This article aims to elucidate how single-cell omics technologies advance livestock research and provides a systematic review of the construction process， current applications， and major challenges of single-cell transcriptomic databases in domestic animals. It seeks to offer data references and analytical frameworks for researchers， thereby promoting deeper application of this technology in livestock studies. This review conducted a comprehensive review and integrated analysis of existing single-cell transcriptomic database resources for livestock， summarizing their construction methodologies and application pathways， while also discussing current technical bottlenecks. The review demonstrates that single-cell transcriptomics offers novel perspectives and abundant data resources for elucidating mechanisms of livestock diseases， molecular breeding， and health management， while also revealing significant challenges in areas such as data integration and annotation standardization. Future efforts should focus on constructing high-quality databases， developing analysis algorithms tailored to livestock species， and promoting multi-omics integration to fully leverage the potential of single-cell technologies in the development of animal husbandry.

Uterine tissue nutrients are nutrients secreted by the uterus during animal reproduction， including amino acids， proteins， lipids， sugars， and other metabolites. Before implantation， the embryo relies on the tissue nutrients secreted by the uterus for nutrition. Their secretion is dynamically regulated by the estrous cycle， pregnancy status， uterine health， and maternal nutritional status. This article summarizes the changes in uterine fluid tissue nutrients under the estrous cycle， pregnancy status， nutritional levels， and endometritis. Through the study of these patterns， a more favorable uterine environment can be provided for the early development of embryos.

The evaluation of blastocyst quality is of great significance for assisted reproductive technology （ART）. Through quality assessment， blastocysts with the highest implantation potential can be selected， reducing the number of embryo transfers and improving the clinical pregnancy rate. However， there are many methods for blastocyst quality evaluation， but there is a lack of horizontal and systematic comparison. At present， the existing blastocyst quality evaluation methods mainly include morphological evaluation， metabolomics， time-lapse monitoring technology， genetic screening technology， artificial intelligence technology， etc. This paper systematically describes and compares the most effective and widely used methods for evaluating the quality of blastocysts at the blastocyst stage by summarizing the existing research systems and comprehensively discussing the advantages and limitations of various blastocyst quality evaluation technologies. Meanwhile， optimization schemes are proposed according to the limitations of various methods. It provides a theoretical basis and technical support for further optimizing the blastocyst quality evaluation technology， improving the clinical pregnancy rate and enhancing the efficiency of embryo selection.

Antibiotics once played an essential role in the process of China’s livestock industry. With the continuous increase in people’s attention to food safety and ecological environment issues， the adverse effects of antibiotic abuse have gradually become prominent. China’s feed industry has ushered in an era of a complete ban on antibiotics， and the livestock industry is facing significant challenges. Probiotics， as feed additive with great potential， can affect the composition of the intestinal flora after being ingested by animals， improve the intestinal barrier and regulate the immune response， showing unique advantages and value. It is expected to replace antibiotics and play a role in the livestock industry. Enterococcus faecalis， as a member of the lactic acid bacteria group， can be used as a feed additive and has attracted much attention. Enterococcus faecalis has relatively strong resistance to the environment， and its biological characteristics determine whether it can reach the host’s intestinal tract with a certain number of viable bacteria， and then determine whether this bacterium can be widely used in the livestock industry. As an active microorganism beneficial to the host， Enterococcus faecalis can regulate the balance of the body’s intestinal flora， enhance the function of the intestinal epithelial barrier， promote the metabolism of nutrients， and enhance the body's immunity. There is an increasing number of studies on the impact of Enterococcus faecalis on livestock and poultry. It has shown positive effects such as improving production performance， reducing the incidence of diarrhea and mortality， and enhancing the immune system in various livestock and poultry， including pigs， cattle， sheep， and chickens. This bacterium can optimize the digestive function of livestock and poultry， improve feed efficiency， and thus increase the economic benefits of farms. Its application range in the livestock industry is also constantly expanding. This article focuses on Enterococcus faecalis， summarizes its application in livestock and poultry in recent years， and reviews its biological characteristics， mechanisms of action， applications in the livestock and poultry industry， and the existing problems of Enterococcus faecalis. The aim is to provide a new insights from previous research about this bacterium and its impact in the livestock and poultry industry.

The gastrointestinal tract is not only a place where nutrients digest， absorb and metabolize， but also serves as both a primary source and a major target of reactive oxygen species （ROS）. Intestinal health is a cornerstone of animal growth and a critical determinant of livestock production efficiency. Tryptophan， an essential amino acid， is metabolized by both host cells and gut microbiota into various bioactive compounds， such as indole， kynurenine and 5-hydroxytryptamine. These metabolites act as endogenous ligands to regulate intestinal oxidative stress and inflammatory damage. This review summarizes the host and microbial pathways of intestinal tryptophan metabolism， explores the physiological functions of tryptophan metabolites in modulating oxidative stress and tissue repair， and discusses the role of microbial tryptophan metabolism in potential nutritional interventions，including probiotics and nutritional supplements. These findings aim to inform research on nutritional strategies for managing gut health.

Fucoidan is a water-soluble polysaccharide derived from brown algae， which possess anti-inflammatory， antioxidant， antiviral， and immunomodulatory function， and also has a protective effect on the intestinal barrier. It has shown promise as a novel additive in animal production. This article reviews the structure， extraction methods， physiological functions， factors affecting biological activity， protective effects on the intestinal barrier， and applications in poultry and livestock production of fucoidan.

Feed accounts for 60% to 70% of costs in pig and poultry production. The technology of diversified diets with low protein and low soybean meal is critical to reduce feed costs and relieve the pressure on the supply of feed grains such as corn and soybean meal. Accurate nutritional values are the keystone to determine the substitutability of various feed ingredients and to formulate diversified diets with low protein and low soybean meal. To obtain accurate nutritional values for feedstuffs in practice， it is critical to establish dynamic nutritional value database for feed ingredients by developing precise and rapid evaluation technologies. Thereby， this article systemically discusses the importance and broad application of simulated digestion technique in nutritional evaluation for feedstuffs from three aspects： the principles of establishing nutritional values database for feed ingredients， the progress in simulated digestion technique for feedstuff evaluation， and the application of simulated digestion technique in feedstuff database establishment and substitutability determination.

N6-methyladenosine （m⁶A） modification and microRNAs （miRNAs） are important factors in gene expression regulation， playing a crucial role in cellular energy metabolism. m⁶A modification participates in various physiological and pathological processes by regulating RNA stability， splicing and translation. miRNAs， as a class of small molecule RNAs， directly affect cellular metabolic pathways by targeting and regulating gene expression. The m⁶A modification-mediated regulation of miRNAs plays a pivotal role in cellular energy metabolism， especially in regulating metabolic processes such as glycolysis and mitochondrial function. By discussing the regulatory effect of m⁶A modification on miRNAs and its impact on energy metabolism， this review elaborating in detail on the mechanism by which m⁶A modification affects cellular energy metabolism by regulating miRNAs， and reveals the possibility of m⁶A modified miRNAs as targets for regulating cellular energy metabolism， in order to provide a theoretical reference for regulating animal growth and development and treating energy metabolism-related diseases.

The RNA genome of coronavirus contains multiple open reading frames， coding for structural proteins， non-structural proteins， as well as accessory proteins. The accessory proteins of coronavirus are species specific， and the amounts of accessory proteins differ between the species. Coronavirus accessory proteins are not necessary for viral replication， but some of them are involved in the host immune response， viral pathogenesis and virus virulence. Research on coronavirus accessory proteins will provide new potential targets for the development of therapeutic drugs and theoretical guidance for disease prevention and treatment. In this paper， the functions of several representative accessory proteins of coronaviruses are reviewed. It focuses on the relationship between accessory proteins and virus-host interactions， including the role of accessory proteins in promoting host cell apoptosis， host innate immune regulation， and pathogenicity in the host. This will help to investigate the infection and pathogenesis of coronavirus， and provide reference for developing new vaccines and antiviral drugs.

Salmonella is a common foodborne pathogen worldwide. With the promotion and use of antibiotics， more and more Salmonella produce or acquire antibiotic resistance genes （ARG） through vertical transmission and horizontal gene transfer （HGT）， causing widespread dissemination of antibiotic resistance. In the process of horizontal gene transfer， ARGs are mainly carried by mobile genetic elements （MGEs）， which are important mediators of HGT and can facilitate the spread of ARGs. Among them， MGEs mainly include plasmids， integrons and conjugative elements， transposons， insertion sequences， and phages， etc. MGE-associated transfer mechanisms， accessory gene compositions， and relationships between ARG dissemination and animal sources and geographic environments vary. The aim of this review is to outline the HGT mechanism of ARG in Salmonella， the different MGE-mediated HGT mechanisms and the influencing factors of HGT occurrence and development， which is of great significance for the in-depth investigation of the HGT mechanism of drug resistance in Salmonella.

The purpose of this study was to analyze the differences of production performance， meat quality traits and serum biochemical indicators between Yushan black pigs and its two-way cross pigs， and provide the reference for the hybrid utilization of Yushan black pig. In this study， the healthy Yushan black pigs and its two-way cross pigs were used and divided into 4 groups which included YY， DY， BY and SY with 3 replicates with 5 individuals per replicate. All of the experimental pigs were uniformly castrated and fattened with same body weight， the feed nutritional level and feeding management were consistent. When the pigs were raised until 250 days， each group selected 8 individuals （half castrated male and half castrated female） for slaughter， and serum was collected to detect biochemical indicators. The results showed that： 1） The average daily gain （ADG） of DY at the early fattening period was highest， the ADG of BY at the late fattening period was highest， the ADG of BY at the entire fattening period was the highest， and ADG of the 3 hybrid groups at the entire fattening period was significantly higher than that of YY group （P<0.01）. 2） The feed conversion ratio （FCR） of YY at the early fattening period was significantly higher than that of DY （P<0.01） and BY （P<0.05）， and the FCR of YY at the late fattening period was significantly higher than that of BY （P<0.01）， the FCR of YY at the entire fattening period was the highest and BY was the lowest. 3） The ADG of BY at the late fattening period was higher than that at the early fattening period （P<0.05）， while the ADG of other 3 groups were not different between the early fattening period and late fattening period （P>0.05）. 4） The FCR of the 4 groups at the late fattening period were significantly higher than that at the early fattening period （P<0.05）. 5） The slaughter performance of the 3 hybrid groups were significantly improved compared to the YY group. 6） The correlation analysis results found that， there was a significant positive correlation （P<0.05） between most slaughter traits and between slaughter traits and fattening traits， but there was a significant negative correlation （P<0.05） between ADG at early fattening period and fat percentage （P<0.05）. 7） The intramuscular fat content of YY was significantly higher than that of BY and SY （P<0.01）， the marbling score of DY was significantly higher than that of BY （P<0.05）， the drip loss of SY was significantly higher than that of YY and DY （P<0.01）， the shear force of BY was significantly higher than that of YY （P<0.01）， and the cooked meat percentage of BY was significantly higher than that of SY （P<0.01）. 8） There was no significant difference （P>0.05） in the level of serum immune indicators， CAT， T-AOC and blood lipid indicators between YY group and 3 hybrid groups. However， the serum GSH-Px level of YY group was significantly lower than that in SY group （P<0.01）， the serum MDA level was significantly higher than that in DY group （P<0.01）， the serum SOD level was significantly higher than that in SY group （P<0.05）， and the GLU level was significantly lower than that in BY （P<0.05） and SY （P<0.01） groups. In summary， the important production indicators such as growth and development traits， FCR and slaughter performance were significantly improved but the meat quality traits were decreased in these 3 hybrid groups compared to Yushan black pigs， while the immune and antioxidant ability were not significantly changed. The study results showed that， the DY and BY two-way cross combination were more suitable for the hybrid utilization of Yushan black pig.

In this study， the objective of this study was to explore the functional candidate genes affecting the apparent digestibility of crude fiber in Suhuai pigs （25% of Suhuai pigs and 75% of Large White pigs）， so as to lay the foundation for the analysis of the genetic mechanism of the apparent digestibility of crude fiber in pigs. A total of 320 160-day-old Sohuai pigs were selected for the study， and the apparent digestibility was calculated by measuring the crude fiber content of feed and feces. At the same time， ear tissue samples were collected for 80K single nucleotide polymorphism （SNP） microarray typing， and 51 625 SNPs were retained after quality control， based on which the heritability was calculated and the microarray data were populated to the resequencing level. Subsequently， genome-wide association study （GWAS） was conducted based on the populated data， and Bayesian fine-tuning method was used for in-depth analysis. The results showed that the apparent digestibility of crude fiber in this population was 54.30%±1.03%， and the coefficient of variation was 33.87%， which showed a large phenotypic variation and certain space for selection and breeding. The heritability was calculated as 0.268±0.106 （P=0.012）， which is a medium heritability trait. GWAS （genome-wide association study） analysis identified 359 SNPs on chromosomes 4， 5， and 9 that were significantly associated with crude fiber apparent digestibility （P<3.30×10^-6）. Three quantitative trait loci （QTL） region were identified by Bayesian fine localization on chromosome 4 （11.48-12.75 Mb）， chromosome 5 （83.39-84.86 Mb）， and chromosome 9 （18.81-19.68 Mb）. After comparison with the Pig QTL database， all of them were newly discovered QTL affecting the apparent digestibility of crude fiber in pigs. Six new functional candidate genes， MYC， ANO4， NR1H4，ACTR6， SCYL2 and DLG2， were identified through database and literature search， and PheWAS analysis of the candidate genes using the PigBiobank database of the FarmGTEx project showed that these genes were associated with daily weight gain， meat color and health of pigs. PheWAS analysis using the PigBiobank database of the FarmGTEx program revealed that these genes were significantly associated with the traits of daily weight gain， meat color and health. In this study， 3 QTLs and 6 functional candidate genes affecting crude fiber digestion in pigs were newly identified， which can be used as a reference for the study of genetic molecular mechanism and the implementation of molecular breeding for the trait of apparent digestibility of fiber.

This study aimed to investigate the differences in intestinal microbial diversity among Chuanxiang Black pigs， Berkshire pigs， and Duroc pigs using 16S rRNA sequencing technology and bioinformatics analysis. When the body weight of the pigs reached 120 kg， Chuanxiang Black pigs， Berkshire pigs， and Duroc pigs were slaughtered， and rectal fecal samples were collected from each breed. The intestinal microbial diversity of the different pig breeds was then analyzed using 16S rRNA sequencing technology and bioinformatics approaches. The results demonstrated that the microbial diversity of Berkshire pigs was significantly lower than that of Chuanxiang Black pigs and Duroc pigs （P<0.05）， and the microbial community structures among the 3 pig breeds showed significant differences （P<0.05）. At the phylum level， the abundance of Firmicutes in Chuanxiang Black pigs was significantly lower than that in Berkshire pigs （P<0.05）， while the abundance of Bacteroidota in both Chuanxiang Black pigs and Duroc pigs was significantly higher than that in Berkshire pigs （P<0.05）. At the genus level， the abundance of Rikenellaceae RC9 gut group in Chuanxiang Black pigs and Duroc pigs was significantly higher than that in Berkshire pigs （P<0.05）. The abundances of Prevotella and Prevotellaceae NK3B31 group in Chuanxiang Black pigs were significantly higher than those in Duroc pigs and Berkshire pigs （P<0.05）， while the abundance of Clostridium sensu stricto 1 in both Duroc pigs and Berkshire pigs was significantly higher than that in Chuanxiang Black pigs （P<0.05）. LEfSe analysis showed that there were 14， 7， and 1 differential microorganisms in Chuanxiang Black pigs， Berkshire pigs， and Duroc pigs at the genus level， respectively. Functional prediction results showed that pathways related to amino acid metabolism were significantly enriched in the microbial community of Chuanxiang Black pigs， pathways related to pyruvate metabolism and others were significantly enriched in Berkshire pigs， and pathways related to protein transport and others were significantly enriched in Duroc pigs. In conclusion， there are significant differences in the composition and function of intestinal microbiota among Chuanxiang Black pigs， Berkshire pigs， and Duroc pigs. These differences may affect the host's nutritional metabolism， energy utilization， immune regulation， and other functions.

This study aimed to reveal the genetic relationships and genomic differences among 3 Xinjiang local chicken breeds including Baicheng-You chickens， Hetian chickens， and Tulufan chickens， so as to provide references for the protection and utilization of genetic resources of local domestic chickens in Xinjiang at the genomic level. The research took 65 chickens whole-genome resequencing datasets as the research objects and utilized softwares such as Rstudio， Plink， and Pedstats to filter the data. The population genetic structure of different chicken breeds was analyzed through identical by state （IBS） multi-dimensional scaling. Gene infiltration analysis was carried out using Treemix and Dsuite. The selection signals were mined by using the cross population extended haplotype homozygosity （XP-EHH） and cross population composite likelihood radio test （XP-CLR） methods. After filtering， a total of 10 228 705 autosomal single nucleotide polymorphisms （SNPs） were obtained for analyzing the introgression and selection signals， while 4 657 217 autosomal SNPs with minor allele frequency （MAF）≥0.2 were used for genetic relationship analysis. The results of genetic relationship showed that the genetic distance between Baicheng-You and Tulufan chickens was farthest， and their genetic differentiation coefficient （F_ST） was 0.077 7， while the genetic distance between Hetian and Baicheng-You， Tulufan chickens were close and the F_ST was 0.053 5 and 0.056 3， respectively. Furthermore， there was an introgression event between Hetian and Tulufan chickens. The highest score of introgression region located in the chromosome 4， which contained some genes associated with heat tolerance， such as ABLIM2. While selection signals analysis between Baicheng-You and Tulufan chickens identified 70 candidate genes involved in important biological processes. Among them， genes such as CLCN6， ACTA2， CRIM1， and IARS2 might be related to the heat resistance performance； Genes such as BNIP2， DTNA， and RAB3GAP2 might be involved in the regulation of muscle growth； Genes such as AGMO， TSNARE1 might be related to the formation of aggressive behavior in cockfighting. The research clearly revealed the genetic relationships among 3 local chicken breeds in Xinjiang， discovered the genomic infiltration regions and related genes between the Hetian and Tulufan chickens， and identified the genomic selection regions between the Baicheng-You and Tulufan chickens and the candidate genes related to characteristic traits such as heat tolerance， muscle growth， and aggressive behavior of fighting chickens. Thus providing molecular basis for the protection and utilization of the characteristic traits of chicken breeds in Xinjiang.

The study aimed to utilize the superior traits of Kirin chicken （a newly identified national genetic resource） and explore the heterosis mechanism of its cross with the local excellent Huaixiang chicken， this study compared the key production performance and muscle quality among Huaixiang chicken， Kirin chicken， and their reciprocal cross offspring， aiming to provide a basis for parental matching in high-quality broiler breeding in tropical and subtropical regions. Huaixiang chickens （strain A， strain C） and Kirin chickens （fast yellow-feather， slow yellow-feather） were used for a complete diallel cross experiment， with 4 mating combinations （Huaixiang purebred group， Kirin purebred group， orthogonal group， reverse-cross group）. Each group had 6 replicates （20 1-day-old healthy chicks per replicate， half male and half female， birth weight error within ±10% SD）， and relevant indicators were measured after 16 weeks of feeding. At 16 weeks of age， the average weight of cocks was reverse-cross chicken （1 790.69 g） > orthogonal chicken （1 761.67 g） > Kirin chicken （1 733.78 g） > Huaixiang chicken （1 582.63 g） with significant differences （P<0.05）， while no significant difference was found in hens （P>0.05）； the maximum growth rate of Huaixiang chicken appeared at 8 weeks， Kirin chicken at 12 weeks， hybrid cocks at 14 weeks， and hybrid hens at 8 weeks； Huaixiang chicken had higher moisture content in breast and leg muscles， and the crude fat content in leg muscles of reverse-cross cocks was significantly higher than that of Huaixiang and orthogonal cocks （P<0.05）； Kirin chicken had significantly smaller muscle fiber diameter and density in breast and leg muscles than the other 3 groups （P<0.05）； there were extremely significant correlations between indicators such as breast muscle moisture and muscle fiber density， crude protein and crude fat （P<0.01）. The hybrid offspring of Kirin and Huaixiang chickens showed excellent growth performance and obvious heterosis， with reverse-cross combinations outperforming orthogonal ones， providing a scientific reference for screening high-quality chicken matching combinations in tropical regions.

The objective of this study was to identify molecular marker loci and candidate genes associated with body weight and size traits in Dabieshan cattle， thereby elucidating their genetic mechanisms. A total of 515 healthy Dabieshan cattle aged between 30 and 36 months were selected， phenotypic measurements of eight traits were performed， including body weight， withers height， body slanting length， chest circumference，abdominal circumference， cannon bone circumference，hucklebone width， and hip width. Genotyping was performed using the Neogen 100K SNP chip， and a genome-wide association study （GWAS） was conducted using a mixed linear model （MLM）. The results revealed 44 single nucleotide polymorphisms （SNPs） loci significantly associated with body weight and size traits， which were annotated to 426 candidate genes. Among these， 6 candidate genes （WFIKKN2， MMP2， MATN1， PUM1， VKORC1， and VKORC1L1） related to muscle development， chondrogenesis， and bone metabolism were of particular interest. Functional enrichment analysis using Gene Ontology （GO） and Kyoto Encyclopedia of Genes and Genomes （KEGG） further indicated that the VKORC1 and VKORC1L1 genes are involved in key biological processes such as vitamin K metabolism， which warrants further investigation. In conclusion， the findings of this study provide clear molecular targets and valuable insights for the genetic improvement of the Dabieshan cattle.

To clarify the genetic basis of modern domestic horses’ adaptation to environmental changes during domestication， this study collected genomic data from 317 individuals of 19 horse breeds at home and abroad for analysis， and explored the genetic diversity and population structure of horses. Combined with 25 environmental factors， genome-wide association study and selective sweep analysis （F_ST and π ratio） were used to screen candidate genes significantly associated with environmental adaptability. The results showed that a total of 107 shared candidate genes significantly associated with environmental adaptability were identified by the two analytical methods. Pathway enrichment analysis indicated that these genes were mainly involved in pathways such as olfactory transduction， heme binding， oxygen binding， and cellular response to hypoxia. Among them， the OR52A1J gene region on chromosome 7 showed a strong selection signal. Haplotype analysis revealed that this region could clearly distinguish horse breeds at high and low altitudes， suggesting that it might be a key candidate gene for the adaptation of Tibetan horses to high altitudes. This study provides a new perspective for revealing the environmental adaptability of modern domestic horses and offers a reference for the management and protection of animal genetic resources.

This study aimed to compare the morphological characteristics of pectoral muscle myofibers and transcriptomic profiles between Shitou geese and Wuzong geese at 40- and 90-day-old stages， and to identify candidate genes underlying divergent breast muscle growth across breeds and ages. A total of 3 male Shitou geese and 3 male Wuzong geese from the same batch were randomly selected at 40 and 90 days of age. Pectoral muscle tissues were collected for morphological analysis of muscle fibers using H&E staining. Transcriptome sequencing was performed to identify differentially expressed genes （DEGs） related to muscle growth， and key candidate genes were further validated by reverse transcription quantitative PCR （RT‑qPCR）. H&E staining results revealed that at 40 days of age， the density of pectoral muscle fibers in Shitou geese was significantly higher than that in Wuzong geese （P<0.001）， while the diameter of pectoral muscle fibers was significantly smaller （P<0.001）. At 90 days of age， however， the density of pectoral muscle fibers in Shitou geese was significantly lower than that in Wuzong geese （P<0.05）， and no significant difference was observed in pectoral muscle fiber diameter between the two breeds （P>0.05）. Transcriptome sequencing of pectoral muscle identified 5 719 DEGs in total， including 3 907 DEGs between different ages within the same breed and 1 812 DEGs between the two breeds at the same age. KEGG enrichment analysis revealed that pathways including ECM-receptor interaction， cell adhesion molecules， and focal adhesion critically regulated pectoral muscle growth across ages within breeds. Cytokine-cytokine receptor interaction and cell adhesion molecule pathways were key regulators of growth differences between breeds at the same age. Eight candidate genes （COL4A2， ITGB3， CAV1， CCND2， MYLK2， PDGFRA， ACTN2， and TNNC2） closely associated with pectoral muscle development were identified. RT-qPCR validation confirmed high correlation （r>0.90） with transcriptome data， supporting the reliability of sequencing results. In summary， this study revealed significant variations in myofiber morphology across developmental stages and between Shitou and Wuzong goose breeds. Key pathways including focal adhesion， ECM-receptor interaction， and cell adhesion molecules were found to mediate pectoral muscle myofibre hypertrophy through regulating the expression of candidate genes （e.g.， COL4A2， ITGB3， CAV1， etc.）. These findings establish a theoretical foundation for molecular marker-assisted breeding in meat geese， accelerating genetic improvement programs and new breed development.

This study aimed to investigate the differences in fur quality and the potential molecular mechanisms influencing the coarse hair percentage of hybrid offspring of Rex rabbits and Hycole meat rabbits， in order to provide a reference for research on fur quality of hybrid rabbits. Twelve 165-day-old F2-generation rabbits produced by crossing Rex rabbits and Hycole meat rabbits were selected. Fur quality indicators， including hair length， hair fineness， and coarse hair percentage， were measured. Based on the statistical result of coarse hair percentage， 10 female rabbits were further selected for transcriptomic sequencing of skin tissues. Among them， 5 individuals with coarse hair percentage ≥ 10% were classified as the high coarse hair percentage group， and 5 with coarse hair percentage <10% were classified as the low coarse hair percentage group. Differentially expressed genes （DEGs） between the two groups were compared， followed by functional enrichment analysis and protein-protein interaction （PPI） network construction. The accuracy of the sequencing results was verified using quantitative real-time PCR. The results showed that in the F2 hybrid rabbits， coarse hair percentage was extremely significantly positively correlated with hair length （P<0.01） and significantly positively correlated with hair fineness （P<0.05）， but not significantly correlated with other indicators （P>0.05）. A total of 281 DEGs were identified between the high and low coarse hair percentage groups. Gene Ontology （GO） enrichment analysis revealed these genes were significantly enriched in functional terms such as drug transport， regulation of myoblast proliferation， contractile fiber， and glycosaminoglycan binding. Kyoto Encyclopedia of Genes and Genomes （KEGG） pathway analysis showed significant enrichment in important biological processes including glycolysis/gluconeogenesis， steroid hormone biosynthesis， motor proteins， and the PPAR signaling pathway. A protein-protein interaction （PPI） network of the differentially expressed proteins was constructed， and 4 candidate genes were identified （FGF7， MMP3， MMP13and FOXP3）. RT-qPCR results confirmed that the expression trends of these 5 DEGs were largely consistent with the RNA-seq data. These results suggest that the FGF7， MMP3， MMP13and FOXP3 genes may be important candidate genes influencing the coarse hair percentage trait. This study provides data support for evaluating the fur quality of hybrid offspring between Rex and Hycole meat rabbits and offers insights for improving fur traits in hybrid breeds.

The aim of this study was to investigate the expression pattern and regulatory mechanism of miR-370 and miR-219a in sow follicular granulosa cells （GCs） under oxidative stress， and provide theoretical basis for the use of endogenous small molecule regulators to inhibit oxidative stress and promote follicular development. In this study， primary sow GCs were used as experimental materials and an in vitro oxidative stress GC model was established using 150 μmol·L^-1 H₂O₂. The regulatory effect of oxidative stress on the transcription of miR-370 and miR-219a was analyzed by RNA-seq and RT-qPCR. Their conservation and expression distribution were detected by bioinformatics analysis and tissue expression profiling. FACS and ELISA were performed to detect the effect of two miRNAs on the oxidative stress and apoptosis of sow GCs. The overexpression plasmid of KLF5 was constructed and its expression efficiency was verified by WB. Furthermore， RT-qPCR， luciferase activity analysis and ChIP were conducted to identify the mechanism by which KLF5 inhibits the transcription of two miRNAs in sow GCs under oxidative stress. The results showed that， oxidative stress inhibits the transcription of miR-370 and miR-219a， resulting in down-regulation of their pri-， pre- and mature expression levels （P<0.01）. Characterization analysis revealed that both miRNAs are conserved and highly expressed in ovary. Correlation analysis revealed that their expression levels were significantly positively correlated with SOD activity （P<0.01）， significantly negatively correlated with MDA level （P<0.01）， suggesting that they have anti-oxidative capacity. Overexpression of two miRNAs effectively and synergistically alleviated the oxidative stress-induced ROS accumulation， low SOD activity， high MDA levels， and high apoptosis rate. Prediction analysis found that their promoters contain potential KLF5 binding sites， and overexpression of KLF5 significantly inhibited their transcription and promoter activities （P<0.01）， while had no effect on the luciferase activities of the reporter vectors containing mutant KLF5 binding sites. ChIP results confirmed that KLF5 directly bound to their promoters， and its expression and binding enrichment were elevated by oxidative stress. In summary， oxidative stress inhibits the transcription of antioxidant miRNAs （miR-370 and miR-219a） by inducing the expression and transcription factor activity of KLF5， which exacerbates the oxidative damage of sow GCs.

This study aimed to investigate the mechanism by which knockdown of androgen receptor （AR） in sheep affects the development of ovarian granulosa cells （GC）. The healthy， adult sheep was selected as experimental subjects， employing surgical procedures to obtain ovarian tissue， from which granulosa cells were subsequently isolated and characterized.After silencing AR expression in granulosa cells （GCs）， cell proliferation and estradiol （E2） production were assessed in sheep ovarian GCs through CCK-8 and ELISA techniques.Furthermore， after AR knockdown， key differentially expressed genes （DEGs） affecting ovarian granulosa cell development were identified through transcriptome sequencing （RNA-seq）. These genes were subjected to functional enrichment analysis， and signaling pathways involved in granulosa cell development， along with their associated DEGs， were validated using RT-qPCR and Western blot assays.The results demonstrated that the study successfully isolated and identified granulosa cells， and that knockdown of AR significantly reduces the proliferation activity of these cells.More importantly， after AR was knocked down， 1 187 differentially expressed genes was identified through transcriptome sequencing， with 465 genes upregulated and 722 genes downregulated.Based on these differentially expressed genes， key signaling pathways involved in granulosa cell development were identified， including the PI3K-Akt pathway and the estrogen signaling pathway. The key genes PI3K， AKT， p-AKT， ESR2， CYP19A1， BAX， BAX/BCL2， and Caspase3 were further validated.Following AR silencing， the expression levels of critical genes within the PI3K-Akt signaling cascade—specifically PI3K， AKT， and p-AKT were significantly reduced （P<0.05）. Similarly， key genes associated with estrogen biosynthesis， ESR2 and CYP19A1， exhibited significant downregulation （P<0.05）. Conversely， genes linked to cellular proliferation， including BAX， the BAX/BCL2 ratio， and Caspase3， showed a significant increase in expression （P<0.05）. In summary， these findings suggest that knocking down AR in sheep ovarian granulosa cells may influence cell proliferation and hormone synthesis through the PI3K-Akt signaling pathway and the estrogen signaling pathway， thereby participating in the process of cellular development.

The study aimed to screen candidate genes associated with litter size in goats and investigate the molecular mechanism by which the RHOU gene regulates goat litter size. The GenoBaits^® Goat 40K liquid chip was used to perform SNP genotyping on a hybrid population of 337 Boer goats and Haimen goats under selection， and a genome-wide association study was conducted in combination with the first-parity litter size phenotype. The coding region of the goat RHOU gene was cloned by the PCR method， and its sequence and structural characteristics were analyzed. The large and small follicles and ovarian granulosa cells of goats were isolated， and methods such as RT-qPCR， CCK-8， and ELISA were used to detect gene expression levels， cell proliferation， and estrogen levels. A C/T mutation on chromosome 28 （position 44 302 456， 177 365 bp upstream of RHOU） was significantly associated with first-parity litter size. The cloned RHOU coding region spanned 768 bp， encoding 255 amino acids with high homology to other mammals. The RHOU gene was widely expressed in various tissues of goats， and its expression was extremely significantly higher in ovarian tissue （P<0.01）， and the expression level in small follicles was extremely significantly higher than that in large follicles （P<0.01）. Overexpression of the RHOU gene significantly reduced cell proliferation ability （P<0.05） and the mRNA expression levels of cell proliferation marker genes PCNA （P<0.05） and MKI67 （P<0.01）， and significantly down-regulated the expression level of the CYP19A1 gene and the E2 concentration in the culture medium of goat ovarian granulosa cells （P<0.05）. This study identified that the RHOU gene was significantly associated with goat litter size based on the goat 40K liquid chip. The study found that it regulates goat litter performance by negatively regulating the proliferation of goat ovarian granulosa cells， reducing the expression of CYP19A1 in granulosa cells， and inhibiting the synthesis of E2.

This study aimed to analyze the metabolic mechanisms of testicular tissue associated with semen quality in ducks from a metabolomics perspective. Semen quality was evaluated in a duck population. Twelve drakes （6 with significantly high semen quality and 6 with significantly low semen quality） were selected， and testicular tissues were collected. Ultra-performance liquid chromatography-tandem mass spectrometry （UPLC-MS/MS） was used to analyze differences in testicular metabolites between groups. Enrichment analysis of differential metabolites was performed to screen potential key pathways related to testicular semen quality. A total of 98 differentially abundant metabolites was identified in testicular tissues of ducks with varying semen quality， including 15 significantly upregulated and 83 significantly downregulated metabolites. These metabolites primarily belonged to categories such as fatty acyls， amino acids and their metabolites， glycerophospholipids， nucleotides and their metabolites， benzene derivatives， coenzymes and vitamins， and hormones. Correlation analysis revealed the strongest positive correlation between fatty acyls and benzene derivatives， while the strongest negative correlation was observed between carbohydrates/their metabolites and aldehydes/ketones/esters. Semen quality parameters （e.g.， sperm motility and kinematic parameters） showed significant positive/negative correlations （|R|≥0.80） with fatty acyls， glycerophospholipids， and other metabolites. Enrichment analysis highlighted two critical metabolic pathways： fatty acid degradation （P=0.000 59） and glycerophospholipid metabolism （P=0.012 76）. This study elucidated differential metabolites and potential metabolic mechanisms associated with semen quality in duck testicular tissues through metabolomics. It identifies 98 differential metabolites dominated by lipids （fatty acyls and glycerophospholipids）， characterized by significant downregulation of carnitines and enrichment of hexadecanoic acid （FFA16：0） and maltitol in the high semen quality group， and identifies fatty acid degradation and glycerophospholipid metabolism as core pathways significantly associated with semen quality. These findings provide key metabolites and pathway targets for research on avian testicular function.

The objective of this study was to investigate the effects of starch with different digestion rates on dietary energy and protein utilization in broilers. Eight dietary treatments from each of 4 starches with different digestion rates including cassava starch （k_d=4.29 h^-1）， wheat starch （k_d=2.51 h^-1）， corn starch （k_d=2.55 h^-1）， and pea starch （k_d=1.03 h^-1） combined with soybean meal or corn gluten meal were arranged in a single-factor completely randomized experiment. In the study on the effects of starch with different digestion rates on nitrogen retention and metabolizable energy of diets， a total of 192 Arbor Acres plus broilers of 22 days of age with similar body weight （BW=1 050±6 g） were selected and randomly assigned to 8 diets. Each treatment contained 6 replicates of 4 broilers in each replicate. The energy metabolizability and nitrogen retention rates were determined for diets fed to broilers aged 25 to 28 days. In the study on the effects of starch with different digestion rates on apparent ileal digestibility of starch and standardized ileal digestibility of amino acid （SIDAA） of diets， a total of 432 Arbor Acres plus broilers of 25 days of age with similar body weight （BW=1 270±10 g） were selected and randomly assigned to 8 diets and a nitrogen-free diet. Each treatment contained 6 replicates of 8 broilers in each replicate. The apparent ileal digestibility of starch and SIDAA were determined for diets fed to broilers at 28 days of age. The results showed as follows： 1） In the starch-soybean meal diets， the apparent ileal digestibility of starch in diets of moderately digestible starch （wheat starch and corn starch） were greater than these in diet of rapidly or slowly digestible starch （cassava starch or pea starch） （P<0.05）. The apparent ileal digestibility of starch in rapidly digestible starch （cassava starch） diet was greater than that in slowly digestible starch （pea starch） diet （P<0.05）. The diets of rapidly or moderately digestible starch （cassava starch， corn starch and wheat starch） had greater energy metabolizability than slowly digestible starch （pea starch） diet （P<0.05）. Starch with different digestion rates didn’t significantly affect the SIDAA of soybean meal. The nitrogen retention rate of corn starch diet was higher than other 3 starch diets （P<0.05）. 2） In the starch-corn gluten meal diets， the apparent ileal digestibility of starch in diets of moderately digestible starch （wheat starch and corn starch） were greater than these in diet of rapidly or slowly digestible starch （cassava starch or pea starch） （P<0.05）. The moderately digestible starch （corn starch） diet had greater energy metabolizability than diet of rapidly or slowly digestible starch （cassava starch or pea starch） （P<0.05）. Compared with rapidly digestible starch （cassava starch）， moderately digestible starch （wheat starch and corn starch） enhanced the standardized ileal digestibility of 13 amino acids and total amino acids in corn gluten meal （P<0.05）. However， no statistically significant difference was observed in nitrogen retention rate across diets with different digestion rates of starch. 3） A significant linear regression relationship between apparent metabolizable energy or nitrogen-corrected apparent metabolizable energy and digestible starch and metabolizable protein was observed in the 8 experimental diets （P<0.05）. The dietary energy metabilizablility and total amino acid digestibility decreased as the increase of the ratio of starch digestibility to total amino acid digestibility （P<0.05）. In conclusion， starches with moderate digestion rates （wheat starch， corn starch） have higher ileal digestibility of starch and dietary energy metabolizability compared to slowly digestible starch （pea starch）. However， when rapidly digestible starch （cassava starch） is combined with rapidly digestible protein （corn gluten meal）， the ileal digestibility of starch， dietary energy metabolizability and amino acid digestibility in broilers is reduced. Generally， the ratio of starch digestibility to total amino acid digestibility is negatively related with the energy metabolizability and amino acid digestibility.

The objective of this experiment was to investigate the effects of different calcium （Ca）， non-phytic phosphorus （NPP） levels and electrolyte balance （DEB） value in a low protein diet on growth performance， serum biochemical indices and metabolic rate of nutrients in broilers. A 3×3 two-factor completely randomized design was adopted. Three dietary calcium and non-phytate phosphorus levels were 0.70% Ca and 0.35% NPP， 0.80% Ca and 0.40% NPP， 0.90% Ca and 0.45%NPP， respectively. And three levels of dietary electrolyte balance （Na⁺+K⁺-Cl^-） were 200， 250 and 300 mmol·kg^-1， respectively. In addition， dietary crude protein level was 19.5%. A total of 324 1-day-old Arbor Acres （AA） male broilers were randomly allotted to 1 of 9 treatments with 6 replicate cages per treatment and 6 birds per cage. The experimental period was 21 days. The results showed that： 1） Dietary Ca， NPP and DEB value and their interaction had no significant effect （P>0.05） on growth performance of broilers from 1 to 21 d of age； 2） The interaction of dietary Ca， NPP and DEB value had significant effect （P<0.05） on the alanine aminotransferase （ALT） activity in serum. As dietary Ca and NPP levels were 0.70% and 0.35%， the serum ALT activity from broilers in the 300 mmol·kg^-1 DEB value group was significantly higher （P<0.05） than that of the 200 and 250 mmol·kg^-1 DEB value groups. As the levels of Ca and NPP were 0.80% and 0.40%， the serum ALT activity from broilers in the 250 or 300 mmol·kg^-1 DEB value groups was significantly lower （P<0.05） than that in the 200 mmol·kg^-1 DEB value group. As the levels of Ca and NPP were 0.90% and 0.45%， DEB levels had no significant effect （P>0.05） on serum ALT activity； 3） As dietary Ca and NPP levels increased， the apparent metabolic rate of Ca decreased significantly （P<0.05）. The apparent metabolic rates of dry matter， crude protein and Ca in broilers from 300 mmol·kg^-1 DEB value group were significantly higher （P<0.05） than those in 250 and 200 mmol·kg^-1 DEB value groups. As the levels of dietary Ca and NPP were 0.70% and 0.35%， 300 mmol·kg^-1 DEB value could significantly increase （P<0.05） the apparent metabolic rate of P compared with the 200 and 250 mmol·kg^-1 DEB value. And as the levels of Ca and NPP were 0.90% and 0.45%， the apparent metabolic rate of P in 300 mmol·kg^-1 DEB value group was significantly higher （P<0.05） than that in the 200 mmol·kg^-1 group. These results indicated that the Ca and NPP levels of 0.80% and 0.40% and DEB value of 300 mmol·kg^-1 in a low protein diet （Crude protein： 19.5%） were optimal for the growth and nutrient utilization in broilers from 1 to 21 d of age.

The aim of this experiment is to investigate the effect of 18β-glycyrrhetinic acid （18β-GA） on oxidative stress induced lung injury in weaned piglets induced by D-galactose （D-gal）.In total， 24 weaned piglets of similar body weight at 28 days old were randomly divided into 3 groups， with 8 replicates in each group and 1 piglet in each replicate. The experimental groups were as follows： the control group （CK） was fed with basal diet， the model group （D-gal） was fed with basal diet supplemented with 10 g·kg^-1 D-gal， and the experimental group （GA+gal） was fed with basal diet supplemented with 10 g.kg^-1 D-gal and 100 mg·kg^-1 18 β-GA. The pre trial period is 7 days， and the main trial period is 28 days. The results showed that compared with the CK group， the D-gal group showed an increase trend in malondialdehyde （MDA） content， 8-hydroxy-2-deoxyguanosine （8-OHdG） content， and catalase （CAT） activity in the lung tissue of weaned piglets （0.05≤P<0.10）， and a significant increase in superoxide dismutase （SOD） activity （P<0.05）； The expression levels of Nrf2， CAT， and SOD1 genes significantly increased （P<0.05）； The levels of inflammatory factors interleukin-8 （IL-8） and transforming growth factor-β （TGF-β） increased significantly （P<0.05）， and the mean linear intercept （MLI） and apoptosis rate of lung tissue cells increased significantly （P<0.05）； Compared with the D-gal group， the GA+gal group showed a significant decrease in the activities of CAT and SOD， content of MDA and 8-OHdG， as well as the expression levels of antioxidant related genes Nrf2， CAT， and SOD1 in the lungs （P<0.05）. The levels of inflammatory factors IL-8， interleukin-18 （IL-18）， and TGF-β were also reduced significantly （P<0.05）， and the apoptosis rate was also reduced significantly （P<0.05）. Transcriptomic analysis showed that oxidative stress has an impact on the cell cycle， PI3K/AKT signaling pathway， and P53 signaling pathway in piglet lung cells. 18β-GA can alleviate lung injury by regulating pathways such as PI3K/AKT signaling pathway and retinol metabolism. Further verification using fluorescence quantitative PCR and Western blot techniques revealed that the expression levels of key genes PI3K， AKT， TP53， as well as proteins P53 in the oxidative stress pathway of piglets increased significantly （P<0.05）. After adding 18β-GA， the expression levels of pathway genes PI3K and TP53 decreased significantly （P<0.05）， while the expression levels of gene AKT and protein P53 showed a downward trend （0.05≤P<0.1）.In summary， the addition of 18β-GA can alleviate D-gal induced lipid peroxidation， DNA oxidative damage， increased inflammatory factors， and cell apoptosis in weaned piglet lungs. The underlying mechanism might involve the alleviation of lung injury through the modulation of the P53 signaling pathways.

Since 2011，the new outbreak of pseudorabies virus（PRV）variant strain in China has greatly increased the detection workload of the virus. At present， the widely use of blocking ELISA kits has raised the greater demand for monclonal antibodies. However， hybridoma cells often lose antibody secretion capacity during passages. This study aimed to prepare single-chain fragment variable with good binding activity on the basis of monoclonal antibody and achieve large-scale production via prokaryotic expression system， providing a foundation for novel detection methods. The prokaryotically expressed PRV gE protein was used to immunize mice. Positive hybridoma cells stably secreting anti-PRV gE mabs were obtained through cell fusion and screening. The cDNA of the positive hybridoma cells was used as a template to amplify the variable region sequence of antibody，and the scFv gene was constructed by linking the variable regions of heavy and light chain with a Linker peptide. The scFv gene was cloned into pET-28a plasmid for prokaryotic expression to produce the recombinant antibody. A monoclonal antibody 7B7 specific to the gE protein of PRV was successfully screened. Using the cDNA of 7B7 hybridoma cells as a template，a single chain fragment variable capable of specifically reacting with PRV gE was successfully prepared which can be expressed by prokaryotic expression system， providing a basis for the development of new detection methods for PRV.

In this study， we aimed to develop recombinant PRV rPRV-AH-gI^-/gE^-/gM^-/gD⁺ with double gD and evaluate its immune efficacy. The recombinant virus rPRV-AH-gI^-/gE^-/gM^-/gD⁺ was constructed by deleting gM gene and inserting gD expression cassette at the deficient region. Four-week-old Kunming mice were immunized twice with 10^7.0 TCID₅₀ inactivated rPRV-AH-gI^-/gE^-， rPRV-AH-gI^-/gE^-/gM^-， rPRV-AH-gI^-/gE^-/gM^-/gD⁺ at an interval of 3 weeks. Commercial vaccine and DMEM were as the control group. After immunization， regular blood was collected， neutralizing antibody levels in sera were detected by neutralization test， and total antibody levels were detected by ELISA. At 6 weeks of first immunization， mice were challenged with 10^5.5TCID₅₀ PRV-AH. The inserted gD gene was expressed with the molecular weight of 53 ku in the rPRV-AH-gI^-/gE^-/gM^-/gD⁺. The neutralizing and total IgG antibody levels of rPRV-AH-gI^-/gE^-/gM^-/gD⁺ group were significantly higher than those of rPRV-AH-gI^-/gE and rPRV-AH-gI^-/gE^-/gM^- at 4 and 6 weeks after first immunization （P<0.01）. However， compared with the commercial vaccine group， the difference was not significant （P>0.05）. After challenged with PRV-AH， the protection rates were 100%， 70%， 60% and 90% of the rPRV-AH-gI^-/gE^-/gM^-/gD⁺， rPRV-AH-gI^-/gE^-/gM^-， rPRV-AH-gI^-/gE^- and commercial vaccine groups respectively. The results showed that the insertion of gD gene can improve the immune protection effect of the recombinant virus which is helpful in developing vaccine candidate for PRV control.

A microdroplet digital polymerase chain reaction （ddPCR） method for the detection of fowlpox virus （FWPV） was established. In this study， a more complete ddPCR reaction system was established through the optimization of the reaction system， including the optimization of primer and probe concentrations， the optimization of annealing temperature and other steps， and reproducibility， sensitivity， and specificity experiments. In this method， the optimal primer concentration was determined to be 900 nmol·L^-1， the optimal probe concentration was 200 nmol·L^-1， and the results of ddPCR were optimized under the reaction condition of 55 ℃. The method showed no cross-reactivity with other common avian viruses and is highly specific. The reproducibility of the method is good， and the coefficients of variation between and within batches are less than 10%. The lowest detection limit of this ddPCR method was 2.37 copies per reaction. Using the established ddPCR detection method and the industry standard （SN/T 1226—2015） detection method for 80 samples， the coincidence rate was 100%， which was higher than the coincidence rate of 75% of the industry standard nested PCR method. In 25 artificially inoculated samples， the detection rate of ddPCR for positive samples reached 100%， while the detection rate of the nested PCR method specified in the industry standard for positive samples was 33.3%. The establishment of this method helps the relevant inspection and quarantine departments at ports to detect the FWPV in a timely manner and reduces the risk of the domestic poultry breeding industry by providing a more accurate and efficient detection method.

This study aimed to express a nanobody targeting H7-subtype avian influenza virus using an E. coli system. Nanobody and antigen expression vectors were constructed via homologous recombination. Recombinant vectors were amplified using E. coli DH5α， followed by transformation into E. coli BL21（DE3） and BEVS for high-yield protein production. Nanobodies and antigens were purified using streptavidin affinity chromatography and IMAC purification， respectively. Finally， immunofluorescence assay （IFA）， enzyme-linked immunosorbent assay （ELISA）， hemagglutination inhibition （HI） and surface plasmon resonance （SPR） were employed to analyze nanobody titer， specificity， immunoreactivity， and antigen-nanobody interaction dynamics. Expression vectors were successfully constructed， followed by the production of a 15 ku nanobody （D67）， a 42 ku fluorescent nanobody （D67-GFP） and a 55 ku avian influenza antigen （H7-HA1）. In IFA， H7-HA1-positive cells incubated with the nanobody exhibited significantly stronger green fluorescence signals compared to the control group. ELISA revealed significant OD₄₅₀ signals exclusively in the H7-HA1 antigen group， with P/N ratios decreasing as D67 concentrations diminished. HI assays demonstrated specific hemagglutination inhibition only for the H7 antigen group， achieving a titer of 8log2. SPR analysis quantified the interaction kinetics， yielding an association rate of 3.99×10³ L·（mol·s）⁻¹， dissociation rate of 3.23×10^-3 s^-1， and equilibrium dissociation constant of 8.1×10^-7 mol·L⁻¹， confirming strong antigen-nanobody affinity.The H7-subtype-targeting nanobody D67 was successfully prepared and validated through a multidimensional evaluation system， demonstrating its high-efficiency and specific binding to H7-HA1. This work provides a technical foundation for developing rapid detection methods for H7-subtype avian influenza.

In order to understand the drug resistance and virulence gene distribution of Riemerella anatipestifer isolates in some areas of China， K-B method was used to determine the sensitivity of 15 serotypes of R. anatipestifer to 10 commonly used antibiotics， and PCR technology was used to detect 16 drug resistance genes and 16 virulence genes of different serotypes of R. anatipestifer isolates. The results showed that the resistance rates of amoxicillin and ampicillin were 93.33% and 80%， respectively. The detection results of drug-resistant genes showed that the detection rates of tet（X） gene of tetracycline， floR gene of amide alcohol and aph（3'）-Ⅱ gene of aminoglycoside were 93.33%， 80% and 73.33% respectively. The results of virulence gene detection showed that tctR， TbdR1， TR， CAMP and AS87-0405 had the highest detection rates， which were 86.67%， 86.67%， 80%， 73.33% and 73.33% respectively. These isolates are sensitive to tetracyclines， quinolones and amide alcohols， and have high resistance to β-lactams. At the same time， these isolates carry a variety of virulence genes， which may indicate that they have strong virulence. The above results provide some reference for the prevention and control of R. anatipestifer in some areas of China.

This study aimed to establish a cost-effective duplex TaqMan real-time quantitative PCR （qPCR） assay for the rapid detection of Brucella infection in animals and animal products， and to differentiate B.abortus from other Brucella species. This method provides a scientifically valid diagnostic tool for distinguishing currently used vaccine strains and novel vaccines under development. Specific primers and TaqMan probes targeting the galU and Omp31 genes were designed based on GenBank sequences. Recombinant plasmids were constructed. The assay's specificity， sensitivity， and repeatability were rigorously evaluated. Clinical serum and tissue samples from animals with brucellosis were tested. A duplex TaqMan qPCR assay for Brucella detection was successfully developed. The limit of detection （LOD） for recombinant plasmid standards was 1.93×10⁰copies·μL^-1. The assay exhibited no cross-reactivity with other Gram-negative bacteria. Both intra-assay and inter-assay reproducibility were excellent， with coefficients of variation （CV） consistently below 2%. Testing of 156 samples （including laboratory-prepared and clinical specimens） revealed a positive agreement rate of 69.75% compared to BCSP31-PCR. Furthermore， the duplex TaqMan qPCR demonstrated significantly higher sensitivity （100%） than conventional PCR （69.75%） and the RBPT （58.65%）. The established duplex TaqMan qPCR assay provides a robust technical foundation for the clinical differential diagnosis， epidemiological surveillance， and eradication programs of brucellosis.

In recent years， diarrhea in cattle has been spreading in cattle farms with a high mortality rate， causing economic losses. This experiment aims to isolate and identify Shigella flexneri， which causes diarrhea in a Beijing cattle farm， and to clarify the biological characteristics and genomic features of the pathogen’s serotype， drug resistance， and pathogenicity. In this study， fecal samples from diarrheal cattle were collected for bacterial isolation and purification， 16S rRNA amplicon sequencing analysis， virulence gene detection， and whole-genome sequencing of isolated strains. The results showed that one strain of Shigella flexneri Fc was identified through bacterial isolation and purification， and PCR identification. Whole-genome sequencing revealed that the Shigella flexneri Fc strain has a genome size of 4.98 Mb and a GC content of 50.76%. It contains 91 tRNA genes， 7 23S rRNA， 7 16S rRNA， 8 5S rRNA， 283 misc_RNA， and 97 carbohydrate-active enzyme genes. TVBD annotation analysis identified 1 363 transporter genes； CARD annotation analysis identified 80 resistance genes； VFDB and PHI-base annotation analysis identified 1 410 potential virulence factor-related genes and 2 052 phenotypic mutation genes. Phylogenetic tree analysis revealed that Shigella flexneri is closely related to Shigella flexneri 29903， belonging to the same branch. This study completed the isolation and identification of a bovine-origin Shigella flexneri strain and whole-genome sequencing analysis， providing a theoretical basis for the prevention and control research of shigellosis.

The aim of this study was to understand the epidemic characteristics and drug resistance of Clostridium perfringens in Xizang’s Tibetan pig population， and to provide theoretical basis for disease prevention and control. In this study， 273 Tibetan pig fecal samples collected from 9 districts and counties in Xizang from 2021-2024 were isolated and identified by bacterial isolation and purification， PCR identification， drug sensitivity test， and drug resistance gene detection and other methods， and the toxin typing and drug resistance phenotype were determined. The results showed that a total of 180 strains of C. perfringens from Tibetan pigs were obtained， with an isolation rate of 65.93% （180/273）； According to toxin gene testing， all strains were identified as type A C. perfringens， with 142 strains containing the cpb2 gene. The results of antibiotic susceptibility tests showed that the isolated strains had high resistance to 6 drugs， including gentamicin， streptomycin， erythromycin， polymyxin B， sulfamethoxazole， trimethoprim. 97.22% （175/180） of the isolated bacteria were multidrug-resistant strains. The proportion of strains resistant to 4-6 types of antibiotics is 71.67% （129/180）. In addition， the isolated strains carried 12 resistance genes， with a detection rate of 23.08%（12/52）. The detection rate of the aminoglycoside resistance gene aadA was the highest， with a detection rate of 85.00%（153/180）. This study clarified the prevalence of C. perfringens from Tibetan pigs in Xizang， providing data support for taking effective prevention and control measures.

The purpose of this study was to prepare feline PD-L1 antigen and screen monoclonal antibody， and preliminary application was carried out in detection and diagnosis of canine and feline oncology diseases. In addition， feline derived chimeric single chain variable Fragment-Feline Fragment crystallizable （scFv-fFc） was prepared， which provided a tool for the treatment of cat tumor in future. The PD-L1 gene of feline was amplified by PCR and prokaryotic expression recombinant plasmid PET-MPD-L1 was constructed， and the antigen of PD-L1 was prepared by expression with host BL21（DE3）. After immunization with mice， cell was fused， and an ELISA was established to screen antibody produced by hybridoma cells. After subcloning three times， the cell line of MPD-L1 hybridoma were established， subtypes were identified， and the ascites were prepared， and titer of the ascites was determined. Characteristics were determined by Western blot and immunohistochemistry （IHC）. Total RNA was extracted from the hybridoma cells， and the heavy chain variable region （VH） and light chain variable region （VL） genes were amplified by RT-PCR， which were compared with the antibody light and heavy chain genes in the IMGT database for confirmation. RNA from peripheral blood of a cat in clinic was extracted， and the Fc gene of IgG1 was amplified by RT-PCR. The recombinant plasmids of pFast-MPD-L1-scFv and PFAST-MPD-L1-scFv-fFc were constructed by splicing VH and VL into scFv and scFv-Fc into scFv-fFc by landing PCR， then expressed in the baculovirus expression system. The results showed that feline PD-L1 was highly expressed in the supernatant of cultures and the purified protein could be used antigen for immunization. The monoclonal antibody of 2A5A2F4D7 belonged to IgG 2a subtype， and the light chain is subtype κ. The titer of the supernatant， ascites was 1：3200， 1：102400 respectively. Western-Blot results showed that monoclonal antibody 2A5A2F4D7 reacted with expressed feline PD-L1， and IHC results showed that the monoclonal antibody secreted by 2A5A2F4D7 hybridoma cells can recognize PD-L1 of tumor cells both canine and feline. The VH and VL genes amplified were consistent with genes in the IMGT database， with 4 framework regions and 3 hypervariable regions. The recombinant plasmids of pFast-MPD-L1-scFv and PFAST-MPD-L1-scFv-fFc were constructed successfully and expressed in the supernatants of insect baculovirus expression system. The prepared feline PD-L1 monoclonal antibody have certain value in the detection and prognosis of canine and feline tumors， while scFv-fFc might hold great potential for application in the treatment of tumors in canine and feline.

To establish a diagnostic ELISA method for distinguishing RHDV infection and vaccination， the RdRp proteins of RHDV1 and RHDV2 were expressed by prokaryotic expression system. And these two soluble RdRp proteins were successfully purified. RdRp protein was used as coated antigen， an indirect ELISA method was established to detect serum antibody against RdRp. After purification and restriction enzyme digestion， the RdRp protein without tag was obtained with a size of 57 ku. Western blot analysis confirmed that both RdRp proteins reacted specifically with RHDV1 or RHDV2 infection sera. And there was no difference between the types of RdRp proteins. So RHDV2-RdRp was selected as a coating antigen at a coating concentration of 2.5 μg·mL^-1. The optimal serum dilution was 1∶100 and the incubation was 60 min at 37 ℃. The optimal dilution of enzyme-labeled antibody was 1∶10 000. The cut-off value was 0.225. It was proved that the ELISA method has good specificity and sensitivity. The coefficient of variation in both intra-batch and inter-batch repeatability test was less than 10%， which indicating a good stability. The samples after RHDV challenge and the serum samples after genetic engineering vaccine immunization were tested， and the results showed that RHDV infection can induce the production of serum antibodies against RdRp protein， but the serum tests after genetic engineering vaccine immunization were negative. In this study， the ELISA method based on RHDV-RdRp protein can distinguish between genetic engineering vaccine immunity and RHDV infection， which provides an effective detection method for clinical screening of RHDV infection.

This study aimed to understand the histopathological changes of goats infected with Mycoplasma ovipneumoniae. An infection group and a control group （5 goats each） were established. Serum， nasal swabs， lung tissue， trachea， and bronchi were collected from each group. Mycoplasma ovipneumoniae-specific antibodies in serum were detected by ELISA， Mycoplasma ovipneumoniae-specific nucleic acids in nasal swabs were identified by PCR， and histopathological examination was performed on lung， tracheal， and bronchial tissues. The results showed that there were varying degrees of cellulosic pneumonia， liver hepatization and carnification in the lung tissue during the autopsy； There were Mycoplasma ovipneumoniae antibodies in the sample serum； The PCR amplification produced specific bands； The lung tissue， trachea and bronchus showed different degrees of pathological characteristics. Goats infected with Mycoplasma ovipneumoniae pneumonia showed obvious histopathological changes， including lung inflammation， the production of serologicalantibodies and positive detection of Mycoplasma ovipneumoniae nucleic acids in lung tissues. These results provide a strong scientific basis for the diagnosis and research of Mycoplasma ovipneumoniae in goats.

The purpose of this study was to investigate the therapeutic effects of deer blood polypeptide （ARPBP） in the treatment of androgenic alopecia and to reveal underlying. By using ARPBP to treat testosterone （TES）-induced C57BL mouse alopecia model， HE staining， immunohistochemical staining qPCR and Western blot experiments were performed on the skin tissue of its back. Results showed that it significantly promoted hair regeneration， and the efficacy exhibited a concentration-dependent manner. Histological analysis showed that the skin thickness， follicle density and diameter in TES group were significantly reduced， which was consistent with the pathological characteristics of androgenic alopecia. After the treatment with ARPBP， the skin thickness and parameters of hair follicle shape in the low-dose ARPBP treatment group （15 mg·mL^-1） recovered nearly to the physiological level， and the hair density and area of hair coverage were better than those of the high-dose treatment group （75 mg·mL^-1）， indicating that the low-dose ARPBP group could reverse the testosterone induced hair follicle miniaturization more effectively. Immunohistochemical results showed that low-dose （15 mg·mL^-1） ARPBP significantly up-regulated the expression of follicle proliferation markers KI67 and PCNA， and enhanced the nuclear localization signal of upstream factor LEF in Wnt/β-catenin pathway. Western blot analysis further confirmed that low-dose ARPBP significantly reversed the inhibitory effect of androgen on LEF1 protein expression， and inhibited the activation of androgen on BMP4 signaling pathway. This study revealed the effective dose-dependent effect of ARPBP in the treatment of androgen alopecia. The mechanism underlying these achieved results could be via promoting the transition of androgen-induced hair follicles from resting period to growth period by activating LEF1-Wnt/β-catenin signaling pathway and inhibiting BMP signaling pathway， thus promoting hair regeneration. We believe our study has laid the foundation for the development of precision medicine strategies based on natural peptides.

The aim of this study was to explore the effect and molecular mechanism of peroxisome proliferator-activated receptor α （PPARα） on skeletal muscle development. We utilized young （6-8 weeks）， adult （3-4 months）， and old （18-20 months） mice （n=8/group） to examine the expression of PPARα in skeletal muscle during development. The role of PPARα in skeletal muscle development was further investigated using a whole-body knockout mouse model. HE staining was used to observe the morphological differences of gastrocnemius muscle of mice of different ages， and immunofluorescence staining was used to detect the expression changes of P21 and P53 in gastrocnemius muscle of mice of different ages to determine the age difference of mice. The expression of PPARα in skeletal muscle was detected by common PCR， and the expression of PPARα in gastrocnemius muscle of mice of different ages was detected by Western blot， real-time quantitative PCR （qRT-PCR） and immunofluorescence staining （IF）. qRT-PCR， Western blot and immunofluorescence staining were used to detect the expression of MyoD， MyoG and Pax7 in gastrocnemius muscles of WT and PPARα knockout mice （PPARα^-/-）. Western blot was used to detect the expression of PPARα downstream signaling pathways AMPK and P38 MAPK. The results showed that PPARα was expressed in the skeletal muscle of mice at all developmental stages， and its expression level gradually decreased with age. Immunofluorescence staining showed that PPARα protein was widely distributed in the nucleus and cytoplasm of mouse gastrocnemius muscle. Further studies found that PPARα gene knockout led to a significant decrease in the expression of MyoD， MyoG and Pax7 in gastrocnemius muscle， while the phosphorylation levels of AMPK and P38 increased significantly.

The purpose of this study is to establish an efficient method for purifying plasminogen from pig blood. In this study， sPLG was purified from pig blood using lysine affinity chromatography combined with size exclusion chromatography. Meanwhile， recombinant swine tissue plasminogen activator （st-PA） and staphylokinase （SAK） were expressed in Escherichia coli. Then， st-PA was purified by refolding of inclusion bodies， and SAK was purified by nickel column affinity chromatography combined with size exclusion chromatography. The activities of the prepared sPLG， SAK and st-PA were evaluated by a plasmin-specific substrate hydrolysis assay， a fibronectin degradation test， and an in vitro pig blood clot dissolution assay. The results showed that sPLG was highly purified by the method established by this study. Approximately 50 mg of pure sPLG was obtained from 250 mL of pig blood plasma. The purified sPLG could be activated by st-PA or SAK， and the resulting plasmin could then cleave the plasmin-specific substrate， degrade fibronectin， and lyse pig blood clots in vitro. In conclusion， this study established an efficient method for the preparation of sPLG， st-PA and SAK. In addition， the complete plasminogen activity of sPLG was verified using st-PA and SAK as well. This study provide essential materials for research on the mechanisms by which pathogens invade pigs via sPLG.

The purpose of this study was to understand the prevalence and drug resistance characteristics of Klebsiella pneumoniae in dairy cow mastitis in Xinjiang. Two thousand and eighty-three milk samples of dairy cows with clinical mastitis or subclinical mastitis were collected from 15 large-scale dairy farms in 9 areas of intensive dairy farming in Xinjiang. Klebsiella pneumoniae in the samples was isolated and cultured， Gram stained. PCR and 16S rRNA sequencing were conducted to identified the isolated strains， and the drug resistance of the isolated strains was detected by micro-broth dilution method. The results showed that 266 strains of Klebsiella pneumoniae were isolated from the milk samples， and the isolation rate was 12.8% （266/2 083）.There was no significant difference in the isolation rate of Klebsiella pneumoniae between clinical mastitis and subclinical mastitis （P>0.05）. The sensitivity of 266 isolates to 16 antimicrobial agents and the production of extended-spectrum β-lactamases （ESBLs） were determined by broth microdilution method. The results showed that the resistance rates of the isolates to tetracycline， ceftiofur， cefepime， cefotaxime and cefazolin were high （23.7%-41.0%）. And 16.9% （45/266） of the isolates were multidrug-resistant bacteria， and 6.4% （17/266） of the isolates produced ESBLs. The results suggest that the average separation rate of mastitis Klebsiella pneumoniae in 15 large-scale dairy farms in Xinjiang is at a relatively low level in the whole country. The isolated strains had strong resistance to tetracycline and cephalosporin antibiotics. This study provided a basis for mastering the epidemiological characteristics of Klebsiella pneumoniae in dairy cow mastitis and guiding clinical medication.

The formation of green eggshell characteristics in chickens is associated with the high expression of Solute Carrier Organic Anion Transporter Family Member 1B3 （SLCO1B3） in eggshell glands initiated by the endogenous retrovirus EAV-HP. As a core metabolic organ， SLCO1B3 is highly expressed in the chicken liver. The insertion mutation of EAV-HP downregulates the expression of SLCO1B3 in the chicken liver. Metabolomics studies of chicken liver during this process have not been reported. This study took the Luhua chicken as the research object. Using the green-shelled egg genotypic primers， it was determined that the frequency of green-shelled eggs produced in 38 Luhua chickens was 47.4%. Both the integration of EAV-HP^+/+ and EAV-HP^+/- significantly reduced the transcriptional level of SLCO1B3 in the liver of Luhua chicken （P<0.05）， especially the effect of the integration of EAV-HP^+/+ was especially significant. A total of 80 differential metabolites were screened out by metabolomics， among which 30 were up-regulated and 50 were down-regulated. The pathways through which metabolites are enriched mainly involve biological processes such as taurine and hypotaurine metabolism， the citric acid cycle （TCA cycle）， carbohydrate metabolism， ether lipid metabolism and alanine， aspartic acid and glutamic acid metabolism. The research results revealed the effect of down-regulation of SLCO1B3 expression caused by EAV-HP insertion mutation on liver metabolites and metabolic pathways in chickens， providing research ideas and directions for fully understanding and utilizing endogenous retroviruses to improve the production performance of chicken flocks.

Non-coding small RNAs （microRNAs） can be involved in the innate immune response of bovine mammary glands and can serve as potential biomarkers for pathogen infection of host cells and bovine mastitis. However， the expression pattern of microRNAs in bovine mammary epithelial cells （MAC-T） after Candida krusei infection remains unclear. This study aims to analyze the differentially expressed microRNAs （DEmicroRNAs） in MAC-T induced by Candida krusei and their functions， providing a basis for revealing the marker microRNAs of Candida krusei infection in MAC-T and for subsequent research on the regulatory mechanism of microRNAs in regulating the immune response of host cells. Utilizing RNA-Seq sequencing technology and bioinformatics methods， microRNA sequencing， DEmicroRNA analysis， and GO and KEGG functional enrichment analysis were conducted on MAC-T cells after infection with Candida krusei （infection multiplicity=1）. A total of 1 465 microRNAs were detected in MAC-T cells of both the normal group and the infection group. Compared with the normal group， 16 microRNAs were significantly upregulated and 7 were significantly downregulated in the infection group. TargetScan and miRanda software were used to predict the target genes of the 11 microRNAs with extremely significant differential expression， and a total of 6 739 target genes were predicted. The results of GO and KEGG functional enrichment analysis indicated that the 11 microRNAs with extremely significant differential expression could regulate bovine mammary gland inflammation through immune-related signaling pathways. Further analysis revealed that the significantly downregulated bta-miR-2377 and the significantly upregulated bta-miR-2285i might participate in the MAPK， NF-κB， and Toll-like receptor signaling pathways through potential target genes， thereby regulating the occurrence and development of host cell inflammation. Twenty-three DEmicroRNA are obtained in Candida krusei induced bovine mammary epithelial cells， which may regulate the occurrence and development of inflammatory response in bovine mammary epithelial cells through potential target genes， and provide a scientific basis for revealing the pathogenic mechanism of microRNA regulating Candida krusei induced bovine mastitis.

Based on network pharmacology and molecular docking technology， the key targets of the main active components of Portulaca oleracea L. （POL） to inhibit mastitis in dairy cows were explored， and the possible mechanism of action was verified by in vitro cell experiments. The TCMSP database was used to search the active ingredients and corresponding targets of POL. The GeneCards database and OMIM database were used to search the disease targets of dairy cow mastitis， and the intersection and integration of the active ingredient targets of POL were carried out， and the PPI network was constructed. DAVID database was used for GO function enrichment analysis and KEGG pathway enrichment analysis， and AutoDock software was used for molecular docking verification. Finally， the effect of purslane extract on bovine mammary epithelial cells was determined by CCK-8 method. LPS induced MAC-T to construct an in vitro inflammation model. RT-qPCR was used to detect the expression of key targets， IL-17 signaling pathway and inflammation-related factors. Results showed that a total of 10 active components and 188 corresponding targets of POL were screened. A total of 2 495 targets related to mastitis in dairy cows were screened from the GeneCards and OMIM databases， and a total of 40 co-expressed targets were found through the Venn platform. Ten key targets such as ALB， TNF， IL6， IL1 B， and MMP9 were obtained through the PPI network， involving AGE-RAGE， lipid and atherosclerosis， cancer， IL-17， PI3K-AKT and other signaling pathways. In vitro cell experiments showed that purslane could increase the content of ALB in MAC-T， and provide IL-17 signaling pathway to down-regulate the transcription of inflammatory factors MMP9， TNF-α， IL-6， IL-1β， IL-8 and IFN-γ genes， and up-regulate the expression of anti-inflammatory factor IL-10 gene. This study revealed that purslane can inhibit the release of inflammatory factors by inhibiting the IL-17 signaling pathway， thereby inhibiting the inflammatory response of dairy cow mammary gland.

The aim of this study was to investigate the target and and molecular mechanism of action of berberine （BBR） against Staphylococcus aureus （S. aureus） infection. This experiment first screened common targets of BBR and S. aureus infection based on network pharmacology， constructed a PPI network， and performed GO/KEGG enrichment analysis. The binding activity of BBR and core targets was verified through molecular docking. Finally， a mouse infection model was constructed to observe pathological changes in the liver and spleen using tissue sections， and qPCR was used to validate the expression levels of the selected target genes’ mRNA. The results showed that： 1） A total of 109 common target points between BBR and S. aureus were successfully screened. Through network pharmacology analysis， 251 GO entries and 62 KEGG entries were ultimately obtained， mainly enriched in the MAPK， PI3K-Akt， and GnRH pathways. Molecular docking results showed that BBR had good binding energy with six proteins， including Casp3 and Jun， among the intersection targets. 2） BBR can alleviate liver tissue lesions caused by S. aureus infection； at the same time， it can significantly upregulate the expression of Casp3 mRNA and Jun mRNA in mouse liver. In summary， this study preliminarily identified Casp3 and Jun as potential targets for BBR’s anti-S. aureus activity. Additionally， a mouse model of S. aureus infection was established to further confirm that BBR can alleviate liver and spleen lesions by regulating the mRNA expression of Casp3 and Jun. The findings of this study provide a theoretical basis for the development and application of BBR as an anti-S. aureus infection drug.

The aim of this study was to investigate the effect of Radix dichroapowder （RDP） on intestinal mechanical barrier at different developmental stages of chicks infected with coccidia. The experiment was divided into 6 groups， which were administered on the day before the challenge， the day of the attack， and the 2nd， 3rd， 4th and 5th days after the attack.Each experimental group included Group I （Healthy control group）， Group Ⅱ （Infection control group） and Group Ⅲ （RDP recommended dose group）. At the end of the administration， the chick cecum of each group were collected to make pathological sections. The immunohistochemical analysis of intestinal tight junction proteins occludin and claudin-1 were performed by Pro PLUS 6.0 image software， and the secretion of intestinal goblet cells and mucin were determined.The results showed that compared with Group Ⅰ， the expression levels of occludin protein， claudin-1 protein， and intestinal mucin in Group Ⅱ and Group Ⅲ were significantly reduced （P<0.05）， and the number of goblet cells was significantly decreased （P<0.05）. Compared with Group Ⅱ， the expression of the above three proteins of Group Ⅲ were significantly improved （P<0.05）， and the number of goblet cells were increased from the day before the challenge to 3 days after the challenge. However， with the continuous development of coccidia in chicks and the delay in administration time， the above three proteins in Group Ⅱ and Group Ⅲ were markedly decreased on the 4th and 5th day of challenge （P>0.05）， and the goblet cells disapeared.In summary， RDP can reduce the damage of coccidia to the host intestinal tract， improve the secretion of intestinal barrier protein， and reduce the damage of coccidia to the intestinal structure； the earlier the drug is administered after the challenge， the better the improvement of intestinal damage caused by coccidia.

This study aimed to explore the extraction method of saponins from the stems and leaves of Panax notoginseng （PN） and investigate its effects on the growth performance， diarrhea index and intestinal health of piglets challenged with lipopolysaccharide （LPS）. Single-factor experiments were conducted and ultrasonic extraction method was used to optimize the extraction conditions of total saponins from Panax notoginseng stems and leaves， such as ultrasonic time， liquid-to-solid ratio， and ethanol volume fraction. The experiment selected 24 “Duroc × Landrace × Large White” piglets with an initial body weight of （7.13±0.74） kg. The piglets were randomly divided into a control group （basic diet）， an LPS group （basic diet）， a DEX （dexamethasone） + LPS group （basic diet） and a PN + LPS group （basic diet + 0.4% Panax notoginseng stem and leaf extract）， with six piglets in each group. On the 28th day of the experiment， serum， colon tissue and colon chyme samples were collected from piglets to test serum biochemical and colon inflammation-related indicators， the composition of colon microbiota were analyzed and colon tissue morphology were observed. The results showed as follows： 1） The extraction yield of total saponins was the highest at solid-liquid ratio of 1∶25（g∶mL）， ultrasonic time of 1.5 h and ethanol volume fraction of 60%. 2） Compared with the LPS group， the feed intake of piglets in PN treatment was significantly increased （P<0.05）， and the diarrhea index was decreased （P=0.06）. 3） Supplementation of PN can effectively improve the morphology of colon tissue induced by LPS and prevent mucosal injury； 4） PN pre-feeding reduced the abundance of Prevotella_9 in the colon of piglets challenged with LPS （P<0.05）. 5） PN treatment could promote the expression of IL-4 at mRNA level （P<0.05） and reduce the expression of TNF-α at mRNA level （P<0.05）. In summary， add 0.4% PN in dietary can improve the growth performance of piglets， alleviate the damage of intestinal morphology caused by LPS， regulate intestinal microorganisms and alleviate intestinal inflammation， thereby improving the diarrhea of piglets.

The aim of this study was to evaluate the accuracy of the early warning model for metritis in dairy cows established by electronic nose detection. The detection of volatile organic compounds （VOCs） in feces and blood samples of 50 healthy dairy cows and 22 metritis cows before onset by electronic nose， preliminary analysis of data by orthogonal partial least squares discriminant analysis （OPLS-DA） model. The training set and test set were divided according to 7∶3， the early warning model was established and the performance of the electronic nose in predicting metritis was evaluated. The results showed that， the feces and blood of healthy and metritis dairy cows were clearly distinguished and clustered respectively. In this study feces are the best sample source for establishing an early warning model. Five different machine learning algorithms， namely decision tree （DT）， random forest （RF）， K-nearest neighbors （KNN）， eXtreme gradient boosting （XGBoost）， and linear discriminant analysis （LDA）， were used to build models. Predictive efficiency is analyzed in conjunction with model evaluation metrics and receiver operating characteristic curves （ROC）. It was found that the test set accuracy （ACC） reached 0.88、0.96、0.88、0.91、0.98. Area under curve （AUC） was 0.86、0.98、0.95、0.98 and 1.00. As a result， the RF and LDA models perform the best in terms of predictive performance. The electronic nose has a high accuracy in predicting the occurrence of uterine infections. In conclusion， the detection of fecal VOCs of dairy cows before onset by electronic nose can achieve the purpose of early warning of metritis inflammation and has a great application prospect in the early diagnosis of dairy cow diseases.

Streptococcus suis （SS） is one of the important pathogens causing serious economic losses in the pig farming industry. Here， we developed a novel rapid detection method for detecting SS and serovars 2， 7 and 9 based on multienzyme isothermal rapid amplification （MIRA） technology. The MIRA assays were validated for detection of SS and it serovars within 5 to 30 min at 20-41 ℃， with relative higher specificity and sensitivity. There are 100% agreement between our MIRA and PCR methods in the detection of clinical samples. Our results showed that the MIRA was a useful diagnostic method for rapid diagnosis of SS infection.