Muscle cells (also known as muscle fibers) are the basic unit of skeletal muscle, accounting for about 50% of the body of livestock and poultry, and are closely related to meat production performance and bone protection of livestock and poultry. They play an important role in regulating the metabolism and endocrine of livestock and poultry, and also provide power for the movement of livestock and poultry. Skeletal muscle is a relatively complex tissue, and the basic unit of these tissues are muscle cells. Skeletal muscle requires a variety of types of mononuclear and multinucleated cells to interact during development, which is the key to the formation of high-quality meat. In recent years, with the rapid development of science and technology, there are more and more comprehensive techniques for identifying skeletal muscle development-related cells, and single cell sequencing technology is most widely used. Its application provides technical support for the study of cell types and related cell development heterogeneity of skeletal muscle, and is of great significance for the study of meat quality. This paper reviews the identification of cells related to skeletal muscle development by cell morphology observation, molecular markers, immunohistochemistry, immunofluorescence, in situ hybridization, and single cell sequencing, and summarizes the marker genes of cells related to skeletal muscle development, in order to understand the structure and function of skeletal muscle. It provides a reference for exploring the mechanism of skeletal muscle development, provides a theoretical basis for the study of meat quality, and also has important significance and practical value in individual breeding of different varieties.

Single-cell sequencing is a cutting-edge technology for high-throughput sequencing of genomes, transcriptomes, and epigenomes of individual cells, offering a powerful tool to characterize individual cells and elucidate interactions between cells, and has provided many new insights in tumorigenesis and stem cell biology. Mammalian skeletal muscle is a heterogeneous tissue dominated by myofibers, including various kinds of cells such as muscle satellite cells, fibro-adipogenic progenitors and macrophages, et al. Benefiting from the rapid development of single-cell sequencing technology, the understanding of the composition of cell populations and the interactions between different kinds of cells within skeletal muscle has gradually expanded. Here, the biological meanings of the interaction of muscle satellite cells with the niche cells on the growth, metabolism and regeneration of skeletal muscle has been reviewed, with the aim to provide new ideas to improve the growth rate and meat quality of meat-producing animals.

Coronary heart disease (CHD) is a common cardiovascular disease that seriously affects human health worldwide. Considering its complex pathogenesis and the difficulty of treatment, the study of CHD has been paid much attention. In recent years, animal models have played a key role in the study of cardiovascular diseases. The cardiovascular system of pigs is similar to that of humans in terms of anatomical structure and pathophysiological mechanism, so the model pig has been widely recognized as an excellent model in the study of atherosclerosis. By referring to the diagnostic indicators and risk factors of human CHD, this manuscript aims to explore the evaluation criteria and construction methods of pigs with CHD model similar to human, so as to provide a good experimental model for pathogenesis and clinical application studies related to CHD. This review will lay the foundation for the development of new diagnosis and treatment methods for CHD.

Oxidative stress is a state of excessive reactive oxygen species produced by changes of intracellular and extracellular environment, which plays an important role in the regulation of uterine function. In recent years, studies have shown that oxidative stress can regulate the function of the uterus by affecting reproductive hormones, immune responses, regulating uterine environment and cell signaling. In addition, excessive oxidative stress can impair maternal and placental function, closely related to reproductive diseases such as endometrial carcinoma, pre-eclampsia, gestational diabetes mellitus, and intrauterine growth retardation. This paper reviewed the research progress on the regulation of oxidative stress on the uterine function of female livestock in recent years, in order to better understanding the effect of oxidative stress on the uterine function of female animals, providing new theoretical guidance and practical application for improving the reproduction efficiency of female livestock.

The reproductive performance of cows is the basis for the development of cattle industry. As a multifunctional hormone, melatonin interacts with MT1 and MT2 receptors, reduces the levels of pro-inflammatory cytokines (IL-1β, TNF-α, IL-6), enhances the levels of anti-inflammatory cytokines (IL-10, IL-1Ra), and promotes the expression of antioxidant enzyme genes (Sod、Cat、Gpx、Gpx4). Additionally, it modulates autophagy and mitochondrial autophagy-related genes expression, alters the composition of rumen and vaginal microbiota, thereby influencing reproductive performance in bovine follicular cells, granulosa cells as well as embryonic development alongside estrus cycles, ovulation processes, and pregnancy outcomes. Consequently, this article reviews the current status and mechanisms underlying exogenous melatonin's role in regulating cow reproduction both in vivo and in vitro while providing a theoretical framework for its rational application to enhance reproductive efficiency in cattle.

The immune response of dairy cows is one of the key factors influencing early pregnancy embryonic loss. The establishment of pregnancy and placental development rely on the coordinated actions of immune cells (such as Tregs, macrophages, and NK cells) and immune regulatory factors, which regulate the uterine receptivity to the embryo, embryo implantation, and maternal immune tolerance. Thus, a comprehensive understanding of the immune response processes at various stages of early pregnancy in cows is essential for improving pregnancy success rates. This paper provides a detailed analysis of the immune regulation mechanisms during artificial insemination and early pregnancy in cows. It examines the balance and complex dynamic regulation between pro-inflammatory and anti-inflammatory factors in the maternal system.This research offer theoretical support for ensuring successful pregnancy through key stages including fertilization, blastocyst hatching, pregnancy recognition, and embryo implantation, aiming to enhance reproductive efficiency in dairy cows.

In recent years, given the rapid increase in population and the frequency of international trade, the risks associated with emerging infectious diseases caused by unknown viral agents have heightened, posing threats to human health, animal husbandry, and public health. Therefore, the ability to rapidly and accurately monitor and detect emerging viruses is among the most effective strategies for controlling and preventing the outbreak of infectious diseases. While traditional methods for detecting virus are simple to operate and require minimal technical expertise, they are limited in terms of accuracy and timeliness. Unknown viruses can be directly detected from clinical samples by using appropriate molecular biological methods and sequencing technology, which is of great significance for the rapid identification of pathogens and the timely discovery of new viruses. This article reviews the basic principles, evolution and application fields of the methods and sequencing technologies used in the detection of emerging viruses in recent years. It also analyzes and compares their differences, advantages and disadvantages, offering valuable reference for the readers.

Glaesserella parasuis (GPS) is one of the important pathogenic bacteria in pigs, and serotype identification has been a long-standing "bottleneck" in the field of GPS research since it was identified as the causative agent of Glasser's disease in pigs in 1910. In 1992, the gel immunodiffusion(GID) typing method based on GPS heat-stable antigens classified GPS as 1-15 for the first time, but about 25% of the strains were not typed, and the composition of the typed antigen was not clear at that time. In 2003, an indirect hemagglutination assay (IHA) typing method for GPS-based "saline extract" antigen was established, and its sensitivity and typing rate were higher than those of GID, but about 15% of the strains were still untypeable. The typing results of IHA and GID methods are generally identical, so it is possible to determine whether the typed antigens are based on the same GPS surface polysaccharide composition, but it is still not certain whether it is a capsular polysaccharide, or LPS, or even other polysaccharide species. In 2013, the synthetic gene cluster of GPS serotype 1-15 capsular polysaccharide was successfully analyzed, which confirmed that the essence of serotype antigen formation was capsular polysaccharide. In 2015, Howell et al. designed primers based on the specific target genes of GPS capsule, and established a PCR typing method for GPS (H-PCR), but it could not distinguish serotype 5 and 12. In 2017, Jia et al. also established a set of PCR typing methods (J-PCR) for specific target genes based on GPS capsule, which could identify serotypes 5 and 12. The combination of the two PCR typing methods was able to type almost all GPS strains, and their consistency with the GID and IHA methods was verified from molecular biology, and the antigen basis of the three typing methods was finally confirmed to be GPS capsule. The PCR typing method has the advantages of simple operation, fast speed and low cost, and has successfully solved many problems in GID and IHA serotyping methods, and has been widely used. In this paper, we systematically reviewed the history of the establishment and application of GPS GID, IHA and PCR typing methods, as well as the discovery process of the same antigen basis, in order to provide systematic theoretical knowledge for the immunological material basis and principle of the three GPS typing methods, and to provide new ideas for the research and development of Glasser's disease prevention and control technology.

West Nile fever (WNF) is an infectious zoonotic ailment engendered by the West Nile virus(WNV), predominantly disseminated via mosquito bites. The clinical presentation of this malady includes symptoms like fever, rash, and lymphadenopathy, with a potential to affect the central nervous system, leading to encephalitic manifestations. Humans demonstrate considerable vulnerability and a relatively elevated mortality rate associated with this disease. Presently, the absence of efficacious vaccines or specific therapeutic agents for WNF necessitates the importance of prompt, accurate, and timely diagnostic procedures for effective patient management and curtailing the swift spread of epidemics. This review delineates the recent advancements WNV detection technologies and the evolving landscape of diagnostic methodologies. Principal etiological diagnostic approaches comprise virus isolation, RT-PCR, and isothermal amplification, whereas serological diagnostics include techniques like ELISA, immunofluorescence, and immunohistochemistry. Additionally, the advent of metagenomics, underpinned by high-throughput sequencing, has been effectively utilized in the diagnosis and exploration of WNF in recent years. The ongoing innovation in novel technologies and their integration into disease detection are pivotal in augmenting the progression of WNF detection and preventive strategies.

Multiple methods for culturing intestinal organoids from domestic animals and companion animals have been established recently. Intestinal organoids exemplify the structures and functions of intestinal epithelium, being an in vitro model somewhere in between stable cell lines and animal models. Currently, animal intestinal organoids can be applied to research on the pathogenesis and treatment of intestinal diseases, as well as to explore host-pathogen interactions. In the study of enteral nutrition and enteral immunology, intestinal organoids can be used to improve feed utilization, screen suitable additives, and promote animal performance. In addition, animal intestinal organoids have great potential in the field of human translational medicine and regenerative medicine. In this paper, the main applications of animal intestinal organoids in the past five years were reviewed, and the future research directions were prospected.

Casein is the main protein in milk, and β-casein is one of the casein proteins. A1 β-casein and A2 β-casein are two different genotypes of β-casein. Due to the difference in the position 67 of the amino acid sequence, the structure of the two proteins are different, which leads to the difference in physiological functions that are related to human health. This article introduces the differences between the structure of A1 and A2 β-casein in milk, as well as the differences in micelle assembly, chaperone activity and product gel. Simultaneously, some of the links between A1 and A2 β-casein in milk and human health are reviewed, mainly reflected in gastrointestinal symptoms, type I diabetes, cardiovascular diseases and mental diseases. In addition, the existing detection methods of A1 β-casein and A2 β-casein in milk were summarized to strengthen the understanding of A1 β-casein and A2 β-casein in milk and provide theoretical basis for the subsequent study of other manifestations in nutrition.

In order to clarify the genetic variation sites and polymorphic information of the Sushan pig population and the Berkshire pig population, the DNA samples from 43 Sushan pigs and 21 Berkshire pigs were extracted and SNP sites were detected by 50K SNP beadchip in this study. Plink software was used for principal component analysis of the SNP sites; The DetectRUNS software package was used for whole-genome ROH detection of the samples; Three methods (ROH, CLR, and iHS) were used to analyze the selection signals. A total of 42 282 SNPs were identified in Sushan pigs and 27 718 SNPs in Berkshire pigs. Both breeds were divided into 3 families. There were 2 071 ROH segments were detected in Sushan pigs with an average F_ROH value of 0.096, and 1 853 ROH segments were detected in Berkshire pigs with an average F_ROH value of 0.199. Four and 40 high-frequency ROH regions were detected in the Sushan pig and Berkshire pig populations, respectively, which were annotated to 8 and 103 genes. There were 50 significant candidate genes were identified through enrichment analysis. Additionally, three selection signal analysis methods (ROH, CLR and iHS) were used to identify selection signal regions in Sushan pigs and Berkshire pigs, which illustrated that 42 genes could be under selection. This study preliminarily revealed the genomic SNP pattern of Sushan pigs and Berkshire pigs and excavated some genes that may affect pig growth and development, meat quality, nutrition, and general disease resistance by high-frequency ROH analysis and selection signal detection, which provided a theoretical basis for the breeding and utilization of Sushan pigs and Berkshire pigs.

This study aimed to reveal the conservation status of the 4 major local pig breeds in Guangdong Province, evaluate the genetic structure for their conservation populations, and provide guidance for protection and utilization of local pig genetic resources. In 2023, a total of 488 pigs from 6 conservation farms representing the 4 major local pig breeds in Guangdong Province were sampled (92 Xinfeng Large black-white pigs, 34 Xinfeng Lantang pigs, 68 Zijin Lantang pigs, 77 Lejiazhuang Small-ear Spotted pigs, 109 Yihao Small-ear Spotted pigs, and 108 Beica Yuedong Black pigs). Samples were genotyped using a 50K SNP chip and compared with 41 pig breeds, including European wild boars, Western Commercial pigs, South China local pigs, and other Chinese local pigs, in total 2 144 individuals. After quality control, 20 590 SNP loci were retained. Genetic diversity, inbreeding status, ancestry composition and family structure analyses were conducted. The results showed that the inbreeding coefficient (F) of Xinfeng Large black-white pigs was 0.409, observed heterozygosity (Ho) was 0.181, expected heterozygosity (He) was 0.172, the total length of runs of homozygosity (ROH) was 475.81 Mb, linkage disequilibrium (LD) length was 467.88 kb, the average F_ROH was 0.212, and the population was divided into 5 families. The inbreeding coefficient (F) of Xinfeng Lantang pigs was 0.316, Ho was 0.210, He was 0.189, ROH length was 441.76 Mb, LD length was 475.78 kb, F_ROH was 0.201, and the population was divided into 4 families. The inbreeding coefficient (F) of Zijin Lantang pigs was 0.239, Ho was 0.233, He was 0.218, ROH length was 224.13 Mb, LD length was 463.53 kb, F_ROH was 0.100, and the population was divided into 5 families. The inbreeding coefficient (F) of Lejiazhuang Small-ear Spotted pigs was 0.319, Ho was 0.208, He was 0.221, ROH length was 262.62 Mb, LD length was 460.88 kb, F_ROH was 0.117, and the population was divided into 7 families. The inbreeding coefficient (F) of Yihao Small-ear Spotted pigs was 0.435, Ho was 0.173, He was 0.171, ROH length was 113.41 Mb, LD length was 418.59 kb, F_ROH was 0.051, and the population was divided into 6 families. The inbreeding coefficient (F) of Beica Yuedong Black pigs was -0.028, Ho was 0.314, He was 0.300, ROH length was 247.47 Mb, LD length was 467.88 kb, F_ROH was 0.110, and the population was divided into 5 families. Ancestry composition analysis of each conservation population showed that, except for the Yuedong Black pig population, which was still significantly genetically influenced by Western commercial pig ancestry with an average Chinese pig ancestry proportion of 69.37%, the other 4 populations had less Western commercial pig ancestry, with an average Chinese pig ancestry proportion greater than 90%. In summary, conservation farms for local pig breeds in Guangdong Province should focus more on increasing the population size and improving breeding scheme within captivity, aiming to reduce the degree of inbreeding while maintaining stable genetic integrity.

This study aimed to investigate whether pigs with a CD163 gene knockout (CD163-KO) resulting from a single base insertion in the SRCR5 domain of the CD163 gene exhibit altered susceptibility to 3 crucial bacterial pathogens compared to their wild-type (WT) counterparts and to evaluate the biosafety profile of CD163-KO pigs. This study selected a total of 34 Large White pigs, 17 CD163-KO pigs and 17 wild-type pigs, all at the age of 50 days with similar body weights and health statuses. Among them, 2 CD163-KO Large White pigs and 2 WT Large White pigs were used as blank controls without any infection treatment. None of the pigs had a history of infection or vaccination against Actinobacillus pleuropneumoniae (APP), Streptococcus suis (SS), and Haemophilus parasuis (HPS). The pigs were randomly divided into 3 groups of 5 CD163-KO and 5 WT pigs each: group A received APP serotype 1, group B received SS serotype 2, and group C received HPS serotype 13. The pigs were observed continuously for 8 days, the clinical symptoms and mortality were recorded. Upon death, the pigs were promptly necropsied to observe lesions in critical organs such as the heart, thorax, and lungs. Lung samples were collected, and bacterial DNA was extracted from the lungs for quantitative PCR analysis. The relative DNA copy numbers of the 3 bacterial species in the lungs of deceased CD163-KO and WT pigs were statistically analyzed and compared. The primary aim of this study was to evaluate whether CD163-KO pigs exhibit altered susceptibility to these 3 key bacterial pathogens compared to their WT counterparts, ultimately assessing the biosafety profile of CD163-KO pigs. Based on the clinical manifestations observed in the experimental pigs, all groups successfully contracted the respective bacterial infections, and there were no significant differences in survival rates between CD163-KO and WT pigs within each group (P>0.05). Furthermore, according to the pathological findings in the lungs of deceased pigs and the results of quantitative PCR analysis for bacterial DNA, no significant differences were detected in the relative DNA copy numbers of APP serotype 1, SS serotype 2, and HPS serotype 13 strains in the lungs between deceased CD163-KO and WT pigs (P>0.05). The findings of this study serve as robust evidence for the biological safety of CD163-KO Large White pigs, demonstrating that the knockout of the CD163 gene does not enhance the susceptibility of pigs to APP, SS, and HPS, nor does it significantly compromise their ability to resist these bacterial infections, which provides strong support for the biological safety assessment of CD163-KO pigs.

This study aimed to analyze the relationships among the flavor compound 1-octen-3-ol in chicken breast meat, fatty acids, and lipid peroxidation markers, including superoxide dismutase (SOD) and malondialdehyde (MDA). In this experiment, the pectoral muscles of 15 42-day-old white feathered broiler chickens available for purchase in supermarkets was utilized. The volatile components of the chicken meat were analyzed via gas chromatography-mass spectrometry, the fatty acid composition was analyzed through liquid chromatography-mass spectrometry/mass spectrometry, and the levels of SOD and MDA in the samples were determined using the reagent kit. The results indicated a significant positive correlation between the chicken flavor compound 1-octen-3-ol and docosaenoic acid (cis-13) (C22:1) (P < 0.05). Additionally, C22:1 exhibited significant positive correlations with 6 unsaturated fatty acids (P < 0.05), including eicosaenoic acid (cis-11) (C20:1), eicosadienoic acid (cis-11, 14) (C20:2), eicosatrienoic acid (cis-11, 14, 17) (C20:3 (n-3)), docosadienoic acid (cis-13, 16) (C22:2), neuraminic acid (C24:1), and HOMO-γ-linolenic acid (C20:3 (n-6)). In the group with high 1-octen-3-ol content, significant differences (P < 0.05) were observed in the levels of 4 fatty acids: octanoic acid (C8:0), dodecanoic acid (C12:0), heptadecanoic acid (C17:0), and γ-linolenic acid (C18:3(n-6)). And no significant correlation was observed between 1-octen-3-ol and the oxidative indicators SOD and MDA. However, SOD showed a significant positive correlation with the unsaturated fatty acids EPA (C20:5) and C20:3 (n-3) (P < 0.05). MDA demonstrated a significant negative correlation with octanoic acid (C8:0) (P < 0.05) and significant positive correlations with the unsaturated fatty acids C22:1 and C24:1 (P < 0.05). In summary, the chicken flavor compound 1-octen-3-ol arises from the oxidation of linolenic acid. Lipid peroxidation in chicken breast muscle tissue generates more unsaturated fatty acids, but the extent of lipid peroxidation does not influence the formation of 1-octen-3-ol.

In order to better protect and utilize the Ninglang Plateau chickens, the population genetic diversity and population genetic structure of Ninglang Plateau chickens conserved population were explored in this study. Whole-genome resequencing technology was used to detect single-nucleotide polymorphism (SNP) in Ninglang Plateau chickens(n=57), Daweishan Mini chickens(n=20), Dulong chickens(n=10) and Nixi chickens(n=11) populations, and population genetic diversity was analyzed by observing heterozygosity (Ho), expected heterozygosity (He), polymorphic nucleotide ratio (P_N), nucleotide diversity (Pi), and minor allele frequency (Maf), and linkage disequilibrium (LD) decay. Principal component analysis, phylogenetic tree, and population structure analysis were employed to examine the population genetic structure of different breeds. The degree of differentiation between breeds was evaluated using the fixation index (Fst). Additionally, the genetic relatedness within the conservation population of Ninglang Plateau chickens were analyzed using identity by state (IBS), G matrix, and the coefficient of inbreeding (F_ROH). The results showed that the observed heterozygosity (Ho) of the Ninglang Plateau chickens population was 0.212, which was lower than its expected heterozygosity (He) of 0.221, while the Ho values of Daweishan Mini chickens, Dulong chickens, and Nixi chickens were higher than their respective He values, indicating that the genetic diversity of the Ninglang Plateau chickens population was relatively high; LD decay analysis showed that the decay rates of the 4 breeds from fastest to slowest was Ninglang Plateau chickens, Daweishan Mini chickens, Nixi chickens, and Dulong chickens, indicating that Ninglang Plateau chickens population had the highest genetic diversity and the lowest degree of genome selection. The results of principal component analysis and phylogenetic tree showed that Ninglang Plateau chickens were divided into 3 branches. Daweishan Mini chickens exhibited significant genetic divergence from Ninglang Plateau chickens, Dulong chickens, and Nixi chickens. Population structure analysis revealed that the optimal number of clusters was K=2, with Ninglang Plateau chickens exhibiting a complex genetic background, while Dulong chickens and Nixi chickens had relatively similar genetic backgrounds. Population genetic differentiation analysis found moderate levels of differentiation between Ninglang Plateau chickens and Daweishan Mini chickens, Nixi chickens, and Dulong chickens, whereas the genetic differentiation index between Dulong chickens and Nixi chickens was lower; IBS matrix and G matrix analysis revealed that most individuals within the conservation population of Ninglang Plateau chickens were distantly related, with a few individuals showing closer relationships. The results showed that there was a moderate differentiation between Ninglang Plateau chickens and Daweishan Mini chickens, Nixi chickens, and Dulong chickens. The genetic diversity of the Ninglang Plateau chickens breeding population was relatively rich, but there was a trend of inbreeding within the conservation population. Therefore, effective breeding programs should be established, and conservation efforts should be strengthened to avoid inbreeding depression.

The objective of this study was to identify novel molecular markers and candidate genes associated with wool traits in plateau Tibetan sheep through a combination of genome-wide selected region signal detection, single nucleotide polymorphism analysis, and trait association analysis. In this study, ear tissue and wool samples were collected from 208 healthy ewes aged 3-4 years old, including 119 plateau-type ewes and 89 Euler-type ewes. Population genetic differentiation index (Fst) and base diversity ratio (Pi Ratio) were employed for genome-wide selective clearance analysis. Candidate genes were identified through functional annotation, followed by GO and KEGG enrichment analyses. Furthermore, correlation analysis between single nucleotide polymorphisms and phenotypic data was conducted using exon Sanger sequencing on a subset of 108 Tibetan plateau sheep to identify functional loci related to wool traits. The results revealed that a total of 1 084 selected regions with annotations for 1 037 candidate genes. Through functional gene annotation and literature analysis, 7 potential candidate genes related to wool traits were identified: GHR, FGFR3, MC1R, MITF, FGF5, WNT2B, and WNT5A. Notably, FGF5 (exon6:c.954C/T: p227P/P) synonymous mutation site and FGFR3 (exon6: c1092C/T: p364A/A) synonym mutation sites were found to be associated with wool fiber performance without deviation from Hardy-Weinberg equilibrium.These two genes may serve as important candidate genes for the improvement of wool traits in plateau Tibetan sheep.This study provides valuable insights into the genetic basis underlying the production of wool traits in plateau Tibetan sheep.It also offers guidance for molecular breeding techniques specific to this breed while providing a scientific foundation for the conservation and utilization of local germplasm resources.

The aim of this study was to study the genetic parameters of milk urea nitrogen and its genetic and phenotypic correlations with milk production traits (milk yield, milk protein percentage, milk fat percentage) and somatic cell score in Holstein cows in Shandong Province. In this study, we used data from 99 732 DHI records of 15 497 first-calf Chinese Holstein cows in Shandong Province between 2016 and 2022, and the effects of farm, calving year, calving season, calving age in months, and stage of lactation were used as fixed effects, and individual additive genetic effects as well as permanent environmental effects were used as random effects, the genetic parameters were estimated using the DMU software, and AI-REML combined with the EM algorithm with the repetition force model for genetic parameter estimation.The results showed that the heritability of milk urea nitrogen, milk yield, milk fat percentage, milk protein percentage and somatic cell score were 0.129, 0.252, 0.188, 0.257, 0.110, respectively, which were low to medium heritability; the repeatability was 0.132, 0.513, 0.231, 0.320, 0.339, respectively, which were medium repeatability except for milk urea nitrogen; the genetic correlation between milk urea nitrogen and milk yield, milk fat percentage, milk protein percentage and somatic cell score had genetic correlations of -0.02, 0.20, 0.04 and -0.11, respectively; and phenotypic correlations of 0.01, 0.05, 0.01 and -0.015 were near zero, respectively. The results indicate that milk urea nitrogen has a weak genetic and phenotypic correlation with milk production traits and somatic cell score. Therefore, it is feasible to select for milk urea nitrogen without adversely affecting milk production traits, as well as incorporating it into Holstein cattle breeding efforts

To accelerate the progress of molecular breeding of Chinese donkeys, this study collected whole genome resequencing data from 251 adult donkeys across 27 donkey breeds and combined it with the results of genetic variation research on important traits of domestic donkeys at home and abroad, designed a 40K liquid chip based on targeted sequencing genotype detection technology for domestic donkeys. The results showed that the variation sites (45 893 SNPs and 1 InDel) in the 40K liquid chip of the domestic donkey were distributed within the domestic donkey genome, with an average spacing of 61.8 kb. Genotyping test was performed on 210 adult Dezhou female donkeys, achieving a detection rate of 98.4%-99.2% across all samples. The average sequencing depth of the loci was 133×, and 42 575 loci had minor allele frequency greater than 0.35. The chip was used for breed identification in 20 donkey-hide samples and preliminarily verified its usability. In summary, the 40K liquid chip developed in this study, the first large-scale genotype detection tool for domestic donkeys, has the advantages of high loci density, good polymorphism, high detection rate, and strong application. It can be used for early molecular marker-assisted selection and breed identification of domestic donkeys, further improving the breeding efficiency.

The study aimed to obtain the full-length transcript and structure information of the antler tissue of Sika deer, and to further mine the functional genes that affect the antler production of Sika deer. In this study, six two-sained healthy male Dongda Sika deer with the same feeding and management conditions were used to collect antler tissues from the same parts of the deer. According to the antler weight, the antler was divided into 2 groups of high and low production with 3 replicates per group. The whole length transcriptome of antler with high and low production were sequenced using PacBio Sequel platform and Illumina platform, respectively. Combined with the next generation sequencing technology of high and low yield groups, the alternative splicing, functional enrichment and Hub genes were predicted and analyzed by SUPPA, KOBOS-I and Cytoscape tools. The effective insertion fragments of 36 074 385 bp and 32 413 962 bp were obtained in the high and low yield groups, respectively. Transcription factor annotation showed that the number of bHLH family transcripts in the high yield group was higher than that of TF_bZIP family, but the opposite was observed in the low yield group. There were 6 644 alternative splicing events in the high production group and 7 626 alternative splicing events in the low production group. COL1A1 played a major role in multiple fusion genes. A total of 207 differentially expressed genes were screened out from the two groups of samples. KEGG enrichment showed that the differentially expressed genes were mainly concentrated in the synthesis and secretion of parathyroid hormone and cholesterol metabolism pathways. Eleven Hub genes were identified, including APOB, SH3GL2, SYT1, ANGPTL4, FGF21, CACNA1E, SERPINF2, CACNB4, KLK4, LRP2, KCNA1. This study provides a new theoretical basis and research path for further functional gene identification and the development of molecular breeding strategies.

This study aimed to compare 3 quantitative polymerase chain reaction (qPCR) methods for detecting the dynamic expression of genes associated with pluripotency and histone acetylase modification in trace cells of porcine early embryo. Porcine parthenogenetic activated embryos at different stages (1-cell, 2-cell, 4-cell, 8-cell, morula and blastocyst) were collected, and the expression of genes associated with cell pluripotency and histone acetylase modification were detected by conventional RT-qPCR, cDNA pre-amplified qPCR and sample direct pre-amplified qPCR. The results indicated that the pre-amplified qPCR exhibited a stable amplification curve, and the melt curve displayed a consistent single peak, the conventional RT-qPCR produced cyclic thresholds above 35 and multiple peaks in the melt curve. Notably, target gene expression was successfully detected even after a 20 000-fold dilution of embryonic cells using pre-amplification, and gene expression at the single embryonic cells could be reliably assessed. The expression patterns of genes related to pluripotency and histone acetylase modification exhibited an initial increase followed by a decline across different stages of porcine parthenogenetic activated embryos, with the highest expression levels occurring at the genome activation stage. In conclusion, pre-amplified qPCR demonstrates superior sensitivity and accuracy, with a relatively simple operational protocol and lower costs, making it a suitable approach for gene expression analysis in trace cells of embryo. This methodology has the potential to advance the understanding for the mechanisms underlying early embryonic development.

The aim of this experiment was to study the effects of Bacillus subtilis preparation on rumen fermentation, performance, blood biochemistry, immune indicators, and meat quality in beef cattle. A completely randomized design was employed, involving 48 Simmental beef cattle in similar physical condition during the fattening period. The cattle were randomly divided into four groups: control group (fed with basic diet, CON), low-dose group (Bacillus subtilis preparation added to the basic diet at 0.3 g·kg^-1 DM, LAL), medium-dose group (Bacillus subtilis preparation added to the basic diet at 0.45 g·kg^-1 DM, LAM), and high-dose group (Bacillus subtilis preparation added to the basic diet at 0.6 g·kg^-1 DM, LAH). Each group had 4 replicates, with 3 cattle in each replicate. The pre-trial period lasted for 10 days, and the formal period lasted for 90 days. The results showed as follows: 1) Adding Bacillus subtilis preparation to the diet did not significantly affect rumen fluid pH, rumen fluid ammonia nitrogen (NH₃-N), dry matter intake (DMI), body measurements, slaughter performance, and meat quality of the experimental cattle (P>0.05). 2)The serum total antioxidant capacity (T-AOC) in the LAL group was significantly higher than that in the CON group (P < 0.05). 3) Compared to the CON group, the molar concentration of butyrate in rumen fluid was significantly lower in LAL and LAM groups (P < 0.05). Additionally, compared to CON group, the ratio of acetate/propionate in rumen fluid in the LAL and LAM groups, total protein (TP) and globulin (GLB) content in blood of the LAM and LAH groups, as well as the activity of alanine transaminase (ALT) and aspartate transaminase (AST) in blood of the LAM and LAH groups, were significantly higher (P < 0.05). 4)Compared to the CON group, the LAH group showed a significant decrease in feed/gain ratio (F/G) (P < 0.05), and the LAH group exhibited significantly higher average daily gain (ADG), triglyceride (TG) levels in blood, haptoglobin (Hp), and serum amyloid A (SAA) compared to the CON group (P < 0.05). In conclusion, Bacillus subtilis preparation can improve the rumen environment, blood antioxidant function, and immune function in beef cattle to varying degrees. The highest weight gain efficiency in cattle was observed when the addition rate was 0.6 g·kg^-1 DM.

The study aimed to estimate the maintenance requirement for essential amino acids of Guangming No. 2 broilers, and to provide a basis for the establishment of a prediction model of amino acid requirement. In trial 1, 12 Guangming No. 2 male and female were selected at 12 to 15 days of age and 31 to 34 days of age, respectively, with 6 replicates per treatment and 2 chickens per replicate. Each replicate was fed in a metabolic cage. The broilers were fed a nitrogen-free diet, and the excreta and shed feather dander of broilers were collected separately, and the ratio of endogenous nitrogen to shed dander nitrogen was calculated. In trial 2, 48 male and 48 female broilers with similar body weight (BW) were randomly divided into 4 treatment groups (12 broilers in each treatment group), and male and female broilers were fed separately in 6 metabolic cages. The four treatment groups were fed metabolic diets with different protein contents, and the excreta (including shed dander) of broilers were collected. Nitrogen deposition (nitrogen intake minus nitrogen expulsion) was calculated, a linear regression equation of nitrogen intake and nitrogen deposition was established to calculate the protein maintenance requirement of broilers. The maintenance requirement of endogenous protein and dander protein was calculated according to the ratio of endogenous nitrogen and shed dander nitrogen, and multiplied respectively by the composition of essential amino acids in endogenous protein (referring to previous data) and in shed dander protein (actual measurement) to calculate the maintenance requirements of endogenous amino acids and dander amino acids, and the sum of the two was the maintenance requirement of essential amino acids of Guangming No. 2 broilers. Experimental 1 showed that the daily nitrogen loss of Guangming No. 2 broiler was mainly due to dander shedding, which accounted for 55.9%~65.1%. There was a significant interaction between age and sex on the proportion of shed dander nitrogen to total nitrogen loss (P < 0.001), the proportion of shed dander nitrogen of male broiler was significantly lower than that of females in the early stage, but significantly higher than that of females in the later stage (P < 0.05). The second experiment showed that the intake, excretion and deposition of nitrogen increased significantly with the increase of protein content in metabolic diets (P < 0.001). The linear regression equations of nitrogen intake and deposition of male and female broilers were established in the two stages. The regression models were significant (P < 0.001), and the coefficient of determination were greater than 0.96. According to the regression equation, the protein maintenance requirements of Guangming No. 2 broilers were calculated, 2.36 and 3.16 g/kg BW^0.75 for male and female broilers at 12~15 days old per day, 2.96 and 2.56 g/kg BW^0.75 for male and female broilers at 31~34 days old per day. The utilization efficiency of dietary protein was 65.55% and 58.73% for 12~15 days old male and female broilers, 79.42% and 73.95% for 31~34 days old male and female broilers. According to the ratio of endogenous nitrogen and shed dander nitrogen obtained from experiment 1, the maintenance requirements of endogenous protein and dander protein in Guangming No. 2 broilers at different stages were calculated. Then, according to the composition of essential amino acids in endogenous protein and dander protein, the maintenance requirements of endogenous amino acids and dander amino acids were calculated. In this study, an improved method was used to estimate the maintenance requirements of endogenous essential amino acids and dander amino acids in Guangming No. 2 broilers, which provided a basis for the establishment of a prediction model of amino acid requirements. The estimated results of this study were close to those of adult chickens measured by the comparative slaughtering method, indicating that the proposed method was more reasonable than the original method.

This trial was conducted to investigate the effect of different kind of fiber and different adding levels on growth performance, fecal nitrogen metabolism, fecal fiber content, serum biochemical index, the gastrointestinal structure and cecal microflora of broilers, in order to provide theoretical basis for the rational utilization of fiber in broilers' diet. Three hundred and sixty one-day-old healthy Shengze "901" male broilers with similar body weight (47.07±0.26 g) were randomly allotted into 6 groups with 6 replicates per group and 10 broilers per replicate. The broilers were randomly subjected to one of the following 6 treatments for 42 days with 2 periods: control group (T6 group) fed the basal diet, the addition groups were fed a basal diet supplemented with 1.5 kg·t^-1 fiber sample 1 (T1 group), 2.5 kg·t^-1 fiber sample 1 (T2 group), 150 g·t^-1 fiber sample 2 (T3 group), 2 kg·t^-1 fiber sample 3 (T4 group) and 3 kg·t^-1 fiber sample 3 (group T5), respectively. The results showed as follows: compared with T6 group, 1) The average daily feed intake (ADFI) for 22-42 d and the feed/gain (F/G) for 1-42 d in T2 group were significantly increased by 5.04% and 3.07% (P < 0.05) respectively, the F/G for 22-42 d and 1-42 d in T3 group were significantly increased by 4.16% and 3.68% (P < 0.05) respectively, and average body weight (ABW) for 21 d and 42 d, average daily gain (ADG) for 1-21 d and 1-42 d and ADFI for 22-42 d in T5 group were increased significantly by 6.26% and 4.93%, 6.70% and 5.02% and 4.87% (P < 0.05) respectively; 2) The nitrogen intake and retention (NI and NR) at 21 d in group T1, the nitrogen retention rate (NRR) at 21 d in group T4, the NRR at 21 d in group T5 and the NR at 42 d were significantly increased by 11.24% and 16.77%, 6.18%, 7.65% and 9.95%, respectively (P < 0.05). Fecal nitrogen content in T5 group at 21 d was significantly decreased by 6.87% (P < 0.05); 3) Urea nitrogen (UN) and total antioxidant capacity (T-AOC) at 42 d in T1 group were significantly increased by 333.33% and 57.14% (P < 0.05) respectively, UR at 21 and 42 d in T2 group were significantly increased by 375.00% and 466.67% respectively, and malondialdehyde (MDA) at 21 d was significantly decreased by 17.69% (P < 0.05). In T3 group, UR at 21 and 42 d was significantly increased by 350.00% and 233.33% respectively, MDA at 21 d was significantly decreased by 15.58%, total protein (TP) and low density lipoprotein (LDL) at 42 d were significantly decreased by 15.34% and 20.00% respectively, and alanine aminotransferase (ALT) was significantly increased by 102.70% (P < 0.05). At 42 d, glucose content in T4 group was significantly increased by 35.36% (P < 0.05), and albumin (ALB), triglyceride (TG) and MDA at 21d in T5 group were significantly decreased by 10.79%, 25.45% and 33.60%, respectively. At 42 d, high density lipoprotein (HDL) and ALT were significantly increased by 25.32% and 62.16%, respectively (P < 0.05); 4) At 42 d, the ileum length (IL) in T1 group, the jejunum weight (JW) and IL in T2 group, the jejunum length (JL) and IL in T3 group and IL in T5 group were significantly increased by 5.04%, 13.71% and 19.26%, 19.38% and 21.84% and 23.18%, respectively (P < 0.05); 5) The villus height (VH) of ileum in T3 group was significantly decreased by 29.20% (P < 0.05) at 42 d, the crypt depth (CD) of duodenum and jejunum in T5 group were significantly increased by 116.67% and 73.33%, respectively, and the VH/CD of duodenum was significantly decreased by 48.02% (P < 0.05). 6) Alpha and Beta diversity analysis showed that caecum microflora has obvious difference between each group. The type and quantity of microbes OTU for 21 d was increased. Bacteroides fragilis A and Alistipes finegoldii in genus of Bacteroides and Allstilpes were the most abundant and were the dominant genera. Bacteroides and Bacteroides fragilis A were the highest richness at 21 days, and Allstilpes and Alistipes finegoldii were the highest richness at 42 days. It mainly played a functional role in carbohydrate metabolism and amino acid metabolism, and transport and replication and repair by KEGG pathway analysis. In conclusion, dietary fiber supplementation can promote intestinal development, improve and stabilize intestinal microflora, improve nutrient utilization, and thus increase daily gain and feed intake of broilers. Under the conditions of this experiment, adding 3 kg·t^-1 Muzhiqian product has the best effect.

This study was designed to understand the prevalence and genetic evolution of field strains of lumpy skin disease (LSD) in cattle in our country, and determine the biological characteristics of lumpy skin disease virus (LSDV). This study conducted PCR testing, virus isolation, immunofluorescence identification, electron microscopy observation, GPCR gene sequencing, and genetic evolution analysis on skin nodule samples from cattle suspected of having lumpy skin disease. The results indicate that the disease affecting cattle in three provinces in our country is Lumpy Skin Disease. Three LSDV strains were isolated using primary lamb testicular cells (PLT) and named LSDV/Heilongjiang/2022, LSDV/Jiling/2022, and LSDV/Jiangxi/2022. The growth curve of the three viruses showed the fastest growth rate in the first 96 hours, with the highest titer at 96 to 120 hours. Afterward, the virus growth rate started to slow down, and the highest titer was reached 96 hours after inoculation, the titers for the three strains were 10^6.0 TCID₅₀·mL^-1, 10^5.3 TCID₅₀·mL^-1, and 10^5.1 TCID₅₀·mL^-1, respectively. Under transmission electron microscopy, virus particles appeared elliptical, with a diameter between 200 and 300 nm. Genetic evolution analysis of the GPCR gene sequences of the three strains, along with prevalent strains in various regions of China and other countries in recent years, showed that the three isolated strains and the prevalent strains in various regions of China are on the same branch. This indicates a strong correlation in the prevalence of Lumpy Skin Disease in various regions of China. This study successfully isolated three strains of LSDV from skin nodules of cattle in Heilongjiang, Jilin, and Jiangxi provinces, enriching the epidemiological and pathogenic data of LSDV in China. It holds significant importance for the continuous monitoring of LSDV and the development of new vaccines.

Bluetongue virus (BTV) is an arbovirus that seriously harms ruminants such as Sheep, while sheep lung microvascular endothelial cells (SLMECs) constitute a semi-selective barrier in order to study the molecular mechanism of interferon antiviral immune response in BTV infection and SLMECs. In this study, BTV plaque assay was used to induce SLMECs at 18 h, 24 h and 36 h with multiple infection (MOI) 1. The mRNA expression characteristics of interferon-related pathway genes were analyzed by real-time fluorescence quantitative PCR, and the protein expressions of MDA5, TRAF3, RIG-I and TBK1 were analyzed by Western blot. The results showed that the changes of interferon signaling pathway gene expression were most obvious, and the mRNA expressions of RIG-I, MDA5, IKKε, IFN-β, TBK1 and TRAF6 genes were up-regulated, and the differences were extremely significant (P < 0.01) at 36 h of BTV induction, while the mRNA expressions of IFN-α, VISA and USP18 genes were significantly downregulated (P < 0.01). At the protein level, the protein expressions of MDA5, TBK1, RIG-I and TRAF3 were mainly upregulated. This study found that BTV infection can induce an IFN immune response of SLMECs, which lays a foundation for further analysis of the mechanism of IFN-Ⅰ signaling pathway activation in the innate immune response against BTV infection.

In order to understand the biological and genome characteristics of mammalian orthoreovirus (MRV) from sheep, a MRV strain named MRV-XJ23 was isolated from sheep suffering diarrhea, and identified by RT-PCR, electron microscopy and indirect immunofluorescence assay (IFA), respectively. The whole genome of the isolated strain was amplified by RT-PCR and the homology and genetic evolution were analyzed further. The results showed that the MRV-XJ23 strain cultured stably in MDBK cells and performed specific cytopathic effect with a virus titer of 10⁶ TCID₅₀·mL^-1. Specific fluorescence was observed in MRV-infected MDBK cells by IFA detection, and electron microscope detection showed that the virus was purified by ultracentrifugation with a diameter of about 70 nm. The whole MRV genome was obtained by RT-PCR, MRV-XJ23 contained 10 segments with the length of 23 534 bp. Nucleotide sequence alignments and genetic evolution analysis showed that the MRV-XJ23 isolate was belonged to MRV-1 serotype. Results of sequence and phylogenetic trees indicate that the novel MRV isolate was a novel reassortant among three MRV strains of BatMRV2/SNU1/Korea/2021, C/bovine/Indiana/MRV00304/2014 strain and Homo sapiens/Osaka2005. In this study, a reassorting strain of MRV-1 type originated from sheep was isolated and identified for the first time, which proved important evidence that sheep could be infected with MRV and broadened the host species. Moreover, the reassortant strain was derived from bat, bovine and homo sapiens-MRV, which indicated that these strains were infected the new host and reassortment was present after possible cross-species infection. This study revealed the risk of MRV transmission circle in various species to public health, and the importance to study the epidemiology, reassortment and pathogenicity of MRV in sheep and even livestock.

Novel duck reovirus (NDRV), which can infect ducklings of many breeds, leads to hemorrhagic necrosis of liver and spleen and cause immunosuppression, and has caused serious economic losses to Chinese waterfowl farming industry. However, there are still no commercial test kits on the market. In this study, a pure new duck reovirus was successfully isolated from clinical materials by plaque purification, named as E232 strain. And by using σC protein expressed in prokaryotes as the coating antigen, an indirect ELISA was established to detect NDRV serum antibodies. The genetic evolution results show that E232 belongs to NDRV and has 96.4%-98.9% nucleotide homology with other NDRV strains. Animal regression test showed that the incidence of E232 is 100%. The spleens of the affected ducklings showed severe swelling, bleeding and necrosis, and the cloacal detoxification and pharynx detoxification reached the peak on the 5th day after infection. This assay detected NDRV antibody titer in positive sera at 1∶6 400 dilution, the coefficients of variation of intra batch and inter batch repeatability tests were 1.53%-7.24% and 1.84%-8.30%. It showed 80.93% positive rate for 236 clinical serum samples but did not react with any other disease positive sera. In conclusion, the successful isolation of the E232 strain in this study has enriched the epidemiological information database of NDRV in China. The successful establishment of the indirect ELISA provides a good technical means for the prevention and control of NDRV.

This study aims to investigate the effects of biomineralization on the biological characteristics and immunogenicity of the Newcastle disease virus (NDV) LaSota strain, and provide new insights for the development of heat-stable live vaccines. The optimal biomineralization conditions for NDV were determined by measuring viral particle size, hemagglutination titers, and spot blots under different mineralization conditions. The effect of mineralization on viral replication was evaluated by inoculating mineralized viruses into BHK-21 cells, and then comparing their titer changes after heat treatment. The immunogenicity of mineralized viruses was evaluated through virus neutralization tests. Finally, the immunological efficacy of mineralized viruses was assessed in SPF chicks via water administration. Results were as follows: Upon optimization of the biomineralization conditions, the LaSota strain exhibited the best mineralization effect under 4 mmol·L^-1 Na₂HPO₄ and 3 mmol·L^-1 CaCl₂ conditions, characterized by the largest particle size of the mineralized virus, the lowest hemagglutination titer, and a high mineralization rate of 98.25%. Compared to the non-mineralized virus, the mineralized LaSota strain showed a delayed onset of replication in BHK-21 cells, however, there was no significant difference in the final replication titers between them. Following neutralization with NDV antibodies, the titer reduction value of the mineralized virus was 10^3.0 TCID₅₀·mL^-1, which was significantly lower than that of the non-mineralized group. After incubation at 56 ℃ for 15 minutes, the viral titer of the mineralized LaSota strain decreased by only 10^3.5 TCID₅₀·mL^-1, demonstrating a heat resistance characteristic comparable to that of the TS09-C heat-resistant strain. Fourteen days post-immunization, antibody levels in SPF chicks immunized with the mineralized LaSota strain were higher than those in chicks receiving the non-mineralized LaSota strain. Challenge experiments conducted 42 and 78 days post-immunization showed survival rates of 100% and 60%, respectively, in the group immunized with the mineralized LaSota strain. This study optimized the best biomineralization conditions for the NDV LaSota strain. Mineralization delays the initial viral replication but does not affect the final titer. After mineralization, it can reduce neutralization reaction of virus with antibodies and enhance thermal stability of virus, providing good protective effects to SPF chicks via drinking water immunization. This study confirms that developing heat-stable live vaccines for Newcastle disease through biomineralization is a practical and feasible approach, and also offers valuable references and inspirations for developing heat-stable live vaccines for other viruses.

Marek's disease (MD), caused by Marek's disease virus (MDV), is one of the most important immunosuppressive and neoplastic diseases. It can be prevented and controlled with MD vaccines, but the virulence of epidemic MDV strains persistently increases under the highly immune pressure of widely used MD vaccines. Recent studies have found that the classical MD vaccines are no longer able to provide ideal immune protection for the current prevalent hypervirulent MDV (HV-MDV) variant, which implies the urgent need to develop a new generation of highly effective MD vaccines. Presently, we have used the newly isolated HV-MDV variant HNSQ01 as the parental virus, first passaged on CEF monolayers in vitro, to generate a meq gene-edited and knocked out mutant of SQ01Δmeq utilizing the CRISPR/Cas9-based gene editing technology. A series of experiments and analysis have demonstrated a stable MD vaccine candidate strain of SQ01Δmeq has been successfully generated. Furthermore, the pathogenicity analysis was performed with 1-day-old specific-pathogen-free (SPF) chickens for virus challenge experiments. During the 77-days animal experiments, the parental HNSQ01 had caused serious atrophy of host immune organs and inhibited the growth of virus-challenged birds, together with the 100% MD morbidity, 100% mortality and 80% gross tumor occurrence. However, SQ01Δmeq had not caused the immunosuppression or inhibited the growth of virus-challenged birds, together with the 0% rates of MD morbidity, mortality and tumor occurrence. Our data indicate that the generation of SQ01Δmeq provides an important basis for the future research and development of novel efficient genetically engineered MD vaccines.

The object of this study was to understand the pathogenicity, virus shedding and horizontal transmission ability of chicken infectious anemia virus (CAV) on SPF chickens. In this study, 1-day-old and 28-day-old SPF chickens were infected with CAV JL17/1204 strain by intraperitoneal inoculation and cohabitation. At 3 days post infection (dpi), 5 dpi, 7 dpi, 9 dpi, 11 dpi, 14 dpi, 21 dpi, 28 dpi, 42 dpi, 56 dpi, 84 dpi and 112 dpi, the anticoagulant blood of 3 chickens in each group was collected and the thymus was dissected to detect anemia and thymus atrophy. Throat swabs and anal swabs of 20 chickens in each group were collected at each time point to detect the virus shedding by PCR method. The clinical observation results showed that the mortality rates of 1-day-old infected chickens and cohabiting infected chickens were 50.0% and 10.0%, respectively, and the death occurred at 12-15 dpi; 28-day-old infected and cohabiting infected chickens did not die. The results of autopsy showed that the thymus atrophy and/or anemia symptoms appeared in the diseased chickens of each group. The incidence rate of the 1-day-old infected chickens and the cohabiting infected chickens were 100.0% and 20.0%, respectively; The incidence of 28-day-old infected chickens and cohabiting infected chickens were 10.0% and 8.0%, respectively. The virus shedding results showed that the respiratory tract and digestive tracts of the 1-day-old infected chickens began to shed from 3 dpi and 5 dpi, respectively. The detoxification period of the respiratory and digestive tracts of the 1-day-old cohabiting infected chickens were 5-84 days and 7-42 days after cohabitation, respectively; The respiratory and digestive virus shedding periods in the 28-day-old infected chickens were 3-9 dpi and 5-14 dpi, respectively; The respiratory and digestive virus shedding periods in the 28-day-old cohabiting infected chickens were 5-9 days and 5-42 days after cohabitation, respectively. The results showed that CAV was highly pathogenic to 1-day-old SPF chickens, and could cause high mortality, thymus atrophy and/or anemia after infection, but its pathogenicity was obviously weakened to 28-day-old SPF chickens. Infected chickens excrete virus through respiratory tract and digestive tract, and the excreted virus can infect cohabiting chickens to get sick or even die, which indicates that CAV has high horizontal transmission ability. The results of this study systematically expounded the pathogenic characteristics and virus shedding of CAV infection, which provided theoretical guidance and scientific basis for the scientific purification of CAV in chickens.

The study was design to investigate the pathogenic agents of respiratory tract diseases of fattening pigs in a pig breeding enterprise in Jingzhou, Hubei Province. The pathogen was screened and isolated from the diseased pig lung tissue. Morphological observation, physiological and biochemical analysis, 16S rDNA gene sequence, serotype typing, multilocus sequence typing, drug sensitivity test, drug resistance gene sequencing analysis and animal pathogenicity test were performed for the isolated strains. The results showed that the isolated strain Pm0525 was Gram-negative brevibacterium. It was identified as Pasteurella multocida by biochemical assay, PCR and 16S rDNA sequence analysis. The isolated strain was identified as Pasteurella multocida type A. Multilocus sequence typing analysis confirmed that the isolated strain is type ST201 and merged with type ST1615. The isolated strain was sensitive 13 kinds of antibiotics, such as gentamicin, kanamycin and medemycin, and resistant to chloramphenicol, clindamycin, cefuroxime, ceftazidime and tetracycline. The isolated strain showed moderate biofilm formation ability, carrying out four resistance genes, SulⅠ, SulⅡ, tetA and bla-TEM. The isolated strain may play the role of anti-β-lactam antibiotics by producing metal-beta-lactamase (MBL). In addition, traditional Chinese medicine Coptis had obvious inhibitory effect on the isolated strain in vitro. The isolated strain carried 18 virulence genes, and showed strong pathogenicity to mice. This study systematically analyzed the serotype, molecular typing, drug sensitivity and pathogenicity of swine Pasteurella multocida, providing scientific basis and data reference for further research on the transmission, prevention and precise treatment of Pasteurella infection.

The aim of this study was to explore the therapeutic effect of Lactobacillus salivarius on latent mastitis of dairy goats, in this study, 12 dairy goats with mastitis were randomly selected, of which 6 were used as probiotic treatment group and 6 were used as mastitis model control group. Another twelve healthy dairy goats were selected, of which 6 were used as probiotics prevention group and 6 were used as blank control group. Probiotic treatment group and probiotic control group were fed Lactobacillus salivary every day, and the rest groups were not treated. The milk, anticoagulant and rectal contents of dairy goats were collected after feeding on day 0 and 28. The changes of blood inflammatory factors, intestinal flora and milk flora were detected by fluorescence quantitative PCR and 16S rRNA microflora sequencing, respectively. The results showed that the incidence of subclinical mastitis of dairy goats fed Lactobacillus salivary decreased from 36.36% to 13.64%, The relative expression levels of inflammatory factors such as IL-17, IL-1β and IL-6 were significantly decreased, while the relative expression levels of anti-inflammatory factor IL-10 were significantly increased. The microbial Alpha diversity increased in the gut and milk, and the diversity of flora increased, which significantly increased the relative abundance of Firmicutes and decreased the relative abundance of Bacteroidetes at the phylum level of intestinal microbiome, and increased the relative abundance of Firmicutes and Cyanobacteria at the phylum level of milk microbiome, and decreased the relative abundance of Proteobacteria.In conclusion, Lactobacillus salivarius has a good therapeutic effect on occult mastitis, and has a clinical prospect for the treatment of occult mastitis.

This study aimed to investigate the regulatory effect of bovine viral diarrhoea virus(BVDV) infection on ferroptosis in Madin-Darby Bovine Kidney(MDBK) cells and its effect on viral replication. Technologies such as confocal microscopy, Western blot, qPCR and electron microscopy were used to detect ferroptosis and the level of viral replication in BVDV-infected cells. Furthermore, the viral replication level and inflammatory cytokines expression in BVDV-infected cells pretreated with Fer-1, a commonly used ferroptosis inhibitor, were also detected. The results showed that, compared with the normal control group, the mortality rate of cells infected with BVDV (MOI=5) was significantly increased (P < 0.05), which was accompanied with increased levels of Fe²⁺ and lipid peroxidation (P < 0.05). Transmission electron microscopy (TEM) analysis revealed that BVDV-infected and Erastin-treated cells displayed shrunk mitochondria with fewer cristae, increased mitochondrial membrane density and decreased mitochondrial mean areas compared with those of mock-infected cells, which was a typical morphological feature of ferroptosis. Fer-1 treatment significantly inhibited the levels of viral replication in BVDV-infected cells (P < 0.05). In addition, ferroptosis induced by BVDV infection had positive regulatory effects on inflammatory cytokines expression, including IL-1β, IL-18 and IFN-β. The results suggested that BVDV infection can induce ferroptosis in host cells, and the induction of ferroptosis enhanced the level of viral replication and the expression of inflammatory cytokines.

This experiment was conducted to obtain the complete mitochondrial genome sequence of Ligula intestinalis, revealed the sequence's structural features, and explored the phylogenetic information of L. intestinalis. Several L. intestinalis were obtained from Pseudorasbora parva and genomic DNA was extracted. The complete mitochondrial genome of L. intestinalis was sequenced, assembled, and annotated using Illumina sequencing technology after quality control of the DNA, followed by bioinformatic analysis. Maximum likelihood (ML) and bayesian inference (BI) analysis were used to construct the phylogenetic tree. The results showed that the complete mitochondrial genome of L. intestinalis was 13 655 bp in length, and its A+T content was 67.6%, exhibiting a clear AT bias. The complete mitochondrial genome was composed of 12 protein-coding genes (PCGs), 22 tRNA genes, two rRNA genes and two NCRs (non-coding regions). Among the 12 PCGs, 11 used ATG as the start codon, except for cox3, which had a TTG initial one. Among the termination codons, five out of twelve were identified as TAA, five as TAG, while neither the cox3 nor nad3 genes had termination codons. The total length of the 22 tRNA genes was 1 272 bp. Most tRNAs have a conventional cloverleaf structure, but trnS1 and trnR lack dihydrouridine arms of tRNA. The nad2, nad6 and nad4 genes are more suitable as molecular markers for L. intestinalis. The results of the phylogenetic tree showed that Ligula and Digramma were most closely related to each other, forming a sister group with Dibothriocephalus. The complete mitochondrial genome of L. intestinalis was obtained. This study will provide a reference for the study of the taxonomy and systematics of L. intestinalis.

This study analyzes the inhibitory effect and its mechanism of salidroside (SAL) on canine parvovirus (CPV). In vitro, drug effects were performed on three stages of virus infection (adsorption, invasion, and replication). Virus titers were detected in cells to access the inhibitory effect of SAL on the virus were evaluated. TUNEL (Terminal deoxynucleotidyl Transferase dUTP Nick End Labeling) assay was used to analyze apoptosis. Quantitative Real-time PCR and Western blot were used to detect the mRNA or protein expression of apoptosis-related proteins and inflammatory factors, respectively, aiming to analyze and preliminarily verify the mechanism by which SAL inhibits virus replication. The results showed that SAL significantly inhibited CPV replication, but had no significant effect on the adsorption and invasion processes of CPV. SAL could inhibit apoptosis induced by CPV and significantly inhibit the protein expression of caspase 8 and tBID. Further research revealed that CPV could induce the upregulation of IL-1β and inflammatory factors, while SAL downregulated the expression of some inflammatory factors in virus-infected cell. The activation of caspase 1 and NLRP3 was closely related to IL-1β. After viral infection of cells, incubation with SAL could inhibit the activation of caspase 1, but had no significant effect on NLRP3. When virus was incubated in cells with down-regulated expression of caspase 8 by siRNA-caspase 8, the expression of IL-1β in cells was inhibited, consistent with the effect of SAL, indicating that SAL mainly inhibits the expression of inflammatory factors by inhibiting the activation of the caspase 8 signaling pathway. In summary, this study shows that SAL can effectively inhibit the replication of CPV. SAL inhibits CPV-induced apoptosis by regulating the caspase 8 signaling pathway and inhibits the expression of some inflammatory factors. This study provides a new approach and method for the effective treatment of CPV.

In order to identify important host factors in cell entry and establishment of infection of porcine circovirus type 2 (PCV2), the effects of porcine lymphocyte specific tyrosine kinase Lck expression and activity on PCV2 infection replication were analyzed, and Lck was identified as a new target for the regulation of PCV2 replication. In this study, based on analysis of the structural characteristics and sequence conservation of porcine Lck, the Lck SH3 domain was selected as the immunogen gene sequence, and the polyclonal antibody against porcine Lck was prepared in mice using the protein expressed the E. coli expression system. Then, the effect of PCV2 infection on the expression and activity of Lck in PK-15 and 3D4/21 cells was detected using Western blot. Finally, the effects of porcine Lck expression and phosphorylation on PCV2 replication in PK-15 cells transiently transfected with overexpressed vector or treated with Lck specific inhibitor (A770041) were detected by Western blot and RT-qPCR, respectively. The results showed that mouse derived polyclonal antibodies against pig Lck were successfully prepared. There was no significant change in the expression level of Lck, but the phosphorylation level of Lck was significantly up-regulated in the early stage of PCV2 infection in PK-15 and 3D4/21 cells. Overexpression of Lck significantly increased PCV2 Cap protein expression and viral copy number, while inhibition of Lck phosphorylation level with A770041 could significantly downregulate the expression of PCV2 Cap protein, viral copy number and virus titer. These results indicated that Lck positively regulated PCV2 replication, which lays an important foundation for exploring the new molecular mechanism of PCV2 infection.

To reduce and improve the heterogeneity and efficacy of mouse-derived monoclonal antibodies in clinical treatment of dogs, the variable region of heavy chain (V_H) and variable region of light chain (V_L) were amplified from mouse-derived hybridomas secreting monoclonal antibody against canine distemper virus (CDV) using RT-PCR, the single chain antibody (scFv) gene was obtained by linking V_H and V_L through Linker, and the canine-derived chimeric single chain antibody (scFv-Fc) gene was obtained by selecting the constant region (Fc) of canine IgG B to connect to the C-terminus of scFv; The prokaryotic expression vectors for expressing mouse-derived scFv and canine-derived scFv-Fc were respectively constructed, which were expressed in Escherichia coli for purification, and the specificity and neutralizing activity of the expressed antibodies were detected by ELISA, IPMA, cell fusion inhibition, and neutralization assay. The detection limit of ELISA for CDV mouse-derived scFv and canine-derived scFv-Fc are 14.38 and 102.75 μg·mL^-1, respectively; Both of scFv and scFv-Fc specifically react with the expressed CDV H protein and CDV; The cell membrane fusion mediated by CDV H and F proteins can be inhibited by scFv and scFv-Fc, and the minimum concentrations of them for complete protection of cells from CPE formation are 0.72 and 0.64 μg·mL^-1, respectively. The mouse-derived scFv and canine-derived chimeric antibody scFv-Fc are successfully developed, providing candidate antibody drugs for the clinical treatment of canine distemper.

Our team previously found that recombinant serine protease inhibitors 4 and 5 (rPsoSP4 and rPsoSP5) of Psoroptes ovis could inhibit the enzymatic activities of chymotrypsin, trypsin and elastase in vitro, thus we speculated that these two recombinant proteins might have anti-inflammation activities. To confirm the above speculation, we assessed whether rPsoSP4 and rPsoSP5 could improve psoriatic-like skin inflammation in mice. BALB/c mice were randomly divided into 5 groups (n=6), Vaseline or imiquimod cream (IMQ) was applied daily on the back skin continuously for 6 days to establish the control group and psoriasis model groups. During this period, the psoriasis model groups were intradermal injected with PBS (IMQ group) or pET32a(+)-vector protein (IMQ+pET32a(+) group) or rPsoSP4 (IMQ+rPsoSP4 group) or rPsoSP5(IMQ+rPsoSP5 group), then the changes of psoriasis-like skin lesions were observed every day, and mice were sacrificed on the 7^th day. Subsequently, the pathological changes and the transcription levels of IL-1β, IL-6, and TNF-α in the skin lesions among each group were compared. Results showed that IMQ induced psoriasis-like lesions were successfully established, and the mice appeared typical psoriasis-like lesions. Compared with the model group (IMQ group), IMQ+rPsoSP4 group can effectively attenuated psoriasis-like skin lesions, including significant inhibition of weight loss (from 4^th to 6^th day, P < 0.05, P < 0.01, P < 0.001) and reductions of skin erythema (5^th and 6^th day), skin scales (from 4^th to 6^th day), skin thickness (from 4^th to 6^th day) and PASI score (from 3^rd to 6^th day) in mice (P < 0.05, P < 0.001). Additionally, compared with the model group (IMQ group), IMQ+rPsoSP4 group showed that the pathological damage in the skin lesion was significantly reduced, accompanied by the significant decrease in epidermal thickness (P < 0.05) and the number of infiltrated inflammatory cells (P < 0.001). Moreover, there was a significantly decreased in mRNA levels of IL-1β, IL-6, and TNF-α in the skin lesion of IMQ+rPsoSP4 group in comparison with IMQ groups, while IMQ+rPsoSP5 group had no significant improvement on psoriatic lesions. In conclusion, rPsoSP4 could significantly improve psoriasis skin lesion in mice and has significant anti-inflammatory activity, while rPsoSP5 seemed to be no obvious effect.

The purpose of this study was to prepare and identify monoclonal antibodies (mAbs) against the VP1 protein of feline calicivirus (FCV) strain SH14. In this study, the whole virus of the SH14 strain of FCV was used as an immunogen to immunize BALB/c mice through intraperitoneal injection, and mAbs against the VP1 protein were prepared. Through ELISA screening, a specific monoclonal antibody clone, 3A3C1, was successfully obtained. A comprehensive biological characterization of the 3A3C1 clone mAb was conducted, confirming it as an IgG₁ type with a κ light chain. The results of Western blot and immunofluorescence assay (IFA) showed that the 3A3C1 clone mAb could specifically recognize and bind to FCV strains SH14, F9, and GZ22. In addition, this study further explored the linear antigenic epitope of the 3A3C1 clone mAb. By segmentally expressing the VP1 protein and conducting detailed Western blot analysis, the linear antigenic epitope of the 3A3C1 clone mAb was finally determined to be located in the⁴²⁶PSRLTPAGDYAITSG⁴⁴⁰ region of the VP1 protein. The 3A3C1 clone mAb prepared in this study is not only an important tool for understanding the immunological characteristics of FCV but also has potential applications in developing FCV diagnostic methods and vaccine strategies.

This work aimed to study the antibacterial synergistic ability and the preliminary combined mechanism of isopropoxy benzene guanidine (IBG) combined with colistin, and to evaluate whether IBG can act as an effective colistin synergist and enhance the anti-bacterial effect of colistin. The findings of this study will provide a theoretical basis for the effective treatment of multidrug resistant bacterial infections in the clinic. This study investigated the preliminary combined mechanism and synergistic effect of IBG with colistin against Klebsiella pneumoniae using the minimal inhibitory concentration, checkerboard test, time killing curves, resistance induction and fluorescent dye test. IBG has no antimicrobial activity against K. pneumoniae alone, but has a synergistic effect against K. pneumoniae in combination with colistin and an additive effect in combination with amoxicillin. Time killing curves indicate that when the two drugs are used in combination, IBG enhances the susceptibility of K. pneumoniae to colistin, with a synergistic decrease in bacterial counts of >2 lg(CFU·mL^-1) compared to the effect of colistin alone. In the long-term induced resistance test, resistance was less likely to be induced by colistin in the combination group than in the colistin monotherapy group. The results of the synergistic mechanism test showed that colistin and IBG, when used in combination, can destroy the permeability of the cytoplasmic membrane, affect the potential of the cell membrane, and dissipate the proton kinetic potential energy, so that it is difficult for cell membranes to perform their normal functions. In this study, we found that the combination of IBG and low concentration of colistin, has good synergistic antibacterial activity against K. pneumoniae and enhances the antibacterial effect of colistin. It suggests that IBG can restore the susceptibility of multidrug resistant K. pneumoniae to colistin, and can be used as a potential therapeutic option for the treatment of K. pneumoniae infections.

The aim of this study was to investigate the role of oxidative stress and ferroptosis in renal tissue injury caused by molybdenum, cadmium and their combined exposure in sheep. Twenty-four sheep aged 2 months were randomly divided into 4 groups, namely control group (Control), molybdenum group (Mo), cadmium group (Cd) and molybdenum cadmium combined group (Mo+Cd). The control group was given equal volume of distilled water, the Mo group was given 45 mg Mo·kg^-1BW, group Cd was given 1 mg Cd·kg^-1BW, and group Mo+Cd was given 1 mg Cd+45 mg Mo·kg^-1BW. The experimental period lasted for 75 d. At the end of the experiment, serum and kidney tissue were collected, pathological and ultrapathological changes of sheep kidney were observed, and the levels of serum renal function indexes, renal tissue oxidative stress and ferroptosis related factors were detected. The results showed that molybdenum, cadmium and their combined exposure increased the levels of serum renal function indicators (creatinine, urea and uric acid). In the Mo, Cd, and Mo+Cd groups, the renal tubular epithelial cells underwent degeneration, manifesting as swelling, structural blurring, and lysis. The cytoplasm contained minute red granules and vacuoles, indicating granular degeneration, vacuolar degeneration, and necrosis. Additionally, the renal tubular lumens were observed to contain pink-stained filamentous components, while the number of red blood cells was elevated in some glomeruli and interstitial spaces. The results of transmission electron microscopy showed that molybdenum, cadmium and their combined exposure resulted in the reduction of mitochondrial volume, blurring of ridge and vacuolation in renal tubular epithelial cells. The contents of oxidative damage related factors (H₂O₂, MDA) and Fe ions, the mRNA expression levels of ferroptosis related factors (NCOA4, ACSL4, TFR1 and PTGS2) and the protein expression levels of PTGS2 were increased in Mo and Cd groups. The mRNA and protein expression levels of antioxidant related factors (GSH, CAT and GSH-Px) and ferroptosis related factors (SLC7A11, GPX4 and FTH1) were decreased, and the above changes were more obvious in Mo+Cd group. Pearson correlation analysis showed that the levels of oxidative damage related factors (H₂O₂, MDA) and Fe ions were positively correlated with the expression levels of ferroptosis related factors (NCOA4, ACSL4, TFR1 and PTGS2), and negatively correlated with the expression levels of ferroptosis related factors (SLC7A11, GPX4 and FTH1). The correlation of antioxidant related factors (GSH, CAT and GSH-Px) and ferroptosis related factors was opposite to that of oxidative damage related factors. This study shows that molybdenum cadmium and its combined exposure induced renal oxidative stress and ferroptosis in sheep, resulting in renal tissue damage, and molybdenum, cadmium toxicity has a synergistic effect.

The aim of this study was to investigate whether heteroresistance exists in milk-derived Escherichia coli, and to characterize the biology of heteroresistance E. coli and its resistant subgroups, in order to explore possible heteroresistance mechanisms.The minimum inhibitory concentration (MIC) of one E. coli strain named D1 which isolated from raw cow's milk was determined by micro broth dilution method. The heteroresistance of E. coli was initially screened by the K-B paper diffusion method, and confirmed by the population analysis profile (PAP), and the heteroresistance characteristics of E. coli were investigated by resistance stability test and biofilm assay, finally, the mechanism of heterogeneous resistance was analyzed by whole genome sequencing and resequencing. The results showed that this E. coli was intermediary to polymyxin E, resistant to sulfisoxazole, and showed sensitivity to the rest of the antibiotics, and two E. coli-antimicrobial heteroresistance combinations were screened out by K-B paper diffusion assay.PAP confirmation showed that the MIC/maximum noninhibitory concentration (MNIC) ratio of E. coli was 8, and the occurence frequency of the resistant subgroups was 2.45×10^-6, confirming D1 to be a heteroresistance doxycycline-resistant strain. The stability of transmission showed that the resistant subpopulation could not be inherited stably, while there was no growth lag in the growth test, and the biofilm production of the resistant subpopulation was significantly greater than that of the parental strain. Whole genome sequencing revealed that there was a gene mutation between the resistant subpopulation and the parental strain, and the mutant gene txR is a specific transcriptional regulator that may lead to heteroresistance to doxycycline in E. coli. In conclusion, the existence of heteroresistance to doxycycline in E. coli from milk sources suggests that doxycycline antibiotics should be used rationally in the clinic, therefore, more attention should be paid to the occurrence of heteroresistance when using doxycycline in clinical treatment, and effective detection methods need to be used to provide guidance for clinical prevention and control and rational use of antibiotics.

The study aimed to investigate the effects of Modified Zhizhu Powder on the ileal intestinal mucosal barrier of weaned rabbits, with the goal of providing new ideas for the prevention and treatment of diarrhea diseases in weaned rabbits. Ninety 35-day-old New Zealand white rabbits, with similar body weights, were randomly divided into 5 groups, based on the principle of 50/50 male and female. Rabbits in control group were fed a basal diet, Enrofloxacin group, low-dose group, medium-dose group and high-dose group were fed the basal diet supplemented with 0.2% Enrofloxacin powder and 0.1%, 0.3% and 0.5% Modified Zhizhu Powder, respectively. The pre-test lasted for 7 days, and the formal test lasted for 14 days. The integrity of the intestinal barrier and its antioxidant capacity were measured after the experiment. The results showed that adding Modified Zhizhu Powder could significantly reduce the intestinal pathological tissue score (P < 0.05). Compared with the blank group, the other treatment groups all significantly increased the relative expression level of ZO2 (zonula occludens protein 2) mRNA in the ileum (P < 0.001). The high-dose group significantly increased the mRNA levels of Occludin, claudin, ZO1 (zonula occludens protein 1), ZO2, andJAM2 (junctional adhesion molecule 2) (P < 0.001). Modified Zhizhu Powder significantly increased the expression of MUC2 (Mucin 2) protein in the ileum (P < 0.05) and the high-dose group significantly reduced MPO (myeloperoxidase) activity (P < 0.01). Modified Zhizhu Powder high-doce group could significantly enhance the secretion of sIgA, reduce the levels of pro-inflammatory cytokinesIL-1β, IL-2, IL-6, andTNF-α, and increase the levels of anti-inflammatory cytokinesIL-10 andTGF-β. Modified Zhizhu Powder could also improve the activity of antioxidant enzymes (SOD, GSH, T-AOC, CAT). In conclusion, the Modified Zhizhu Powder could effectively improve the morphology and structure of the ileum of weaned rabbits, strengthen the tight connection between intestinal cells, maintain the permeability of intestinal mucosa, reduce the inflammatory response of the intestinal tract, enhance the function of the intestinal mucosal barrier, and play an antioxidant role, which can have a positive effect on the use of substitute antibodies.

In order to evaluate the efficacy of Chinese traditional medicine against African swine fever virus (ASFV) in vitro, five experimental drugs were used in this study. The effects of different Chinese herbal medicines on ASFV encored capshell protein p72 in porcine alveolar macrophages (PAMs) infected with African swine fever virus were detected by qPCR. Modified Yuyin decoction (MYY) was selected as a Chinese medicine that could significantly reduce the expression of ASFV-p72 gene. The main components of anti-ASFV were detected by LC-MS analysis. CCK8 method was used to observe the effect of modified Yuyin decoction on the activity of PAMs. The expression of ASFV-p72 gene was detected by fluorescence quantitative PCR. Western blot and ELISA were used to detect CGAS-STING signaling pathway protein expression. RU.521 was used as a cGAS inhibitor to verify the anti-ASFV effect of MYY in the CGAS-STING pathway. The results showed that MYY can significantly reduce the expression of ASFV-p72 gene in PAMs, and the best effect is given at 2 h after ASFV infection, and it has a concentration-dependent improvement effect on the cell viability after ASFV infection of PAMs. The expression levels of interferon gene stimulating protein (STING), TANK binding kinase 1 (TBK1), interferon regulatory factor 3 (IRF3) and interferon induced transmembrane protein 3 (IFITM3) in the supernatant of PAMs cells were decreased by MYY 2 h after the challenge. The expression of cyclic GMP-AMP synthetase (cGAS) and interferon β (IFNβ) protein in PAMs cells increased, and MYY could activate the cGAS-STING-TBK1-IRF3-IFNβsignaling pathway and promote the expression of IFITM3. After treatment with RU.521, MYY could still increase cell viability and decrease the expression of ASFV-p72 gene. In summary, MYY has a potential anti-ASFV effect, which may be related to the activation of cGAS-STING signaling pathway to promote the expression of IFITM3.

The aim of the study is to investigate the incidence rate of Angular Limb Deformities (ALDs) in newborn foals, to compare the differences of blood physio-biochemistry, the inflammatory factors and the hormones in ALDs foals and their mares with the normal counterparts. Four hundred and sixty newborn foals at the age of 2-28 days were clinically surveyed, the ALDs foals were diagnosed by clinical observation combined with the X-ray imaging. The blood physio-biochemical indices, the inflammatory factors, and the hormones in ALDs foals and their mares were measured in the comparison with those in their normal counterparts. The results showed that 30 newborn foals were found with limb abnormalities, accounting for 6.52% of all investigated foals, in which 16 foals were diagnosed as ALD suffers, and accounting for 53% of all limb abnormality foals. The incidence rate of ALDs was 3.48%. The monocytes and eosinophils of ALDs foals were significantly higher than those of normal foals, and the average red blood cell volume and average red blood cell hemoglobin content of ALDs mares were significantly higher than those of normal mares. The blood calcium, blood phosphorus, blood glucose, creatinine, and magnesium levels of ALDs foals were significantly lower than those of normal foals, while alkaline phosphatase, total protein, and albumin were significantly higher than those of normal foals; the blood calcium, Serum phosphorus, blood sugar, total bilirubin, triglycerides, total cholesterol, and magnesium levels were significantly lower than those of normal mares, while aspartate aminotransferase, alkaline phosphatase, and albumin were significantly higher than those of normal mares. The levels of tumor necrosis factor and interleukin 6 in ALDs mares were significantly higher than those in normal mares, while the levels of interleukin 10 were significantly lower than those in normal mares. The levels of parathyroid hormone and 1, 25-dihydroxyvitamin D3 in ALDs foals were significantly higher than those in normal foals. There were no significant changes in the remaining indicators. Our study has ascertained the current incidence of ALDs in newborn foals in Zhaosu Count, Xinjiang. That the significant changes in calcium, phosphorus, blood lipid metabolism, and the specific hormone in ALDs foals and their mares compared with normal controls are closely associated with the newborn foal' bone development abnormalities and the occurrence of ALDs. This study provides blood physiological and biochemical data support for revealing the cause of ALDs, and has important clinical reference value for the early auxiliary diagnosis of ALDs.

In order to investigate the epidemic characteristics and variation of canine adenovirus type 2 (CAV-2) in Henan Province, a total of 790 dog fecal samples were randomly collected in eight regions of Henan Province from 2020 to 2021. The pathogen detection of CAV-2 was carried out by PCR method, and the genetic evolution analysis was carried out based on E3 gene. At the same time, MDCK cells were used to isolate the virus, and the isolated strain was further identified by negative staining transmission electron microscopy, cell sensitivity spectrum test, erythrocyte hemagglutination spectrum test and physical and chemical characteristics analysis. The results showed that the total positive rate of CAV-2 was 1.39% (11/790). Region, age and immunization status could significantly affect the positive rate of CAV-2 (P < 0.05). Among them, Zhoukou City (3/40, 7.50%) had the highest infection rate. Dogs within 6 months old and immunocompromised were susceptible, and the positive rates were 2.69% (8/297) and 1.91% (10/524), respectively. There was no significant relationship between season and sex of dogs and viral infection (P>0.05). Eleven positive samples were sequenced and 5 sequences were obtained. Based on the genetic evolution analysis of CAV-2 E3 gene, 4 sequences were located in the same branch as the domestic CAV-2 HB1 strain, and 1 sequence was located in the same branch as the European and American strains. The positive samples were identified by plaque purification and virus identification. It was confirmed that the isolated virus was CAV-2, named CAV2-HN21. This study enriched the molecular epidemiological data of CAV-2 and successfully isolated a CAV-2 strain, which provided a theoretical basis for the follow-up study of CAV-2 prevention and control measures.

This study aimed to develop a dual-fluorescence quantitative RT-PCR detection method capable of simultaneously identifying African horse sickness virus (AHSV) and West Nile virus (WNV). Specific primers and probes were designed based on highly conserved regions of the AHSV VP7 gene and WNV Poly Protein gene. The reaction conditions and system were optimized, standard curves were established, and the method's specificity, sensitivity, and reproducibility were assessed. Clinical sample testing was conducted to validate the method. Results demonstrated that the method could effectively detect both AHSV and WNV with excellent specificity. No cross-reactivity was observed with equine arteritis virus (EAV), equid Herpesvirus-1 (EHV-1), equine infectious anemia virus (EIAV), Streptococcus equi subsp. zooepidemicus (SEZ), equine influenza virus (EIV) and other equine nucleic acids. The method exhibited high sensitivity, with the lowest detection limits for AHSV and WNV both at 10 copies·μL^-1. Intra-assay coefficients of variation ranged from 0.04% to 0.93%, inter-assay coefficients of variation ranged from 0.17% to 4.83%, demonstrating good reproducibility. Testing 30 equine whole blood samples using this method yielded negative results. The detection method established in this study holds significant importance for equine animal quarantine, monitoring, and control of African horse sickness and West Nile fever.

This study aimed to asseess the prevalence of tet(X4)-containing E. coli, along with their antimicrobial resistance and disinfectant susceptibility profiles, as well as the presence of disinfectant resistance genes, in E. coli strains isolated from pig farms. A total of 440 pig fecal samples were collected and analyzed from pig farms located in Hangzhou, Zhuji, Zhoushan, within Zhejiang province. The presence of tet(X4) and disinfectant resistance genes was determined by PCR. Strain clustering was performed through Enterobacterial repetitive intergenic consensus (ERIC)-PCR, and species identification was confirmed using Sanger sequencing of the 16S rRNA gene. The phenotype of antimicrobial susceptibility and disinfectant resistance were exanimated using microdilution broth method. The results revealed that 117 tet(X4)-positive E. coli strains were isolated from samples collected across the three cities in Zhejiang province, with proportions ranging from 24.0% to 29.5%. These strains exhibited 100% resistance to ampicillin, amoxicillin/clavulanate, florfenicol, tigecycline, but remained sensitive to colistin and meropenem. Notably, the minimum inhibitory concentration (MIC) of sodium hypochlorite and potassium hydrogen peroxymonosulfate were higher than other disinfectant, reacing half of their working concentrations. Compared to ATCC 25922, only a few strains displayed higher MICs for hydrogen peroxide, peracetic acid, chlorhexidine acetate, chlorhexidine, benzalkonium bromide solution than the standard strains. Of note, 92.3% of isolates showed higher MICs for benzalkonium bromide than ATCC 25922. The predominant disinfectant resistance genes in tet(X4)-carrying E. coli were sugE(c), qacF and qacEΔ1, with detection rates of 100%, 25.6%, 11.1%, respectively. ERIC clustering showed that the 117 strains were mainly divided in to 9 groups. The study underscore the multidrug resistance observed in tet(X4)-containing E. coli strains across the three cities. While many of these strains harbored disinfectant resistance genes, they were sensitive to working concentration of tested disinfectant. Consequently, pig farms can make informed decisions regarding disinfectant selection to mitigate the spread of multi-drug resistance bacteria.