Animal reproduction plays a crucial role in community continuation, species evolution, and evolutionary variation in animal population development and life evolution. Reproduction results from the dynamic changes and interaction effects of various germ cells. The analysis of the dynamic change mechanism of germ cells is the basis for understanding the reproductive process of animals. Single-cell transcriptome sequencing technology deeply interprets information in a single-cell dimension in population cells. It gradually becomes the primary choice for interpreting complexes, diverse and dynamic biological problems such as cell group heterogeneity, key gene screening, related pathway expression, and cell interaction. Currently, single-cell transcriptome sequencing technology has begun to explore the related mechanisms of animal reproduction from the perspective of animal germ cells to study the related processes of animal reproduction further. Therefore, this paper summarizes the related content of single-cell transcriptome sequencing technology and its application in animal reproduction.

Porcine reproductive and respiratory syndrome (PRRS) is a highly contagious infectious disease caused by porcine reproductive and respiratory syndrome virus (PRRS virus, PRRSV), which seriously endangers the pig industry in China and even the world. However, due to the variability of PRRSV antigen, the current prevention and control measures, including vaccination and drug treatment, are ineffective. Therefore, with the continuous development of modern molecular biology technology, the disease-resistant breeding of PRRS in pigs based on gene editing technology has gradually developed. This paper briefly describes the clinical symptoms of PRRS, and focuses on the research progress of PRRS disease-resistance breeding at home and abroad. By analyzing the pathogenic mechanism of PRRSV, the PRRSV receptors and the in vivo and in vitro antiviral effects of editing against different receptors were emphasized to provide a theoretical basis for further research of the pathogenic mechanism of PRRSV and the development of PRRS-resistant varieties in the future.

DNA methylation is a dynamic, reversible and heritable epigenetic modification pattern that mainly occurs in mammalian primordial germ cells and early embryonic development. DNA methylation can attach to the CpG region of DNA through highly dynamic and cooperative ribozyme networks, and it can also regulate gene expression by altering functional state of the regulatory regions without affecting genetic information carried by the DNA sequence. DNA methylation is mainly involved in a variety of key physiological processes such as genomic imprinting, transposable element silencing, X-chromosome inactivation and senescence, and plays an important role in mammalian oocyte and embryo development. This review introduces the establishment and removal mechanism of DNA methylation and the biological functions, with emphasis on the dynamic processes of precise generation, maintenance, reading and deletion of DNA methylation during mammalian oocyte and embryo development, providing basis for further studies on mammalian epigenetic regulation.

In vitro embryo cryopreservation technology is an important part of embryo transfer technology, which plays an important role in assisted reproduction technology, and it is also important for germplasm resource conservation, enhancing genetic improvement and promoting international circulation of high-quality germplasm. However, the high lipid content, elevated levels of reactive oxygen species and mechanical damage in in vitro embryo cryopreservation lead to low efficiency of in vitro embryo cryopreservation, which greatly limits the wide application of in vitro embryo cryopreservation technology. Numerous studies have shown that the survival rate and developmental capacity of frozen embryos can be effectively improved by means of lipid removal, optimization of in vitro embryo culture medium, artificial collapse of blastocyst cavities and optimization of freezing procedures. Therefore, this paper outlines the research progress of in vitro embryo cryopreservation technology and the problems in cryopreservation process, and summarizes the methods that can improve the efficiency of in vitro embryo cryopreservation, aiming to provide the reference for improving the efficiency of in vitro embryo cryopreservation.

MicroRNA(miRNA) is a class of highly conserved endogenous non-coding single-stranded small RNA molecules, about 19~25 nt in length, which usually plays a regulatory role in the post-transcriptional level of gene expression and participates in a variety of life activities such as cell development, proliferation, apoptosis and immunity. A large number of studies have shown that a variety of miRNAs regulate viral replication, cell proliferation or apoptosis and tumor development during viral infection through direct or indirect methods. This paper mainly reviews the regulatory mechanism of miRNA in immune response and viral replication during viral infection, aiming to provide reference for the development and application of miRNA and antiviral related treatment strategies.

As a natural polyphenolic plant extract, curcumin has many biological activities such as anti-inflammatory, anti-oxidant, anti-stress and improving animal intestinal health, and has become a green, safe and efficient feed additive. In recent years, studies have shown that curcumin has a close interaction with the gut microbiota. Curcumin can regulate the composition and diversity of the gut microbiota, and the gut microbiota affects the conversion of curcumin. This two-way regulation may be very important to the physiological function of curcumin. In addition, curcumin has been confirmed to resist multiple viral infections through different mechanisms, suggesting that it has the potential to become a new type of antiviral drug. Therefore, this article mainly reviews the interaction between curcumin and the gut microbiota and the related mechanisms of curcumin against different viral infections, with the final aim of providing theoretical basis for further understanding the mechanism of curcumin on improving animal health, and developing novel environment-friendly feed additive.

Lipopolysaccharide (LPS) is the main component of the cell wall of Gram-negative bacteria and widely exists in the environment. It can induce inflammatory response and is related to various diseases of dairy cows. Environmental and disease factors cause the increase of LPS level in the body. LPS acts with macrophages, neutrophils and epithelial cells, activates NF-κB and MAPKs signaling pathways, releases inflammatory factors, changes the levels of hormones and adipokine related to glucose and lipid metabolism, and further affects glucose and lipid metabolism, resulting in metabolic diseases such as type 2 diabetes, ketosis, fatty liver and obesity in dairy cows. This paper reviews the interaction between LPS and inflammatory response, glucose and lipid metabolism and the mechanism of abnormal glucose and lipid metabolism, which provides a reference for the mechanism of abnormal glucose and lipid metabolism induced by LPS in dairy cows.

Nucleotide-binding oligomerization domain-like receptor protein 1 (NLRP1) is a member of the NOD-like receptors (NLRs) family, and is the first NLR family protein found to form inflammasome. The activation of NLRP1 can cause the activation of pro-caspase-1 and further promote the maturation and release of inflammatory factors, which plays an important role in innate immunity. The domain structure of NLRP1 varies among different species. At present, the mechanisms that can cause NLRP1 activation mainly include degradation and activation of NLRP1 through proteasome pathway, activation of NLRP1 through inhibition of DPP9, and activation of NLRP1 by Toxoplasma gondii and some metabolic inhibitors. Some viral proteins or RNAs can also activate NLRP1. How the virus activates NLRP1 and the role of NLRP1 in antiviral infection are not clear, and need to be further studied.

Mobile colistin resistance (mcr) gene was first reported by Chinese scholars in 2016. Subsequently, 43 mutants of 10 mcrs were detected in more than 50 countries and 20 host bacteria worldwide. The coding protein MCRs have two conserved domains and similar predictive protein structure, and the amino acid sequence homology is about 32%-82.93%. It was found that mcr can spread widely with host bacteria in animals, humans and the environment, seriously reducing the therapeutic efficacy and use value of colistin, the "last line of defense" to control multidrug-resistant Gram-negative bacterial infections in veterinary clinics. The global transmission of mcr may be based on its complex genetic background. A total of 14 positive plasmid-species have been identified so far, further more, the horizontal transfer of mcr is also related to many mobile genetic elements such as insertion sequence ISApl1. The horizontal dissemination of mcr among different bacteria and species is posing a global threat to the public health safety, and how to control the spread of mcr needs further attention.

The aim of this study was to screen the key genes of lipid metabolism differences in back fat and abdominal fat of large Diqing Tibetan pigs (TPs) at different growth stages by transcriptome sequencing. In this study, 36 TPs with the same parity, birth date and weight of about 10 kg were randomly divided into 3 groups for fattening experiment under the same conditions. The pigs were slaughtered at the weight of 40, 80 and 120 kg, respectively, and carcass perfor-mance was measured. Back fat (BF) and abdominal fat (AF) of 3 pigs in each group were collected for high-throughput transcriptome sequencing. The sequencing data were spliced and compared to screen for genes with significant differences related to lipid metabolism, and then GO, KEGG analysis and gene interaction network analysis were performed. The results showed that 486, 765 and 339 differentially expressed genes (DEGs) were screened from AF vs. BF of large Diqing Tibetan pigs weighing 40, 80 and 120 kg, respectively. The qPCR results of randomly selected 5 significantly DEGs such as EGR2 and SOD3 were consistent with the transcriptome sequencing results. These DEGs were mainly enriched in GO items such as muscle contraction, cell adhesion and positive regulation of mesenchymal cell proliferation, and KEGG pathways such as cardiac muscle contraction, PI3K-Akt signaling pathway, and Hippo signaling pathway. In 40 kg group, EGR2, RARRES2, TMOD4 and SFRP2 genes were located in the network core, EGR2, RARRES2 and SFRP2 were up-regulated in abdominal fat, and TMOD4 was down-regulated. In 80 kg group,THBS1, PPARA, NRIP1 and LPL genes were located in the core of the network, and all 4 core genes were up-regulated in AF. In 120 kg group, HTRA1, TSHR, LRRK2, STC2, SHOX2 and SOD3 genes were located in the network core, LRRK2 and TSHR were up-regulated in AF, while SHOX2, SOD3, STC2 and HTRA1 were down-regulated. The results suggested that 14 core genes including EGR2, THBS1 and TSHR finely regulated the lipid metabolism of BF and AF at different growth stages of TPs. 10-40 kg, 4 genes such as EGR2 were located in the network core, the genes promoting adipocyte differentiation and proliferation were up-regulated in AF, and the switch genes for fat synthesis were down-regulated. 40-80 kg, THBS1 and other 3 genes were located in the network core, and the genes promoting triglyceride synthesis, cholesterol formation and lipid accumulation were up-regulated in AF. 80-120 kg, 6 genes such as LRRK2 were located in the network core, the genes promoting triglyceride accumulation and fatty acid oxidation were up-regulated in AF, and the genes inhibiting fat decomposition and fat droplet formation were down-regulated. The results can provide basic data for the analysis of the regulation mechanism of differential fat deposition in different parts of local pigs, and provide reference for the targeted breeding of TPs.

The study aimed to reveal the genetic basis of hatching traits of white-feathered broilers. In this experiment, two groups of White-feather broilers A and B were used as materials to determine the fertilization rate and hatching rate of 40-week-old eggs in 5 generations (556) of group A and 3 generations (398) of group B. The 55K SNP chip was used to genotype 954 healthy individuals in the two groups. Genetic parameter estimation based on pedigree and single nucleotide polymorphisms (SNPs) showed that the heritability of fertilization rate of group A was 0.21 and 0.14, respectively. Genome-wide association study (GWAS) of fertilization rate and hatching rate was performed using mixed linear model. A total of 12 significant SNPs were obtained by genome-wide association study, distributed on chromosome 1, 9, 11, 12, 20. Among them, 9 SNPs were significantly associated with fertilization rate, 3 SNPs were significantly associated with hatching rate, RNA-seq was performed on testis tissues of 4 roosters in each group with high or low fertilization rate, 2 differentially expressed genes were identified by qPCR. Nine genes related to fertilization rate were identified by genome-wide association study, including COPG1, ADAMTS18, FABP2, CDH8, SLCO4A1, ATP13A3, NELL2, VEZT and IGHMBP2,3 genes related to hatching rate, including TMEM, SCO1 and MYH1A, RNA-seq and qPCR identified two candidate genes, HMGCLL1 and COA6, which were related to fertilization rate. In this study, GWAS and RNA-seq were used to identified candidate genes related to hatching traits, which provided important molecular markers for the genetic improvement of hatching traits of White-feathered broilers.

The purpose of this study was to explore the expression of m6A methyltransferase-like protein 16 (METTL16) in different types of chicken muscle tissue and its regulatory role in chicken skeletal muscle function. In the present study, the tissue expression profile of METTL16 in different muscles of 120-day-old Guangxi partridge hens and the expression of genes related to proliferation, differentiation and muscle fiber formation after siRNA interference by qRT-PCR were analyzed. The results showed that METTL16 gene was widely expressed in different muscle tissues of chickens. White muscles, including major pectoralis, minor pectoralis and lateral iliotibial muscles, have higher METTL16 gene expression. Cell proliferation assay showed that the proliferation activity of chicken myoblasts was inhibited after METTL16 interference. Interfering with METTL16 gene during myoblast differentiation could reduced the methylation level of m6A and slow-MyHC expression in chicken myoblasts, significantly reduced MyoD expression (P<0.05), and significantly elevated fast-MyHC expression (P<0.001). In conclusion, the expression of METTL16 gene in different muscles is related to the composition of muscle fiber types. METTL16 gene may play a significant role in chicken myoblast proliferation and differentiation, and inhibit the formation of fast-twitch muscle fibers. These results indicated that METTL16 might play a crucial role in chicken muscle function regulation.

The aim of this study was to analyze the genetic diversity and population structure of Chinese native chicken breeds. A total of 157 chickens from 8 Chinese native breeds and 233 commercial chickens were genotyped using Affymetrix Axiom 600K high-density chicken chip. Each breed's genetic diversity was calculated with observed heterozygosity, expected heterozygosity, minor allele frequency, inbreeding coefficient and nucleotide diversity. Population structure was analyzed with neighbor-joining phylogenetic analysis, principal component analysis, population structure analysis and multidimensional scaling (MDS). Identity by state (IBS) and pairwise differentiation coefficient (Fst) were used to study the genetic relationship between and within breeds. Runs of homozygosity (ROH) analysis was used to obtain more accurate inbreeding coefficients. The results showed that the observed heterozygosity of each population was higher than the corresponding expected heterozygosity. Minor allele frequencies ranged from 0.175 to 0.236. Inbreeding coefficients ranged from 0.018 to 0.205. Nucleotide diversity ranged from 0 to 6×10^-4. The obvious genetic differentiation was observed between breeds according to the phylogenetic tree and principal component analysis. MDS analysis revealed a relatively close genetic relationship between Chinese native chickens and purebred broiler lines. IBS genetic distance ranged from 0.092 9 to 0.319 9. The populations had a moderate genetic differentiation based on the pairwise Fst data (0.09-0.22). Furthermore, 5 242 ROHs with lengths ranging from 1 Mb to 41.51 Mb were discovered. The ROH-based inbreeding coefficient (F_ROH) ranged between 0.010 and 0.150. These results revealed that the overall genetic diversity of local chickens is richer. Langshan chicken and Wannan three-yellow chicken had the most genetic diversity. High-levels inbreeding occurred in Fighting chickens, Gushi chickens and Chahua chicken, which might had ever been suffered from inbreeding events. Different breeds existed high genetic differentiation. The results of this study will aid in designing and implementing conservation strategies, which will promote the utilization and conservation of genetic resources.

Adipose tissue of mammals can be divided into white adipose tissue and brown adipose tissue. Brown adipose tissue and white adipose tissue are different in cell morphology and function, which play an important role in heat production and energy balance in mammals. In order to investigate the distribution characteristics of brown adipose tissue in sheep, perirenal fat, cervical fat, dorsal fat, tail fat, sternal fat, inguinal fat and pericardial fat of Sonid lamb at the 1 day, 7 day and 30 day after birth were collected. Different fat types were identified by HE staining, transmission electron microscope and immunohistochemical; And the characteristics of brown adipose tissue at different parts and different ages of Sonid lambs were explored by real-time fluorescent quantitative PCR and Western blot. The results showed that there were two different types adipocytes in Sonid lambs, brown adipocytes with small lipid droplets and white adipocytes with vacuolar lipid droplets. There were more mitochondria with cristae in brown adipocytes, and the expression of brown adipose tissue-specific protein UCP1 was detected. White adipocytes, on the other hand, had few mitochondria with regular cristae and did not express UCP1. Brown adipocyte numbers and UCP1 expression were not significantly different at 1 and 7 days of age, and decreased significantly at 30 days of age. In this study, the brown fat and white fat of Sonid lambs were identified by morphological observation, marker gene and protein detection, and it was proved that perirenal fat and tail fat were the main sources of brown fat and white fat, respectively. Sonid lambs had more brown fat at 1 and 7 days of age, and the phenotypic changes of brown fat at 30 days of birth showed a decreasing trend. The current study explored the characteristics of brown fat in Sonid lamb, and provided a certain basis for the study of brown fat in ruminants.

The aim of this study was to investigate the genetic diversity and genetic structure of Kirgiz sheep, and effectively protect and utilize its genetic resources.Sheep SNP 50K v3 chip was used to detect the single nucleotide polymorphism (SNP) of 61 Kirgiz sheep (31 rams and 30 ewes). Plink software (V1.90) was used to conduct the quality control of SNP genotyping results, and calculate the population effective content, the polymorphic marker proportion, observed heterozygosity, expected heterozygosity, polymorphic information content, effective number of alleles, minor allele frequency to analyze the genetic diversity of the Kirgiz sheep; Using Plink to calculate the runs of homozygosity (ROH) and obtain the inbreeding coefficient F_ROH based on ROH; The state homologous distance matrix (identical by state, IBS) was established, and G matrix were constructed by Gmatrix software, the genetic distance and genetic relationship of Kirgiz sheep were explored. Mega X software was used to construct evolutionary tree and analyze the family structure of Kirgiz rams. The results showed that a total of 64 734 SNPs were obtained from 61 Kirgiz sheep, and the number of SNPs passing quality control was 56 763; The average polymorphism information content was 0.273±0.112, the average observed heterozygosity and the average expected heterozygosity were 0.368±0.140 and 0.368±0.130, respectively, and the average minor allele frequency was 0.263±0.147. The average IBS genetic distance of Kirgiz sheep was 0.294. The results of G matrix and IBS distance matrix showed that the genetic relationship between individuals of Kirgiz sheep was farther. A total of 200 ROHs were detected in 61 Kirgiz sheep, 67.5% of which were within 1-5 Mb in length, and the ROH length of 56 Kirgiz sheep was 0-50 Mb. The average inbreeding coefficient based on ROH was 0.008 19±0.018 8, of which the average inbreeding coefficient of rams was 0.004 65±0.008, indicating that the average inbreeding coefficient degree of Kirgiz sheep population was low. The results of phylogenetic tree showed that there were 25 families in Kirgiz sheep population, and most families have too few rams. To sum up, the Kirgiz sheep population has rich genetic diversity and low inbreeding degree in these population, but the number of male sheep in each family is small, so it is necessary to increase the breeding of offspring and prevent the loss of blood to maintain the genetic diversity of Kirgiz sheep.

The aim of this study was to construct a recombinant interference vector of myocyte enhancer factor 2A (MEF2A) gene to explore the effect of MEF2A on bovine myoblasts. In this study, 3 healthy 3-day-old female Guanling cattle, with the body weight of about 21 kg, were selected to culture myoblastasts from longissimus dorsi muscle tissue. Four shRNA interference sequences of MEF2A gene and one NC negative control sequence were designed and connected to pGPU6-GFP-Neo vector, and the recombinant vector was transfected into Guanling bovine myoblasts. qRT-PCR was used to screen the vector with the best interference efficiency, and the effects of interfering MEF2A gene on the mRNA expression levels of myogenic factors MEF2B, MEF2C, MEF2D, cycle and apoptotic factors CDK2, CCNA2 and BCL2 were detected. Subsequently, flow cytometry and enzyme marker were used to investigate the effect of interference vector on myoblast proliferation and growth. Three biological replicates were set in each experimental group. Online software was used to predict the physicochemical properties and network spectra of bovine MEF2A protein. The results showed that the shRNA-MEF2A-3 vector with the best interference efficiency was selected successfully (P<0.01). After interfering MEF2A gene, MEF2B, MEF2C and MEF2D gene expressions in myoblasts were significantly up-regulated (P<0.01); The expressions of CDK2 and BCL2 were significantly down-regulated (P<0.05), the expression of CCNA2 was significantly down-regulated (P<0.01); Compared with the control group, the cell cycle in the interference group was significantly prolonged, and the proliferative activity of the interfered myoblasts was significantly lower than that in the control group (P<0.01). It can be preliminarily speculated that the MEF2A interference vector successfully transfected into bovine myoblasts can effectively inhibit the expression of MEF2A gene, change the gene expression pattern, and affect the division and proliferation of Guanling cattle myoblasts, which provides data support for further exploring the regulatory mechanism of MEF2A gene on the meat quality traits of Guanling cattle and mining local germplasm resources.

To explore the characteristics of Mongolian horse skeletal muscle in terms of movement and meat quality, 52 pieces of major skeletal muscle (2×26 pieces) of 2 5-year-old healthy untaught adult stallions were selected as the research objects. Paraffin sections, immunohistochemistry and HE staining were used to obtain skeletal muscle morphology, fast and slow muscle fiber distribution, and average cross-sectional area of muscle fibers of 26 sites. Due to the differences of skeletal muscles at different parts, the muscle tissue was divided into 5 groups (head and neck, forelimbs, trunk, abdominal wall side and hind limbs) for statistics. The corresponding 24 parts were compared with the thoroughpure breds skeletal muscle obtained in the previous studies in the proportion of fast and slow muscle fibers.The results showed that the phenotype spectrum of the main skeletal muscles of Mongolian horses. Among them, the proportion of slow muscle fibers in cervical serratus, supraspinatus, biceps, wrist radial flexor, gastrocnemius, rhomboid muscle and thoracoventrlateral serratus muscle was relatively low. The proportion of slow muscle fibers in wrist radial extensors, triceps brachia, longest dorsal muscle and gluteus mesoamericas accounted for more than 70%; the proportion of slow muscle fibers was negatively correlated with the cross-sectional area of muscle fibers. The proportion of slow muscle fibers in Mongolian horse skeletal muscle was basically higher than that in thoroughpure, the difference in forelimbs and trunks were very significant (P<0.01), and the differences in hindlimbs and abdominal wall side were significant (P<0.05). Among them, the difference of the proportion of slow muscle fibers between Mongolian horses and thoroughbred horses in brachial triceps, longest dorsal muscle, gluteus medius and semimembranous muscle were greater than 50%. The results indicate that serratus equinagia, supraspinatus, biceps brachia, flexor carpal radial, gastrocnemius, rhomboid and thoracoventral serratus muscle have the potential for endurance training. The wrist radial extensors, triceps brachia, longus dorsius and gluteus medius have good quality and can be the focus of horse meat development; and the triceps arm, dorsal maximus, gluteus medius and semimembranous muscles can be used as the key muscles of horse athletic performance testing. These results provides a theoretical basis for Mongolian horse sports training and meat quality development.

The study aimed to compare the predictive accuracy of genomic selection for growth-related traits in sika deer(Cervus Nippon) based on models such as GBLUP. The heritability of growth-related traits such as body weight and body size of sika deer was estimated for 261 sika deer from a deer farm in Jilin Province from 2014 to 2019 (96 males and 165 females). Based on 5-fold cross-validation method, the prediction accuracy of GBLUP, Bayes A, Bayes B, Bayes C, Bayes Lasso and RRBLUP genomic selection models were compared. The suitable genome selection model for the growth-related traits of sika deer was screened. The results showed that:1) The heritability of shin circumference and high hips were 0.43 and 0.50, respectively, which belonged to high heritability; the heritability of body weight, body height and body length were 0.22, 0.30 and 0.27, respectively, which belonged to medium heritability; while the heritability of chest girth was 0.15, which belonged to low heritability. 2) In GBLUP, there was a positive correlation between the accuracy of genomic selection prediction and heritability of traits, but there was no significant positive correlation in Bayes and RRBLUP methods. 3) When the sample size was small, selecting GBLUP as the model of genome selection had certain advantages, and Bayes A could be used as the first choice for traits with low heritability. The highest prediction accuracy of body weight, body height, body length, shin circumference, chest girth and high hips were GBLUP, Bayes B, Bayes C, Bayes B, Bayes A and RRBLUP, respectively. In the actual production, there is no model fully suitable for all the traits, and the best model must be selected according to the accuracy and timeliness of prediction.

The aim of this study was to analyze the correlation between environmental parameter of rolling shed and lactation performance and behavior of dairy cows. A cowshed was used, which was equipped with roller shutter on both south and north walls. The 200 healthy multiparous Holstein lactating cows (3 to 4 parity, (650±100) kg body weight, 5 to 6 years old) were used in this study, and indoor ambient parameters of rolling shed were detected for a natural year, as well as lactation performance and cow behavior. The ambient parameters included thermal para-meters (temperature (Ta), relative humidity (RH), wind speed (Ws)), airborne microorganisms (bacteria and fungi), dust (PM_2.5 and PM₁₀), harmful gases (carbon dioxide (CO₂) and ammonia (NH₃)). The study was performed to investigate correlation of ambient parameters of rolling shed with lactation or behavior of dairy cow. The results showed that:1) All ambient parameters demonstrated the seasonal variation. Among seasons, the content of fungus (1 049.91 cfu·m^-3) and two kinds of dusts(PM_2.5=17.86 μg·m^-3; PM₁₀=193.07 μg·m^-3) were the highest in summer, and bacteria content was the highest in autumn (1.11×10⁴cfu·m^-3), while CO₂ concentration(1 302.85 mg·m^-3) and NH₃ concentration (2.51 mg·m^-3) exhibited the highest value in winter. 2) The correlation between ambient parameters and lactation performance demonstrated the seasonal variation. Particularly in summer and winter, summer Ta or RH was linearly negatively and significantly correlated (P<0.05) with milk yield, and Ws was linearly positively and signifi-cantly correlated with milk yield (P<0.01). In winter, Ta or RH demonstrated a great influence on milk yield, and milk yield increased with the increasing temperature, showing a linear positive and significant correlation (P<0.01), while the correlation of RH with milk yield showed an opposite law. 3) Correlation between ambient parameters and behavioral parameters showed seasonality. In spring, Ta and CO₂ were key parameters affecting cow behavior. Ta was linearly positively and significantly correlated with feeding time or lying time (P<0.05), while CO₂ concentration was linearly negatively and significantly correlated with feeding time or lying time (P<0.05). In summer, Ta, RH and Ws affected mainly cow behavior. With increasing Ta, feeding frequency linearly and significantly decreased (P<0.05), drinking frequency, single drinking time and single standing time linearly and significantly increased (P<0.05, P<0.01). Also, the greater the Ws, the longer the feeding time (P<0.05). In addition, Ta and RH played important roles also in behavior in winter, Ta was linearly positively and significantly correlated with lying time (P<0.01). The correlation between ambient parameters and milk performance or behavior parameters of dairy cows showed seasonal regularity. There was a stronger correlation between environmental parameters and milking performance in both summer and winter, and Ta and RH were key parameters affecting cow behavior.

The purpose of this experiment was to study the effect of rutin on the ileal tissue morphology, immunity, antioxidant and barrier function of broilers. A total of 256 1-day-old AA broilers were selected and randomly divided into 4 groups, with 8 replicates in each group and 8 chickens in each replicate, and were fed the basal diet supplemented with 0 (control group), 250, 500 and 1 000 mg·kg^-1of rutin, respectively. The experiment was divided into early stage (1-21 d) and late stage (22-42 d), and the experiment lasted for 42 days. The results were showed as follows:1) Dietary rutin significantly increased the mRNA expression levels of Bcl-2 and ZO-1 in ileum mucosa of broilers at 21 d (P_Q<0.05), and linearly increased the villus height (VH) of ileum and the mRNA expression levels of Bcl-2, ZO-1 and Mucin2 in ileum mucosa of broilers at 42 d (P_L<0.05). Moreover, 500 mg·kg^-1 rutin supplementation significantly increased the expression of ki67 mRNA in ileal mucosa and the ileal VH at 42 d (P<0.05). 2) The addition of rutin to the diet linearly and quadratic increased the content of secreted immunoglobulin (sIgA) in the ileal mucosa at 21 d (P_L<0.05; P_Q<0.05), and decreased the mRNA expression of interleukin-2 (IL-2) in ileum mucosa at 42 d (P_L<0.05; P_Q<0.05), also linearly decreased the mRNA expression of tumor necrosis factor -α (TNF-α) (P_L<0.05). At the same time, compared with the control group, the addition of 250 and 500 mg·kg^-1 rutin decreased the expression of nuclear factor-κB (NF-κB) mRNA in the ileal mucosa at 21 d, while the addition of 500 mg·kg^-1 rutin decreased the mRNA expression level of NF-κB in ileal mucosa at 42 d (P<0.05). 3) At 21 d, dietary rutin supplementation increased the T-AOC in ileum mucosa linearly and quadratic (P_L<0.05; P_Q<0.05), as well as GSH-Px activity (P_L=0.096;P_Q<0.05) and HO-1 mRNA expression (P_L<0.05; P_Q<0.05). Also linearly increased the expression level of NQO1 mRNA (P_L<0.05), quadratic decreased the content of MDA in ileum mucosa (P_Q<0.05), and increased the expression level of Nrf2 mRNA (P_Q<0.05); Compared with control group, the expression level of HO-1 mRNA in ileum mucosa in rutin treatment group were significantly increased (P<0.05), the content of MDA in ileum mucosa in 250 and 500 mg·kg^-1 rutin groups were significantly decreased (P<0.05), and the activity of GSH-Px in ileum mucosa was increased (P<0.05). T-AOC and the mRNA expression of NQO1 in ileum mucosa of 500 mg·kg^-1rutin group were also significantly higher than those in control group (P<0.05). At 42 d, the supplementation of rutin linearly and quadratic decreased the content of MDA in ileum mucosa (P_L<0.05; P_Q<0.05), the mRNA expression levels of Nrf2 and HO-1 increased quadratic (P_Q<0.05), and compared with the control group, the supplementation of 500 mg·kg^-1 rutin significantly decreased the content of MDA in ileum mucosa (P<0.05). The activity of T-SOD and mRNA expression levels of Nrf2 and HO-1 were increased (P<0.05). In summary, supplementation of rutin in the diet could improve the ileal morphology and structure of broiler chickens, improve intestinal immunity and barrier function, and improve its antioxidant capacity by enhancing the Nrf2 signaling pathway in ileal tissue. Under the conditions of this experiment, considering the effect of rutin on the whole period of broilers, the recommended amount of rutin in the diet was 500 mg·kg^-1.

The objective of this study was to observe the effects of tail docking on the growth performance, slaughter performance, fat deposition distribution and serum adipokines in Lanzhou fat-tailed sheep. The results were expected to provide reference for improving the production of fat-tailed sheep by fat deposition intervention. Eighteen 5 days old healthy Lanzhou fat-tailed lambs with clear genealogy and uniform weight were randomly divided into control group(C group) and test group(T group), 9 lambs each group,the tail from T group lambs were ligated with rubber band. The two groups were fed with the same diet in the trial period, with the feed concentrate-roughage ratio of 70:30, and the animals had free access to the water. The trial lasted for 240 days. The results were showed as follows:1) Average daily gain of tail docking sheep was significantly lower than that in C group (P<0.05) in the first 30 days. There was no significant difference in average daily gain between the two groups during 31~240 d (P>0.05). 2) The body weight of tail docking sheep was significantly lower than that in C group in the first three stages (0~90 d)(P<0.05), but there was no significant difference between the two groups in other stages (P>0.05). The feed to gain ratio in tail docking group was significantly lower than that in C group (P<0.05) during 61~90 d, and there was no significant difference between the other stages (P>0.05). 3) Serum TNF-α in the tail docking group was significantly higher than that of the control group (P<0.05) during 0~60 d, and was numerically higher during 61~240 d (P>0.05). Serum GLU, LEP, RETN and ADPN in the tail-docking group were higher, and the difference between two group increased with the extension of test period, but the difference was not significant (P>0.05). Serum TG, IL-6 and NEFA were not significantly different in the trial period (P>0.05). 4) The tail fat and total fat index in tail docking group were significantly lower (P<0.05). The subcutaneous fat, kidney fat, abdominal fat and visceral fat index in tail docking group were significantly higher (P<0.05). There was no significant difference in heart fat, omentum fat and mesenteric fat index (P>0.05), but tail length, tail middle width, tail circumference and tail weight index decreased significantly (P< 0.05) in tail docking group compared with the control growp. 5) The slaughter rate of sheep in the tail docking group significantly increased compared with the control group (P<0.05), while backfat thickness, GR value and eye muscle area were numerically higher compared to the control group with no significant difference (P>0.05). The meat color (brightness, redness, yellowness) and pH of the Longissimus dorsi muscle had no significant difference between two groups (P>0.05). The shear force was significantly lower in tail-docking group (P<0.05). Water loss and cooking loss had no significant difference between the two groups (P>0.05). The results showed that tail docking at the early age of Lanzhou fat-tailed sheep could decrease the tail size, weight and fat weight proportion, change the distribution of fat deposition, and make more fat deposits in muscle and other parts of the body, thus improve the slaughter rate and improve the quality of meat.

Infectious bursal disease (IBD) is a highly lethal and immunosuppressive infectious disease that seriously harms the poultry industry. In order to develop a recombinant herpesvirus of turkey (HVT) vector vaccine against IBD, a recombinant HVT expressing the protective antigen VP2 gene of infectious bursal disease virus (IBDV) was constructed and its biological characteristics in vitro were analyzed. The VP2 gene of very virulent IBDV (vvIBDV) was amplified by RT-PCR and cloned into pCI vector to obtain the recombinant eukaryotic expression plasmid pCI-VP2. The expression frame of VP2 gene carrying CMV promoter was cut off by restriction endonuclease and ligated into entry plasmid pENTR to construct a recombinant entry plasmid pENTR-VP2. The recombinant expression fosmid H3-VP2 were constructed by LR recombination reaction between pENTR-VP2 entry plasmid and HVT recombinant fosmid H3-Kan/ccdB. The recombinant virus rHVT-VP2 was obtained by co-transfection of H3-VP2 with four other fosmids that overlap each other and cover the whole genome of HVT into chicken embryo fibroblasts (CEF). After continuously passaged in CEF for 20 generations, the recombinant virus was detected by PCR, indirect immunofluorescence, and Western blot. The growth curve of recombinant virus in vitro was determined and its replication characteristics in vitro were analyzed. The results showed that the recombinant virus rHVT-VP2 stably expressed VP2 protein, and the replication ability of rHVT-VP2 in CEF was not significantly different from that of the parent virus. The recombinant virus rHVT-VP2 induced virus neutralization antibodies against IBDV and provided 90% protection against vvIBDV-induced death in chickens. The construction of recombinant virus rHVT-VP2 lays a foundation for the development of recombinant HVT live vector vaccine against IBD and is of great significance for the prevention and control of this disease.

This study aimed to investigate the effects of gga-miR-155 on the transcriptomic level of Marek's disease virus transformed tumor cell line MDCC-MSB1 cells. In this study, MDCC-MSB1 cells were transfected with gga-miR-155 mimics and gga-miR-155 mimics NC, the total RNA of MDCC-MSB1 cells transfected with gga-miR-155 mimics and its negative control was extracted at 48 h after transfection and the integrity of total RNA was analyzed by Agilent 2100 nucleic acid detector respectively. After analyzing the overexpression of gga-miR-155 in MDCC-MSB1 cells by RT-qPCR, the changes in transcription level of MDCC-MSB1 cells after overexpression of gga-miR-155 were analyzed using the high-throughput sequencing technology. On this basis, the differentially expressed genes were screened, and the involved target mRNAs of gga-miR-155 in the differentially expressed genes were predicted combined with bioinformatics analysis. The RNA samples of gga-miR-155 overexpression in MDCC-MSB1 cells were prepared and a high-throughput sequencing library was constructed. Compared with the negative control group, 87 differentially expressed genes were found in the gga-miR-155 overexpression group, including 47 up-regulated genes and 40 down-regulated genes. GO and KEGG analysis showed that these differentially expressed genes were significantly enriched in metabolic and protein binding processes/signaling pathways. Chicken BACH1 was predicted as the target mRNA of gga-miR-155 by Targetscan and miRada software (P<0.05). The transcriptional level of MDCC-MSB1 cells was regulated by overexpressed gga-miR-155, and BACH1 gene in the differentially expressed genes may be involved in the metabolic process of MDCC-MSB1 cells under the regulation of gga-miR-155.

In order to comprehensively understand the epidemiological situation of bovine coronavirus (BCoV) in beef cattle herds in Jilin Province, blood, nasal swabs, fecal swabs and tissue organs of clinically diseased and dead cattle were collected in different seasons from 12 counties and cities in the east, central and western regions of Jilin Province, using serological and molecular diagnostic testing techniques to conduct an epidemiological investigation of BCoV in the The epidemiological situation of BCoV in some areas of Jilin Province. A total of 1 298 clinical serum samples, 462 clinical samples (including fecal samples, liver, lung, spleen, trachea and other tissue samples) were collected, and PCR detection of clinical samples was performed by applying commercial BCoV antibody detection kits to detect serum antibodies and a novel detection technique of nano-PCR, and sequencing and analysis of positive results detected by nucleic acid. The results showed that the serum positive rate of BCoV antibodies was 1.08%, and the positive rate of clinical samples such as feces and liver was 21.10%. The BCoV prevalent strain in the investigated area was more than 99% homologous to the prevalent strain in Sichuan, China, after sequencing analysis. This study provides a comprehensive survey of BCoV prevalence in central Jilin Province, which enriches the epidemiological survey data of bovine coronavirus and lays the foundation for guiding the prevention and control of bovine coronavirus.

The present study was aimed to investigate the effect of heat shock protein 90 beta family member 1 (HSP90B1) on the replication of bovine viral diarrhea virus (BVDV). The expression of HSP90B1 mRNA and protein in MDBK cells after BVDV infection were detected by using quantitative real time polymerase chain reaction (qRT-PCR) and Western blot. HSP90B1 KO cells were constructed using CRISPR/Cas9 technology. The effect of knockdown of HSP90B1 on cell growth was detected by counting. After infecting with BVDV TC strain, BVDV replication in HSP90B1 KO and control Scramble cells were detected using qRT-PCR, immunofluorescence, viral titer and cytopathic effects (CPE). The qRT-PCR results showed that the transcription level of HSP90B1 mRNA was significantly increased at 24 h after BVDV infection compared with the blank group (P<0.05), and was significantly increased after 36 h (P<0.01). Meanwhile, Western blot results showed that the expression level of HSP90B1 protein of BVDV infection group was significantly increased compared with the uninfected group; Western blot results showed that the expression of HSP90B1 protein in HSP90B1 KO cells was significantly lower than that in MDBK cells; There was no difference in the number of cells; qRT-PCR results showed that BVDV 5'UTR RNA levels in HSP90B1 KO cells were significantly reduced after 12 h of BVDV infection (P<0.05) and highly significantly reduced after 36 h compared with the control group (P< 0.01); the results of immunofluorescence detection showed that the green fluorescence in HSP90B1 KO cells was significantly reduced compared with the control group; viral titer after BVDV infection was significantly lower in HSP90B1 KO compared to control (P<0.05) after 12 h and highly significantly lower after 36 h (P<0.01), CPE showed that control cells showed The CPE showed that control cells showed significant CPE after 12 h of infection, while HSP90B1 KO cells showed only a small amount of CPE, and HSP90B1 KO cells showed significant CPE after 36 h of infection, at which time control cells showed a large amount of CPE with cell shedding. The above results show that BVDV induces the expression of HSP90B1 in MDBK cells; the HSP90B1 gene in MDBK cells was successfully knocked out by CRISPR/Cas9 technology, and HSP90B1 KO cells were constructed, experiments show that knockout of HSP90B1 can inhibit BVDV replication.

The increase of interleukin-10 (IL-10) is one of the hallmarks during foot-and-mouth disease virus (FMDV) infection. The aim of this study was to investigate the effects of IL-10 on the proliferation and the expressions of function-related cytokines of T cells in peripheral blood of mice infected with FMDV. The proliferation and the expressions of effector function-related cytokines (TNF-α, IFN-γ and IL-2) of T cells in peripheral blood of mice were detected by CCK-8 and flow cytometry, respectively. The results showed that the proliferations of T cells in peripheral blood of FMDV-infected mice at 12, 24, 36 and 48 hpi were significantly decreased compared with that of mock-mice (P<0.05 or P<0.01); and the expressions of TNF-α and IL-2 of CD4⁺ T cells in peripheral blood of infected mice were significantly decreased compared with that of mock-mice (all P<0.01); and the expressions of TNF-α, IFN-γ and IL-2 of CD8⁺ T cells in peripheral blood of infected mice were also significantly decreased compared with that of mock-mice (P<0.01 or P<0.000 1). However, blocking IL-10/IL-10R signaling in vivo or knocking out IL-10 contributed to restore the proliferation of T cells in peripheral blood following FMDV infection (P<0.05 or P<0.01), but did not affect the expressions of TNF-α, IFN-γ and IL-2 of CD4⁺ and CD8⁺ T cells. The study for the first time revealed that the proliferation and the expressions of TNF-α, IFN-γ and IL-2 of T cells were inhibited after FMDV infection, which contributed to evade immune responses. Although blocking IL-10/IL-10R signaling in vivo or knocking out IL-10 did not affect the expressions of TNF-α, IFN-γ and IL-2 of CD4⁺ and CD8⁺ T cells, it contributed to restore the proliferation of T cells in peripheral blood of FMDV-infected mice, providing new perspectives and new strategies for the design of new products for FMD prevention and control.

Previous studies have shown that the D1133L gene encoded by African swine fever virus (ASFV) is crucial to ASFV replication. In order to further explore the role of D1133L in ASFV replication, in this study, we used homologous recombination technology and Escherichia coli lac repression operating system to knockout D1133L gene conditionally, constructed recombinant transfer vector ASFV Δi130 using pUC118 as vector, transfected BMDM cells with recombinant transfer vector, and infected BMDM cells with ASFV CN/GS/2018 wild type strain. In the presence of isopropyl-β-D-thiogalactoside (IPTG), conditional knockout D1133L recombinant strain vD1133Li was identified by green fluorescence and qPCR. The replication of the recombinant virus strain and the parent virus strain in PAM cells was observed with fluorescence microscope. Differences between vD1133Li and the parent virus strain were analyzed by qPCR. The replication difference between conditionally knockout D1133L recombinant strain with or without IPTG was also further investigated. The vD1133Li with conditional deletion of D1133L was constructed successfully in this study. Replication level of vD1133Li was significantly lower than that of the wild type virus strain. In MA-104 cell lines that overexpressing stably D1133L, the replication ability of vD1133Li was recovered. In summary, D1133L is crucial for ASFV replication. These results provide a basis for further research on the function of D1133L in ASFV replication, the pathogenic mechanism and the development of D1133L targeted drugs.

In order to explore the role of host protein Beclin1 in the process of autophagy activated by NS5A, a non structural protein of classical swine fever virus (CSFV), and the specific molecular mechanism, this study used qRT-PCR to detect the expression changes of Beclin1, PI3K/Akt signaling pathway related factors in ST cells infected with CSFV and expressing NS5A protein. The interaction between Beclin1 and NS5A was studied by laser confocal, Co IP and GST pulldown methods. By overexpressing or knocking down Beclin1 in ST cells, we studied its effect on CSFV replication. The results showed that ST cells infected with CSFV or expressed NS5A protein externally, the transcription and protein expression levels of Beclin1 were significantly increased, and the expression levels of PI3K/Akt signaling pathway related factors were positively correlated with them. In addition, CSFV NS5A protein and Beclin1 protein have co localization and interaction in cells. Finally, we found that overexpression of Beclin1 in cells significantly promoted CSFV replication; On the contrary, knockdown of Beclin1 with siRNA inhibited the activation of PI3K/Akt signaling pathway, and CSFV proliferation showed significant inhibitory effect. The above results indicate that Beclin1 protein can promote the replication of CSFV, and its mechanism is through the interaction with NS5A to regulate PI3K/Akt signaling pathway.

Herein, we attempted to clarify the adhesion characterization of 43K OMP of bovine Fusobacterium necrophorum.In this study, 43K OMP gene of F. necrophorum was cloned into pET-32a vector and the proteins were subsequently expressed on the surface of E. coli BL21 DE3 cells. The attachment assay, antibody inhibition attachment assay, native protein inhibition assay and proteinase treatment assay were used to determine the adhesion characterization of 43K OMP in bovine F. necrophorum. Meanwhile, the recombinant protein and naive 43K OMP were co-incubated with bovine endometrial epithelial cells or bovine mammary epithelial cells(MAC-T), and then evaluated the adhesion effect of 43K OMP of F. necrophorum to bovine epithelial cells. The 43K OMP gene was cloned into pET-32a vector and the recombinant 43K OMP in the form of an inclusion body was present in the bacterial precipitation. When E. coli carrying the recombinant plasmid (H2019) was induced by IPTG, there was significant enhancement in the binding to host cells compared to the E. coli carrying control vector only(P<0.05). When fixed cells were incubated with purified native 43K OMP, H2019 showed lower levels of binding(P<0.05). Pre-incubation of induced H2019 with polyclonal antibodies or monclonal antibodies against the 43K OMP reduced the binding amount to host cells(P<0.05). The adhesion of F. necrophorum was significantly decreased after proteinase K treatment(P<0.05), and dose-dependent relationship was shown between the decrease degree of adhesionto host cells and the concentrations of proteinase K. At the same time, the native 43K OMP and recombinant 43K OMP could bind to bovine endometrial epithelial cells or MAC-T cells. The 43K OMP of bovine F. necrophorum possessed the ability of adhesion to bovine host cells, and the 43K OMP acted as an adhesion protein to improve the binding ability of bovine F. necrophorum to host cells.

The aim of this study was to investigate the antiviral activity of goat interferon α (IFN-α) to caprine parainfluenza virus 3 (CPIV3). The sequence characteristics of goat IFN-α was analyzed, and the homology of IFN-α from different species was compared. Then the recombinant expression plasmid pET-30a-gIFN-α by inserting goat IFN-α gene (removing the signal peptide gene sequence) into vector pET-30a was constructed and transformed into Rosetta (DE3), after induced by IPTG, the goat IFN-α was expressed and purified. Then the relative expression level of interferon-stimulated genes (ISGs) was measured, and the anti-CPIV3 activity was measured after exogenous goat IFN-α treatment on Madin-Darby bovine kidney cell(MDBK cell) by TCID₅₀ and Western blot. The results showed that, the protein concentration of goat IFN-α was 0.20 mg·mL^-1, and Western blot analysis showed that the relative molecular weight was about 20 ku, which was consistent with expectations. The RT-qPCR result showed that the incubation of goat IFN-α on MDBK cells induced the up-regulation of the six ISGs including RSAD2, STAT1 and ISG15. Meanwhile, the goat IFN-α inhibited the CPIV3 replication, and down-regulated the expression level of the viral nonstructural protein C. All above results indicated that goat IFN-α could significantly inhibit the proliferation of CPIV3 on MDBK cells. This study extended the research type I interferon, and promoted the prevention and control of ruminant diseases.

Oxidative stress is closely related to the growth retardation and the occurrence and development of diseases in animals. Chito-oligosaccharide (COSs) has the effect of anti-oxidative stress, but the effect and molecular mechanism of COSs in inhibiting oxidative stress in hippocampus of brain in piglets are not clear. In this study, the oxidative stress model of piglets was established by intramuscular injection of dextran iron (FeDex), and on this basis, the effects of COSs on the average daily gain, oxidation and anti-oxidation related indexes of serum and some tissue, expression levels of apoptosis related protein gene and neuropeptide cocaine and amphetamine regulated transcript (CART) genes of hippocampus in piglets were investigated. Furthermore, the correlation between the expression levels of CART gene and apoptosis-related protein gene was analyzed. The results showed that compared with the control group, the daily gain, the levels of glutathione (GSH) and total anti-oxidant capacity (T-AOC) in serum, liver, lung, hippocampus and cerebral cortex of piglets with oxidative stress were significantly decreased (P<0.01 or P<0.05), while the contents of hydrogenperoxide (H₂O₂) and malondialdehyde (MDA) were significantly increased (P<0.01 or P<0.05). Intragastrical administration of 50 mg·kg^-1 COSs significantly increased the daily gain, the levels of GSH and T-AOC in serum, liver, lung, hippocampus and cerebral cortex (P<0.01 or P<0.05), while decreased the contents of H₂O₂ and MDA in serum and liver, lung, hippocampus and cerebral cortex of piglets with oxidative stress (P<0.01 or P<0.05). Compared with the control group, the expression levels of Cleaved Caspase-3 and Bax genes were significantly up-regulated in hippocampus of piglets with oxidative stress (P<0.05), while the expression level of Bcl-2 gene was significantly down-regulated (P<0.05). COSs significantly decreased the expression levels of Bax and Cleaved Caspase-3 genes in the hippocampus of piglets with oxidative stress (P<0.05), while significantly increased the expression level of Bcl-2 (P<0.05). Further study showed that compared with the control group, the expression levels of CART gene were significantly decreased in piglets with oxidative stress (P<0.01), while COSs significantly increased the expression levels of CART gene (P<0.01). The results of correlation analysis showed that CART was significantly correlated with the expression level of apoptosis-related protein genes. COSs can inhibit oxidative stress of hippocampus of piglets by weakening apoptosis signal pathway, which may be mediated by neuropeptide CART.

This study explored the effects of low-concentration azithromycin on protein expression, capsular polysaccharide and drug susceptibility of Streptococcus suis type 2, so as to lay a foundation for further study on the effects of low-concentration antibiotics in the environment on microorganisms. After S. suis type 2 was exposed to low-concentration azithromycin, the key differentially expressed proteins were screened by proteomic iTRAQ technology. At the same time, the capsular polysaccharide content and drug susceptibility of S. suis type 2 were determined. One hundred and seventy-four differentially expressed proteins were identified, accounting for 11.6% of the total identified proteins. Most differentially expressed proteins were involved in catalytic and metabolic processes. Most differentially expressed proteins belonged to membrane proteins. Among them, three capsular polysaccharide proteins, nine ABC transporters, one 50S ribosomal protein, one ribosomal RNA methyltransferase and one DNA gyrase were up-regulated; eight capsular polysaccharide proteins, four 50S ribosomal proteins, four 30S ribosomal proteins, one ribosomal RNA methyltransferase and one DNA polymerase IV were down regulated. When S. suis type 2 was exposed to low-concentration azithromycin, S. suis type 2 had reduced sensitivity to a variety of antibiotics. The drug sensitivity of the surviving strains recovered after returning to normal culture. When S. suis type 2 was exposed to low-concentration azithromycin, the content of capsular polysaccharide did not change significantly. S. suis type 2 adapted to the selection pressure of azithromycin by changing the expression of its own proteome. When coexisting with low-concentration azithromycin, S. suis type 2 started the efflux pump system. The efflux effect would increase the risk of bacteria producing multiple drug resistance.

The aim of this study was to detect fluoroquinolones (FQs), in chicken, chicken liver, and fish, an indirect competitive enzyme-linked immunosorbent assay (icELISA) was developed based on immunomagnetic beads for sample clean-up and purification. (Method) Optimizing the addition amount of monoclonal antibody, coupling time, pH of buffer solution, the addition amount of quinolone antigen, capture time of antigen, temperature, and encapsulation condition of immunomagnetic beads, an icELISA method based on immunomagnetic beads clean-up was preliminarily established. Results were as follows:1) In 1 mg magnetic beads, the optimal coupling amount of sarafloxacin (SAR) monoclonal antibody was 15 μg, coupling time was 60 min, pH was 4.4; 2) The optimal antigen dosage was 1 ng·mL^-1, capture time was 40 min, and the buffer ion concentration was 0.01 mol·L^-1 PBS. The IC₅₀ was 0.73 ng·mL^-1 with a linear range of 1.0-3.2 ng·mL^-1; 3) The detection limits of fluoroquinolones in chicken, chicken liver and fish were less than 1.33, 2.17 and 2.31 μg·kg^-1, and the recoveries ranged from 76.83%-98.70% with intraday and interday variation coefficients lower than 15%. The recovery results were further confirmed using liquid chromatography-tandem mass spectrometry. The results suggest that, compared with the traditional instrumental detection method, this method can improve the simplicity, selectivity, and detection efficiency of fluoroquinolones, and provide a new idea for fluoroquinolones residue detection.

This study was conducted to investigate the protective effects of dexmedetomidine (DEX) on renal injury caused by acute stress in rats and to explore the protective pathways of DEX on rat kidney from the perspective of oxidative stress. In this study, an acute restraint stress model was used, in which rats were forced to swim for 15 minutes and restrained for 3 hours. This experiment was performed with biochemical assays, histopathological section observation to assess renal function, followed by determination of oxidative stress and proteins of pathways related to oxidative stress. The open-field experiments confirmed that the acute stress model had been successfully established. DEX decreased NOX4 expression and increased Nrf2/HO-1/NQO1 expression, and the kidney biochemical results were significantly normalized in the DEX-treated group compared with the acute stress group, and the damage was significantly reduced in the pathological sections. The experimental results suggest that DEX treatment of acute stress can affect NOX4/Nrf2/HO-1/NQO1 signaling pathway and inhibit oxidative stress. Therefore, DEX has a protective effect on acute stress-induced renal injury and has potential clinical applications in stress syndromes.

The aim of this experiment was to study the effect of ferroptosis on cadmium-induced liver damage of chicken. After 7 d pre-feeding, thirty 1-day-old Hylan white chickens were randomly divided into control group (group C) and cadmium exposure test group (group Cd), with 15 chickens in each group. Chickens in group C were fed the basal diet, and chickens in group Cd were fed the diet supplemented with 140 mg·kg^-1 CdCl₂. Samples were taken at 20, 40 and 60 d after cadmium exposure to observe liver histopathological and ultra-pathological changes, and to detect liver functional enzyme activities, levels of inflammatory factors, oxidative stress, ferroptosis-related factors and mitochondrial fusion-related factors in the liver. Based on the establishment of liver cancer cell line (LMH) exposed to cadmium, groups of iron death activator and iron death inhibitor were put up as well, and the cell activity, expression of inflammatory factors, iron death related factors and mitochondrial fusion related factors were detected after 24 hours. The results showed that the activity of liver functional enzymes in the serum of chickens in the group Cd was significantly increased; Liver cells were disorder, vacuolar degeneration or even necrosis; Liver congestion, serousand fibrinous exudation, and inflammatory cell infiltration; The relative expression levels of inflammatory factors LOX, NF-κB, TNF-α, IL-6 and IL-1β mRNA in the liver were up-regulated, and the contents of TNF-α, IL-6 and IL-1β were increased; The content of peroxide MDA was significantly increased, the activities of antioxidant enzymes GSH-Px and SOD were significantly decreased; The relative expression levels of ferroptosis metabolism-related factors FTH1 and TFR mRNA were significantly increased levels. The expression levels of GPX4 was significantly decreased, and the expression levels of ACSL4 and PTGS2 were extremely significantly increased; Mitochondrial fusion-related factors OPA1, Mfn1/2 mRNA expression levels were significantly decreased. Cadmium exposure and ferroptosis activators can both induce ferroptosis in LMH cells, promote the release of inflammatory factors, cause mitochondrial dysfunction, and lead to cell damage; Ferroptosis inhibitor significantly inhibited the cadmium-induced release of inflammatory factors and mitochondrial damage in LMH cells, and alleviated the decrease in cell viability caused by cadmium. The results indicated that cadmium exposure caused the accumulation of lipid peroxides, the disturbance of iron metabolism, and ferroptosis, which eventually promoted inflammatory damage to the liver.

At present, acute kidney injury (AKI) has become the most important renal disease in canine, especially in the elderly canine with an increasing incidence year by year. Acupuncture therapy has been widely used in pet clinic in recent years, and has gradually developed from treating paralysis and other surgical diseases to treating pet medical diseases. In this study, adenine was used as the modeling drug to establish the dog model of acute kidney injury, and electroacupuncture was used to treat it. To investigate the effects of electroacupuncture (EA) on kidney function, calcium and phosphorus metabolism, antioxidant capacity and NRF2 pathway related proteins in dogs, and to explore the therapeutic effect of EA on acute kidney injury in dogs. Twenty-four healthy beagles (3-4 kg) were randomly divided into control group, model group, conventional treatment group, EA intervention group, EA treatment group and combined treatment group. The 1st to 15th day for the modeling period, and the 16th to 30th day for the treatment period. After trial period, the changes of urine specific gravity, serum urea nitrogen (BUN), creatinine (CREA), uric acid (UA), calcium (Ca²⁺) and phosphorus (P³⁺) were detected. Imaging diagnosis X-ray detection of renal changes; SOD and MDA in serum and kidney were detected. The severity of renal tissue lesion was observed by histopathology. qRT-PCR and WB were used to detect the expression of antioxidation-related genes and proteins in renal tissues of experimental dogs. The distribution of antioxidant-related proteins in renal tissues was detected by immunohistochemistry. Here, we found that urine proportion increased after electroacupuncture intervention. Serum biochemical results showed that compared with adenine model group, BUN, CRE, UA, Ca²⁺ significantly increased, P³⁺ significantly decreased in serum after electroacupuncture treatment. X-ray results showed that kidney size decreased after electroacupuncture treatment. SOD activity in blood and kidney tissue were significantly increased, while MDA content decreased significantly. The results of HE staining showed that the edema degree of renal tubular epithelial cells was reduced, necrosis and vacuolar degeneration were also significantly improved after electroacupuncture treatment. qRT-PCR and WB results showed that KEAP1 gene and protein expression were up-regulated and NRF2, HO-1, NQO1 gene and protein expression were down-regulated in the modeling group compared with the blank group. Compared with the modeling group, the expressions of KEAP1 gene and protein were down-regulated in all treatment groups, while the expressions of NRF2, HO-1 and NQO1 gene and protein were up-regulated. The changes of KEAP1 gene and protein expression in the combined treatment group were more obvious than those in the other treatment groups. The changes of NRF2 protein expression in electroacupuncture intervention group were more obvious than those in other treatment groups.Electroacupuncture therapy can relieve the symptoms of acute kidney injury and kidney damage in dogs. Among them, electroacupuncture combined with conventional therapy has a better therapeutic effect on acute kidney injury, and its therapeutic effect is better than electroacupuncture alone or symptomatic treatment alone.

This experiment was conducted to explore the anatomic differences of medial patellar luxation (MPL) dogs with various degrees symptoms. And comparing the consistency, advantages and disadvantages of CT and X-ray techniques. Thirty-four hindlimbs of small breed canines were divided into normal group, MPL asymptomatic group and MPL symptomatic group according to the symptoms. CT images were used to measure the depth of trochlear groove/patella thickness, length of patellar ligament/patella length, aLDFA, mLDFA, aLPFA, mLPFA, FIA, and analyzing the anatomical structure differences of femur and stifle in each group. In addition, to analyzed two imaging techniques in assessing skeletal malformations by comparing X-ray and CT measurements in a group of dogs. The results showed that there were significant differences in the depth of trochlear groove/patella thickness between normal group (0.47±0.07) and MPL asymptomatic group (0.27±0.14) and MPL symptomatic group (0.35±0.14) (P<0.05), and there were significant differences in aLDFA, mLDFA between normal group[(89.7±4.1)°, (95.6±3.3)°] and symptomatic MPL group[(97.4±6.2)°, (101.2±4.6)°](P<0.05). There were statistical differences in patellar ligament length/patella length, aLPFA, mLPFA and mLDFA between radiographic and CT groups (P<0.05). These results indicated that MPL dogs tend to have superficial trochlear grooches, and symptomatic dogs are more likely to have severe femoral deformities. There is a significant difference in the evaluation of skeletal deformities between X-ray and CT.

This study aimed to investigate the mechanism of Shenling Baizhu powder on improving intestinal homeostasis and relieving weaning stress of newborn rats. Nine pregnant SD rats were randomly divided into three groups, including blank group (CON), antibiotics group (ABX) and Shenling Baizhu powder group (SLBZS). After delivery, antibiotics were added to the drinking water of the female rats in ABX group and SLBZS group, the female rats in CON group were treated normally, and the offsprings in SLBZS group were gavaged with Shenling Baizhu powder decoction for 7 consecutive days from the 14th day after delivery, the offsprings in CON group and ABX group were gavaged with the same amount of normal saline. On day 14 and day 21 after delivery, the fecal samples of the offsprings in each group were collected and analyzed by 16S rRNA gene sequencing. Western blot was used to detect the expression of ZO-1 and Occludin proteins in the colon of the offsprings. Moreover, the histopathological changes of the colon section were detected by hematoxylin and eosin (HE) staining. The results showed that the intestinal microbial diversity in ABX group was significantly lower than that in CON group (P<0.05), and the Shenling Baizhu powder treatment reduced the relative abundance of pathogenic bacteria, such as Enterococcus, Sutterella, and Shigella, while increased the relative abundance of Lactobacillus, Blautia and Akkermansia. The expression of tight junction proteins ZO-1 and Occludin in colon of offspring rats were significantly lower than CON group (P<0.05). After treated with Shenling Baizhu powder, the gut barrier of offspring rats had been improved. The histopathological section of the colon showed obvious inflammatory cell infiltration in the ABX group, while the inflammatory cell infiltration was reduced in the SLBZS group. In conclusion, the use of antibiotics in maternal rats during the period of lactation could change the gut microbes structure in offspring rats, which may affect the permeability of the intestinal mucosa, and has the potential to promote intestinal inflammation. The use of Shenling Baizhu powder on sucking rats could modulate the structure of gut microbiota and increase the expression level of intestinal tight junction protein ZO-1 and Occludin, thus improving the health of intestinal.

The purpose of this study was to investigate the effect of bilobalide on IL-1β-induced autophagy, proliferation and apoptosis of ATDC5 chondrocytes. 10 ng·mL^-1 IL-1β was used to induce ATDC5 chondrocytes to construct an in vitro inflammatory model, and then the cells were randomly divided into control group, IL-1β group and bilobalide groups (low-, medium- and high-dosage). The newly synthesized DNA of cells was detected by EdU, and the cell proliferation rate was detected by double labeling combined with the nuclear marker (Hoechest). The apoptosis of ATDC5 chondrocytes was analyzed by flow cytometry using membrane Annexin-V/PI. Autophagic flux was detected by a combined measurement of the mRFP-GFP-LC3 dual fluorescence system. Western blot and qRT-PCR methods were used to detect the protein and mRNA expression levels of LC3-II, Beclin1, BAX, Caspase-3 and Bcl2 in chondrocytes of each group. The results showed that after IL-1β-induced ATDC5 chondrocytes, cell proliferation was attenuated, autophagy was down-regulated and apoptosis was improved. Bilobalide intervention can promote autophagy, proliferation and inhibit apoptosis. Bilobalide promoted the proliferation of IL-1β-induced ATDC5 chondrocytes (P<0.05). Compared with IL-1β group, bilobalide inhibited the protein and mRNA expression of LC3-II, Beclin1, BAX and Caspase-3 (P<0.05), and promoted the protein and mRNA expression of Bcl2 (P<0.05). Autophagy flux was activated, and the apoptosis rate was significantly reduced (P<0.05). The results suggest that bilobalide can promote autophagy of IL-1β-induced ATDC5 chondrocytes and inhibit cell apoptosis, promote cell proliferation and protect chondrocytes.

The present study established a universal TaqMan qPCR detection method that can quickly, efficiently and sensitively detect porcine epidemic diarrhea virus (PEDV), and further understand the genetic variation of PEDV in Hebei Province. Here we designed specific primers and probes with reference to the conservative region of M gene of the PEDV variant AJ1102, and optimized the primer concentration, annealing temperature and other conditions, a qPCR method for screening PEDV in pig farms was established, and the S gene of the positive samples was amplified and sequenced for genetic evolution analysis. The results showed that the specificity of this method was strong, and there was no cross reaction with common pig diseases such as porcine circovirus type 2 (PCV2), porcine circovirus type 3 (PCV3) and transmissible gastroenteritis virus (TGEV); The minimum detection limit of the established detection method for pMD19T-PEDV standard is 1.09×10¹ copy·μL^-1. It is about 100 times more sensitive than ordinary PCR and has high sensitivity; The coefficient of variation within and between groups was less than 1%, with good repeatability. The nine sequences successfully cloned based on the whole S gene were distributed in two subgroups of GⅡ, and the nucleotide homology of the nine cloned sequences were 96.6%-99.1%; The homology of amino acids were 94.6%-98.7%. The results showed that the epidemic strains of PEDV obtained in this study were closely related to the domestic strains isolated in recent years, but far related to the vaccine strains currently used in China and the European strains, which indicated that the current epidemic strains of PEDV in some areas of Hebei Province were more complex and had a trend of variation, suggesting the necessity of continuous detection of the variation dynamics of the epidemic strains of PEDV. This study not only provides technical support for the clinical diagnosis of PEDV, but also provides a reference for further understanding the genetic evolution of PEDV.