Obesity, now a prevalent global epidemic, is a primary driver of metabolic disorders and chronic diseases. Genetic and adipose tissue-specific mechanisms are increasingly recognized as important contributors to human obesity, making the ASIP adipose tissue-specific overexpression model relevant for studying obesity-associated metabolic dysfunction. In this study, a high-protein peptide diet (HPPD) derived from soybean meal fermented by Bacillus sp. D3 was evaluated in an adipose tissue-specific ASIP-overexpressing obese mouse model. Through an integrated multi-omics approach, we found that HPPD significantly reduced body weight gain (∼45%) and adiposity index (0.72-fold) in male mice compared to the ASIP control, while mitigating fat deposition, hepatic lipid accumulation, and adipose tissue morphological deterioration. Mechanistically, HPPD was associated with increased Akkermansia abundance and alterations in the gut–liver–adipose axis, accompanied by changes in PPAR-related signaling, fatty acid β-oxidation, and bile acid metabolism-associated pathways. These findings indicate that fermented soybean peptides effectively may alleviate lipid dysregulation in a genetic obesity mouse model, providing mechanistic insights and supporting their potential as functional food ingredients for managing obesity-related dyslipidemia.

Exosomes are crucial mediators of intercellular communication. As a key component of milk, milk-derived exosomes are abundant in genetic cargo, particularly microRNAs (miRNAs), indicating their potential role in regulating mammary gland physiology. Therefore, this study aimed to investigate the specificity of miRNAs in milk-derived exosomes and their regulatory roles in lipid synthesis in bovine mammary epithelial cells (BMECs). Based on 17,838 DHI records showing a significantly higher milk fat percentage (MFP) in late lactation (4.24

BACKGROUND:Insufficient lactation represents a critical global public health concern, profoundly impacting infant growth and development. Food-derived egg white peptides (EWPs) are believed to have lactation-promoting effects; however, the molecular mechanisms underlying these effects remain unclear. RESULTS:This research investigates EWPs as a potential functional food component to enhance lactation and dissects the underlying mechanisms using a combined phenotypic and omics approach in an overload breastfeeding mouse model. Our phenotypic analyses reveal that dietary supplementation with EWPs significantly increases milk production and promotes mammary gland epithelial cell proliferation. Additionally, it effectively mitigates maternal reproductive and lactational burdens, thereby supporting post-partum physiological recovery. Transcriptomic and western blot analyses further demonstrate that EWPs are associated with lactogenic effects through modulation of both direct and indirect signaling pathways. Direct pathways include the prolactin, oxytocin, and insulin signaling cascades, which regulate milk synthesis and secretion. Indirect pathways involve AMPK, JAK-STAT, glycolysis, and gluconeogenesis, which modulate energy metabolism and cellular homeostasis to support lactation. At the protein level, EWPs upregulate the expression of STAT5A, PFKM, and CRYAB, which are key regulators of milk protein synthesis. CONCLUSION:Collectively, our findings establish EWPs as a novel functional food supplement that may improve lactation performance and support maternal-infant health. This work provides a mechanistic framework for the development of personalized nutritional interventions to address lactation insufficiency, offering a promising strategy to improve outcomes for mothers and infants. © 2026 Society of Chemical Industry.

Cell proliferation plays a pivotal role in multiple physiological processes, including osteoporosis alleviation, wound healing, and immune enhancement. Numerous novel peptides with cell proliferation-promoting activity have been identified. These peptides exert their functions by modulating key cellular signaling pathways, thereby regulating diverse biological processes related to cell proliferation. This work summarizes peptides derived from animals and plants that stimulate cell proliferation, focusing on their amino acid composition, physicochemical properties, and preparation techniques. Furthermore, we highlight the major signaling pathways—such as the PI3K/Akt, MAPK/ERK, and Wnt/β-catenin pathways—that have been implicated in the mechanistic studies of food-derived peptides. Through the analysis and summary of previous studies, we observe a notable lack of in vivo animal models and clinical trials, indicating that these may represent promising directions for future research on food-derived bioactive peptides. Meanwhile, the potential safety concerns of proliferation-enhancing peptides—such as immunogenicity, appropriate dosage, and gastrointestinal stability—warrant greater attention. In summary, this review provides a comprehensive overview of the sources and mechanisms of cell proliferation-promoting peptides and addresses the challenges in industrializing bioactive peptide-based functional foods; therefore, further research in this area is encouraged.

The increasing global rates of obesity underscore the need to investigate its impact on infant health. Breast milk, crucial for infant nutrition, varies in composition due to maternal obesity during pregnancy. Research reveals that obese or overweight mothers tend to have higher saturated fatty acids (SFAs) levels, like palmitic and myristic acids, while stearic acid levels are lower. Monounsaturated fatty acids (MUFAs), particularly oleic acid in milk, decline in obesity. Polyunsaturated fatty acids (PUFAs), essential for infant brain and nervous system development, show imbalances in obese mothers, with an increased omega-6 (ω-6): omega-3 (ω-3) ratio and reduced levels of key ω-3 fatty acids such as α-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These changes could disrupt normal immune and nervous system development in infants. This review highlights the critical impact of maternal obesity on breast milk quality.

Background/Objectives: Breast milk provides essential nutrition and immune protection to support infant growth and development. However, insufficient breast milk remains a serious issue, and bioactive peptides represent a potential strategy to promote lactation. In this study, we investigated the impact of a methionine-containing dipeptide, EM, on MCF-10A mammary epithelial cells. Methods: MCF-10A cells were treated with EM, and cell proliferation and the expression of key milk protein genes were assessed. Integrated transcriptomic and untargeted metabolomic analyses were performed to identify EM-induced changes in metabolic and gene expression pathways. Results: EM treatment significantly enhanced cell proliferation and upregulated the expression of key milk protein genes (CSN1S1 (casein alpha-S1, encoding alpha-S1 casein), CSN2 (casein beta, encoding beta-casein), and CSN3 (casein kappa, encoding kappa-casein)) at both transcriptional and protein levels compared to controls. Integrated transcriptomic and metabolomic analyses revealed that EM reprogrammed amino acid metabolism, lipid biosynthesis, and nutrient transport pathways. Core genes such as SLC7A11, APOE, and ABCA1 were identified as critical nodes linking metabolic and transcriptional networks. Conclusions: These findings indicate that EM may promote lactogenic activity by modulating metabolic and transcriptional networks in vitro, highlighting the potential of dipeptide-based nutritional interventions, which warrants further in vivo validation.

Background Exosomes have recently been considered as major players in cell-cell communication. Milk-derived exosomes contained abundant genetic cargos and the potential biological functions in the synthesis of milk fat remain poorly understood. Milk fat percentage is a crucial trait that influences dairy quality and consumer preference. This study focused on the regulatory role of milk-derived exosomal miRNAs in lipid synthesis within BMECs. Results Initially, based on 17,838 DHI milk production performance data collected from January 2021 to February 2023, compared with early lactation , mid-lactation from 100 to 199 days, late lactation from 200 to 299 days, duration lactation the milk fat percentage (MFP) of late lactation (4.24±1.07%) significant higher than other stages. The milk protein percentage during this stage (3.43±0.36) is significantly higher compared to other stages. The heritability estimates for milk fat and milk protein percentage show a positive correlation. Subsequently, 10 cows with high MFP （5.96±0.26 ) and ten cows with low MFP (1.68±0.23) were selected during the late lactation stage, and milk samples were collected for further analysis. Milk-derived exosomes isolated via differential ultracentrifugation exhibited a spherical vesicle structure ranging in size from 50 to 150 nm and were enriched in exosome-specific protein markers CD9, CD81, and TSG101. Through miRNA-seq, 1320 differentially expressed miRNAs were identified including 496 up-regulated and 824 down-regulated miRNAs by high-throughput miRNA sequencing. Furthermore, the exosome uptake experiment revealed that upon BMECs, exosomes predominantly localized in the cytoplasm.The results of exosomal q-PCR demonstrated that miR-423-5p and miR-125b were significantly up-regulated and down-regulated in HMF_EXO and LMF_EXO groups, respectively. Conclusions Milk-derived exosomal miRNAs associated with lipid metabolism can provide preliminary insights into the effects of exosomes on lactation mechanisms and potentially identify biomarkers for distinguishing molecular markers and loci related to high or low milk fat content in dairy cattle.

Stearoyl-CoA desaturase-1 (SCD1) is a key enzyme in the biosynthesis of monounsaturated fatty acids and is considered a candidate gene for improving milk and meat quality traits. Sanger sequencing was employed to investigate the genetic polymorphism of the fifth exon and intron of bovine SCD1, revealing four SNPs, g.21272246 A>G, g.21272306 T>C, g.21272422 C>T, and g.21272529 A>G. Further variance analysis and multiple comparisons were conducted to examine the relationship between variation sites and economic traits in Chinese Simmental cattle, as well as milk production traits in Holstein cows. The findings revealed these four loci exhibited significant associations with carcass traits (carcass weight, carcass length, backfat thickness, and waist meat thickness), meat quality (pH value, rib eye area, and marbling score), adipogenic traits (fat score and carcass fat coverage rate), and fatty acid composition (linoleic acid and α-linolenic acid). Furthermore, these loci were additionally found to be significantly associated with average milk yield and milk fat content in cows. In addition, a haplotype analysis of combinations of SNPs showed that H2H3 has a significant association with adipogenic traits and H2H2 was associated with higher levels of linoleic acid and α-linolenic acid than the other combinations. These results suggest that the four SNPs are expected to be prospective genetic markers for the above economic traits. In addition, the function of SNPs in exon 5 of SCD1 on gene expression and protein structure needs to be explored in the future.

The CD44 gene is a critical factor in animal physiological processes and has been shown to affect insulin resistance and fat accumulation in mammals. Nevertheless, little research has been conducted on its precise functions in lipid metabolism and adipogenic differentiation in beef cattle. This study analyzed the expression of CD44 and miR-199a-3p during bovine preadipocyte differentiation. The luciferase reporter assay demonstrated that CD44 was a direct target of miR-199a-3p. Increased accumulation of lipid droplets and triglyceride levels, altered fatty acid metabolism, and accelerated preadipocyte differentiation were all caused by the upregulation of miR-199a-3p or a reduction in CD44 expression. CD44 knockdown upregulated the expression of adipocyte-specific genes (LPL and FABP4) and altered the levels of lipid metabolites (SOPC, l-arginine, and heptadecanoic acid). Multiomics highlights enriched pathways involved in energy metabolism (MAPK, cAMP, and calcium signaling) and shifts in mitochondrial respiration and glycolysis, indicating that CD44 plays a regulatory role in lipid metabolism. The findings show that intracellular lipolysis, glycolysis, mitochondrial respiration, fat deposition, and lipid droplet composition are all impacted by miR-199a-3p, which modulates CD44 in bovine adipocytes.

Delta-like non-canonical Notch ligand 1 (DLK1), which inhibits the differentiation of precursor adipocytes, is a recognized marker gene for precursor adipocytes. Lipids play a crucial role in energy storage and metabolism as a vital determinant of beef quality. In this study, we investigated the mechanism of the DLK1 gene in lipid metabolism by constructing adipose tissue-specific knockout mice. We examined some phenotypic traits, including body weight, liver coefficient, fat index, the content of triglyceride (TG) and cholesterol (CHOL) in abdominal white adipose tissue (WAT) and blood. Subsequently, the fatty acid content and genes related to lipid metabolism expression were detected in DLK1−/− and wild-type mice via GC-MS/MS analysis and quantitative real-time PCR (qRT-PCR), respectively. The results illustrated that DLK1−/− mice exhibited significant abdominal fat deposition compared to wild-type mice. HE staining and immunohistochemistry (IHC) results showed that the white adipocytes of DLK1−/− mice were larger, and the protein expression level of DLK1−/− was significantly lower. Regarding the blood biochemical parameters of female mice, DLK1−/− mice had a strikingly higher triglyceride content (p < 0.001). The fatty acid content in DLK1−/− mice was generally reduced. There was a significant reduction in the expression levels of the majority of genes that play a crucial role in lipid metabolism. This study reveals the molecular regulatory mechanism of fat metabolism in mice and provides a molecular basis and reference for the future application of the DLK1 gene in the breeding of beef cattle with an excellent meat quality traits. It also provides a molecular basis for unravelling the complex and subtle relationship between adipose tissue and health.

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.

Breast milk is widely considered to be the most natural, safe, and complete food for infants. However, current breastfeeding rates fall short of the recommendations established by the World Health Organization. Despite this, there are few studies that have focused on the promotion of human lactation through nutrient supplementation. Therefore, the aim of this study was to investigate the effect of methionine on milk synthesis in human mammary epithelial cells (MCF-10A cells) and to explore the underlying mechanisms. To achieve this, MCF-10A cells were cultured with varying concentrations of methionine, ranging from 0 to 1.2 mM. Our results indicated that 0.6 mM of methionine significantly promoted the synthesis of milk protein. An RNA-seq analysis revealed that methionine acted through the PI3K pathway. This finding was validated through real-time quantitative polymerase chain reaction (RT-qPCR) and Western blotting. In addition, PI3K inhibition assays confirmed that methionine upregulated the expression of both mTOR and p-mTOR through activation of PI3K. Taken together, these findings suggest that methionine positively regulates milk protein synthesis in MCF-10A cells through the PI3K-mTOR signaling pathway.

The purpose of this study was to identify Guyuan cattle as relatively independent beef cattle genetic resources， further describe their growth and development rules， and provide certain theoretical basis for the identification and breeding of germplasm resources for meat of Guyuan cattle. The evolutionary history of Guyuan cattle was analyzed through historical documents and investigation. The whole genome genetic variation data of 337 individuals of 13 breeds including Guyuan cattle were detected through GGP Bovine 100K gene chip and downloaded from public databases， and the genetic background of Guyuan cattle was analyzed by multidimensional scaling analysis and adjacent phylogenetic tree. Taking the Red Angus×Guyuan crossbred cattle as the control population， the phenotypic data such as body weight， body size， backfat thickness and loin eye area of Guyuan cattle at different growth stages were measured and collected， with reference to the phenotypic data of Qinchuan cattle and Mongolian cattle published in the Journal of Chinese Livestock and Poultry Genetic Resources， the population rule of relevant indicators of Guyuan cattle is excavated from the phenotypic description. The results showed that 1) Guyuan cattle is a unique population with the same shape and appearance after long-term breeding due to the mutual influence of Guyuan native cattle with neighboring Mongolian cattle and Qinchuan cattle; 2) The genetic structure of existing Guyuan cattle population is close to the neighboring Qinchuan cattle and Jinnan cattle， and it is a relatively independent resource population. 3) Compared with heifer of Guyuan cattle， somatic index of adult cow of Guyuan cattle was increased by 9.57%; 4) After crossbreeding with Red Angus cattle， brassiere index and somatic index of adult cow of crossbred Guyuan cattle were respectively increased by 11.59% and 12.70%， body length index and brassiere index of bull of crossbred Guyuan cattle were respectively increased by 15.15% and 19.26%; 5) Beef-purpose index of adult cow of Guyuan cattle was 2.65±0.46， Beef-purpose index of bull of Guyuan cattle was 2.87±0.35， and Guyuan cattle is draft cattle; 6) The backfat thickness of bull of Guyuan cattle was （5.29±1.41）mm， higher than the backfat thickness of bull of Mongolian cattle （4.00±1.00）mm; 7) The loin eye area of bull of Guyuan cattle was （62.17±8.51）cm 2 ， between the loin eye area of of Qinchuan cattle （79.80±9.70）cm 2 and Mongolian cattle （50.40±9.80）cm 2 . Guyuan cattle is a new genetic resource of beef cattle， which has good germplasm characteristics for meat. However， its body size indexes and beef-purpose index have not reached the standard of specialized beef cattle. In the later stage， strengthen breeding and the stock breeding and genetic improvement of Guyuan cattle are needed to further develop its germplasm resource characteristics.

Transcriptome sequencing showed that syndecan-3 (SDC3) was differentially expressed in high-fat and low-fat mammary epithelial cells of Chinese Holstein cows. Previous studies found that SDC3 plays an important role in inflammatory diseases and virus infection. However, those studies did not confirm whether or not the functional gene SDC3, which plays an important role in regulating milk fat metabolism, has an effect on susceptibility to breast tissue diseases. Therefore, we studied the effects of SDC3 on milk lipid metabolism and inflammation in bovine mammary epithelial cells (BMECs) and further explored the common regulatory pathway of SDC3 in both. The overexpression of SDC3 increased the contents of triglycerides and cholesterol, reduced the content of non-esterified fatty acids, inhibited the expression of inflammatory factors (IL-6, IL-1β, TNF-α and COX-2), and reduced the production of ROS in BMECs. However, silenced SDC3 had the opposite effect. Further exploring the mechanisms of SDC3, we found that SDC3 upregulated the expression of peroxisome proliferator-activated receptor gamma (PPARG) through the AMPK/SIRT1 signal pathway to promote milk fat synthesis. It also regulated the activation of the NF-κB pathway through the AMPK/SIRT1 signal pathway, reducing the expression of inflammatory factors and ROS production, thus inhibiting the inflammatory response of BMECs. Nuclear factor kappa B subunit 1 (NF-κB p50) was an important target of SDC3 in this process. To sum up, our results showed that SDC3 coregulated milk fat metabolism and inflammation through the AMPK/SIRT1 signaling pathway. This study laid a foundation for the comprehensive evaluation of breeding value based on multi-effect functional genes in dairy cow molecular breeding.

In this study, effects of dietary supplementation of two different hormones on growth, sex conversion and reproduction of electric yellow cichlid, Labidochromis caeruleus were investigated.Moreover, possible negative (sterilization, mortality, reproduction performance etc.) and positive (growth, sex conversation etc.) impacts of hormone administration were also assessed.This study had two experiments.In the first experiment, six experimental feeds were prepared by adding two different hormones (17α-Methyltestosterone (Mt), 17β-Estradiol (Es) at three different doses (20, 40, 60 mg kg -1 ) and control feed was without hormone.All six experiment groups receiving experimental diets and control were conducted in 3 replicates in 21 aquariums for 3 months in the first experiment.L. caeruleus were fed orally with these hormone-supplemented feeds and growth parameters, sex conversion and survival rate were examined.In the second experiment, fish from the first experiment were fed with commercial cichlid feed containing no hormones and numbers of fry produced was recorded.At the end of 90-day feeding period in the first experiment, the best growth was obtained in 60 mg kg -1 Mt treated group (1.97±0.17g).Sex conversion to all male population (100% male) was observed in 17α-Mt treated groups, while, conversion to 82.22, 86.67 and 86.67% females was observed in 17β-Es treated (20, 40 and 60 mg kg -1 ) groups, respectively.In the second experiment, after feeding the fish with a commercial feed for 3 months, fish fry was released from fish mouth and numbers of fry were counted.The present findings revealed that 17α-Mt hormone was more effective in growth and sex conversion, while the survival rate and number of fry produced were negatively affected by the increased dose of both hormones.

Chitosan oligosaccharide (COS) is a variety of oligosaccharides, and it is also the only abundant basic amino oligosaccharide in natural polysaccharides. Chitosan oligosaccharide is a low molecular weight product of chitosan after enzymatic degradation. It has many biological effects, such as lipid-lowering, antioxidant and immune regulation. Previous studies have shown that chitosan oligosaccharide has a certain effect on fat synthesis, but the effect of chitosan oligosaccharide on milk fat synthesis of bovine mammary epithelial cells (BMECs) has not been studied. Therefore, this study aimed to investigate chitosan oligosaccharide's effect on milk fat synthesis in bovine mammary epithelial cells and explore the underlying mechanism. We treated bovine mammary epithelial cells with different concentrations of chitosan oligosaccharide (0, 100, 150, 200, 400 and 800 μg/mL) for 24 h, 36 h and 48 h respectively. To assess the effect of chitosan oligosaccharide on bovine mammary epithelial cells and determine the concentration and time for chitosan oligosaccharide treatment on cells, several in vitro cellular experiments, including on cell viability, cycle and proliferation were carried out. The results highlighted that chitosan oligosaccharide (100, 150 μg/mL) significantly promoted cell viability, cycle and proliferation, increased intracellular cholesterol content, and reduced intracellular triglyceride and non-esterified fatty acids content. Under the stimulation of chitosan oligosaccharide, the expression of genes downstream of Phosphorylated AMP-activated protein kinase (P-AMPK) and AMP-activated protein kinase (AMPK) signaling pathway changed, increasing the expression of peroxisome proliferator-activated receptor alpha (PPARα) and hormone-sensitive lipase (HSL), but the expression of sterol regulatory element-binding protein 1c (SREBP1) and its downstream target gene stearoyl-CoA desaturase (SCD1) decreased. In conclusion, these results suggest that chitosan oligosaccharide may inhibit milk fat synthesis in bovine mammary epithelial cells by activating the AMP-activated protein kinase signaling pathway, promoting the oxidative decomposition of fatty acids and inhibiting fatty acid synthesis.

Acyl-CoA synthetase family member 3 (ACSF3) carries out the first step of mitochondrial fatty acid synthesis II, which is the linkage of malonate and, to a lesser extent, methylmalonate onto CoA. Malonyl-coenzyme A (malonyl-CoA) is a central metabolite in mammalian fatty acid biochemistry that is generated and utilized in the cytoplasm. In this research, we verified the relationship between expression of the ACSF3 and the production of triglycerides (TGs) at the cellular level by silencing and over-expressing ACSF3. Subsequently, through Sanger sequencing, five polymorphisms were found in the functional domain of the bovine ACSF3, and the relationship between ACSF3 polymorphism and the economic traits and fatty acid composition of Chinese Simmental cattle was analyzed by a means of variance analysis and multiple comparison. The results illustrated that the expression of ACSF3 promoted triglyceride synthesis in bovine mammary epithelial cells and bovine fetal fibroblast cells. Further association analysis also indicated that individuals with the AG genotype (g.14211090 G > A) of ACSF3 were significantly associated with the fatty acid composition of intramuscular fat (higher content of linoleic acid, α-linolenic acid, and arachidonic acid), and that CTCAG haplotype individuals were significantly related to the fatty acid composition of intramuscular fat (higher linoleic acid content). Individuals with the AA genotypes of g.14211055 A > G and g.14211090 G > A were substantially associated with a larger eye muscle area in the Chinese Simmental cattle population. ACSF3 played a pivotal role in the regulation of cellular triacylglycerol and long-chain polyunsaturated fatty acid levels, and polymorphism could serve as a useful molecular marker for future marker-assisted selection in the breeding of intramuscular fat deposition traits in beef cattle.

Carnitine palmitoyltransferase 1B (CPT1B) is a candidate gene that regulates livestock animal lipid metabolism and encodes the rate-limiting enzyme in fatty acid β-oxidation. To explore the effect of this gene on lipid metabolism in cattle, this study examined CPT1B gene polymorphism in Chinese Simmental cattle and the effect of CPT1B on lipid metabolism. The results showed that the triglyceride content increased significantly with increasing CPT1B gene expression in bovine fetal fibroblasts (BFFs) (p < 0.05), while CPT1B knockout led to decreased CPT1B expression and a downward trend in triglyceride levels. Correlation analysis showed a significant association between the g.119896238 G > C locus and Chinese Simmental cattle backfat thickness (p < 0.05). Backfat thickness was significantly greater in individuals with the GC genotype (0.93 ± 0.67 cm) than in those with the CC genotype (0.84 ± 0.60 cm). The g.119889302 T > C locus was significantly correlated with arachidonic acid content in Chinese Simmental cattle (p < 0.05). The arachidonic acid content in the longissimus muscle was significantly higher in CC genotype beef cattle (0.054 g/100 g) than in those with the other two genotypes (0.046 g/100 g, 0.049 g/100 g). These molecular markers can be effectively used for marker-assisted selection in cattle breeding.

Glycerol-3-phosphate acyltransferase mitochondrial (GPAM) is an enzyme in animal lipid metabolism pathways that catalyzes the initial and most committed step of glycerolipid biosynthesis. The present study mainly focused on exploring the relationship between the GPAM gene and the lipid metabolism of mammary epithelial cells and the effect of GPAM on the related pathways of lipid metabolism. The GPAM gene was knocked out entirely in bovine mammary epithelial cells(BMECs) using CRISPR/Cas9 technology, and the mechanism by which the GPAM gene regulates lipid metabolism in BMECs was confirmed. Furthermore, after the complete loss of GPAM, BMECs' triglycerides (TGs) and cholesterol (CHOL) levels were significantly decreased (p < 0.05). Concurrently, the content of octanoic acid, a medium-chain saturated fatty acid, increased substantially in BMECs. RNA-seq of GPAM-/- BMECs revealed that GPAM could affect the expression of genes related to lipid metabolism, downregulated the expression of Acyl-CoA synthetase long-chain family member 5 (ACSL5), Fatty Acid Binding Protein 3 (FABP3), Hormone-sensitive lipase (HSL), Protease, serine-2 (PRSS2), 1-Acylglycerol-3-Phosphate O Acyltransferase 4 (AGPAT4), and regulated the milk synthesis metabolism pathway.The findings revealed that a number of genes were expressed, a number of genes were differentially expressed genes (DEGs), and a number of GO terms were enriched, with a number of GO terms considerably increased. Further, the differentially expressed genes (DEGs) were significantly enriched in Fat digestion and absorption pathway, Fatty acid metabolic pathway, Biosynthesis of unsaturated fatty acids, Biosynthesis of unsaturated fatty acids and steroids, NF-kappa B signalling pathway, MAPK signalling pathway. In conclusion, the current research results show that GPAM is a crucial regulator of BMEC lipid metabolism. GPAM-/- BMEC may also become useful genetic materials and tools for future research on gene functions related to lipid and fatty acid metabolism. This study will contribute to the discovery of gene regulation and molecular mechanisms in milk fat synthesis.

MicroRNAs (miRNAs) play significant roles in mammalian spermatogenesis. Sertoli cells can provide a stable microenvironment and nutritional factors for germ cells, thus playing a vital role in spermatogenesis. However, few studies elucidate the regulation of bovine testicular Sertoli cells by miRNAs. Here, we have reported that miRNA-34c (miR-34c) regulates proliferation, apoptosis, and relative transcripts abundance gene in bovine Sertoli cells. In bovine Sertoli cells, overexpression of miR-34c inhibited proliferation and relative abundance of gene transcripts while promoting apoptosis of Sertoli cells, and the effects were the opposite when miR-34c was knocked down. Receptor tyrosine kinase (AXL) was identified as a direct target gene of miR-34c in Sertoli cells, validated by analysis of the relative abundance of AXL transcript and dual-luciferase reporter assay. The relative abundance of the transcript of genes related to male reproduction in Sertoli cells was changed after the AXL gene was overexpressed, as demonstrated by the RT2 Profiler PCR Array results. In summary, miR-34c specifically regulated the AXL gene by targeting a sequence in the 3′-UTR, which could influence proliferation, apoptosis, and relative abundance of the transcript of male reproduction-related genes. Therefore, miR-34c could be considered an essential regulator in the process of bull spermatogenesis.