased with age (p<0.05). Furthermore, the alpha diversity of rumen bacteria improved with age (p<0.05), with no gender differences observed. Males had higher relative abundances of Bacteroidota, Verrucomicrobiota, and Cyanobacteria, while females had higher Firmicutes and Desulfobacterota (p<0.05). The cellulose-degrading genus Ruminococcus and propionateproducing genus Succiniclasticum were more abundant in females, whereas the antiinflammatory genus Lachnospiraceae_NK4A136_group and the hemicellulose-degrading genus Prevotella were more abundant in males (p<0.05). Age-related differences in bacteria were found in Pseudobutyrivibrio and several members of the Lachnospiraceae. Functional prediction indicated that "Amino acid metabolism" and "Lipid metabolism" were mainly enriched in females, whereas "Carbohydrate metabolism" and "Glycan biosynthesis and metabolism" were enriched in males (p<0.05). RDA analysis highlighted butyrate as a key factor influencing the rumen bacterial community. NK4A214_group and Ruminococcus were positively correlated with butyrate, while Prevotella and Pseudobutyrivibrio were negatively correlated with butyrate (p<0.05). CONCLUSION:We observed a significant improvement in the diversity and stability of rumen microbiota as age increased. Ruminococcus, NK4A214_group, and Prevotella were likely contributors to variations in energy utilization and fat deposition between male and female Qinchuan cattle.