The inhibin subunit beta E (INHBE) gene encodes activin E, a hepatokine belonging to the TGF-β superfamily, and plays important roles in regulating lipid metabolism, energy homeostasis and immune responses. Our previous study identified INHBE as a potential candidate gene for milk traits through liver transcriptome analysis of Holstein cows. Herein, we systematically evaluated the genetic effects of INHBE on milk yield and composition traits in 947 Chinese Holstein cattle. Two single nucleotide polymorphisms (SNPs) were identified, including 5:g.56006974C>T located in the 5′ regulatory region and 5:g.56004276G>A in the 3′ regulatory region. Phenotype-genotype association analysis indicated that the 5:g.56006974C>T locus was significantly associated with milk fat yield (p = 0.0015; p = 0.0036) and fat percentage (p = 0.0339; p = 0.0216) across two lactations, as well as milk protein yield in the first lactation (p = 0.0378). The 5:g.56004276G>A variant was significantly associated with milk fat yield in the second lactation (p = 0.0181). Linkage disequilibrium (LD) analysis showed that the two SNPs formed a haplotype block (r2 = 1.0), which was significantly associated with 305-day milk yield (p = 0.0049; p = 0.0220), milk fat yield (p = 0.0002; p < 0.0001), milk fat percentage (p = 0.0249, the second lactation), milk protein yield (p = 0.0009, the first lactation) and milk protein percentage (p = 0.0464, the second lactation). Furthermore, JASPAR analysis indicated that the T allele at the 5:g.56006974C>T locus may introduce a predicted binding motif for the transcription factor ZNF341. Notably, dual-luciferase reporter assays showed that this variant significantly reduced the transcriptional activity of the INHBE promoter (p = 0.0005). These findings suggest that INHBE is a promising candidate gene associated with milk yield and composition traits, and its regulatory variants may serve as useful genetic markers for future genomic selection programs in dairy cattle breeding.

The issue of biogenic amines (BAs) in fermented sausages has attracted widespread consumer attention. In this study, whole-genome sequencing identified genes involved in BAs degradation and flavor formation in Pediococcus pentosaceus 37×-9, and the effect of tea polyphenols (TP) on its amine-degrading activity was evaluated. High-throughput sequencing revealed the microbial community structure and analyzed the synergistic effects of 37×-9 and TP on microbial diversity and volatile flavor compounds. Results showed that 3 mg/mL TP significantly promoted the growth and acid production of 37×-9, upregulated MCO gene expression, enhanced multicopper oxidase activity, and increased the tyramine degradation rate to 86.6%. The combined application of 37×-9 and TP promoted the formation of trans-2-decenol and ethyl hexanoate. After inoculation with 37×-9, Pediococcus became dominant, showing a negative correlation with BAs and a positive correlation with some esters. These findings suggest that 37×-9 and TP together can reduce BAs and improve flavor.

The confirmatory factor analysis technique was used to quantify a latent variable for test-day lactation performance (TDLP) in the first parity of Chinese Holstein dairy cows by applying five measurable traits, including test-day milk yield (TDMY), test-day milk fat percentage (TDFP), test-day milk protein percentage (TDPP), test-day somatic cell score (TDSCS) and test-day milk urea nitrogen (TDMUN). The standardised factor loadings of TDMY, TDFP, TDPP, TDSCS, and TDMUN for describing TDLP were 0.46, -0.52, -0.70, -0.14 and -0.19, respectively. Genetic analysis was conducted using a multivariate repeatability model within a Bayesian framework. The posterior means for the heritability and repeatability estimates of TDLP were 0.26 ± 0.02 and 0.34 ± 0.02, respectively. In general, posterior means for heritability and repeatability estimates of the measurable traits were low to medium. The heritability estimates ranged from 0.05 for TDSCS to 0.28 for TDPP, and repeatability estimates ranged from 0.15 for TDMUN to 0.38 for TDMY. The latent variable of TDLP exhibited positive genetic (0.62) and phenotypic (0.40) correlations with TDMY, whereas its genetic and phenotypic correlations with other measurable traits were negative, ranging from -0.96 (TDLP-TDPP) to -0.11 (TDLP-TDSCS). The corresponding phenotypic correlations ranged from -0.85 (TDLP-TDPP) to -0.07 (TDLP-TDSCS). It may be concluded that breeding for higher TDLP might increase TDMY but could reduce milk composition traits. In general, the negative genetic and phenotypic correlations suggest a trade-off between milk quantity (yield) and quality (composition).

Meat quality and carcass traits are the most economically important traits affecting the value and the quality characteristics of the animal at slaughter. In this study, we analyzed the genomes of 295 domestic cattle from 20 global breeds using next-generation sequencing to identify signatures of positive selection associated with meat production and quality traits. The results of population genetic analysis revealed genetic differentiation among worldwide cattle groups. We observed clustering of samples in agreement with their geographic origins and production characteristics. We further observed noticeable genetic variety between cattle groups from different geographical regions. Generally, the lowest genetic diversity was determined for commercial cattle breeds, while the highest genetic diversity was found in African local cattle breeds. Our search for putative selective genomic regions in beef cattle populations revealed several candidate genes such as BMP2, EGR1, MAGEL2, U6, TMEM201, ELK3 and 5S_rRNA that were previously explored to be associated with carcass traits and meat quality in beef cattle. The enriched pathways and candidate genes discovered in this study could supply a basis for future improvement through the use of whole-genome technologies and selective breeding.

The experiment aimed to investigate the effects of β-carotene on the serum biochemical, immune, and antioxidant indices in beef cows during the peripartum period. Fifteen healthy Simmental cows (45 days before calving) with good body condition, similar body weight, and parity were selected, and randomly divided into three groups with five replicates per group and one cow per replicate. The control group was fed a basal diet, while trial group Ⅰ and Ⅱ were supplemented with 500 mg/(head·d) and 1 500 mg/(head·d) of β-carotene, respectively. The pre-feeding period lasted 15 days, and the formal trial period was 60 days. The results showed that compared with the control group, serum albumin (ALB) and high-density lipoprotein (HDL) concentrations were significantly increased in the trial group Ⅱ (P<0.05). Serum superoxide dismutase (SOD) activity was extremely increased (P<0.01), and malondialdehyde (MDA) content in both trial groups Ⅰ and Ⅱwas extremely reduced (P<0.01). Compared with the control and trial group Ⅰ, serum glutathione peroxidase (GSH-Px) and catalase (CAT) activities were extremely increased in the trial group Ⅱ (P<0.01). Serum concentrations of interleukin-4 (IL-4), immunoglobulin G (IgG), and immunoglobulin M (IgM) were significantly higher in the trial group Ⅱ compared to the control group (P<0.05), while interleukin-10 (IL-10) content was extremely increased (P<0.01). The return-to-estrus time after calving was significantly shorter in trial groups Ⅰ and Ⅱ compared to the control group (P<0.05), and the concentrations of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in the serum were higher than those in the control group. The study shows that dietary supplementation with 1 500 mg/(head·d) of β-carotene can enhance immune function and antioxidant capacity, shorten the return-to-estrus interval, and promote the secretion of reproductive hormones in peripartum beef cows.

Bovine colostrum is rich in many immune components. Milk exosomes are secreted by mammary epithelial cells and contain proteins, nucleic acids, microRNAs (miRNAs) and other bioactive substances related to immune response and growth. MiRNAs are short non-coding RNAs (ncRNA)with various biological functions through translational inhibition or mRNA destabilisation. Mature miRNAs are involved in various regulatory pathways, including development, viral defense, cell proliferation and apoptosis, and fat metabolism. MiRNA sequencing of bovine colostrum and milk exosomes was performed, and the miRNA and mRNA data were jointly analyzed. The results suggest that bta-miR-19b, bta-miR-186 and bta-miR-151-5p may be key miRNAs associated with the immune function of bovine colostrum exosomes. Target gene prediction revealed that miRNAs are involved in multiple signalling pathways through target genes such as IL1R1, BOLA-DOA, MAP3K1, MAPK8, RELA and TNF. Our results indicate that specific miRNAs and their target genes likely contribute to immune regulation, yet the exact molecular mechanisms governing these interactions remain to be fully elucidated.

Crossbreeding is a cornerstone of modern livestock improvement, combining desirable traits to enhance productivity and environmental resilience. This study conducts the first comprehensive genomic analysis of Red Angus × Chinese Red Steppe (RACS) crossbred cattle, evaluating their genetic architecture, diversity, and selection signatures relative to founder breeds (Red Angus and Chinese Red Steppe) and global populations. A total of 119 cattle, comprising 104 RACS crossbreds and 15 Chinese Red Steppes cattle, were genotyped using the GGP Bovine 100k SNP array. Additionally, the public available genotypic data generated using the BovineSNP50 chip from 550 animals across eight beef breeds (Angus, Hereford, Limousin, Charolais, Mongolian, Shorthorn, Red Angus, and Simmental) and one dairy breed (Holstein) were incorporated into the analysis. We aimed to (1) define the population structure of RACS cattle, (2) quantify their genomic diversity and inbreeding levels, and (3) pinpoint regions under selection linked to adaptive and economic traits. We employed runs of homozygosity (ROH) and population differentiation (Fst) analyses to detect selection signals. The results revealed that the crossbred (RACS), Angus, and Red Angus breeds exhibited similar clustering patterns in principal component analysis (PCA), but the crossbred population showed the highest nucleotide diversity and lowest inbreeding coefficients compared to other breeds. Notably, candidate regions associated with immune response, cold adaptation, and carcass traits were identified within the RACS population. These findings enhance our understanding of the genetic makeup of crossbred beef cattle and highlight their potential for genetic improvement, informing future selection and breeding strategies aimed at optimizing beef production in challenging environments.

The current study investigated the application of structural equation models for genetic analysis of lifetime reproductive traits and latent variable modelling in the Murciano-Granadina goat breed. In the current investigation, data collected between 2016 and 2023 in a private dairy farm of the Murciano-Granadina goat breed in Ghale-Ganj city, located in the southern area of Kerman Iranian province were used. The investigated lifetime reproductive traits included overall litter size at birth (OLSB), overall litter size at weaning (OLSW), overall litter weight at birth (OLWB), and overall litter weight at weaning (OLWW). Four multivariate animal models, including standard (SMM), Inductive Causation algorithm-based structural equation (ICM), ICM with biological modification (ICM-BM), and fully recursive (FRM) models were fitted on the data and compared in terms of predictive ability measures including mean squared prediction error (MSE) and Pearson's correlation coefficient between the observed and predicted values (r(y, y ̂ )) of records. ICM-BM performed better than other models in terms of the lowest MSE and the highest r(y, y ̂ ). Under ICM-BM, heritability estimates were low values of 0.08, 0.08, 0.11, and 0.10 for OLSB, OLSW, OLWB, and OLWW, respectively. Genetic correlations among lifetime reproductive traits were positive and varied from 0.72 (OLSB-OLWW) to 0.95 (OLSB-OLWB). The confirmatory factor analysis technique was used to construct a latent variable named reproductive performance (RP) from the investigated lifetime reproductive traits. The posterior mean for heritability of RP was estimated at 0.06. The genetic correlations between RP and the investigated lifetime reproductive traits were high and positive, ranging from 0.92 (RP-OLSB) to 0.99 (RP-OLSW). The corresponding phenotypic correlations were also high and positive, ranging from 0.81 (RP-OLWB) to 0.95 (RP-OLSW). Considering causal structure among the traits detected via ICM-BM had more advantages for genetic evaluation of the lifetime reproductive traits in the Murciano-Granadina goat compared with SMM. The low heritability estimates implied that the studied lifetime reproductive traits and RP were mainly controlled by non-additive genetic and environmental effects which limits the efficiency of direct genetic selection for improving these traits. Furthermore, positive genetic and phenotypic correlations favoured using RP latent variable for breeding purposes.

Consumer perception of beef is heavily influenced by overall meat quality, a critical factor in the cattle industry. Genomics has the potential to improve important beef quality traits and identify genetic markers and causal variants associated with these traits through genomic selection (GS) and genome-wide association studies (GWAS) approaches. Transcriptomics, proteomics, and metabolomics provide insights into underlying genetic mechanisms by identifying differentially expressed genes, proteins, and metabolic pathways linked to quality traits, complementing GWAS data. Leveraging these functional genomics techniques can optimize beef cattle breeding for enhanced quality traits to meet high-quality beef demand. This paper provides a comprehensive overview of the current state of applications of omics technologies in uncovering functional variants underlying beef quality complexities. By highlighting the latest findings from GWAS, GS, transcriptomics, proteomics, and metabolomics studies, this work seeks to serve as a valuable resource for fostering a deeper understanding of the complex relationships between genetics, gene expression, protein dynamics, and metabolic pathways in shaping beef quality.

Abstract Background Understanding the evolutionary forces related to climate changes that have been shaped genetic variation within species has long been a fundamental pursuit in biology. In this study, we generated whole-genome sequence (WGS) data from 65 cross-bred and 45 Mongolian cattle. Together with 62 whole-genome sequences from world-wide cattle populations, we estimated the genetic diversity and population genetic structure of cattle populations. In addition, we performed comparative population genomics analyses to explore the genetic basis underlying variation in the adaptation to cold climate and immune response in cross-bred cattle located in the cold region of China. To elucidate genomic signatures that underlie adaptation to cold climate, we performed three statistical measurements, fixation index (FST), log2 nucleotide diversity (θπ ratio) and cross population composite likelihood ratio (XP-CLR), and further investigated the results to identify genomic regions under selection for cold adaptation and immune response-related traits. Results By generating WGS data, we investigated the population genetic structure and phylogenetic relationship of studied cattle populations. The results revealed clustering of cattle groups in agreement with their geographic distribution. We detected noticeable genetic diversity between indigenous cattle ecotypes and commercial populations. Analysis of population structure demonstrated evidence of shared genetic ancestry between studied cross-bred population and both Red-Angus and Mongolian breeds. Among all studied cattle populations, the highest and lowest levels of linkage disequilibrium (LD) per Kb were detected in Holstein and Rashoki populations (ranged from ~ 0.54 to 0.73, respectively). Our search for potential genomic regions under selection in cross-bred cattle revealed several candidate genes related with immune response and cold shock protein on multiple chromosomes. We identified some adaptive introgression genes with greater than expected contributions from Mongolian ancestry into Molgolian x Red Angus composites such as TRPM8, NMUR1, PRKAA2, SMTNL2 and OXR1 that are involved in energy metabolism and metabolic homeostasis. In addition, we detected some candidate genes probably associated with immune response-related traits. Conclusion The study identified candidate genes involved in responses to cold adaptation and immune response in cross-bred cattle, including new genes or gene pathways putatively involved in these adaptations. The identification of these genes may clarify the molecular basis underlying adaptation to extreme environmental climate and as such they might be used in cattle breeding programs to select more efficient breeds for cold climate regions.

Genome selection (GS) technology is an important means to improve the genetic improvement of dairy cows, and the mining and application of functional genes and loci for important traits is one of the important bases for accelerating genetic improvement. Our previous study found that the apolipoprotein A5 (APOA5) and AKT serine/threonine kinase 3 (AKT3) genes were differentially expressed in the liver tissue of Chinese Holstein cows at different lactation stages and influenced milk component synthesis and metabolism, so we considered these two genes as the candidates affecting milk production traits. In this study, we found in total six single nucleotide polymorphisms (SNPs), three in APOA5 and three in AKT3. Subsequent association analysis showed that the six SNPs were significantly associated with milk yield, fat yield, protein yield, or fat percentage (p ≤ 0.05). Three SNPs in APOA5 formed a haplotype block, which was found to be significantly associated with milk yield, fat yield, and protein yield (p ≤ 0.05). In addition, four SNPs were proposed to be functional mutations affecting the milk production phenotype, of which three, 15:g.27446527C>T and 15:g.27447741A>G in APOA5 and 16:g.33367767T>C in AKT3, might change the transcription factor binding sites (TFBSs), and one is a missense mutation, 15:g.27445825T>C in APOA5, which could alter the secondary structure and stability of mRNA and protein. In summary, we demonstrated the genetic effects of APOA5 and AKT3 on milk production traits, and the valuable SNPs could be used as available genetic markers for dairy cattle’s GS.

The investigation of carcass traits to produce meat with high efficiency has been in focus on Japanese Black cattle since 1972. To implement a successful breeding program in carcass production, a comprehensive understanding of genetic characteristics and relationships between the traits is of paramount importance. In this study, genomic heritability and genomic correlation between carcass traits, including carcass weight (CW), rib eye area (REA), rib thickness (RT), subcutaneous fat thickness (SFT), yield rate (YI), and beef marbling score (BMS) were estimated using the genomic data of 9,850 Japanese Black cattle (4,142 heifers and 5,708 steers). In addition, we investigated the effect of genetic relatedness degree on the estimation of genetic parameters of carcass traits in sub-populations created based on different GRM-cutoff values. Genome-based restricted maximum likelihood (GREML) analysis was applied to estimate genetic parameters. Using all animal data, the heritability values for carcass traits were estimated as moderate to relatively high magnitude, ranging from 0.338 to 0.509 with standard errors, ranging from 0.014 to 0.015. The genetic correlations were obtained low and negative between SFT and REA [-0.198 (0.034)] and between SFT and BMS [-0.096 (0.033)] traits, and high and negative between SFT and YI [-0.634 (0.022)]. REA trait was genetically highly correlated with YI and BMS [0.811 (0.012) and 0.625 (0.022), respectively]. In sub-populations created based on the genetic-relatedness ceiling, the heritability estimates ranged from 0.212 (0.131) to 0.647 (0.066). At the genetic-relatedness ceiling of 0.15, the correlation values between most traits with low genomic correlation were overestimated while the correlations between the traits with relatively moderate to high correlations, ranging from 0.380 to 0.811, were underestimated. The values were steady at the ceilings of 0.30-0.95 (sample size of 5,443-9,850) for most of the highly correlated traits. The results demonstrated that there is considerable genetic variation and also favorable genomic correlations between carcass traits. Therefore, the genetic improvement for the traits can be simultaneously attained through genomic selection. In addition, we observed that depending on the degree of relationship between individuals and sample size, the genomic heritability and correlation estimates for carcass traits may be different.

Context Fat colour is one of the most important economic traits in the marketing of beef. There are many factors that affect fat colour, such as breed, age, diet and gender. Fat colour is observed in different ranges of colours, including white, yellow and brown. The main issue with improving fat colour is that consumer preferences of fat colour vary across the globe. Therefore, investigating the metabolic mechanisms of fat colour may provide new biomarkers for phenotyping, so as to develop effective selection strategies to achieve the locally desired fat colour. Aims This study aimed to perform a comparative metabolic analysis between white and yellow fat from crossbred cattle so as to identify potential biomarkers for the selection of fat colour and to better understand the metabolism of white and yellow fat depots. Methods Carcass samples of subcutaneous fat were collected from crossbred cattle (Simmental × Mongolian cattle) and scored for fat colour. Liquid chromatography–mass spectrophotometry analysis of extracted metabolites from the subcutaneous fat of six animals with white fat and six animals with yellow fat was performed. Key results The comparison between metabolites of white and yellow fat colour samples indicated that there were five categories of 235 significant metabolites, which included hydrocarbons, lipids and lipid-like molecules, organic acids and their derivatives, organic oxygen compounds and organoheterocyclic compounds. The principal-component analysis illustrated that yellow and white fat samples can be classified in groups; however, the metabolites of white fat samples showed greater variation than those in the yellow fat. In the white fat, there were 163 metabolites that had a higher relative abundance than in yellow fat and 72 that had a lower relative abundance than in yellow fat. 3-Hydroxyoctanoic acid, anethofuran, 9,10-DiHODE, furanoeremophilane, pregeijerene, N-glycolylneuraminic acid, and glycocholic acid were identified as the metabolites that differed the most in abundance between the white and yellow fat samples. Conclusions This study has provided insights into the metabolic differences between white and yellow fat depots and identified key metabolites associated with beef fat colour. Implications This study has provided potential biomarkers that may be useful for selection of beef fat colour in live animals.

为全面分析近 30 年(1995-2021 年)国内外肉牛肠道菌群功能基因相关研究的发展现状、研究热点和前沿动态,本研究以Web of Science、中国知网为来源数据库,检索肉牛肠道菌群功能基因的相关文献信息为研究对象;应用CiteSpace(6.0.R1)分别对文献年度发文量、国家、作者、机构、关键词进行共现分析、聚类分析、突显分析以及可视化呈现.结果显示:共发表英文文献 170 篇,中文文献 45 篇.近 30 年国内外肉牛肠道菌群功能基因相关研究领域论文数量整体呈上升趋势,且自 2011 年以来迅速增长;欧美学者逐步建立了理论框架、模型方法,奠定了该领域的研究基础,其中美国占主导地位,Guan Leluo、Auffret M D和Bryan A White等关键作者具有突出贡献.我国起步较晚但发展迅速,发文被引量居第 2,中国农业科学院等机构研究水平世界领先,毛胜勇、蒋林树、王加启和杨舒黎等研究团队代表了我国该领域研究的先进水平.近 30 年,该领域研究热点从 1995 年关注抗菌肽,到 2005 年首次关注 16S rRNA多样性和宏基因组;随着二代测序技术的成熟,自 2015 年以后 16S rRNA和宏基因组研究再度火热,以宏基因组、宏转录组等多组学对瘤胃微生物分解纤维素以及生成甲烷的功能基因研究成为目前的研究热点.此外,肠道微生物功能基因在肉牛营养代谢、饲料开发、免疫调控以及肉牛品种选育中的作用机制及应用是未来该领域的研究方向.

In the present study, we generated complete genome sequence data from 45 Mongolian cattle.Together with published sequence data from worldwide cattle populations, we explored the genetic diversity and population structure of worldwide cattle breeds.Our findings revealed clustering of cattle populations into three major groups, including commercial (Red-Angus, Hereford, Holstein and Jersey), Chinese (Mongolian and Tibetan) and other native cattle (including African cattle and Rashoki breed from Iran) breeds.The results from admixture analysis revealed evidence of shared genetic ancestry between different cattle populations.Furthermore, our findings showed a markedly higher level of linkage disequilibrium (LD) across all genomic distances in commercial breeds (specially Holstein cattle) compare to other native cattle groups.Our results provide valuable insights into the architecture of Mongolian Indigenous cattle breeds and their genomic relationship with other cattle populations.Pomelo.

Cashmere goats produce wool from primary hair follicles (PHF)and cashmere from secondary hair follicles(SHF). Numerous genetic factors have been identified to affect HF formation, but the mechanism that controls the distinct morphogenesis of PHFs and SHFs remains unclear. To better describe goat’s hair follicle proteome, we applied iTRAQ technology to study protein expression profiling from nine skin samples of cashmere goats in three fetal periods including 45-day-old embryos (E45), 55-day-old embryos (E55), 65-day-old embryos (E65). A total of 1172 proteins identified are expressed in fetal skin. The numbers of differentially expressed proteins in E45 vs. E55, E45 vs. E65, and E55 vs. E65 were 103, 144, and 118, respectively. Sixty-three proteins were constantly increased through the whole embryonic developmental stages of placode formation. Keratin 1, 4, 5, 10, 13, 15, 17, and 75 belonging to the hair keratin family (KRTs) were identified during keratinocyte proliferation. Some proteins involved in these pathways probably have a role in the HF and might be the mediators of HF initiation in Cashmere goats. Our systematic investigation identified some signaling factors that drive the large-scale cellular rearrangements necessary for HF initiation, which provide an insight into the fundamental mechanisms of cashmere growth.

BACKGROUND:Hypoxia refers to the condition of low oxygen pressure in the atmosphere and characterization of response to hypoxia as a biological complex puzzle, is challenging. Previously, we carried out a comparative genomic study by whole genome resequencing of highland and lowland Iranian native chickens to identify genomic variants associated with hypoxia conditions. Based on our previous findings, we used chicken as a model and the identified hypoxia-associated genes were converted to human's orthologs genes to construct the informative gene network. The main goal of this study was to visualize the features of diseases due to hypoxia-associated genes by gene network analysis.RESULTS:It was found that hypoxia-associated genes contained several gene networks of disorders such as Parkinson, Alzheimer, cardiomyopathy, drug toxicity, and cancers. We found that biological pathways are involved in mitochondrion dysfunctions including peroxynitrous acid production denoted in brain injuries. Lewy body and neuromelanin were reported as key symptoms in Parkinson disease. Furthermore, calmodulin, and amyloid precursor protein were detected as leader proteins in Alzheimer's diseases. Dexamethasone was reported as the candidate toxic drug under the hypoxia condition that implicates diabetes, osteoporosis, and neurotoxicity. Our results suggested DNA damages caused by the high doses of UV radiation in high-altitude conditions, were associated with breast cancer, ovarian cancer, and colorectal cancer.CONCLUSIONS:Our results showed that hypoxia-associated genes were enriched in several gene networks of disorders including Parkinson, Alzheimer, cardiomyopathy, drug toxicity, and different types of cancers. Furthermore, we suggested, UV radiation and low oxygen conditions in high-altitude regions may be responsible for the variety of human diseases.

鄂尔多斯市鄂托克旗2020年出台了《鄂托克旗优质肉牛产业高质量发展方案(2020—2022年)》旨在加速发展当地肉牛养殖业.随着进一步优化畜牧结构及乡村振兴战略的实施,发展优质肉牛产业迫在眉睫,秉承助力鄂托克旗优质肉牛产业发展及发挥内蒙古农牧业科技支持力量,对鄂托克旗肉牛产业现状进行全面调研,旨在发现问题、解决问题,为当地肉牛养殖户及产业从业者提供帮助的同时可以为当地政府及政策制定者提供参考.

反刍家畜瘤胃及肠道微生物处于一个复杂的微生态系统,其多样性及营养代谢与该系统中的各项因素存在紧密联系.了解反刍家畜瘤胃及肠道微生物多样性变化和营养代谢机制,是通过人为干预手段改善动物福利、提高动物生产效率、提升动物产品质量、减少温室气体排放的基础.关于反刍动物瘤胃及肠道微生物多样性及营养代谢与单个环境因子的关系得到了广泛的研究并取得了一些进展,对指导生产实践和保护环境起到了一定作用.综述了近年来国内外反刍家畜瘤胃及肠道微生物多样性,以及微生物与宿主动物、日粮结构、环境因子相互作用及机制方面的研究进展,以期为探索瘤胃及肠道微生物在反刍动物营养代谢中的作用及其机制提供参考.

[目的]研究不同部位西门塔尔牛肉原料肉的理化品质,评价烤制加工后的食用品质和感官品质.[方法]选取体重为550 kg左右的西门塔尔肉牛10头,屠宰分割后取不同部位牛肉(里脊、外脊、前腿、后腿、眼肉、米龙).4℃排酸72 h后,采用常规方法测定不同部位牛肉的蛋白质含量、脂肪含量、水分含量、pH值以及色泽指标,并对大理石花纹等级进行评分;220℃烤制10 min后,对不同部位牛肉进行剪切力和加工损失率测定,并对感官品质指标进行评价.[结果]不同部位牛肉的脂肪含量、大理石花纹评分、L*值、a*值、剪切力、色泽评分、嫩度评分、多汁性评分、香气评分和总体可接受性评分差异显著(P<0.05或P<0.01),不同部位牛肉中的蛋白质含量、水分含量、pH值、b*值、加工损失率、滋味评分差异不显著(P>0.05).眼肉中脂肪含量最高(P<0.01),前腿、后腿脂肪含量相同,均为最低(P<0.01);眼肉、外脊的大理石花纹评分显著(P<0.01)高于其他部位;眼肉、外脊的L*值显著(P<0.05)高于其他部位,里脊、后腿的L*值显著(P<0.05)低于其他部位;外脊和眼肉的a*值显著(P<0.01)低于其他部位;眼肉、外脊的剪切力显著(P<0.01)低于其他部位;眼肉的总体可接受性评分显著(P<0.05)高于其他部位,前腿、后腿和米龙的总体可接受性评分相同,均为最低(P<0.05).[结论]外脊、眼肉的肌内脂肪含量高于其他部位,烤制后产品的嫩度、滋味及总体可接受性较好.眼肉和外脊是西门塔尔牛肉中最适宜加工烤制产品的部位.