Body conformation traits in early-lactation associated with clinical mastitis and lameness in lactating Chinese holstein cows.

BACKGROUND: Comprehending the correlation between body conformation traits of cows at the early stages of lactation and prevalent lactation diseases might facilitate the execution of selection and feeding strategies that prioritize cow health. This study aimed to evaluate the impact of body conformation traits on the incidence of clinical mastitis and lameness in Chinese Holstein cows. From a pasture herd of 1472 early lactating Chinese Holstein cows, we evaluated 20 body conformation traits. During lactation, this pasture herd was visited weekly to gather clinical mastitis and lameness data. A nine-point scale was used to determine the conformation traits of cows to clarify their linear characters, including frame capacity, rump (RU), feet and leg (FL), mammary system (MS), and dairy character. A longitudinal binary disease (0 = healthy; 1 = diseased) data structure was created by allocating disease records to adjacent official test dates. The impact of body conformation traits on the risk of developing diseases (clinical mastitis and lameness) was analyzed using the logistic regression models. RESULTS: Compared to cows with low total scores (75-79 points), those with high total scores (80-85 points) of body conformation traits had a significantly lower risk of mastitis (P < 0.001). The disease status (0 or 1: binary variable) of clinical mastitis in lactating cows was significantly impacted negatively by age (P < 0.05). The fore udder attachment (FUA), angularity, rear attachment height (RAH), and rear teat placement (RTP) were all significantly associated with clinical mastitis during lactation (P < 0.05). The rear leg-rear view (RLRV) was significantly correlated with correlated considerably (P < 0.05) with lameness during lactation. An ideal score of four points on the lameness risk dimension of the RLRV may indicate a low risk of lameness. Since the risk of mastitis decreased as this trait score increased, the RTP may be an ideal marker for mastitis risk. CONCLUSIONS: According to the study, clinical mastitis and lameness risks in cows can be estimated using their body conformation traits. Cows with more centrally located rear teats have a lower risk of mastitis. These results may help dairy farmers identify cows at high risk of disease early in lactation and aid in breeding for disease resistance in cows.

Long non-coding RNA (CMR) involved in autoprotection in S. aureus mastitis in dairy cows by regulating miR-877/FOXM1.

Long non-coding RNAs (LncRNAs) are dysregulated in a variety of human diseases and are highly involved in the development and progression of tumors. Studies on lncRNAs associated with cow mastitis have been lagging behind compared to humans or model animals, therefore, the aim of this study was to explore the mechanism of LncRNAs (CMR) involved in autoprotection against S. aureus mastitis in Bovine Mammary Epithelial Cells (BMECs). First, qRT-PCR was used to examine the relative expression of CMR in a S. aureus mastitis model of BMECs. Then, cell proliferation and apoptosis were detected by EdU and apoptosis assay. Finally, the targeting relationship between miRNAs and mRNA/LncRNAs was determined by dual luciferase reporter gene, qRT-PCR and western blotting techniques. The results showed that CMR was upregulated in the S. aureus mastitis model of BMECs and promoted the expression of inflammatory factors, and SiRNA-mediated CMR inhibited the proliferation of mammary epithelial cells and induced apoptosis. Mechanistically, CMR acts as a competitive endogenous RNA (ceRNA) sponge miR-877, leading to upregulation of FOXM1, a target of miR-877. Importantly, either miR-877 overexpression or FOXM1 inhibition abrogated CMR knockdown-induced apoptosis promoting cell proliferation and reducing inflammatory factor expression levels. In summary, CMR is involved in the regulation of autoprotection against S. aureus mastitis through the miR-877/FOXM1 axis in BMECs and induces immune responses in mammary tissues and cells of dairy cows, providing an important reference for subsequent prevention and control of cow mastitis and the development of targeted drugs.

Eukaryotic initiation factor 6 repression mitigates atherosclerosis progression by inhibiting macrophages expressing Fasn.

Atherosclerosis, a chronic inflammatory disease that often leads to myocardial infarction and stroke, is mainly caused by lipid accumulation. Eukaryotic initiation factor 6 (Eif6) is a rate-limiting factor in protein translation of transcription factors necessary for lipogenesis. To determine whether Eif6 affects atherosclerosis, Eif6+/- mice were crossed into Apoe-/- background. Apoe-/-/Eif6+/- mice on high fat diet showed significant reduction in atherosclerotic lesions and necrotic core content in aortic root sections in comparison with Apoe-/- mice. RNA-Seq was used to investigate the effect of Eif6 in aorta. Deficiency of Eif6 shows broad effect on cell metabolism. Expression of genes for fatty acid synthesis including Fatty acid synthase (Fasn), Elovl3, Elovl6 and Acaca are down-regulated in aortas. Importantly, Fasn is decreased in macrophages. Results suggest that Eif6 deficiency may decrease atherosclerosis through inhibition of Fasn and lipids metabolism in macrophages.

Expression profile and functional prediction of novel LncRNA 5.8S rRNA-OT1 in cattle.

Long non-coding RNAs (LncRNAs) are generally longer than 200 bp in length and play an important regulatory role in the growth and development of skeletal muscle. In the previous work, the non-coding RNAs with abundant expression in bovine tissues were screened out. After quantitative real-time PCR (qPCR), 33 lncRNAs with differential expression in various bovine tissues were identified. Differential expression analysis base on tissue expression profiles of 33 lncRNAs, a long non-coding RNA LncRNA13, which may have effects on bovine muscle development, was found. The expression levels in embryo muscle and adult cattle muscle were significantly different (p < 0.01), so it is speculated that it may have a certain impact on the development of cattle muscle. It was named LncRNA 5.8S rRNA-OT1, and its overexpression vector pcDNA3.1-LncRNA 5.8S rRNA-OT1 was cloned and constructed. The purpose of this study is to further explore its impact on the proliferation and differentiation of bovine muscle cells and accumulate data to lay a foundation for further exploration of the function of LncRNA 5.8S rRNA-OT1 and add basic data for the study of the regulatory mechanism of lncRNA.

Molecular mechanisms in the miR-33a/LPPR4 pathway regulating unsaturated fatty acid synthesis in bovine mammary epithelial cells.

The regulatory mechanisms governing metabolism of fatty acids in cow mammary gland are crucial for establishing relationships between milk quality and fatty acid content. Both, microRNAs (miRNAs) and protein-coding genes are important factors involved in the regulation of milk fat synthesis. In this study, high-throughput sequencing of miRNAs and mRNAs in bovine mammary gland tissue was performed during peak lactation (3 samples) and late lactation (3 samples) periods to characterize expression profiles. Differential expression (DE) analyses of miRNA and mRNA and miRNA-mRNA regulatory pathway screening were performed. Two-hundred eighty regulatory miRNA-mRNA pairs were identified, including the miR-33a-lipid phosphate phosphatase-related protein type 4 (LPPR4) pathway. Bioinformatics prediction, dual-luciferase reporter system detection, qRT-PCR, and Western blotting revealed that miR-33a can directly target LPPR4 and inhibit its expression. Experiments also revealed that miR-33a promotes the synthesis of triglycerides and increases the content of unsaturated fatty acids (UFAs) in bovine mammary epithelial cells (BMECs). These results indicate that miR-33a via LPPR4 plays an important role in the regulation of milk fat synthesis and UFA levels.

Longitudinal genome-wide association studies of milk production traits in Holstein cattle using whole-genome sequence data imputed from medium-density chip data.

Longitudinal traits, such as milk production traits in dairy cattle, are featured by having phenotypic values at multiple time points, which change dynamically over time. In this study, we first imputed SNP chip (50-100K) data to whole-genome sequence (WGS) data in a Chinese Holstein population consisting of 6,470 cows. The imputation accuracies were 0.88 to 0.97 on average after quality control. We then performed longitudinal GWAS in this population based on a random regression test-day model using the imputed WGS data. The longitudinal GWAS revealed 16, 39, and 75 quantitative trait locus regions associated with milk yield, fat percentage, and protein percentage, respectively. We estimated the 95% confidence intervals (CI) for these quantitative trait locus regions using the logP drop method and identified 581 genes involved in these CI. Further, we focused on the CI that covered or overlapped with only 1 gene or the CI that contained an extremely significant top SNP. Twenty-eight candidate genes were identified in these CI. Most of them have been reported in the literature to be associated with milk production traits, such as DGAT1, HSF1, MGST1, GHR, ABCG2, ADCK5, and CSN1S1. Among the unreported novel genes, some also showed good potential as candidate genes, such as CCSER1, CUX2, SNTB1, RGS7, OSR2, and STK3, and are worth being further investigated. Our study provided not only new insights into the candidate genes for milk production traits, but also a general framework for longitudinal GWAS based on random regression test-day model using WGS data.

Identification and Classification of Long Non-Coding RNAs in the Mammary Gland of the Holstein Cow.

The mammary glands, responsible for milk secretion, are regulated at a local level by various hormones, growth factors, non-coding RNAs, and other elements. Recent research has discovered the presence of lncRNAs in these glands, with suggestions that they may be essential for the maintenance and function of mammary glands. Besides directly controlling the gene and protein expression, lncRNAs are believed to play a significant part in numerous physiological and pathological processes. This study focused on examining the mammary gland tissues of Chinese Holstein cows, to identify and categorize long non-coding RNAs (lncRNAs). The research intended to distinguish lncRNAs in the mammary tissues of Holstein cows and contrast them between lactation and non-lactation periods. In this study, mammary gland tissues were sampled from three Holstein cows in early lactation (n = 3, 30 days postpartum) and non-lactation (n = 3, 315 days postpartum) on a large dairy farm in Jiangsu province. Mammary tissue samples were collected during early lactation and again during non-lactation. In total, we detected 1905 lncRNAs, with 57.3% being 500 bp and 612 intronic lncRNAs. The exon count for lncRNAs varied from 2 to 10. It was observed that 96 lncRNA expressions markedly differed between the two stages, with 83 genes being upregulated and 53 downregulated. Enrichment analysis results revealed that Gene Ontology (GO) analysis was primarily abundant in cellular processes. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis indicated that target genes were predominantly abundant in metabolic pathways, fatty acid biosynthesis, the immune system, and glycosphingolipid biosynthesis. This study analyzed the expression profile and characteristics of lncRNAs in the mammary gland tissues of Holstein cows during both lactation and non-lactation stages, forming a foundation for further investigation into the functional roles of lncRNAs in Holstein cows throughout lactation.

The polymorphism of bovine Cofilin-1 gene sequence variants and association analysis with growth traits in Qinchuan cattle.

In our study, four single nucleotide polymorphisms (SNPs) were identified in exon 2 of cofilin-1 (CFL1) gene in 488 Chinese Qinchuan (QC) cattle, which included two missense mutations T 2084G and G 2107C, two synonymous mutations T 2052C and T 2169C. Further, we evaluated haplotype frequency and linkage disequilibrium (LD) coefficient of four SNPs. At SNP T 2052C, G 2107C and T 2169C, the QC cattle population belonged to intermediate genetic diversity (0.25 < PIC-value < 0.5), whereas SNP T-2084G belonged to low polymorphism (PIC-value < 0.25). Haplotype analysis showed that 6 different haplotypes (frequency > 0.03). LD analysis showed that SNP G 2107C and T 2169C, SNP G 2107C and T 2084G were high LD, respectively (r2 > 0.33). Association analysis indicated that SNP T 2052C was significantly associated with body length, chest breadth, chest depth and body mass in the QC population (p < 0.01 or p < 0.05). SNP G 2107C was significantly associated with rump length (p < 0.05). SNP T 2169C was significantly associated with chest breadth and chest depth (p < .01 or p < .05). The results of our study suggest that the CFL1 gene may be a strong candidate gene that affects growth traits in the QC cattle breeding program.

Association of residual feed intake with peripartal ruminal microbiome and milk fatty acid composition during early lactation in Holstein dairy cows.

Residual feed intake (RFI) is a moderately heritable trait of feed efficiency in dairy cows. The main objective of the present study was to assess potential differences in the ruminal microbiome, milk fatty acid (FA) composition, and plasma concentrations of glucose, nonesterified fatty acids (NEFA), and ß-hydroxybutyrate between the most (M-EFF) and the least efficient (L-EFF) dairy cows during early lactation. Forty-seven multiparous Holstein dairy cows with daily ad libitum access to a total mixed ration from 30 d before calving to 30 d in milk were used. Cows were retrospectively classified into M-EFF (i.e., low RFI, n = 29) and L-EFF (high RFI, n = 18) based on a linear regression model. Ruminal digesta and milk samples were collected from each cow at 15 and 30 d in milk for microbiome analysis using 16S rRNA gene sequencing. Microbiome sequencing data were analyzed with the QIIME 2 platform (http://qiime.org/), whereas the microbiome statistical analyses and visual explorations were performed using the web-based MicrobiomeAnalyst platform. Milk FA composition was measured via gas chromatography-mass spectrometry. The statistical model used in SAS 9.4 (SAS Institute Inc.) included RFI, time, and their interactions as fixed effects. The cor() function in R programming was used to determine Pearson correlations between relative abundance of significant bacteria and milk FA. Overall, daily milk yield did not differ due to RFI and averaged 42 ± 1.6 kg for L-EFF and 43 ± 1.3 kg for M-EFF cows. However, M-EFF cows had lower overall dry matter intake (14.9 ± 0.5 kg/d) compared with L-EFF cows (19.2 ± 0.6 kg/d). No incidence of clinical disease was recorded for cows in the study. Compared with L-EFF, overall glucose concentration was lower, whereas NEFA and ß-hydroxybutyrate concentrations were greater in M-EFF cows. Ruminal digesta from both RFI groups had similar bacterial composition, but differed in the relative abundance of some bacteria. Compared with L-EFF, M-EFF cows had greater relative abundance of Lachnospiraceae, Lachnoclostridium, Papillibacter, Desulfovibrio, Sphaerochaeta, Acetobacter, and Histophilus. In contrast, relative abundance of Bifidobacterium, Ruminiclostridium, Prevotellaceae, and Erysipelotrichaceae bacterium was lower in M-EFF cows. Compared with L-EFF, M-EFF cows had greater proportions of long-chain monounsaturated FA, including 16:1 trans-9, 16:1 cis-9, 17:1 trans-10, 17:1 cis-10, 18:1 cis-9, 18:1 cis-11, whereas proportions of medium-chain saturated and 16:0 were lower in M-EFF. Acetate-producing bacteria (Sphaerochaeta and Acetobacter) were positively and significantly correlated (r ≥ 0.24) with concentrations of 16:1 cis-9 and 17:1 cis-10, whereas Prevotellaceae was significantly and negatively correlated (r = -0.25) with these FA. Butyrate-producing bacterium (Papillibacter) had a significant negative correlation (r = -0.27) with concentration of 15:0. Overall, data suggested that feed-efficient cows have unique profiles of ruminal microbiota, some of which are correlated with concentrations of milk FA during early lactation.

Assessment of the performance of different imputation methods for low-coverage sequencing in Holstein cattle.

Low-coverage sequencing (LCS) followed by imputation has been proposed as a cost-effective genotyping approach for obtaining genotypes of whole-genome variants. Imputation performance is essential for the effectiveness of this approach. Several imputation methods have been proposed and successfully applied in genomic studies in human and other species. However, there are few reports on the performance of these methods in livestock. Here, we evaluated a variety of imputation methods, including Beagle v4.1, GeneImp v1.3, GLIMPSE v1.1.0, QUILT v1.0.0, Reveel, and STITCH v1.6.5, with varying sequencing depth, sample size, and reference panel size using LCS data of Holstein cattle. We found that all of these methods, except Reveel, performed well in most cases with an imputation accuracy over 0.9; on the whole, GLIMPSE, QUILT, and STITCH performed better than the other methods. For species with no reference panel available, STITCH followed by Beagle would be an optimal strategy, whereas for species with reference panel available, QUILT would be the method of choice. Overall, this study illustrated the promising potential of LCS for genomic analysis in livestock.

Lead exposure promotes the inflammation via the circRNA-05280/miR-146a/IRAK1 axis in mammary gland.

Lead, the most widely used heavy metal in industry, is detrimental to human health if exposed to living and occupational environment. Although several studies have been conducted on lead exposure, little has been reported on its harm to mammary gland and its mechanisms. In view of this, our study is the first to verify that lead exposure could promote apoptosis and inflammation in mouse mammary tissue (in vivo) and cow mammary epithelial cells (in vitro). After establishing a lead exposed mouse model, the expression profile of mammary gland tissue was constructed by high-throughput sequencing technology. In the profile, 917 differentially expressed genes were screened, of which IRAK1 was up-regulated by 4.33 times. Then, from qRT-PCR, Western blot and Luciferase report, IRAK1 was found to promote the release of inflammatory factors and tissue apoptosis and could be a specific target of miR-146a. On the other hand, double luciferase reporter system and qRT-PCR predicted the existence of a binding site between circRNA-05280 and miR-146a sequence. Experiments such as immunohistochemistry, apoptosis and EdU demonstrated that circRNA-05280 could promote not only cell apoptosis but also the expression level of inflammatory genes. Nevertheless, the function of miR-146a is opposite to that of circRNA-05280. Specifically, circRNA-05280 can regulate the level of apoptosis and inflammation of mammary gland by binding miR-146a and releasing the expression of miR-146a on target gene IRAK1. This study concludes that circRNA-05280/ miR-146a/ IRAK1 signaling pathway could mediate the mammary gland damage resulting from lead exposure. Accordingly, it sheds new light on further exploration of molecular mechanisms of mammary gland tissue damage caused by lead exposure, the risk assessment of lead, and the mechanism of lead mammary gland toxicity.

Heterogeneous Degradation in Thick Nickel-Rich Cathodes During High-Temperature Storage and Mitigation of Thermal Instability by Regulating Cationic Disordering.

The thermal instability is a major problem in high-energy nickel-rich layered cathode materials for large-scale battery application. Due to the scarce investigation of thick electrodes at the practical full-cell level, the understanding of thermal failure mechanism is still insufficient. Herein, an intrinsic origin of thermal instability in fully charged industrial pouch cells during high-temperature storage is discovered. Through the investigation from crystals to particles, and from electrodes to cells, it is shown that serious top-down heterogeneous degradation occurs along the depth direction of the thick electrode, including phase transition, cationic disordering, intergranular/intragranular cracks, and side reactions. Such degradation originates from the abundant oxygen vacancies and reduced catalytic Ni2+ at cathode surface, causing microstructural defects and directly leading to the thermal instability. Nonmagnetic elements doping and surface modification are suggested to be effective in mitigating the thermal instability through modulating cationic disordering.

miR-144/451 inhibits c-Myc to promote erythroid differentiation.

Ablation of miR-144/451 disrupts homeostasis of erythropoiesis. Myc, a protooncogenic protein, is essential for erythroblast proliferation but commits rapid downregulation during erythroid maturation. How erythroblasts orchestrate maturation processes through coding and non-coding genes is largely unknown. In this study, we use miR-144/451 knockout mice as in vivo model, G1E, MEL erythroblast lines and erythroblasts from fresh mouse fetal livers as in vitro systems to demonstrate that targeted depletion of miR-144/451 blocks erythroid nuclear condensation and enucleation. This is due, at least in part, to the continued high expression of Myc in erythroblasts when miR-144/451 is absent. Specifically, miR-144/451 directly inhibits Myc in erythroblasts. Loss of miR-144/451 locus derepresses, and thus, increases the expression of Myc. Sustained high levels of Myc in miR-144/451-depleted erythroblasts blocks erythroid differentiation. Moreover, Myc reversely regulates the expression of miR-144/451, forming a positive miR-144/451-Myc feedback to ensure the complete shutoff of Myc during erythropoiesis. Given that erythroid-specific transcription factor GATA1 activates miR-144/451 and inactivates Myc, our findings indicate that GATA1-miR-144/451-Myc network safeguards normal erythroid differentiation. Our findings also demonstrate that disruption of the miR-144/451-Myc crosstalk causes anemia, suggesting that miR-144/451 might be a potential therapeutic target in red cell diseases.

Metformin activated AMPK signaling contributes to the alleviation of LPS-induced inflammatory responses in bovine mammary epithelial cells.

BACKGROUND: Lipopolysaccharides (LPS) derived from gram-negative bacterial are often regarded as primary inducer of bovine mammary inflammation. This study evaluated the biological response of metformin activated AMPK signaling on LPS-induced inflammatory responses and metabolic changes in primary bovine mammary epithelial cells (pbMEC). The pbMEC were exposed to either 3 mmol/L Metf. for 12 h as Metf. group (Metf.) or 2 µg/mL LPS for 6 h as LPS group (LPS). Cells pretreated with 3 mmol/L metformin for 12 h followed by washing and 2 µg/mL LPS exposure for 6 h were served as ML group (ML). PBS was added to cells as the control group (Con.). RESULTS: Pre-incubation with Metf. inhibited LPS-induced expression of pro-inflammatory genes (TNF, IL1B, IL6, CXCL8, MYD88 and TLR4) and proteins (IL-1ß, TNF-α, NLRP3, Caspase1, ASC) and was accompanied by increased activation of AMPK signaling. Compared with the LPS group, phosphorylation of p65 and IκBα in the ML group were decreased and accumulation of NF-κB in the nucleus was significantly reduced by pretreatment with metformin. Metformin protects the cells from the increase of LPS-induced binding activity of NF-κB on both TNFA and IL1B promoters. Compared with the LPS group, genes (G6PC, PCK2) and proteins (SREBP1, SCD1) related to lipogenesis and carbohydrate metabolism were downregulated while catabolic ones (PPARA, ACSL1, Glut1, HK1) were upregulated in the ML group. Furthermore, increased acetylation of H3K14 by LPS challenge was reversed by pretreatment with metformin. CONCLUSION: Altogether, our results indicated that pretreatment with metformin dampens LPS-induced inflammatory responses mediated in part by AMPK/NF-κB/NLRP3 signaling and modification of histone H3K14 deacetylation and metabolic changes.

Cadmium promotes apoptosis and inflammation via the circ08409/miR-133a/TGFB2 axis in bovine mammary epithelial cells and mouse mammary gland.

Cadmium is a common environmental heavy metal pollutant that can accumulate over long periods of time and cause disease. Thus, analysis of the molecular mechanisms affected by cadmium in the body could be of great significance for the prevention and treatment of cadmium-related diseases. In this study, flow cytometry, immunofluorescence, transmission electron microscopy, H&E (Hematoxylin Eosin) staining and TUNEL (TdT-mediated dUTP Nick-End Labeling) assays were used to verify that cadmium induced apoptosis and immune responses in bovine mammary epithelial cells (BMECs) and in mouse mammary gland. Isolated BMECs cultured with or without cadmium were collected to screen miRNA (microRNA) using high-throughput sequencing. There were 42 differentially-expressed miRNAs among which 27 were upregulated and 15 downregulated including bta-miR-133a, bta-miR-23b-5p, bta-miR-29e, bta-miR-365-5p, bta-miR-615, bta-miR-7, bta-miR-11975, bta-miR-127, and bta-miR-411a. Among those, miR-133a (which can specifically target TGFB2 (Recombinant Transforming Growth Factor Beta 2) was the most significantly downregulated with a fold-change of 5.27 in BMECs cultured with cadmium. Application of the double luciferase reporter system, western blotting, and qRT-PCR (Quantitative Real-time PCR) revealed that circ08409 can directly bind to miR-133a. Experiments demonstrated that circRNA-08409 could adsorb bta-miR-133a. Both circ08409 and TGFB2 significantly increased apoptosis and altered expression level of a series of inflammatory factors in BMECs. In contrast, miR-133a decreased significantly apoptosis and inflammation in the cells. Compared with cultures receiving only cadmium, the miR-133a+cadmium cultures exhibited significant reductions in the occurrence of late apoptosis. Overall, results indicated that circ08409 could relieve the inhibitory effect of miR-133a on TGFB2 expression by combining with miR-133a and subsequently modulating cell proliferation, apoptosis and inflammation. Overall, the data suggested that the circ08409/miR-133a/TGFB2 axis might play a role in mediating the effect of cadmium on BMECs. As such, data provide novel insights into controlling hazards that cadmium could induce in the mammary gland.

AGPAT3 Gene polymorphisms are associated with milk production traits in Chinese Holstein cows.

The current study reports the identification of previously undiscovered single-nucleotide polymorphisms (SNPs) in the bovine AGPAT3 gene and further investigates their associations with milk production traits. Our results demonstrate that the major allele C of the SNP g.12264 C > T is positively correlated with test-day milk yield, protein percentage and 305-day milk yield. Importantly, in silico analysis showed that the C/T transition at this locus gives rise to two new transcription factor binding sites (TFBS), E2F1 and Nkx3-2. Polymorphism g.18658 G > A was the only SNP associated with milk urea nitrogen (MUN) with the G allele related to an increase in milk urea nitrogen as well as fat percentage. The GG genotype of SNP g.28731 A > G was associated with the highest fat and protein percentage and lowest 305-day milk yield and somatic cell score (SCS). The association between AGPAT3 locus and milk production traits could be utilized in marker-assisted selection for the genetic improvement of milk production traits and, probably in conjunction with other traits, for selection to improve fitness of dairy cattle.

The Circadian Physiology: Implications in Livestock Health.

Circadian rhythms exist in almost all types of cells in mammals. Thousands of genes exhibit approximately 24 h oscillations in their expression levels, making the circadian clock a crucial regulator of their normal functioning. In this regard, environmental factors to which internal physiological processes are synchronized (e.g., nutrition, feeding/eating patterns, timing and light exposure), become critical to optimize animal physiology, both by managing energy use and by realigning the incompatible processes. Once the circadian clock is disrupted, animals will face the increased risks of diseases, especially metabolic phenotypes. However, little is known about the molecular components of these clocks in domestic species and by which they respond to external stimuli. Here we review evidence for rhythmic control of livestock production and summarize the associated physiological functions, and the molecular mechanisms of the circadian regulation in pig, sheep and cattle. Identification of environmental and physiological inputs that affect circadian gene expressions will help development of novel targets and the corresponding approaches to optimize production efficiency in farm animals.

MicroRNA-212 targets SIRT2 to influence lipogenesis in bovine mammary epithelial cell line.

In this research paper we filter and verify miRNAs which may target silent information regulator homolog 2 (SIRT2) gene and then describe the mechanism whereby miRNA-212 might regulate lipogenic genes in mammary epithelial cell lines via targeting SIRT2. Bioinformatics analysis revealed that the bovine SIRT2 gene is regulated by three miRNAs: miR-212, miR-375 and miR-655. The three miRNAs were verified and screened by qRT-PCR, western blot, and luciferase multiplex verification techniques and only miR-212 was shown to have a targeting relationship with SIRT2. The results of co-transfecting miR-212 and silencing RNA (siRNA) showed that by targeting SIRT2, miR-212 can regulate the expression of fatty acid synthetase (FASN) and sterol regulatory element binding factor 1 (SREBP1) but not peroxisome proliferator-activated receptor gamma (PPARγ). Measurement of triglyceride (TAG) content showed that miR-212 increased the fat content of mammary epithelial cell lines. The study indicates that miR-212 could target and inhibit the expression of the SIRT2 gene to promote lipogenesis in mammary epithelial cell lines.

Molecular characterization of bovine leukemia virus reveals existence of genotype 4 in Chinese dairy cattle.

Bovine leukemia virus (BLV) causes enzootic bovine leucosis and is widely spread worldwide, except several European countries, Australia and New Zealand. Although BLV is highly prevalent in China, information about the genetic diversity and evolutionary dynamics of BLV among Chinese dairy herds is still lacking. To determine the genetic variability of BLV, 219 cows from four cities of Ningxia province of China were screened for BLV infection by fluorescence resonance energy transfer (FRET)-PCR and sequencing, 16 selected positive samples were subjected to molecular characterization. Phylogenetic analysis using the neighbor-joining (NJ) method on complete sequences of envelope (env) gene of BLV obtained from China and those available in GenBank (representing BLV genotypes 1-10) revealed that those Chinese strains belonged to genotypes 4 and 6. Totally, 23 mutations were identified and 16 of them were determined to be unique mutations among Chinese strains. Alignment of the deduced amino acid sequences demonstrated six mutations in glycoprotein 51 (gp51) and three mutations in glycoprotein 30 (gp30) located in the identified neutralizing domain (ND), CD8+ T cell epitope, E-epitope, B-epitope, gp51N12 and cytoplasmic domain of transmembrane protein. This study reported for the first time the BLV genotype 4 in China, and further studies are warranted to compare its immunogenicity and pathogenicity with other BLV genotypes.

Screening of noise-induced hearing loss (NIHL)-associated SNPs and the assessment of its genetic susceptibility.

BACKGROUND: The aim of this study was to screen for noise-induced hearing loss (NIHL)-associated single nucleotide polymorphisms (SNPs) and to construct genetic risk prediction models for NIHL in a Chinese population. METHODS: Four hundred seventy-six subjects with NIHL and 476 matched controls were recruited from a cross-sectional survey on NIHL in China. A total of 83 candidate SNPs were genotyped using nanofluidic dynamic arrays on a Fluidigm platform. NIHL-associated SNPs were screened with a multiple logistic model, and a genetic risk model was constructed based on the genetic risk score (GRS). The results were validated using a prospective cohort population. RESULTS: Seven SNPs in the CDH23, PCDH15, EYA4, MYO1A, KCNMA1, and OTOG genes were significantly (P < 0.05) associated with the risk of NIHL, whereas seven other SNPs were marginally (P > 0.05 and P < 0.1) associated with the risk of NIHL. A positive correlation was observed between GRS values and odds ratio (OR) for NIHL. Two SNPs, namely, rs212769 and rs7910544, were validated in the cohort study. Subjects with higher GRS (≧9) showed a higher risk of NIHL incidence with an OR of 2.00 (95% CI = 1.04, 3.86). CONCLUSIONS: Genetic susceptibility plays an important role in the incidence of NIHL. GRS values, which are based on NIHL-associated SNPs. GRS may be utilized in the evaluation of genetic risk for NIHL and in the determination of NIHL susceptibility.