Bovine mastitis is a common disease that has an adverse effect on animal welfare and the economic growth of dairy farms. A decrease in the milk production and quality is found in dairy cows with mastitis, especially those with Staphylococcus aureus (S. aureus) mastitis. Moreover, dairy cows with severe mastitis would even lose their production capacity. Research related to mastitis has become a key issue in the animal husbandry industry. The present article reviews and details the main research fields of bovine mastitis and S. aureus mastitis published in recent years, which mainly focus on the study of genetics and breeding of bovine mastitis resistance from the perspective of transcriptomics and epigenetics. A detailed review is expected to provide scientific basis and reference for the prevention and control of mastitis, especially S. aureus mastitis in dairy industry.

Precision-cut tissue slices are widely used by many researchers as in vitro models of organs, preserving the major advantages of in vitro systems, compensating for the lack of functionality of cell lines, and maintaining tissue activity, functional activity sufficiently for toxicity, induction and infection studies. This paper reviews the general development process, advantages and application prospects of precision tissue sectioning techniques, and reviews the preparation methods, culture systems and activity determination indexes of precision-cut tissue slices,as well as the application of precision-cut tissue slices as a novel ex vivo model for the study of various organs. It is expected to provide reference for subsequent researchers to use precision-cut tissue slices as a novel biological in vitro, ex vivo model for research.

The purpose of this study was to screen the selection signatures on the whole genome of Hainan pigs, discover the candidate genes of the important economical traits, and analyze the selected process of Hainan pigs in the history of evolution and domestication. Based on the GeneSeek Genomic Profiler (GGP) Procine SNP 80K BeadChip genotypes of 68 Hainan pigs, the integrated haplotype score (iHS) method was carried out to detect the selection signatures for Hainan pigs across the whole genome, and the runs of homozygosity (ROH) analysis was employed. The SNPs with Standard iHS scores > 1.96 (P<0.05) were used as candidate SNPs, and candidate regions detected by iHS were the 200 kb window around the candidate SNPs. In this analysis, the completely overlapping candidate regions detected by both iHS and ROH were defined as potential selected regions. To further explore the biological functions of the selection signatures on Hainan pigs, bioinformatics analysis including gene annotation, quantitative trait locus (QTL) analysis and enrichment analysis were applied. In this study, a total of 44 578 SNPs was remained after quality control. Moreover, 395 candidate selected SNPs were detected by iHS method, 172 ROH segments were detected. And 469 candidate genes were annotated totally in the 136 potential selected regions overlapped. The QTL analysis of the potential selected regions showed that selection signatures of Hainan pigs were associated with meat quality, growth and disease resistance traits. In addition, the QTLs associated with the age of puberty were mostly reported to be overlapped with the potential selected regions on the SSC12 (Sus Scrofa chromosome 12). Moreover, enrichment analysis of gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG) pathway of candidate genes showed that 91 candidate genes were significantly enriched in 21 function (P<0.05) terms totally, which were mainly associated with growth and metabolism, immunoresponse and estrogen signaling pathway. This study reveals the possible selection process of Hainan pigs populations in their domestication history. This research suggests that screening the selection signatures on the whole genome of Hainan pigs contributes to a better understanding of the evolution progress and the genetic mechanisms of the important traits, which also provides reference for further analysis about protection and utilization of germplasm resource and related research about southern China pig breeds.

The aim of this study was to analyze the population genetic structure of several Chinese indigenous pig breeds, and detect genomic selection signals and candidate genes related to litter size. The Illumina PorcineSNP60 microarray data of 102 pigs from 6 Chinese indigenous breeds was used, and constructed a low litter size group including 19 Diqing Tibetan pigs, 16 Mingguang Xiaoer pigs and 16 Wuzhishan pigs, and a high litter size group including 11 Jiangquhai pigs, 20 Lantang pigs and 20 Meishan pigs. After quality control and genotype imputation, softwares were used for genetic relationship analysis, principal component analysis, linkage disequilibrium attenuation analysis, population genetic structure analysis, phylogenetic tree construction and selection signal analysis, and gene localization and functional enrichment analysis of selected sites were carried out. A total of 33 285 SNPs was obtained after data quality control and genotype imputation. The genetic relationships among the 6 Chinese indigenous pig breeds were far, whereas the relationships of individuals within breeds were close. The LD decay rates of the 6 populations were very fast, which were Meishan pigCHD7 was related to growth retardation and genital abnormalities, FBXO43 was related to reproductive ability and affected the number of sperm in circular motion, RUNX1 affected the secretion of estrogen, androgen and prostaglandin, STRBP was related to ovary development, and TEDDM1 was specifically expressed in the epididymis. CHD7, FBXO43, RUNX1, STRBP and TEDDM1 may be the candidate genes for litter size traits in Chinese indigenous pigs.

With the convenience of transportation and market-oriented cross utilization, the genetic resources of local chickens in China are facing the problems of blood mixing and the unclear breed source and genetic relationship among breeds. The study aimed to provide a basis for the Third National Census of Livestock and Poultry Genetic Resources. A simplified genomic GBS sequencing was carried out on 118 individuals from 6 local chicken populations (10 males and 10 females in each population) located in Daba Mountains and Wumeng Mountains in China. The nucleotide polymorphism (Pi), observed heterozygosity (Ho), expected heterozygosity (He), polymorphic information content (PIC), number of observed alleles (Na), number of effective alleles (Ne), genetic differentiation (Fst), genetic distance (DR) and gene flow (Nm) of these populations were analyzed. It was found that the genetic diversity of black feather population of Yanshui chicken was low (He=0.154; PIC=0.125), and the genetic diversity of Daninghe chicken was the most abundant (He=0.197, PIC=0.162). The genetic differentiation between Chengkou mountain chicken and Daninghe chicken was the lowest (Fst =0.053), the gene flow was the highest (Nm=4.50), the genetic differentiation between Fengyan black bone chicken and black feather population of Yanshui chicken was the highest (Fst=0.183), and the corresponding gene flow was the lowest (Nm=1.12). Phylogenetic tree and principal component analysis showed that the white feather population and black feather population of Yanshui chicken were clustered into one class. Chengkou mountain chicken, Daninghe chicken and Jiuyuan black chicken were clustered into one class, while Fengyan black bone chicken was a separate class. Structure analysis showed that the blood of Chengkou mountain chicken and white feather population of Yanshui chicken was mixed. This study proved the genetic relationship of local breeds in adjacent areas. Fengyan black bone chicken located in Wumeng Mountain has a long genetic distance from Jiuyuan black chicken, Chengkou mountain chicken, Daninghe chicken, black feather and white feather populations of Yanshui chicken in Daba Mountain. This study provides a basis for the protection, development and utilization of local chicken breeds.

In order to discover candidate genes related to hair follicle development and depilation traits, genome-wide selection signals were used to study the population structure and genetic differentiation of sheep with different wool types. In current study, the population of 290 sheep from 21 breeds with three types of wool was selected as research object, using Illumina Ovine SNP 50K microarrays genotyping data, based on Fst and θπ Ratio methods, the selection signal detection of hair sheep, fine wool sheep and medium wool sheep were detected. Apply the top 5% of Fst and θπ Ratio as the threshold to detect and annotate the strongly selected SNPs. The results showed that genes related to hair follicle development and hair loss traits such as SOX18, ALX4, FGF1 and LRP4 were strongly selected. In this study, two methods of Fst and θπ Ratio were adopted to detect important genes related to hair follicle development cycle, hair formation, and some cells of hair follicles and sebaceous glands. This will provide a meaningful reference for further research on the mechanism of important economic traits in sheep.

This study aimed to construct the molecular pedigree based on investigating of Guangling donkey population in breeding farm, and analyze its genetic structure. A total of 107 (including 13 males and 94 females) jugular vein blood of healthy adult donkey (body weight:350-400 kg) were collected, after condensant treatment, the DNA was extracted. After using 12 SSR markers for fluorescence PCR amplification, the products were genotyped on ABI3730 sequencing instrument. The molecular pedigree was constructed by Cervus 2.0 and Pedigraph 2.4 softwares, and the population genetic parameters were calculated by STRUCTURE2.3 and Fstat softwares. Moreover, the phylogenetic tree(NJ tree)of 7 male donkey and their offspring was established by hclust function of R software. In all, 107 donkey were included in the molecular pedigree and only 30 offspring were matched with their fathers, and 7 offspring were matched with their mothers, the reliance level of pedigree was higher than 90%. The H_Ob and PIC of SSR markers were 0.676 5 and 0.593 9, respectively. NJ phylogenetic tree included 7 male families, the F_ST of the current population was 0.184, the F_IT was 0.033, and F_IS was -0.238, the population was in Hardy-Weinberg equilibrium. This study constructed a high reliable molecular pedigree of Guangling donkey and analyzed its genetic structure. The results show that the Guangling donkey population has high genetic polymorphisms, with low inbreeding coefficient. Therefore, it is worthful to preserve the genetic information and develop its breed potentials.

This study aimed to find the main volatile flavor compounds of fast-large meat duck and small-size high meat-quality duck, and to construct the flavor profile of different meat duck breeds and explore the effect of breed on meat flavor. The breast muscle of 9-week-old Pekin ducks, Liancheng White ducks and Mallards were used as materials, and the flavor compounds from breast muscle of 3 breeds ducks were detected by solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS), then the main volatile flavor compounds in breast muscles were detected by calculating the relative odor activity value (ROAV). Orthogonal partial least squares discriminant analysis (OPLS-DA) was used to screened the different volatile flavor compounds in the breast muscles of 3 breeds of ducks. At the same time, the electronic nose was used for detection. A total of 104 compounds were detected by SPME-GC-MS. These compounds contained aldehydes, alcohols, ketones and furans. Alcohols accounted for 40.01% of total volatile substance in Pekin ducks, which was the highest, then followed by aldehydes and furans. Aldehydes accounted for the highest proportion of volatile substances and followed by furans and alcohols in Liancheng White ducks and Mallards. There were 43 volatile compounds that contributed to the flavor of duck breast muscles by calculating ROAV, of which 32 compounds were common in 3 breeds ducks. Also, the electronic nose could distinguish the 3 types of breast muscles based on its volatile flavor compounds. Based on the results of analyzing the volatile compounds in the breast muscles of 3 breeds ducks, the characteristic aroma markers of the breast muscles of the 3 breeds ducks were explored. The main flavor compounds in breast muscle of Pekin ducks are (E)-2,4-decadienal, nonanal, 2-octenal, 2-pentylfuran and 1-octene-3-one; the main flavor compounds in breast muscle of Liancheng White ducks are (E)-2,4-decadienal, nonanal, 2-pentylfuran, 2-octenal and hexanal; the main flavor compounds in breast muscle of Mallards are nonanal, 2-pentylfuran, N-octanal and hexanal. The results of OPLS-DA showed that the mainly different flavors of the 3 breeds duck meats were basically concentrated in aldehydes and alcohols. The volatile flavor compounds in the breast muscles of 3 cooked duck breast meats were detected in this study. It is important for construsting the flavor profile of 3 breeds ducks and exploring the effect of variety on meat flavor.

The study aimed to detect the miR-148a-3p expression in different tissues of mice, conduct bioinformatics analysis and construct gene network to further clarify the role of miR-148a-3p in the body. The stomach, lung, spleen, skin, liver, heart and kidney of 6-week-old male C57BL/6 J mice were used as research materials, and 3 parallel experiments were conducted with 3 replicates in each group. The qRT-PCR was used to analyze the miR-148a-3p expression in different tissues of mice. miBase was used to analyze the conservation of miR-148a-3p among different species, and to predict its transcription factor binding site through Promoter Scan and TRANSFAC. TargetScan, PicTar and miRanda were used to predict the target genes of miR-148a-3p, then the target genes intersection was took, and GO and KEGG analysis was performed. Cytoscape was used to construct a TF-miRNA-mRNA interaction network. The results of qRT-PCR showed that among all tissues, the expression level of miRNA-148a-3p was the highest in spleen (P<0.001), followed by liver (P<0.001), and gradually decreased in skin, stomach, heart, kidney and lung. Transcription factors such as bata-pol, CREB, E4F1 and NF-S could bind to miR-148a-3p and regulate its expression. GO enrichment and KEGG pathway analysis showed that the target genes of miR-148a-3p mainly involved in the functions of ion transport, acetylcholine-activated cation-selective channel activity, and external side of plasma membrane. Target genes were mainly involved in TGF-β, hypertrophic cardiomyopathy and adhesion pathways. The TF-miRNA-mRNA interaction network was composed of 70 sites and 70 edges, including 5 transcription factors and 63 mRNAs. The results indicate that miR-148a-3p is highly expressed in mouse spleen tissues and is regulated by a variety of transcription factors, which is closely related to cancer development.

To dig out the genes related to the follicular development and reveal the genetic resorce for strong nesting, the transcriptome profiles of ovaries of Bian chickens at different physiological stages were analyzed. The transcriptome profiles of ovaries of Bian chickens at 70 d (stage of ovary development), 165 d (beginning of egg laying), 220 d (eggs laying at peak) and 330 d (nesting) were constructed, RSEM method was used to analyze the correlations of ovarian gene expression at different ages, basing on the differentially expressed genes (DEGs), GO and KEGG analysis, the candidate genes related to follicular development were screened and verified by quantitative real-time PCR. The analysis of transcriptome profiles showed that in total, there were 18 891 genes were identified among which 18 063 were known genes and 828 were unknown genes. Among the differentially expressed genes, 40 genes correlated with follicles development were screened, of which 35 genes were positively related to the number of developed follicle. The expression level of FDX1L in Bian chicken ovary at 70, 220, 165 and 330 d gradually decreased, and the expression level of NDRG4 in Bian chicken ovary at 70, 165, 220 and 330 d showed a decreasing trend with the increase of age; The expression levels of MC3R and PRLHR were higher in ovaries of Bian chicken at 70 and 330 d than those at 165 and 220 d; VIP was only expressed in Bian chicken ovary on 70, 165 and 220 d. The 11 randomly selected DEGs were verified by real-time fluorescent quantitative PCR that their relative expression were consistent with the transcriptional expression profile. Furthermore, GO function enrichment found that the DEGs were mainly concentrated in "biological processes", followed by "cell components", and finally "molecular functions"; KEGG analysis found that the DEGs are mainly concentrated in signal transduction, immune system and signal molecules, and interaction pathways. By analyzing gene expression profiles of Bian chicken ovary at different physiological stages, mining genes related to follicular development, and using GO function enrichment analysis and KEGG analysis, the functional classification and signaling pathway of differentially expressed genes was obtained. It provides the basis for revealing the molecular regulation of the related genes and their nesting properties of the Bian chicken follicle development.

The objective of this study was to explore the effect of miR-495-3p on the function of goat ovarian granulosa cells and its regulation mechanism. In this study, healthy 3-4 months female Dazu black goats were selected to collect ovarian granulosa cells, miR-495-3p mimics and inhibitor were used to construct overexpression and inhibition cell models. The phenotype of apoptosis and cell cycle were detected by flow cytometry. The secretion of estradiol (E2) and progesterone (P4) in granulosa cells were tested by ELISA kits. The qRT-PCR and Western blot were used to detect mRNA and protein expression levels of genes involved in cell apoptosis, proliferation, cycle and steroid hormone synthesis, respectively. The results showed that miR-495-3p significantly promoted ovarian granulosa cell apoptosis (P<0.01), enhanced BAX expression (P<0.05) and inhibited BCL2 expression (P<0.01) in ovarian granulosa cell. Moreover, overexpression of miR-495-3p inhibited cell proliferation in a time-dependent manner and significantly reduced the expression of PCNA (P<0.05). Meanwhile, overexpression of miR-495-3p significantly increased the percentage of cells at G2/M phase (P<0.05), and significantly reduced the mRNA level of cell cycle-related genes CDK4 (P<0.001) and CCND1 (P<0.05). Others, inhibition of miR-495-3p significantly reduced the mRNA level of CCNE1 gene (P<0.01). Meanwhile, miR-495-3p could promote the secretion of E2 and P4 in granulosa cells. Overexpression of miR-495-3p significantly increased the mRNA and protein expression levels of 3β-HSD (P<0.001), CYP11A1 (P<0.01), CYP19A1 (P<0.05). Interference with miR-495-3p significantly inhibited 3β-HSD(P<0.01), promoted CYP11A1 expression (P<0.01). Overall, the above results indicated that miR-495-3p can promote granulosa cell apoptosis, inhibit proliferation, arrest in the G2/M phase of cell cycle, stimulate the secretion of steroid hormones, thereby affect the follicular development of goat.

This study aimed to isolate primary bovine mammary epithelial cells (BMECs) from mammary gland tissue and explore its biological characteristics after culture. In this study, the mammary glands of healthy lactating cows were collected from the slaughterhouse, the primary bovine mammary epithelial cells were isolated from the mammary glands by modified enzymatic digestion and verified by morphological observation, immunofluorescence and chromosome karyotype analysis. Meanwhile, the growth curve, population doubling time, resuscitation rate, secretion of milk protein, milk fat, lactose, and mRNA expression of lactation-related genes were investigated at the 3rd, 6th, and 9th generations of mammary epithelial cells. The results showed that the isolated bovine mammary epithelial cells had good purity, and the cell growth presented an S-shaped curve, the population doubling time was 34.87, 41.45 and 65.04 h of the 3 generations of cells respectively, and the resuscitation rate was 88%-93%. In terms of cell secretion function, the secretion of casein, triglycerides, and lactose were detected after induction culture for 2 days, and there were no significant differences among all groups. In addition, all the 3 generations of cells could express the lactation-related genes after induction. This study successfully obtained primary bovine mammary epithelial cells, and proved that the cells still had normal biological functions up to the 9th generation, which could provide experimental materials and technical support for exploring the mechanism of mammary cell proliferation and differentiation in vitro.

This experiment was intended to research the effect of melatonin(MT)on the growth, antioxidant activity and function in yak luteal cells. The 2nd-passage luteal cells from healthy yak were used as research object in this experiment, and the effect of different concentrations (0 (Control), 25, 125, 250, and 500 pg·mL^-1) of melatonin on the growth and function in yak luteal cells were compared. Cell proliferation and viability were evaluated by CCK-8 assay. qRT-PCR was conducted to analyse the mRNA expression levels of several genes, including proliferation-related gene PCNA, apoptosis-related genes BCL-2, BAX, FAS, antioxidant-related genes SOD1, SOD2, GPX1 and CAT, as well as progesterone synthesis-related genes HSD3β, STAR and CYP11A1. The levels of ROS and progesterone were determined by ELISA. The results showed that the supplementation of different concentrations of MT could promote luteal cells proliferation and accelerate them into the plateau phase. MT could promote the mRNA expression of cell-proliferated gene PCNA and anti-apoptosis-related gene BCL-2, and repress the expression of apoptosis-related genes BAX, FAS. MT could reduce the ROS level and promote progesterone secretion significantly in luteal cells, moreover, the above effects were most obvious when the MT concentration was 250 pg·mL^-1. At this concentration, the mRNA expression levels of antioxidant-related genes SOD2, GPX1, CAT, and progesterone synthesis-related genes STAR and CYP11A1 significantly up-regulated. Compared with MT treatment alone, the co-treatment with MT and MT receptor inhibitor Luzindole could significantly increase the ROS level and decrease the expression level of SOD2, GPX1 and CAT. The level of progesterone and the expression of STAR and CYP11A1 decreased significantly. In conclusion, MT promotes yak luteal cells proliferation by up-regulating the mRNA expression level of PCNA and BCL-2, and repressing the expression level of BAX and FAS. MT may regulate the ROS level and progesterone level through its receptor. This study provides theoretical basis for the application of MT in the treatment of reproductive diseases caused by corpus luteum abnormality and the improvement in the reproductive performance of yak.

The purpose of this study was to prepare polyclonal antibody against early pregnancy factor (EPF) of yak and lay the foundation for developing an efficient and rapid diagnosis of early pregnancy for yak in clinical field. EPF gene was amplified by RT-PCR using RNA extracted from yak placenta and ovarian tissue and reverse transcribed as template. Then the EPF gene was subcloned into the modified vector pET28-His10-Sumo to construct the pET28-His10-Sumo-EPF recombinant plasmid.After PCR and sequencing identification,the positive recombinant plasmid was transformed into BL21(DE3) for expression.IPTG was used to induce and optimize the reaction conditions.The recombinant EPF protein was purified and immunized mice to produce polycolonal antibodies. The results showed that, after PCR amplification,the target was about 300 bp,which was consistent with the expected results, sequencing identification confirmed the recombinant positive plasmid was successfully constructed.After EPF protein was expressed in E. coli, the protein molecular weight was 29 ku (includes target proteins and SUMO tagged proteins) using IPTG inducer.The protein expression level reached the highest at 37℃ than other controls and induced concentration of IPTG was 300 nmol·L^-1 for 6 h.Western blot results showed that the protein was expressed in both supernatant and inclusion body, and the mouse immunized antiserum could react with the purified recombinant EPF protein. The recombinant EPF protein was successfully expressed by prokaryotic expression system,and the mouse anti-EPF polyclonal antibodies with good immunogenicity was prepared.

This study was conducted to clone the PPP1R11 gene in cattle-yak, detect the expression and location in testes of cattle-yak at different developmental stages, as to provide a theoretical basis for further research of the mechanism of function in male reproduction. The testis, epididymis, heart, liver, spleen, lung, kidney, large intestine, small intestine, stomach, muscle and adipose tissue of adult cattle-yak were collected (n=3), testicles of cattle-yak and yak in the fetal period (5-6 months old), juvenile period (1-2 years old) and adult period (3-4 years old) (n=3) were collected as experimental materials. The PPP1R11 CDS region of cattle-yak was cloned by RT-PCR and analyzed by bioinformatics softwares. qRT-PCR was used to detect the expression patterns of PPP1R11 mRNA in different tissues of cattle-yak, and compared the expression difference in testes at different development stages between cattle-yak and yak. The cell location and expression of PPP1R11 protein were detected by immunohistochemistry (IHC) staining. The results showed that the CDS region of PPP1R11 gene in cattle-yak was 324 bp, which encoded 107 amino acids. The corresponding PPP1R11 protein of cattle-yak had high homology with other mammals. The protein function prediction showed that PPP1R11 could interact with PPP1R2, PPP1R7, PPP1CB, UTP20 and other proteins, and mainly related to the phosphorylation of proteins, which could regulate biological processes such as testicular development, spermatogenesis and sexual maturity. PPP1R11 gene was wildly expressed in various tissues of cattle-yak, and the relative expression level in testis was significantly higher than other tissues (P<0.01). The expression of PPP1R11 gene in cattle-yak testis increased with age. Furthermore, there was significant difference of the expression level of PPP1R11 (P<0.01) in testis at juvenile and adult stage of cattle-yak compared with the counterpart of yak. In addition, IHC staining result showed that PPP1R11 protein was significantly lower expressed in cattle-yak spermatogonia and sertoli cells, and there was significant difference compared with yak, and the number of primary spermatocytes in cattle-yak was reduced significantly and meiosis arrested at this stage. This study showed that there were temporal and spatial differences in the expression of PPP1R11 between cattle-yak and yak testis, suggesting that PPP1R11 may be related to to male cattle-yak infertility. However, its specific mechanism needs to be further studied.

The aim of this study was to investigate the effect of L-Arginine (L-Arg) on the proliferation and apoptosis of bovine intestinal epithelial cells injured by heat stress. The bovine primary intestinal epithelial cells cultured in vitro were divided into control group (Con group, 37℃) and experimental groups (after being cultured at 42℃ for 6 h, the medium without L-Arg (HS group) or the medium with different concentrations (2, 4, 6, 8, 10 mmol·L^-1) of L-Arg were changed to culture at 37℃ for 12 h). The cell viability was detected by CCK-8 and the best healing concentration of L-Arginine was screened. Then the third generation bovine intestinal epithelial cells with good condition were divided into control group (Con group, cultured at 37℃), heat stress group (HS group, cultured at 42℃ for 6 h and then cultured at 37℃ for 12 h) and 6 mmol·L^-1 L-Arg group (42℃ for 6 h and then replaced with 6 mmol·L^-1 L-Arg medium at 37℃ for 12 h). The morphological changes of cells were observed by DAPI staining, the leakage of lactate dehydrogenase (LDH) was detected by micro method, and the cell cycle was detected by flow cytometry. The relative expression levels of cysteine proteolytic enzyme-3 (Caspase-3), cysteine aspartate proteolytic enzyme-9 (Caspase-9), Bcl-2-associated X protein (Bax) and B lymphocyte tumor-2 (Bcl-2) mRNA and protein were detected by real-time fluorescence quantitative PCR and enzyme-linked immunosorbent assay (ELISA) to evaluate the effect of L-Arg on the proliferation and apoptosis of bovine intestinal epithelial cells injured by heat stress. The results showed that in the range of 2~6 mmol·L^-1, compared with HS group, the activity of intestinal epithelial cells was increased by adding L-Arg under heat stress and the activity was the highest when the concentration of L-Arg was 6 mmol·L^-1(P<0.05), which could be used as the experimental concentration of L-Arg group in the follow-up experiment. Compared with Con group, the nuclear morphology of HS group was irregular, chromatin was condensed, the leakage of LDH was significantly increased (P<0.05), the ratio of cells at S stage was significantly decreased (P<0.05), the relative expression levels of Bax, Caspase-9, Caspase-3 mRNA and protein were significantly increased(P<0.05), while the protein content of Bcl-2 was significantly decreased in HS group (P<0.05). These results indicated that heat stress promoted the apoptosis of intestinal epithelial cells in dairy cows. Compared with HS group, the nuclear morphology was regular and the leakage of LDH in intestinal epithelial cells of dairy cows treated with 6 mmol·L^-1 L-Arg were significantly decreased (P<0.05), the S stage cell ratio increased (P<0.05), and the relative expression levels of Bax, Caspase-3, Caspase-9 mRNA and protein were significantly decreased(P<0.05), while the relative expression levels of Bcl-2 mRNA and prfotein were significantly increased (P<0.05). It is concluded that L-Arg can promote the proliferation of small intestinal epithelial cells injured by heat stress, and reduce cell apoptosis thus alleviate the damage of heat stress on intestinal epithelial cells of dairy cows in vitro.

In order to understand the genetic diversity of Mycoplasma synoviae (MS), seven MS strains isolated from Sichuan were sequenced and analyzed by bioinformatics. Illumina HiSeq platform and PE library were combined for whole genome sequencing, and the whole genome were annotated by several database. The complete genomes of 7 MS isolates were compared with those of 8 MS strains included in NCBI by MEGAX software. The results showed that the gene numbers, species and virulence factors of 4 MS strains MS251, MS254, MS221, MS231 isolated from the same chicken farm were the same or had little difference, while the gene number and virulence factor numbers of MS isolates MS12H, MS1G and MSK1 isolated from other three different chicken farms were quite different. Comparing the 7 MS Sichuan isolates with the 8 MS strains published by NCBI, it was found that the Sichuan MS isolates were significantly different from Brazilian MS53, American WVU-1853, Australian 86079/7 NS and vaccine strain MS-H, however, most similar to Henan HN01, China. There was genetic diversity among MS isolates from different farms and within the same farm. This study provided a necessary theoretical basis for further study of the pathogenic mechanism of MS isolates, the development of MS subunit vaccine and the establishment of specific detection technology.

The aim of this study was to investigate the adhesive function of elongation factor thermo unstable (EF-Tu) of Mycoplasma synoviae (MS). The primer pairs Tu-F/Tu-R were designed according to the sequence of EF-Tu gene of MS WVU1853 strain in GenBank. The MS EF-Tu gene was amplified by PCR and cloned into pET-28a (+). The recombinant plasmid pET-EF-Tu was constructed and transformed into Escherichia coli (E. coli) BL21(DE3). Then the recombinant proteins (rMSEF-Tu) were expressed after induction by IPTG, and the expression product was purified and used to immunize New Zealand rabbits to prepare anti-serum. Subsequently, the immunogenicity of the rMS EF-Tu and the distribution of EF-Tu in MS were respectively analyzed by Western blot, ELISA and immunofluorescence tests. The complement mediated mycoplasmacidal activity of recombinant protein antiserum was assessed by complement mediated bactericidal assay, and the adhesion function of MS EF-Tu was evaluated by adhesion and inhibition assay. The results showed that MS EF-Tu was expressed mainly in soluble form in E. coli. The relative molecular mass of rMS EF-Tu was about 43 ku, and had good immunogenicity. The anti-rMS EF-Tu serum has complement-mediated mycoplasmacidal activity. In addition, the MS EF-Tu was distributed both in MS membrane and cytoplasm, and was an adhesion-related protein of MS. This study showed that EF-Tu was an immunogenic protein related to MS membrane surface adhesion. The verification of its biological function laid a foundation for further study of MS EF-Tu.

The QseBC two-component system (TCS) is related to quorum sensing of bacteria. As a global regulator of virulence in Enterobacteriaceae and Pasteurellaceae, its role still unclear in Glaesserella (Haemophilus) parasuis. In this study, the double gene deletion mutant ΔqseBC of SC1401 was constructed by natural transformation method. The serum resistance ability, biofilm formation, antibiotic resistance and stress tolerance of ΔqseBC mutant strain and wild strain SC1401 were measured. Results were as follows:the biofilm-forming ability of ΔqseBC was significantly weaker than that of the wild strain SC1401. The survival rate of the ΔqseBC mutant in porcine serum was 55.12%, which was lower than that of the wild strain SC1401 (83.76%). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of ΔqseBC mutant strain to enrofloxacin, gentamicin, ceftiofur and penicillin were significantly decreased. The ΔqseBC mutant strain showed high sensitivity to high temperature (39 and 42℃), hydrogen peroxide (1, 2, 4, 8 and 16 mmol·L^-1) and NaCl (50, 100 and 150 mmol·L^-1). The results showed that the TCS QseBC plays an important role in the serum resistance, antibiotic resistance and stress tolerance of Glaesserella parasuis. The above findings revealed that QseBC might be closely related to the pathogenicity of Glaesserella parasuis, but further studies are needed to determine the specific mechanism.

Here, we describe the development of a visual and easy-to-operate rapid detection technology for Streptococcus suis. Specific primers were designed for the sequence of the species-specific gene glutamate dehydrogenase (gdh) of S. suis. The recombinant polymerase amplification combined with a lateral flow dipstick (RPA-LFD) detection technology was established, which can detect all serotypes of S. suis simultaneously. The reaction temperature and time were optimized, and its specificity and sensitivity were evaluated. At the same time, 45 samples of suspected S. suis infection were detected by this method. The results showed that the detection sensitivity of S. suis RPA-LFD method can reach 100 copies·μL^-1, which is superior to the conventional PCR method and does not cross-react with other common pathogens. The amplification reaction can be carried out efficiently in a wide temperature range (30-45℃), and the detection can be completed in 20-30 min. Using 45 clinical samples of suspected S. suis infection to evaluate the detection system, the detection rate of RPA-LFD is higher than that of bacterial isolation and conventional PCR method, indicating that it has strong practicability. The RPA-LFD detection method of S. suis established in this study has the characteristics of strong specificity, high sensitivity, easy operation. At the same time, it does not rely on instruments and professional operators, and is suitable for field and on-site detection.

This study aims to investigate the prevalence and drug resistance of Pseudomonas aeruginosa (PA) in breeder farms in Guangdong Province. Samples of dead embryos of breeding chickens and their surrounding environment were collected from different regions of Guangdong Province for the separation and identification of PA. The K-B paper disk diffusion method was used to analyze its antimicrobial sensitivity, and its resistance genes were detected by conventional PCR. The results showed that a total of 77 strains of PA (77/679, 11.3%) including 2 strains from environmental samples (2/24, 8.3%) and 75 strains (75/655, 11.5%) from dead embryos were isolated. The drug susceptibility test showed that the highest drug resistance rate was compound trimethoprim (100%) and tetracycline (100%), followed by chloramphenicol (75.4%). In addition, drug-resistant strains were also detected in the third-generation cefotaxime, the drug resistance rate reached 9.3%; It is worth noting that the multi-drug resistance rate is as high as 62.3%; the resistance genes qacE△1-sul1 (29.9%) and ant(3″)-I (29.9%) have the highest detection rate, followed by DHA (28.3%), and the positive rate of oprD₂ gene was 11.7%, suggesting that its resistance to carbapenem antimicrobial drugs has a high level of transfer risk. In summary, there were varying degrees of PA infection or pollution in the five breeder farms and their surroundings in Guangdong Province, and the isolated and identified strains showed strong drug resistance. Therefore, it is suggested that the five poultry farms should strengthen the breeding management during the breeding process, clean and disinfect the breeding eggs. On the other hand, drug susceptibility tests should be conducted regularly, and antibiotics should be used rationally to minimize the emergence of drug-resistant and multi-drug resistant strains.

Toxoplasma gondii is an opportunistic pathogen with a worldwide distribution, which can cause fatal encephalitis. Human acute toxoplasmosis is closely related to the contamination of T. gondii oocysts. To explore the pathogenic mechanism of T. gondii oocyst infection on the host and to prevent and control toxoplasmosis, we used iTRAQ to analyze the differential expression of proteins in mouse brain tissue after acute and chronic infection with T. gondii PRU strain oocysts. Compared with the control group, 85 and 51 differentially expressed proteins were identified in the acute and chronic infection, respectively, while 114 proteins were differentially expressed in the chronic versus acute infection. The functional analysis revealed that these differentially expressed proteins are mainly involved in pathways such as immune and metabolic processes. The results of our study provide important data for elucidating the host brain tissue damage and pathogenic mechanism caused by T. gondii oocysts in the acute and chronic infection.

The object of this study was to analyze the transcription profiles of the MMP2 in Psoroptes ovis var. cuniculi (PocMMP2), and to establish an indirect ELISA method (iELISA) for detecting IgG antibody against recombinant PocMMP2 (rPocMMP2). The transcription profiles of PocMMP2 across four life-cycle stages, "fed" and "starved" mites were investigated by quantitative real-time PCR. The rPocMMP2 was obtained in Escherichia coli expression system, and this recombinant protein was used to develop rPocMMP2-iELISA by the checkerboard titration tests. Finally, the field investigation using this iELISA was performed for analysis of 86 sera samples collected from a rabbit farm with a previous history of psoroptic mange in Chengdu. Results were as follows:PocMMP2 was expressed across four life-cycle stages, and expression level of MMP2 was significantly higher in "starved" mites than in "fed" mites (P<0.05). The rPocMMP2 was mainly presented in inclusion bodies with the size of~72 ku. The cut-off value for rPocMMP2-iELISA was 0.223, the sensitivity and specificity for the test were 86.0% and 83.3%,respectively. Additionally, the area under the receiver operating curve (AUC) for the test was 0.876,and both the intra-and inter-coefficients of variation were less than 10.00%. Further field study showed 74.42% (64/86) seropositive rate, which was higher than etiological detection rate (10.47%, 9/86). In summary, PocMMP2 might play an important role in the developmental physiology and the invasion process. The rPocMMP2-iELISA appeared good sensitivity, specificity and high repeatability, and could be used to detect serum antibody of psoroptic mange in rabbits.

The preparation and preliminary application of monoclonal antibodies (mAbs) specific to chicken Toll-like receptor 15 (ChTLR15) is described. The gene fragment encoded 162-386 amino acids of ChTLR15 were amplified by PCR and cloned into the vector pET-30a. IPTG was used to induce expression of the recombinant plasmid, the collected target protein was first purified by Ni-NTA affinity chromatography medium method, and the purified protein was renatured by dialysis using urea with concentration gradient. The renatured protein was purified again by gel filtration chromatography to obtain high-purity recombinant ChTLR15 (162-386 aa) protein. The 6-week-old female BALB/c mice were immunized with multi-loci subcutaneous injections, and the spleen cells of mice with higher serum antibody levels after immunization were fused with SP2/0 myeloma cells, and the limiting dilution method was used for multiple rounds of screening to obtain mAbs against ChTLR15 protein. The ChTLR15 gene was truncated and expressed by the prokaryotic expression system, and the ChTLR15 epitopes targeted by the mAbs were identified. The mAb 6C7 was used to locate the ChTLR15 in chicken HD11 cells with laser confocal microscopy. At the same time, the distribution of ChTLR15 in some chicken tissues was determined by immunohistochemistry. The recombinant plasmid pET-30a-ChTLR15 (162-386 aa) was successfully constructed, and the recombinant protein ChTLR15 (162-386 aa) at about 26 ku in the form of inclusion body was obtained after induced expression by IPTG. The optimal antigen coating concentration (0.35 μg·mL^-1) and the optimal serum dilution (1:6 400) were determined by indirect enzyme-linked immunosorbent assay (ELISA). A total of 4 mAb hybridoma cell lines that can stably secrete antibody against ChTLR15 were obtained, and they were named 2G4, 6C7, 6D10 and 7C4. The subclass of 2G4 and 6C7 was IgG2a, and the subclass of 6D10 and 7C4 was IgG1. Western blot results showed that the 4 mAbs can react specifically with ChTLR15, but not with other tested proteins. The prokaryotic expression system was used to express the truncated ChTLR15 (162-386 aa), and the epitopes of ChTLR15 mAbs were identified. The results showed that the epitope recognized by mAbs 2G4 and 7C4 was ²³⁰QLGTVLEF²³⁷, and the epitope recognized by 6C7 and 6D10 was ²⁴⁵EMDLLS²⁵⁰. Observation under a laser confocal microscopy suggested that ChTLR15 protein was located on the cell surface. Immunohistochemistry showed that the liver, spleen, lung, and kidney from the health birds had weak positive staining, and the positive staining of liver, spleen, lung, and kidney from the avian pathogenic Escherichia coli(APEC) challenged birds was enhanced. In this study, four mAbs against ChTLR15 protein were successfully developed and the epitopes recognized by them were identified, which is conducive to further research on the structural and functional characteristics of ChTLR15. It provides a robust tool for subsequent research in related fields such as signal pathways, immune mechanisms, and vaccine development.

As an important zoonotic virus, orf virus (ORFV) not only seriously affects the sheep breeding, but also threatens human health. Stimulator of interferon genes (STING), as DNA sensor of the cell, plays an important role in innate immunity of the host. In order to explore the role of STING in infection and replication of ORFV, cell model of ORFV infection of ovine fetal turbinate cells (OFTu) was constructed and dynamic expression of STING and related genes after ORFV infection in cells were analyzed. The effects of STING on ORFV proliferation were investigated under the state of interference expression and overexpression in OFTu cells. The results showed that the transcription of STING, cGAS, TBK1, IRF3, IRF7, IL-6, IFN-β, IL-1β and TNF-α were significantly increased after OFTu cells infected with ORFV. OFTu cells with STING overexpression resulted in up-regulated transcription of RIG-Ⅰ,DDX41, IFI16, IRF3, IRF7, IL-6, TNF-α, IFN-α and IFN-β.Infection of OFTu cells with STING overexpression can increase the expression of TBK-1, IRF3, IFN-β and TNF-α genes and inhibit the replication of ORFV. While, infection of OFTu cells with the interference of STING expression can decrease the transcription of TBK-1, IRF3, IFN-β and TNF-α and increase the replication of ORFV. These results indicated that STING protein can enhance the expression of antiviral cytokines and inhibit the proliferation of ORFV in OFTu cells. The results provide scientific theoretical basis for further understanding the role of STING in infection and replication of ORFV, and provide basic data for further exploration of the molecular mechanism of ORFV infection and pathogenicity.

The aim of this study was to prepare monoclonal antibody(mAb) against VP2 protein of chicken infectious anemia virus (CIAV) for diagnosis of CIAV and further research in characteristics of CIAV. The VP2 gene of CIAV was amplified and cloned into the pET-32a plasmid. The VP2 fusion protein was expressed in Escherichia coli induced by IPTG. Hybridoma cells were fused between SP2/0 cells and spleen cells of BALB/c mice immunized with the expressed protein and screened by immunofluenscence assay. The epitope recognized by mAb was further identified by the truncated VP2 proteins in Western blot. One hybridoma cell line named CIAV-VP2-4A12 that can stably secrete mAb against CIAV VP2 protein was successfully obtained. The isotype of the mAb was IgG1 and the light chain was kappa chain. Western blot assay showed that mAb could react with the VP2 protein expressed in Escherichia coli, Sf9 cells or DF1 cells transfected with pCAGSS-VP2-Flag. The epitope recognized by the mAb CIAV-VP2-4A12 was identified as ¹⁵⁵KTVRW¹⁵⁹of VP2, which sequence is highly conserved among different CIAV strains. In this study, a monoclonal antibody against CIAV VP2 was successfully developed and the antigenic epitope recognized by the mAb was identified, which will be useful tool for research on the function of the VP2 protein and development of diagnostic methods for CIAV.

FliC amino acid sequences alignment of three serovars in Salmonella enterica serogroup D revealed that S. Enteritidis sharing the same pattern with S. Gallinarum displayed different amino acid residue at the 91th position. The objective of this work is to investigate the effect of arginine mutation at the 91th position of FliC protein on flagellar shape and S. Enteritidis colonization in liver and spleen in BALB/c mice. fliC gene was deleted from the genome of CICC10467 using λ-Red homologous recombination system and a series of trans-complemented strains were constructed. The growth characteristics and FliC expression were evaluated through growth curve analysis and Western blot assay. Flagellar motility and shape were analyzed with soft agar plates and transmission electron microscope, respectively. The ability of cellular adhesion and invasion of wild type and its derivates in vitro and in vivo were tested. The result suggested that there was no difference on bacterial growth and FliC expression between wild type and complements besides loss of expression in fliC mutant. R91S substitution changed the flagellar shape of S. Enteritidis into blunt and straight and weaken flexibility and nearly abrogated bacterial motility (P<0.000 1), the ability of adhesion and invasion to HCT116 and RAW264.7 and the load of mutant in liver and spleen of BALB/c mice was decreased comparison with wild type (P<0.001). Taken together, arginine at the 91th position is essential for bacterial motility, R91S substitution remarkably changes the flagellar shape of S. Enteritidis and impairs bacterial colonization in BALB/c mice.

The study aimed to analyse the structure of the intestinal flora of Kunming mice injected with matrine by 16S rDNA sequencing. Twenty Kunming mice were randomly divided into 2 groups named as matrine group (MT group) and negative control group (NC group). The intraperitoneal administration was administered twice a day for 5 days, the feces and intestinal tissues of each group were collected for β diversity, Lefse and Metastats analysis. qPCR was used to detect the mRNA expression of different strains in each intestinal segment, and KEGG was used to analyze the differences in metabolic pathways caused by the changes in intestinal flora. The rarefaction curve results showed that the measured sample data was sufficient to reflect the species diversity in the samples. The results of β diversity analysis showed that matrine regulated the structure of the intestinal flora. Lefse and Metastats analysis results showed that matrine significantly increased the abundance of Bacteroidetes, Bacteroidales, Muribaculaceae and probiotic Lactobacillus acidophilus, and significantly reduced the abundance of Firmicutes, Ruminococcaceae and Desulfovibrio. The qPCR results showed that the expression of Lactobacillus acidophilus in the feces of mice in the matrine group was increased, which was consistent with the results of Lefse and Metastats analysis. It was also found that matrine enhanced the colonization of Lactobacillus acidophilus in various segments of the intestine. KEGG analysis found that there were significant differences in metabolic pathways such as glycan biosynthesis and metabolism, transport and catabolism between NC and MT groups. The study results showed that matrine significantly changed the structure of the intestinal flora in mice, increase the colonization of probiotic Lactobacillus acidophilus in the intestine and caused the differences in metabolic pathways such as glycan biosynthesis and metabolism, transport and catabolism. These results have accumulated data for further study of the mechanism of matrine exerting its pharmacological effects.

The aim of this study was to investigate the alleviation effect of puerarin on the differentiation of osteoblasts inhibited by cadmium (Cd) in rat femur and tibia. Forty 3-week-old SD male rats were randomly divided into 4 groups with 10 rats per group:control group (CON), cadmium group (Cd), puerarin group (Pur) and cadmium plus puerarin group (Cd + Pur). The rats in the control group and the cadmium group were gavaged with ultrapure water for 5 consecutive weeks. The rats related to puerarin group (puerarin group and cadmium plus puerarin group) were gavaged with puerarin solution (200 mg·kg^-1BW) daily for 5 consecutive weeks. From the fifth week, rats in control group and puerarin group were intraperitoneally injected with normal saline, and the cadmium containing groups (cadmium group and cadmium plus puerarin group) were intraperitoneally injected with cadmium acetate (2.5 mg·kg^-1BW) daily for 1 consecutive week. The contents of cadmium, calcium (Ca) and phosphorus (P) of the femur and tibia in rats were detected by atomic absorption spectrometry. The level of osteoblastic marker genes (RUNX2, OCN, ALP and OSX) were detected by qRT-PCR. The expression of Wnt/β-catenin signaling pathway-related proteins (β-catenin, Wnt3A, LEF1 and TCF1) were detected by Western blot. The results showed that the content of Cd of the femur and tibia in cadmium group was significantly up-regulated (P<0.01), the level of osteoblastic marker genes were down-regulated, the expression of Wnt/β-catenin signaling pathway-related proteins were extremely significantly down-regulated (P<0.01) compared with the control group, but the content of Ca and P were not significantly changed (P>0.05). The content of Cd, Ca and P of the femur and tibia in puerarin group was not significantly changed (P>0.05), the level of osteoblastic marker genes (RUNX2, ALP and OCN) were extremely significantly up-regulated (P<0.01), and the expression of Wnt/β-catenin signaling pathway-related proteins were extremely significantly up-regulated (P<0.01). The content of Cd of the femur and tibia in the cadmium plus puerarin group was extremely significantly down-regulated (P<0.01), the level of osteoblastic marker gene was extremely significantly up-regulated (P<0.01), and the Wnt/β-catenin signaling pathway-related proteins were extremely significantly up-regulated (P<0.01) compared with the cadmium group, but the content of Ca and P in the femur and tibia had no significant changes (P>0.05). The results showed that puerarin had an alleviation effect on the differentiation of osteoblasts inhibited by cadmium in rats, which was involved in Wnt/β-catenin signaling pathway.

The study aimed to investigate the protective effect and mechanism of lycopene (LYC) on subchronic poisoning of nonylphenol (NP) in spleen of mice. Forty ICR mice were randomly divided into four groups including control group (CON), poisoning group (NPG), lycopene control group (LCG) and lycopene intervention group (LNG). Mice in CON were given 0.1 mL corn oil at 8:30 every day, and the operation was repeated after two hours; mice in NPG were administrated 0.1 mL corn oil at 8:30 every day, and then were given 150 mg·kg^-1 NP two hours later; mice in LCG were given 5 mg·kg^-1 LYC at 8:30 every day, and then were given 0.1 mL corn oil two hours later; mice in LNG were given 5 mg·kg^-1 LYC at 8:30 every day, and then were administrated 150 mg·kg^-1 NP two hours later. After 30 days of consecutive gavage, the weight of mice was recorded, blood samples were collected from submaxillary vein, then mice were euthanized, and the spleen of mice was collected and weighed after dissection, and the difference between the groups of weight growth rate and spleen body coefficient were analyzed. The changes of immunity cytokines IL-2, IFN-γ and TNF-α in serum were examined, and the spleen oxidation and anti oxidative indexes MDA, T-AOC, CAT, GSH-Px and SOD was observed, and the protein expression in p53/Bcl-2 apoptosis pathway was detected. The results showed that compared with NPG, the weight growth rate of mice was significantly increased after LYC treatment (P<0.05), serum cytokines and spleen antioxidant enzyme activity were significantly increased (P<0.05); the expression levels of key molecules of apoptosis pathway Akt, p-Akt and Bcl-2 protein in spleen of mice after LYC treatment were significantly increased (P<0.05), and the expression level of p53 and Bax protein was significantly decreased (P<0.05). LYC has protective effect on NP induced spleen injury in mice, which was related to enhancing the anti-oxidation ability of spleen and inhibiting apoptosis of spleen cells.

In order to reveal the genetic diversity of local chicken breeds in Jiangxi and its surrounding areas, 125 blood samples were collected from 5 local chicken breeds in Jiangxi province, 1 in Guangdong province, 1 in Zhejiang province and 1 in Jiangsu province. The population structure, network relationship and phylogeny of 8 local chicken breeds were analyzed by the whole genome SNP chip. The results showed that the polymorphic information content of the most of 45 647 loci in 8 local chicken was 0.25<PIC<0.5, which was moderate polymorphic, indicated that the 8 local chicken breeds had rich genetic diversity. Cluster analysis showed that 8 local chicken breeds had weak geographical relationship, the genetic distance between breeds was 0.254 9-0.360 9, the genetic distance between Xiushui yellow feather blcak chicken and Taihe black-bone silky chicken was 0.254 9, and that between Dongxiang green-eggshell layer and Chongren partridge chicken was 0.306 9. The genetic distance between Anyi gray chicken and other breeds was between 0.274 7 and 0.340 8, among which the genetic distance between Anyi gray chicken and Xiushui yellow feather black chicken was the closest, and the genetic distance between Anyi gray chicken and Chongren partridge chicken was the furthest. The results indicated that the 8 local chicken breeds have rich genetic diversity, which can provide genetic material for future breed development and utilization. There was no significant genetic differentiation among the 8 local chicken breeds, two black chicken breeds (Taihe black-bone silky chicken and Xiushui yellow feather black chicken) and Anyi gray chicken have relatively close genetic relationship.

This experiment was conducted to explore the molecular pathogenic mechanism of the interaction between novel goose parvovirus (NGPV) and host cells. In this study, transcriptome sequencing was performed on the liver, thymus and ileum of ducklings 14 days after infection with NGPV SD strain. The results showed that there were 78 up-regulated genes and 31 down-regulated genes in the ileum of the infected group; 111 up-regulated genes and 78 down-regulated genes in the thymus of the infected group; 128 up-regulated genes and 313 down-regulated genes in the liver of the infected group. The differentially expressed genes in thymus, ileum and liver of ducklings infected with NGPV are involved in many immune related biological processes, such as immune response process and lymphocyte mediated immunity. The differential genes are enriched in multiple signaling pathways such as Toll-like receptor signaling pathway, JAK-STAT signaling pathway, NF-κB signaling pathway, PI3K-Akt signaling. It is suggested that NGPV infection activates the body's immune response and the relevant antiviral signal pathways of host cells. This study provides new clues for the study of the pathogenic mechanism of NGPV.

This study aimed to prepare the dual yolk antibody of Trichomonas gallinae and Candida albicans and study its therapeutic effect. Based on isolates of T. gallinae and C. albicans, we prepared a bivalent vaccine, harvested high-level antibody by inoculating to layers and produced into powders using freeze-dry system under low temperature. Moreover, antibody levels were determined to check quality control using in-house ELISA method. To test efficacy, pigeon models were developed by artificial infection with T. gallinae and C. albicans, respectively. The OD values of T. gallinae antibody and C. albicans antibody in the yolk reached their peaks after second immunization, which were 0.90 and 0.66, respectively, and the antibody maintenance time reached 2 months.In vivo study, both oral- and crop lesions score were reduced significantly(P<0.05)post feeding with 1 g of hyperimmune antibody powders per bird for 5 days and no significant difference was found compared to those pigeons treated with metronidazole and nystatin. Moreover, pathogen loads were reduced greatly compared to the control group(P<0.01). The hyperimmune antibody powder is a promising approach to replace metronidazole and nystatin, contributing to a novel solution for healthy development of pigeon industry.