【Objective】 Proteus mirabilis (P. mirabilis),a prevalent zoonotic pathogen,was commonly found in the natural environment.The escalating resistance of P. mirabilis posed a significant threat to public health and safety,prompting widespread concern.This study was aimed to analyze the genomic data,virulence factors,and drug resistance gene profiles of P. mirabilis NXQI.22 isolated from chickens,and provide a bioinformatic basis for further investigation of the mechanism of action of the drug against multidrug-resistant P.mirabilis.【Method】 Employing the third-generation Nanopore platform,whole genome sequencing and bioinformatics analysis were conducted on P. mirabilis NXQI.22 to elucidate its genomic features and drug resistance mechanisms.【Result】 The genomic analysis revealed that P. mirabilis NXQI.22 harbored a circular chromosome measuring 3 862 364 bp with a GC content of 38.83%.A total of 3 551 coding genes were predicted in P.mirabilis NXQI.22.Six prophages and two CRISPR sequences were identified in P. mirabilis NXQI.22,along with the presence of typical T3SS and T6SS secretion system proteins.This strain also harbored 15 gene islands,genes conferring resistance to sulfonamides and disinfectants,as well as various virulence genes associated with the secretion system and effector proteins found in Salmonella.The annotation results showed that the isolated strains harbored a total of 362 virulence genes associated with functions such as iron uptake,cellular adhesion,proteolysis,resistance to antibiotics,and the formation of biofilms.It contained a diverse array of genes associated with resistance to various drugs,including quinolones,aminoglycosides,tetracyclines,β-lactams,and quaternary ammonium compound.Resistance mechanisms employed by these strains encompassed antibiotic efflux,antibiotic inactivation,antibiotic target alteration and replacement,and multiple drug resistance genes showed multiple drug resistance phenotypes.Multiple virulence genes and drug resistance genes in P. mirabilis NXQI.22 were associated with mobile genetic elements.【Conclusion】 P. mirabilis NXQI.22 from chicken harbored a significant number of virulence genes and drug resistance genes.

【Objective】 To improve the muscle development of Yellow-feathered chickens,RNA-Seq was used to identify key genes involved in the development of the breast muscle in fast-growing and slow-growing Yellow-feathered chickens followed by functional analysis. 【Method】 The live weight,breast muscle weight and leg muscle weight of 15-week-old Taihang chickens (slow Yellow-feathered chickens) and New Pudong chickens (fast Yellow-feathered chickens) were measured.Additionally,the breast muscle index and leg muscle index were calculated.HE stained sections were made for breast muscle and leg muscle tissues of Taihang and New Pudong chickens to analyze the histomorphological differences between two breeds.The breast muscle tissues of Taihang and New Pudong chickens were utilized as test samples for RNA-Seq to identify the differentially expressed genes (DEGs) associated with the muscle development of Yellow-feathered chickens,and 7 DEGs were randomly selected for Real-time quantitative PCR verification.【Result】 The live weight,breast muscle weight,leg muscle weight,breast muscle index and leg muscle index of Taihang chickens were extremely significantly lower than those of New Pudong chickens (P＜0.01).The muscle fiber cross sectional area and muscle fiber diameter of breast muscle in Taihang chickens were extremely significantly or significantly lower than those in New Pudong chickens (P＜0.01 or P＜0.05),and its muscle fiber density was significantly higher than that in New Pudong chickens (P＜0.05).There was no significant difference in the histomorphology of leg muscle between Taihang and New Pudong chickens (P＞0.05).A total of 332 DEGs in breast muscle between Taihang and New Pudong chickens were obtained,including 75 up-regulated genes and 257 down-regulated genes.GO function enrichment analysis showed that DEGs were mainly involved in positive regulation of smooth muscle cell migration,collagen-containing extracellular matrix and laminin binding.KEGG pathway enrichment analysis showed that DEGs were mainly enriched in focal adhesion,ECM-receptor interaction and MAPK signaling pathway.Through GO function and KEGG pathway enrichment analysis,THBL1,ENSGALG0000000814,LAMA1 and PDGFRB genes were closely related to breast muscle development.Real-time quantitative PCR results of 7 DEGs randomly selected were consistent with the expression trend of RNA-Seq,indicating that the sequencing results were reliable.【Conclusion】 THBL1,ENSGALG0000000814,LAMA1 and PDGFRB were selected as important candidate genes for breast muscle development,which laid a foundation for further analysis of muscle development of Yellow-feathered chickens.

【Objective】 The aim of this study was to explore the molecular structural characteristics of fibroblast growth factor 10 (FGF10) gene in Jiuyishan rabbits and its expression levels in different tissues of Jiuyishan rabbits at different ages.【Method】 The longissimus dorsi muscle of Jiuyishan rabbit was used as material in the experiment to clone the coding region sequence (CDS) of FGF10 gene in Jiuyishan rabbits.The amino acid sequence similarity of FGF10 was analyzed with MegAlign software，and a phylogenetic tree was constructed using Mega 11.0 software.The physicochemical properties,secondary structure,and tertiary structure of the FGF10 protein were predicted and analyzed using online tools like ProtParam and SOPMA.The expression of FGF10 gene in heart,liver,spleen,lung,kidney and longissimus dorsi muscle of 1,35,84 and 180 days old Jiuyishan rabbits was detected by Real-time quantitative PCR.【Result】 The length of CDS of FGF10 gene in Jiuyishan rabbits was 663 bp,which encoded 220 amino acids.The similarity of its encoded amino acid sequence with Oryctolagus cuniculus，Lepus europaeus，Gallus domestiaus,Pelobates fuscus，Ovis aries，Bos taurus，Equus caballus，Homo sapiens and Mus musculus by 100.0%,99.5%,87.3%,73.1%,97.2%,97.2%,99.1%,99.0% and 93.8%,respectively.The results of the phylogenetic tree showed that the genetic relationship between Jiuyishan rabbits and Equus caballus was relatively close. FGF10 protein of Jiuyishan rabbits was characterized as an hydrophilic unstable protein.It was characterized by the presence of a transmembrane region and a signal peptide.The structural domains of the FGF10 protein included a transmembrane region,a low-complexity region,and a homologous domain that was typical of the FGF family,in addition to two sites designated for glycosylation and 40 sites for phosphorylation.Its secondary structure was predominantly composed of random coils (49.55%),with extended chains making up another 25.91%.The predicted tertiary structure aligned with the secondary structure.Protein interaction predictions revealed that FGF10 protein interacted with KL,FGFR2,FGFR4,and other proteins.Real-time quantitative PCR results revealed that the expression of FGF10 gene at four stages was the highest in lung,followed by kidneys,and the lowest in liver.In addition,the expression of FGF10 gene in longissimus dorsi muscle showed a downward trend with time,and reached the lowest level at 84 days of age.【Conclusion】 FGF10 protein from Jiuyishan rabbits had the highest similarity with Oryctolagus cuniculus and Lepus europaeus and was an unstable hydrophilic protein with transmembrane regions,signal peptides,glycosylation sites,and phosphorylation sites. FGF10 gene was differentially expressed in different ages and tissues of Jiuyishan rabbits.These findings provided important reference for further studying the potential role of FGF10 gene in muscle development.

【Objective】 The purpose of this study was to explore the differential genes affecting fat deposition in longissimus dorsi muscle of Tan sheep at different growth stages.【Method】 The longissimus dorsi muscle of Tan sheep aged 3,6 and 9 months was collected for RNA extraction and library construction.The data was filtered,quality controlled,and compared using Illumian software.After HTSeq statistics,P_adj (corrected P-value)＜0.05 and |log₂FoldChange|＞1 were used as criteria to screen different expressed genes, GO function and KEGG pathway enrichment analysis was performed for genes, and Real-time quantitative PCR was performed to verify the 5 randomly selected genes.【Result】 Compared with 3 months of age,129 differentially expressed genes (47 up-regulated and 82 down-regulated) were detected at 6 months of age and 521 differentially expressed genes (119 up-regulated and 402 down-regulated) were detected at 9 months of age.Compared with 6 months of age,207 differentially expressed genes (45 up-regulated and 162 down-regulated) were detected at 9 months of age.GO function enrichment results showed that,compared with 3 months of age,the differentially expressed genes were enriched to arachidonic acid monooxygenase activity and phosphoglycerate dehydrogenase activity at 6 months of age and enriched to the positive regulation of cytoplasmic calcium ions,multicellular biological development regulation and other processes at 9 months of age.Compared with 6 months old,9 months old differentially expressed genes were enriched to intracellular calcium-mediated signal transduction and lipid phosphatase activity.The annotation results of KEGG pathway showed that compared with 3 months old,the differentially expressed genes at 6 months of age were mainly concentrated in the signaling pathways of cholesterol metabolism,amino sugar and nucleotide sugar metabolism and the differentially expressed genes at 9 months of age were mainly concentrated in signaling pathways such as extracellular matrix receptor interaction and insulin resistance.Compared with 6 months of age,the differentially expressed genes at 9 months of age were mainly concentrated in c-AMP signaling pathway,synthesis,secretion and action of growth hormone.Real-time fluorescence quantitative PCR results of 5 randomly selected genes,including FGF10 and ADCY7,were consistent with transcriptome sequencing results.【Conclusion】 Through transcriptomic sequencing analysis of longissimus dorsi muscle of Tan sheep at different ages,FGF10 and STAR were selected as candidate genes for the regulation of fat deposition in longissimus dorsi muscle of Tan sheep at 3 and 6 months of age,and ADCY7 and CNR1 were selected as candidate genes for the regulation of fat deposition in longissimus dorsi muscle of Tan sheep at 6 and 9 months of age.PPARGC1A and SLC2A4 were selected as candidate genes for the regulation of fat deposition in longissimus dorsi muscle of Tan sheep aged 3 and 9 months.The results provided theoretical basis for further investigation of fat deposition in longissimus dorsi muscle of Tan sheep at different growth stages.

【Objective】 The aim of this study was to explore the potential regulatory mechanisms of miR-144-5p in lipid metabolism within plasma exosomes of Bactrian camels.【Method】 The exosomes were separated from two groups of Bactrian camels with different levels of fat and lean using ultracentrifugation in this study.The morphology of the exosomes was observed by transmission electron microscopy and identified using nanoparticle tracking analysis.Total exosomal RNA was extracted for small RNA sequencing,and the differentially expressed miRNA in plasma exosomes from two groups of Bactrian camels was selected.TargetScan and miRWalk online software were used to predict candidate target gene of differentially expressed miRNA,followed by GO function and KEGG pathway enrichment analysis of the target genes using DAVID and KEGG bioinformatics systems.The wild-type vectors containing target sites and mutant expression plasmids were constructed.The transfection of miR-144-5p minicis with 293T cells was done for dual-luciferase reporter assay to validate the relationship between miR-144-5p and its candidate gene,exploring its mechanism of action in the regulation of lipid metabolism.【Result】 The results revealed that plasma exosomes from Bactrian camels exhibited cup-shaped or round morphology with a diameter of approximately 100 nm,with a particle size distribution ranging between 30 to 150 nm.A total of 40 differentially expressed miRNAs were identified between the two groups,including significant differential expression of miR-144-5p (P＜0.01).The sequence of miR-144-5p was highly conserved among different species.PGC-1α was predicted as its target gene,mainly involved in processes like cholesterol balance and lipid phosphorylation,enriched in glycerolipid metabolism,cholesterol metabolism,and atherosclerosis signaling pathways.miR-144-5p significantly inhibited the relative luciferase activity of the wild-type PGC-1α-3'-UTR vector (P＜0.01),while it had no effect on the mutant PGC-1α-3'-UTR vector compared to the negative control group at 48 hours after transfection (P＞0.05),indicating that miR-144-5p inhibits PGC-1α gene expression by binding to the gene’s seed sequence.【Conclusion】 This study revealed the expression differences of miR-144-5p in plasma exosomes of Bactrian camels with different body types and confirmed its important role in lipid metabolism by regulating PGC-1α.

【Objective】 This experiment was aimed to investigate the effects of different concentrate supplementation levels on the fermentative parameters and microflora structure of feces flora in Junggar Bactrian camels,so as to enrich the understanding of the fermentation characteristics and microbial community in digestive tract of camels.【Method】 Thirty-six female Junggar Bactrian camels were selected and randomly divided into three groups:Grazing+supplementary roughage group (group A),and on the basis of group A,groups B and C were assigned to supplement 2 and 4 kg/d concentrate supplementation,respectively.The pre-trial period was 18 days,and the formal period was 42 days.On the 42nd day of the experiment,fecal samples were collected from female camels using the rectal sampling method.The samples were utilized for the detection and analysis of fermentation parameters,microbial diversity and community structure.【Result】 ①With the increase of concentrate supplementation,the concentrations of isobutyric acid and isovaleric acid in feces of Bactrian camels in group A were significantly higher than those in groups B and C (P＜0.05),while the concentration of valeric acid and acetic acid/propionic acid in group A were significantly lower than those in group C (P＜0.05).②The Chao1 and Observed species indexes in group A were significantly higher than those in group C (P＜0.05),but concentrate supplementation had no significant effect on the other indexes (P＞0.05).③At the phylum level,the top 3 of fecal flora in Bactrian camels among 3 groups were Firmicutes,Bacteroidetes and Verrucomicrobia,respectively.The relative abundance of Bacteroidetes in feces of Bactrian camels in group A was significantly lower than that in groups B and C (P＜0.05),while the relative abundance of Microsporidia of glycolysis was significantly higher than that in groups B and C (P＜0.05).The relative abundance of Actinobacteria in feces of Bactrian camels in groups A and B was significantly higher than that in group C (P＜0.05).④At the family level,the top 3 of fecal flora in Bactrian camels among 3 groups were Ruminococcaceae,Lachnospiraceae and Bacteroidaceae,respectively.The relative abundance of Bacteroidaceae in feces of Bactrian camels in group A was significantly higher than that in group C (P＜0.05),while the relative abundance of Rikenellaceae was significantly lower than that in groups B and C (P＜0.05).⑤At the genus level,the top 3 of fecal flora in Bactrian camels among 3 groups were Akkermansia, Oscillospira and Ruminococcus,respectively.The relative abundance of Ruminococcus in feces of Bactrian camels in group A was significantly higher than that in groups B and C (P＜0.05),while the relative abundance of Clostridium was significantly lower than that in groups B and C (P＜0.05).⑥When supplementing with concentrate,the relative abundance of certain bacterial communities in feces of Bactrian camels showed a significant correlation with the volatile fatty acid concentration,and these changed as the amount of concentrate added increasing. ⑦There were 7 metabolic pathways were detected in fecal flora in Bactrian camels among 3 groups.【Conclusion】 Under the conditions of this experiment,different amounts of concentrate supplement significantly affected the fermentation parameters and microbial abundance in feces of Junggar Bactrian camels,and altered the structure of the microbial community.The results had enriched the understanding of fecal flora structure in camels.

【Objective】 The aim of this study was to investigate the effects of supplementary complex plant additive on the antioxidant capacity and gel properties of post-slaughter mutton during storage,so as to provide a basis of complex plant additive to improve meat quality and processing performance.【Method】 Ten Mongolian sheep×Small-tailed Han sheep crossbred lambs in good conditions and with similar body weights at 5 months age were randomly divided into two groups for 5 lambs of each.The lambs in control group (CG) were fed with a basic ration (concentrate/crude ratio at 70∶30),and the lambs in complex plant additive group (PG) were supplemented with a complex plant additive at 1.5% of the concentrate fraction on the basis of basic ration.The adaptation period was 15 days and the experimental period lasted for 60 days.At the end of experiment,all lambs were slaughtered and the longissimus dorsal muscle was collected as samples to determine the nutritional quality and color.Meanwhile,the changes of oxidative stability and gel properties for samples were determined after storing at ―20 ℃ for 0,30,90 and 150 d.【Result】 ①Compared with CG group,supplementary complex plant additive could significantly increase the crude fat and ash contents,and the redness and yellow value of mutton (P＜0.05).②Compared with CG group,the oxidation degree of protein and fat of mutton in PG group at the storage of 150 d was significantly decreased (P＜0.05), and the T-AOC activity was significantly increased (P＜0.05).③In the early periods of storage,the gel strength (0 d) and water retention of gel (30 d) of mutton in PG group were significantly higher than those in CG group (P＜0.05),and the gels of mutton in PG group had a denser microstructure than that of CG group.With the extension of storage time (90 and 150 d),although the gels of mutton in PG group had higher protein solubility than that of CG group (P＜0.05),there were no significant differences of gel strength and emulsification stability of mutton between the two groups (P＞0.05),and the microstructures in both groups appeared to be aggregated granular.【Conclusion】 Supplementary complex plant additive was an effective pre-slaughter feeding method to enhance the antioxidant capacity and improve the gel properties of mutton,which could delay the oxidization process of the mutton during long-term storage and make the mutton show better gel properties at the same time.

The improvement of meat quality is an important goal of livestock production.As an important part of muscle tissue,muscle fiber has an important impact on meat quality.Mature muscle fibers are formed by mesodermal progenitor cells through several developmental processes including myoblasts,myotubes,primary and secondary muscle fibers.The physical and chemical properties of muscle fibers in domestic animals are not uniform,but it is found that most studies classify muscle fibers according to the type of myosin heavy chain in muscle fibers.Conventional molecular typing methods can classify and identify myosin heavy chain.These methods classify muscle fibers into type Ⅰ (oxidized) fibers,type Ⅱ (glycolytic) fibers and intermediate types of fibers,it is found that type Ⅰ and type ⅡA muscle fibers have more positive effects on meat quality.Moreover,muscle fibers have strong plasticity and are regulated by a variety of pathway factors and epigenetic phenomena.Although the pathway factors regulating muscle fiber in livestock are relatively clear,due to the complexity of muscle fiber type traits,there is still a lack of consistent molecular genetic markers.According to the current research,SSC gene family may be the target gene family for further mining and validation research.In addition to the screening of molecular markers,the further excavation and verification of loci is the focus of genetic improvement of muscle fibers in livestock.

【Objective】 Silage bacteria preparation can improve silage quality,feed utilization and animal digestibility,at the same time,it can effectively inhibit the activity of harmful microorganisms,thereby improving the palatability of silage.Bacillus licheniformis plays a key role in the early aerobic fermentation stage of corn silage with its unique biological oxygen capture,which can significantly regulate the silage quality and ensure the stability of the whole fermentation process and the quality of the final product.The purpose of this study was to investigate the effects of different concentrations of Bacillus licheniformis on the quality and mycotoxin of corn silage,in order to provide reference for the application of Bacillus licheniformis in silage.【Method】 Whole silage maize was used as raw material in the experiment.A completely randomized block design was adopted,and control group (without adding Bacillus licheniformis,CK),group Ⅰ (adding 0.8×10⁶ CFU/g DM Bacillus licheniformis),group Ⅱ (adding 1.6×10⁶ CFU/g DM Bacillus licheniformis) and group Ⅲ (adding 3.2×10⁶ CFU/g DM Bacillus licheniformis) were set up,each group had 3 replicates.After silage for 60 days,the nutritional composition,fermentation quality,feeding value,mycotoxin and comprehensive quality of corn silage in each group were analyzed.【Result】 ① Compared with CK group,Bacillus licheniformis had no significant effect on the content of dry matter,crude protein,starch,soluble carbohydrates and ash in corn silage (P＞0.05),the fat content of corn silage in group Ⅲ was significantly increased (P＜0.05),and the contents of neutral detergent fiber and acid detergent fiber of corn silage in groups Ⅱ and Ⅲ were significantly decreased (P＜0.05).② There was no significant difference in lactic acid content among all treatment groups (P＞0.05).The NH₃-N content of corn silage in group Ⅲ was significantly lower than that in CK group (P＜0.05).Bacillus licheniformis significantly affected pH and acetic acid content of corn silage (P＜0.05),and with the increase of Bacillus licheniformis,pH showed a linear decrease,while the acetic acid content showed a linear and quadratic curve increase (P＜0.05).③ The comprehensive analysis by the fuzzy membership function method showed that corn silage in group Ⅲ had the highest membership function mean value.④ Compared with CK group,the contents of vomitoxin,fumonitoxin and aflatoxin in experimental groups were significantly decreased (P＜0.05),but there was no significant effect on the contents of zeralenone and T2-toxin (P＞0.05),and the contents of vomitoxin and fumonitoxin were linearly and conically decreased with the increase of Bacillus licheniformis supplementation (P＜0.05).【Conclusion】 Under the conditions of this experiment,Bacillus licheniformis could improve the quality of corn silage,especially when 3.2×10⁶ CFU/g Bacillus licheniformis was added.

【Objective】 This study was conducted to investigate the effects of chlorogenic acid (CGA) supplementation on reproductive performance of female rabbits and the growth of their offspring,as well as to screen optimal dosage of CGA.【Method】 Four hundred and sixty Hyla female rabbits with similar body weight and parity were randomly divided into five groups:Control group (basal diet),CGA200 group (basal diet＋200 mg/kg CGA),CGA400 group (basal diet＋400 mg/kg CGA),CGA600 group (basal diet＋600 mg/kg CGA),and CGA800 group (basal diet＋800 mg/kg CGA).The test diets were administered from 6 d before female rabbits mating until 35 d postpartum (weaning of suckling rabbits).Blood samples were collected from pregnant female rabbits on 15 d of pregnancy for the assessment of serum progesterone and estradiol levels,as well as the determination of total antioxidant capacity (T-AOC),activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px),and malondialdehyde (MDA) levels.The postpartum performance of each female rabbit was recorded,including conception rate,litter size,number of live-born kits,weight of live-born kits,total litter weight,and number of kits born dead.Furthermore,the conception rate and live birth rate were calculated based on this data.Additionally,the number of kits per litter and the litter weight were recorded in a fasted state at 7,14,21,and 35 d,and the average weight of kits was calculated based on these parameters.【Result】 Compared to the control group,①The treatment of CGA400 significantly increased the litter size,the number of kits born alive,the total litter weight,and the litter weight born alive (P＜0.05).The treatment of CGA800 significantly increased the total litter weight and the litter weight born alive (P＜0.05).②The litter weight and average weight of kits at 7 days were significantly increased in CGA400,CGA600,and CGA800 groups (P＜0.05),and the average weight of kits at 14 days was significantly increased in CGA600 group (P＜0.05).The litter weight at 21 days were significantly increased in CGA400,CGA600,and CGA800 groups (P＜0.05),and the litter weight of the weaning kits at 35 days were significantly improved in all groups supplemented with CGA (P＜0.05).③The average daily feed intake during pregnancy was significantly increased in CGA200,CGA400,and CGA600 groups (P＜0.05).④The serum estradiol level at 15 days of pregnancy was significantly elevated in group CGA400 (P＜0.05),and the serum level of total antioxidant capacity were significantly increased in CGA400 and CGA600 groups (P＜0.05).The activities of SOD and GSH-Px were significantly enhanced in all CGA groups (P<0.05),while malondialdehyde (MDA) level in serum was significantly reduced (P＜0.05).【Conclusion】 Dietary supplementation of appropriate amount of CGA could improve reproductive performance of female rabbit,promote growth of suckling rabbits,and reduce oxidative stress levels in female rabbits,and the best effect was achieved with a dosage of 400 mg/kg.

Amino acid is the basic unit of protein synthesis,an important substance for growth and energy metabolism of organisms,and also an indispensable nutrient in feed.According to the taste characteristics of amino acids,they can be divided into sweet amino acids,umami amino acids,sour amino acids and bitter amino acids,collectively referred to as flavor amino acids.Common flavor amino acids mainly include serine,glycine,glutamic acid,aspartic acid and alanine.Recent studies have shown that the application of flavor amino acids as feed additives in pig and chicken production can promote animal growth and intestinal health,alleviate heat stress,improve antioxidant levels and meat quality.Although amino acids have a lot of advantages in feed,excessive addition will cause adverse reactions to animals.Therefore,it is necessary to determine the appropriate addition amount according to the needs of animal growth and development and the gap of amino acid content in feed.Based on this,the authors review the research progress on the application of flavor amino acids in pigs at different growth stages and chickens with different production uses,aiming to provide reference for its future application in pig and chicken production and feed.

【Objective】 To study the effects of low protein with 7 essential amino acids balanced (lysine,methionine,threonine,isoleucine,arginine,tryptophan and valine) diet on growth and digestive function of Qingyuan partridge chickens at 31 to 60 days of age,and provide support for the application of low protein diet on Qingyuan patridge chickens. 【Method】 A total of 960 healthy Qingyuan partridge chickens (female) at the age of 31 days were selected and divided into 4 groups with 6 replicates per group and 40 chickens per replicate.The chickens in control group were fed a basal diet (crude protein level was 17.5%),the others in experimental groups were fed diets with crude protein level reduced to 16.5% (group A),15.5% (group B) and 14.5% (group C),respectively,with the same levels of lysine,methionine,threonine,isoleucine,arginine,tryptophan and valine as control group.The experiment lasted for 30 days.At 60 days of age,chickens were weighted,and blood and intestinal tissues were collected,and the growth performance,slaughter performance,serum biochemical indexes，apparent digestibility of nutrients and intestinal tissue morphology were determined.【Result】 Compared with control group,① There were no significant differences in growth performance,slaughter performance,serum biochemical indexes and apparent digestibility of nutrients in experimental groups (P＞0.05).② The spleen index of chickens in group B was significantly increased (P＜0.05).③ For duodenum,the crypt depth in 3 experimental groups was significantly increased (P＜0.05),and the ratio of villus to crypt in groups A and B was significantly decreased (P＜0.05).For jejunum,the villus height in group C was significantly increased (P＜0.05),the crypt depth in group B was significantly increased (P＜0.05),and the ratio of villus to crypt was significantly decreased (P＜0.05).For ileum,the villus height and crypt depth in group A were significantly increased (P＜0.05).【Conclusion】 Under the condition of balanced 7 essential amino acids, reducing dietary crude protein level to 16.5%,15.5% and 14.5% could inhibit the development of intestinal tissue morphology to a certain extent,but had no obvious negative effects on growth,serum biochemistry and other indicators.Considering all factors,it was recommended to have a crude protein level of 15.5% in an amino acid balanced diet for Qingyuan partridge chickens.

【Objective】 This experiment was to explore the effects of different additives on the nutritional value,fermentation quality and microbial community of fermented total mixed ration containing distillers grains.【Method】 The whole mixed diet with 15% distillers grains was selected for fermentation.Five treatment groups were set up for the experiment,with the addition of 0.5‰ compound microbial supplement (LB group),0.5‰ compound microbial supplement+0.4‰ complex enzyme preparations (LB-CE group),0.5‰ compound microbial supplement+0.3% calcium propionate (LB-CAP),0.5‰ compound microbial supplement+0.1% potassium sorbate (LB-PS),0.5‰ compound microbial supplement+0.5% sodium diacetate (LB-SDA),respectively.The nutrient contents,fermentation quality and microbial community structure of silage were determined after 90 days of silaging.【Result】 The nutrient contents of fermented total mixed ration containing distillers grains showed that the crude fat content of LB group was signifcantly higher than other groups (P＜0.05).The crude protein content of LB-CE group was slightly higher than other groups (P＞0.05).The neutral detergent fiber content of LB-CE group was significantly lower than LB,LB-CAP and LB-PS groups (P＜0.05).The acid detergent fiber content of LB-CE group was significantly lower than LB-CAP group (P＜0.05).The soluble carbohydrates content of LB-CAP and LB-SDA groups were significantly higher than other groups (P＜0.05).The fermentation quality of fermented total mixed ration containing distillers grains showed that the lactic acid content of LB-CE group was significantly higher than other groups (P＜0.05),the acetic acid content of LB-CAP group was significantly higher than other groups (P＜0.05),pH of LB-PS group was significantly lower than other groups (P＜0.05),the propionic acid and ammonia nitrogen contents in all groups were not significantly different (P＞0.05),no butyric acid were detected in all groups.In terms of microbial diversity,the abundance of Firmicutes,Lactobacillus in LB-CE group was significantly higher than other groups (P＜0.05),while the abundance of Proteobacteria,Actinobacteria,Bacteroidotes,Aeriscardovia,Klebsiella and Acinetobacter in LB-CE group was significantly lower than other groups (P＜0.05).Correlation analysis showed that the abundance of dominant phylum Firmicutes and its main genus Lactobacillus were significantly or extremely significantly positively correlated with crude protein content (P＜0.05 or P＜0.01),which was extremely significantly negatively correlated with neutral detergent fiber content (P＜0.01),and had extremely significantly or significantly negatively correlated with NH₃-N content (P＜0.01 or P＜0.05).【Conclusion】 Under the experimental conditions,the addition of 0.5‰ compound microbial supplement combined with 0.4‰ complex enzyme preparations had the best effect on improving the nutritional value,fermentation quality，and microbial community structure of fermented total mixed ration containing distillers grains.

【Obiective】 The experiment was conducted to investigate the effects of different levels of α-mangostin in basic diet on growth performance,immune function,antioxidant capacity and detoxification function of Yellow-feathered broilers,and to provide evidence for its application in broilers.【Method】 A total of 900 1-day-old Ephedra broiers (female) were divided into 6 treatment groups with 6 replicates per group and 25 broilers per replicate.The diets in 6 treatment groups were supplemented with 0,15,30,60,120,and 240 mg/kg α-mangostin in the basal diet, respectively.The experiment lasted for 54 d.One broiler weighted close to the average body weight was selected from each replicate for blood collection and slaughter on the end of experiment,plasma was separated to determine cytokine content and antioxidant index,liver was collected to determine antioxidant and detoxification function related index.【Result】 ①The body weight and average daily gain of broilers increased linearly and quadratically with the increase of α-mangostin supplemental level (P＜0.05).There were no significant differences in average daily feed intake,feed to gain ratio and mortality rate of broilers among different treatment groups (P＞0.05).②The contents of interleukin-1β (IL-1β),IL-6,IL-10 and malondialdehyde (MDA) in plasma of broilers were significantly affected by different α-mangostin supplemental levels (P＜0.05),and the contents of IL-1β,IL-6 and MDA were linearly and quadratically decreased with the increase of α-mangostin supplemental levels (P＜0.05),IL-10 content increased linearly and quadratically (P＜0.05).③Dietary supplemental different levels of α-mangostin significantly affected the liver malondialdehyde (MDA) content,total superoxide dismutase (T-SOD) and glutathione S transferase (GSH-ST) activities of broilers (P＜0.05),and with the increase of α-mangostin supplemental levels,the MDA content was linearly and quadratically decreased (P＜0.05),T-SOD activity increased linearly and quadratically (P＜0.05),GSH-ST activity increased linearly (P＜0.05).【Conclusion】 Dietary α-mangostin could improve growth performance,immune function,antioxidant capacity and detoxification function of Yellow-feathered broilers aged 1 to 54 days.Using the body weight and average daily gain as main evaluation indexes,according to the quadratic curve model,the optimal supplemental levels of α-mangostin in diet were 188 and 156 mg/kg, respectively.

【Objective】 The objective of this study was to compare the gut microbiota composition between quiet and lively dogs,elucidating the link between neurotype and intestinal microbiota,thereby providing a scientific basis for early screening and behavioral training of working dogs.【Method】 A paired design was adopted in the experiment,with neurotype as the only variable.fourteen Malinois dogs (12-month-old,mean weight was 25.62 kg±2.23 kg,eight males,six females) were divided into quiet and lively groups,each with 7 replicates and one dog per replicate.The experimental period was 30 days,comprised a 7-day adaptation phase followed by a 23-day experimental phase.On the final day,fresh feces were collected for high-throughput sequencing to analyze microbial community differences and their associations with neurotypes.【Result】 ①The α-diversity analysis showed that Chao1 index of fecal microbiota of dogs in quiet group was lower than those of lively group (P＜0.05),with no significant difference in Shannon index (P＞0.05).β-diversity analysis revealed significant differences in overall fecal microbiota composition between two groups (R²＝0.59,P＜0.01).②At the phylum level,five bacterial phyla with relative abundance greater than 1% were identified in the fecal microbiota of all dogs.The relative abundances of Fusobacteria and Proteobacteria in the fecal microbiota of quiet dogs were extremely significantly higher than those in lively dogs (P＜0.01),and were significantly lower than those of Firmicutes and Bacteroidetes (P＜0.05).At the genus level,eight bacterial genera with relative abundance greater than 5% were identified in fecal microbiota of all dogs.The relative abundances of Fusobacterium,Lactobacillus,and unclassified-Porphyromonadaceae in feces of quiet dogs were significantly higher than those in lively dogs (P＜0.05),while the relative abundances of Allobaculum,Blautia,Clostridium-ⅩⅣa,Clostridium-Ⅺ and Prevotella were lower than those in lively dogs (P＜0.05).③LEfSe analysis highlighted significant enrichment of Fusobacteria and its subclasses,along with Proteobacteria in fecal microbiota of quiet group,while Firmicutes and its subclasses in lively group (P＜0.05).【Conclusion】 Gut microbiota composition might be intimately related to dog neurotypes,potentially influencing behavior and mood via the gut-microbiota-brain axis.This study could offer novel insights into the relationship between neurotypes and gut microbiota in working dogs,informing early screening and behavioral training strategies.

Bamboo vinegar is a by-product of bamboo pyrolysis,containing a variety of organic compounds and having a significant antibacterial effect.Because bamboo vinegar contains many antibacterial components,the possibility of harmful microorganisms developing resistance to it is extremely small,bamboo vinegar has great potential as an alternative to antibiotics in livestock breeding.However,there are few research reports on the application of bamboo vinegar in animal production.Most of the reports focus on pigs and chickens.The authors summarized the effects and possible mechanisms of bamboo vinegar products in pig and poultry.It can reduce diarrhea in piglets by regulating the intestinal microbial flora,and exhibit selective antibacterial properties similar to acidifiers,such as reducing E.coli and increasing lactic acid bacteria.Bamboo vinegar also improves the intestinal morphology of chickens and enhances the quality of eggshells.Although bamboo vinegar and antibiotics have similar effects on promoting growth of animals,bamboo vinegar is better in improving meat quality and increasing its nutritional value.The positive impacts of bamboo vinegar on animal health can be attributed to the combined effects of its components including organic acids,phenols,aldehydes,ketones,and alcohols etc. There are still many issues that require further research,such as the identification of key active substances in bamboo vinegar,and the establishment of a database of its nutritional components.Research on the application of bamboo vinegar in the future should focus on the following aspects.Firstly,conducting safety assessments to ensure the safety of bamboo vinegar as a feed additive. Secondly,conducting research on processing technology to increase the content of active ingredients in products,and the third is strengthening the study of applied technologies and evaluating application effects to expand the scope of product application.

【Objective】 The aim of this study was to explore the effects of quercetin on follicular development,immune and antioxidant function,follicular fluid reproductive hormone secretion and ovarian steroidogenesis related genes in ewes.【Method】 In this study,thirty Mongolian ewes with similar body weight were randomly divided into two groups:Control group and quercetin group.The control group of ewes were fed with basic diet,and each ewe in quercetin group was fed a basal diet supplemented with quercetin 7 g/d.Each group had three replicates,and five sheep in each replicate were raised in a separate pen.Blood samples were collected on the 13th day of the second estrus stage for the detection of antioxidant indexes and reproductive hormone indexes,and ovarian tissues were collected for the detection of steroidogenesis related gene expression.【Result】 ①Compared with control group,the number of large and middle follicles in quercetin group increased significantly(P＜0.05),the levels of interleukin-6,tumor necrosis factor,immunoglobulin G,and immunoglobulin A in serum of ewes in quercetin group were extremely significantly or significantly reduced (P＜0.01 or P＜0.05),while the total antioxidant capacity,superoxide dismutase,and glutathione peroxidase activities in serum were extremely significantly or significantly increased (P＜0.01 or P＜0.05).②Compared with control group,the levels of estrogen,progesterone,follicle stimulating hormone and gonadotropin-releasing hormone in the large follicles of ewes in quercetin group were extremely significantly or significantly higher than those in control group(P＜0.01 or P＜0.05).The levels of estrogen and follicle stimulating hormone in medium follicles were extremely significantly increased(P＜0.01).The levels of luteinizing hormone were significantly or extremely significantly reduced in the follicles at different grades (P＜0.05 or P<0.01).③Compared with control group,the mRNA expression of steroidogenic acute regulatory protein (STAR) and cytochrome P450 family 19 subfamily A member 1 (CYP19A1) in ewe ovaries were extremely significantly upregulated by adding quercetin to the feed (P＜0.01).【Conclusion】 Adding 7 g/d quercetin to the feed could effectively improve the anti-inflammatory and antioxidant functions of ewes,and regulate the secretion of reproductive hormones in follicular fluid and the expression of genes related to ovarian steroid production,thereby affecting the development of ewe follicles.

【Objective】 The aim of this study was to compare the effects of granular alfalfa and fresh pasture partially replacing complete feed on growth,slaughter performance,organ index and meat quality of Linwu ducks,and to provide theoretical basis for the scientific application of alfalfa granules in duck feed.【Method】 600 Linwu ducks consists of half males and half females with similar body weight at 39 days of age were randomly divided into groups Ⅰ,Ⅱ and Ⅲ，with 10 replicates per group and 20 ducks per replicate.The ducks in groups Ⅰ,Ⅱ and Ⅲ were fed complete feed,80% complete feed+20% granular alfalfa and complete feed + fresh pasture,respectively.The experiment period was 30 days.At the age of 70 days,1 male and 1 female ducks close to the average body weight were selected from each replicate for slaughter performance measurement.The heart,liver,muscle stomach,glandular stomach and spleen were collected to measure organ indexs,and the left breast muscle was collected to detect meat quality.【Result】 ①There were no significant difference on final weight and daily gain of ducks among the three groups (P＞0.05),and the average daily feed consumption and F/G of ducks in group Ⅱ was significantly lower than that of the other two groups (P＜0.05).②There were no significant differences in slaughtering rate,all evisceration rate,abdominal fat percentage,sebaceous fat percentage and leg muscle percentage of ducks among the three groups (P＞0.05).The breast muscle rate of ducks in group Ⅱ was the highest and significantly higher than that in group Ⅰ (P＜0.05).③Except gizzard index,there were no significant differences on other organ index of ducks among all groups (P＞0.05).The gizzard index of ducks in group Ⅱ was significantly higher than that of groups Ⅰ and Ⅲ (P＜0.05).④The yellowness value (b^*) of breast muscle of ducks in group Ⅱ was significantly higher than that in groups Ⅰ and Ⅲ (P＜0.05).The post-cooking shear force of breast muscle of ducks in group Ⅰ was significantly higher than that in group Ⅱ (P＜0.05),but had no significant difference with that in group Ⅲ (P＞0.05).The cooking loss rate of ducks in groups Ⅱ and Ⅲ were significantly lower than that of group Ⅰ(P＜0.05).The pH_{45 min} of breast muscle of ducks in group Ⅰ was significantly lower than that in groups Ⅱ and Ⅲ (P＜0.05).【Conclusion】 The granular alfalfa and fresh pasture partially replacing complete feed had no negative effects on growth and slaughter performance of Linwu ducks aged 39 to 70 days,and substitution of 20% complete feed with granular alfalfa effectively reduced feed cost and improved meat quality.

【Objective】 Mitochondrial DNA (mtNDA) D-loop sequence polymorphism was used as a marker to explore the genetic structure and maternal origin of 7 Kazakh cattle populations in Xinjiang,so as to provide basic data for the rational utilization and biodiversity protection of Xinjiang cattle breeds.【Method】 DNA was extracted from the blood of 179 Kazakh cattle,and the mtDNA D-loop sequence was determined,SnapGene software was used to compare and correct the sequencing sequence with the reference sequence to determine the length and position of the mtDNA D-loop region sequence,and the base content was counted.DnaSP 5.10 software was used to statistically analyze and calculate the parameters of single nucleotide polymorphism (SNP),number of haplotypes (H),nucleotide diversity (Pi) and haplotype diversity (Hd),respectively.The genetic structure of Kazakh cattle population was analyzed by Arlequin 3.0 software.The genetic distance of Kazakh cattle population in mtDNA D-loop region was calculated by Mega 11.0 software,and the Neighbor-Joining (NJ) phylogenetic tree was constructed.【Result】 The complete sequence of mtDNA D-loop region in Kazakh cattle population was 909-911 bp,the average contents of A,G,T and C were 32.8%,13.8%,28.8% and 24.6%,respectively.The content of AT was higher than that of GC.A total of 131 SNPs were detected in 179 individuals,of which the variation sites accounted for 14.40% of the total length of the measured nucleotides,and 89 haplotypes were defined,Hd and Pi were 0.974 and 0.01288,respectively,indicating that the genetic diversity of Kazakh cattle population was very rich.The results of molecular variation analysis showed that 97.13% of the variation was within the population,2.87% was from the variation between populations,and the genetic distance ranged from 0.0109 to 0.0186,the genetic differentiation index (Fst) ranged from ―0.0053 to 0.0782,and there was no significant differentiation (P＞0.05).Phylogenetic tree analysis showed that 7 Kazakh cattle populations in Xinjiang had two maternal origins:Common cattle and zebu cattle.【Conclusion】 Kazakh cattle in Xinjiang were derived from two maternal lines and had rich genetic diversity.Although there was genetic differentiation between populations,while there was no obvious geographical isolation,and the differences in genetic structure were narrowing.The results provided a theoretical reference for conservation and utilization of Kazakh cattle genetic resources.

【Objective】 This study was aimed to analyze the distribution and expression of glutathione peroxidase-5 (GPx5) in testis and epididymis of normal and cryptorchidism in Bactrian camels,so as to explore the regulatory effect on reproduction of GPx5 in sperm antioxidant function during cryptorchidism in Bactrian camels.【Method】 The testis and epididymis from adult (5-year-old) Bactrian camels were collected,including 10 pairs of normal group and 6 pairs of cryptorchid group,the histological structural characteristics were observed using HE staining,collagen staining and reticular staining.The expression and distribution of GPx5 were studied by immunohistochemistry staining,Western blotting,immunofluorescence staining,and Image Pro Plus 13.0 image analysis.【Result】 Compared with normal group,Bactrian camels in cryptorchid group showed underdeveloped seminiferous tubules with extremely significantly reduced lumen diameter (P＜0.01),fewer interstitial cells,shrunken lumen with epithelial vacuolation in epididymise,but more abundant reticular and collagen fibers of interstitium in testis and epididymis.The immunohistochemistry results revealed that there was no obvious expression of GPx5 in testis of Bactrian camels in normal group,while there was evident expression in Sertoli cells of Bactrian camels in cryptorchid group.Western blotting results showed that compared with normal group,the expression of GPx5 in testis and corpus epididymidis of Bactrian camels in cryptorchid group was extremely significantly increased (P＜0.01),the expression of GPx5 in caput epididymidis was extremely significantly decreased (P＜0.01),but there was no significant difference in cauda epididymidis (P＞0.05).The results of immunofluorescence localization indicated that compared with normal group,the expression of GPx5 in testis and cauda epididymidis of Bactrian camels in cryptorchid group was extremely significantly increased (P＜0.01),the expression of GPx5 in caput epididymidis was extremely significantly decreased (P＜0.01),but there was no significant difference in corpus epididymidis (P＞0.05).【Conclusion】 The testis and epididymis of cryptorchidism in Bactrian camels showed a tendency towards fibrosis.The expression of GPx5 protein was significantly increased in the testis of cryptorchidism in Bactrian camels,with enhanced expression in Sertoli cells.The oxidative stress in seminiferous tubules affected normal spermatogenesis.The weak expression of GPx5 in the principal cells of caput epididymidis suggested an abnormal antioxidant activity in the epididymal microenvironment,leading to obvious sperm damage.

【Objective】 The purpose of this experiment was to investigate the alterations in the antioxidant capacity of semen in Hainan Black goats under heat stress,and screen the potential biomarkers in seminal plasma.【Method】 Simulated in vitro heat stress treatment,the semen of Hainan Black goats was collected,and the samples were randomly divided into control group (Con) and heat stress group (HS),and the antioxidant indices of semen were determined.Additionally,non-targeted metabolome analysis of the seminal plasma was conducted using liquid chromatography-mass spectrometry,the differential metabolites were screened,and KEGG pathway enrichment analysis was carried out.【Result】 Compared with control group,the total antioxidant capacity (T-AOC) and the activity of glutathione peroxidase (GSH-Px) in semen of Hainan Black goats in heat stress group was significantly or extremely significantly decreased (P＜0.05 or P＜0.01),and the contents of reactive oxygen species (ROS) and malondialdehyde (MDA) were significantly or extremely significantly increased (P＜0.05 or P＜0.01),mitochondrial membrane potential (MMP) and adenosine triphosphate (ATP) concentration were significantly decreased (P＜0.05).The results of orthogonal partial least square discriminant analysis (OPLS-DA) indicated that there were significant variations in seminal plasma metabolism of Hainan Black goats in heat stress group,and the cluster analysis demonstrated that there was significant differences and distinct clustering between the two groups.A total of 64 distinct metabolites were identified.Among them,2-deoxyribose 5-phosphate,malonic acid,D-arginine,methyldopa and niacinamide mononucleotides in seminal plasma might respond to heat stress via pyrimidine metabolism,β-alanine metabolism,D-amino acid metabolism,niacin and niacinamide metabolism.【Conclusion】 Heat stress was significantly decreased the semen quality and antioxidant capacity of Hainan Black goats.Malonic acid,D-arginine,methyldopa acid and niacinamide mononucleotides in seminal plasma were served as potential biomarkers of the heat stress state in semen of Hainan Black goats.

【Objective】 This study was aimed to comprehensively evaluate the health and nutritional status of Xinjiang Brown cattle and Chinese Simmental cattle,and optimize the feeding management strategy,so as to achieve the purpose of improving their overall production performance.【Method】 The data of DHI of 702 Xinjiang Brown cattle (1 085 records) and 4 079 Chinese Simmental cattle (6 352 records) from four cattle farms in Xinjiang from 2016 to 2023 were collected.The effects of farm,calving year,calving season and parity on milk urea nitrogen were analyzed using SAS 9.2 software.The genetic parameters of urea nitrogen in milk of Xinjiang Brown cattle and Chinese Simmental cattle were estimated using a single trait repeatability model by DMU software.【Result】 The farm and calving year had extremely significant effects on milk urea nitrogen in Xinjiang Brown cattle and Chinese Simmental cattle (P＜0.01).The calving season had an extremely significant effect on milk urea nitrogen in Chinese Simmental cattle (P＜0.01).The parity had significant or extremely significant effect on milk urea nitrogen in Xinjiang Brown cattle and Chinese Simmental cattle (P＜0.05 or P＜0.01).The heritability of milk urea nitrogen in Xinjiang Brown cattle and Chinese Simmental cattle were 0.10±0.05 and 0.15±0.03,respectively,both of which belonged to low heritability.The average estimated breeding value of milk urea nitrogen increased with the increase of calving year.【Conclusion】 The milk urea nitrogen of the two breeds of cattle was a low heritability trait.In recent years,the genetic trends of milk urea nitrogen in Chinese Simmental cattle had increased,while had shown a decreasing trend in Xinjiang Brown cattle.Therefore,attention should be paid to the influence of different factors on milk urea nitrogen,and the feeding and management methods should be adjusted reasonably to strengthen the importance of its selection.The results provided a theoretical basis for improving the production performance of the two breeds of cattle.

【Objective】 This study aimed to compare the slaughter performance and meat quality of Holstein cattle and their Angus crossbred offspring (Holstein-Angus F1) after linear fattening.【Method】 Six Holstein steers and six Holstein-Angus F1 steers were selected for the experiment.All cattle were born in June 2020.Castration was performed immediately after birth using rubber bands,weaning occurred at 2 months of age,and linear fattening began at 4 months of age.The diet and feeding conditions were the same for both groups.All cattle were slaughtered at 18 months of age.【Result】 Compared to Holstein steers,the Holstein-Angus F1 steers showed significant or extremely significant improvements in pre-slaughter live weight,carcass weight,backfat thickness,and loin muscle area (P＜0.05 or P＜0.01),with a significant reduction in drip loss rate (P＜0.01).The dressing percentage showed an increasing trend (P=0.069).There were extremely significant differences in the yield of high-quality meat cuts between the two groups.Specifically,the proportion of the weight of the chunk roll and rib eye roll in Holstein steers was significantly lower than that in Holstein-Angus F1 steers (P＜0.05),resulting in a noticeable decrease in the weight proportion of high-grade meat cuts (P＜0.01).In terms of high-quality meat,Holstein steers had significantly higher shoulder meat weight proportion than Holstein-Angus F1 steers (P＜0.05).In terms of meat quality,Holstein steers had lower shear force than Holstein-Angus F1 steers (P＜0.05).The intramuscular fat content in the chuck tender and striploin of Holstein-Angus F1 steers was lower than that of Holstein steers (P＜0.05).After crossbreeding,the content and composition of amino acids and fatty acids in the beef were changed,with varying degrees of change across different cuts.Holstein-Angus F1 steers had higher amino acid content in the outside flat but lower umami amino acids.Fatty acid changes were mainly concentrated in saturated fatty acids C15∶0 and C16∶0,which were significantly higher in Holstein-Angus F1 steers than in Holstein steers (P＜0.05).【Conclusion】 Under the same feeding conditions,Holstein-Angus F1 steers exhibited better slaughter performance than Holstein steers when fattened to 18 months of age.However,the intramuscular fat deposition ability of Holstein-Angus F1 steers was lower than that of Holstein steers.

【Objective】 The aim of this experiment was to explore the mechanism of Y chromosome (Zfy) gene during the development of sperm tails in adult male mice.【Method】 Twenty 8-week-old Kunming strain (KM) male mice were selected and divided into experimental and control groups,with 10 mice in each group.The mouse testis Zfy gene interference model was established by injecting the Zfy gene interference vector and the mixture of Lipofectamine^TM LTX & PLUS^TM transfection reagent into the rete testis,and injecting the empty vector and the mixture of Lipofectamine^TM LTX & PLUS^TM transfection reagent into the rete testis as the control group.After injection for 72 hours,testis tissues from both groups were collected for detecting the interference effect of Zfy gene interference vector on testis Zfy gene by Real-time quantitative PCR,and measuring the expression changes of SUN5,CATSPER1 and Odf1 genes related to the development of sperm tail of mice.The protein expression levels of the above genes were detected by Western blotting.The correlation between Zfy protein and SUN5,CATSPER1 and Odf1 proteins were detected by immunoprecipitation.The epididymal sperm of experimental and control groups were collected,for comparing the changes of 8 head and tail malformation rates by eosin sperm staining,and detecting the changes of sperm movement parameters by computer assisted sperm analysis (CASA) system.【Result】 After interference for 72 hours,compared with the control group,the mRNA and protein relative expression levels of Zfy gene in experimental group were extremely significant decreased (P＜0.01).The mRNA and protein relative expression levels of SUN5,CATSPER1 and Odf1 genes in testis of experimental group were extremely significantly decreased (P＜0.01).Zfy protein could form immunoprecipitation complex with SUN5 and CATSPER1 proteins.Compared with control group,the rates of head without hook deformity,abnormally large head deformity,amorphous deformity,tail folding deformity,tail curling deformity and tail breaking deformity of mouse sperm in the experimental group were extremely significant or significantly increased (P＜0.01 or P＜0.05).The results of CASA showed that compared with the control group,the semen parameters (sperm density,motility,progressive motility) and sperm locomotion parameters (curvilinear velocity,straight-line velocity,average path velocity,amplitude of lateral head displacement,linearity,wobble,straightness and beat-cross frequency) of mouse in experimental group were significantly or extremely significantly decreased (P＜0.05 or P＜0.01). 【Conclusion】 The expression levels of SUN5,CATSPER1 and Odf1 genes and their proteins decreased in the Zfy gene interference model of mouse testis,which affected the head-tail connection of sperm,the energy supply of tail motor and the formation of outer layer structure of tail flagella,resulting in the abnormality of sperm tail and the decrease of motor ability.

【Objective】 The purpose of this experiment was to establish a prokaryotic expression system of Porcine rotavirus (PoRV) VP6 truncated protein,and establish an indirect ELISA method to detect PoRV antibody,so as to provide a means for serological monitoring of PoRV.【Method】 A pair of specific primers for truncated VP6 gene was designed to amplify VP6 truncated gene using pMD19-T-VP6 recombinant plasmid as template.The recombinant plasmid pET32a-PoRV-VP6 was constructed using pET-32a(+) prokaryotic expression vector.Using Escherichia coli Rosetta(DE3) competent cells as host bacteria,the recombinant plasmid was induced to express and the expression conditions were optimized.pET32a-PoRV-VP6 recombinant protein was purified by His labeled nickel column and used as coated antigen.Single variable method was used to optimize the working conditions such as antigen coated concentration,serum dilution,secondary antibody dilution and incubation time of primary antibody and secondary antibody.The critical value of negative and positive of indirect ELISA method was determined,and its specificity,sensitivity,repeatability and compliance were tested.384 clinical pig serum samples collected from different pig farms in Guizhou during 2021-2024 were tested.【Result】 The recombinant expression vector pET32a-PoRV-VP6 was successfully constructed,and the prokaryotic truncated expression of VP6 protein was realized.The molecular weight of the protein was about 40 ku,and it had good reactivity.The optimal concentration of VP6 coated antigen was 2 μg/mL,the dilution of positive serum was 1∶100,the incubation time of serum samples and the second antibody was 60 min,the TMB reaction time was 10 min,and the negative and positive critical value (D_{450 nm}) was 0.410.The established indirect ELISA method did not react with Porcine epidemic diarrhea virus (PEDV),Porcine coronavirus (PDCoV),Porcine transmissible gastroenteritis virus (TGEV) and other standard positive sera,and had strong specificity.The variation coefficients of both intra-batch and inter-batch replicate tests were both ＜10%,and the repeatability was good.The overall coincidence rate with ELISA antibody detection kit of PoRV A was 96.80%.The total positive rate of 384 clinical pig serum samples detected by indirect ELISA was 28.91%.【Conclusion】 In this study,truncated expression of PoRV VP6 protein was successfully achieved,and an indirect ELISA method for PoRV antibody detection was established,which was suitable for clinical PoRV antibody detection and vaccine immune effect evaluation.

【Objective】 The aim of this study was to understand the prevalence and molecular characteristics of Bovine viral diarrhea virus (BVDV) in yaks in Haibei,Qinghai province.【Method】 Viral RNA was extracted from 148 diarrhea yak feces samples collected from Haibei,Qinghai province,and cDNA was synthesized by reverse transcription.BVDV 5'-UTR conserved region was amplified with the template,and a Real-time quantitative PCR method was established to detect BVDV infection in yak farms in Haibei,Qinghai province.4 BVDV positive samples were selected for PCR amplification and sequencing of the BVDV 5'-UTR region sequence,similarity comparison with different subtypes of BVDV and strains of the same genus in NCBI,and genetic evolution analysis was conducted based on the BVDV 5'-UTR region.【Result】 In this study,Real-time quantitative PCR detection method was successfully established based on BVDV 5'-UTR.The correlation coefficient (R²) of standard curve was 0.997,and the linear relationship was good when the standard concentration was 2.69×10²-2.69×10⁹ copies/μL,and the minimum detection limit was 2.69×10² copies/μL.The results of repeatability test showed that the coefficient of variation was less than 1.7%,which had good repeatability and stability.Yak diarrhea feces samples from Menyuan,Qilian,Haiyan and Huangyuan counties in Haibei area of Qinghai province were detected by Real-time quantitative PCR method，the positive rates of BVDV were 45.00%,36.00%,30.77% and 29.00%,respectively.The results of BVDV 5'-UTR sequence comparison showed that the 4 yak BVDV isolates were clustered in the same independent branch with the BVDV-1a subtype strains from Iran and United States,and the nucleotide sequence similarity was 76.6%-99.7%.【Conclusion】 This study identified BVDV-1a as one of the important pathogens causing yak diarrhea in Haibei area of Qinghai province,and provided scientific basis for yak farms in this area to take timely and effective prevention and control measures.At the same time,the molecular epidemiological data of local BVDV were enriched,which provided a theoretical basis for the prevention and control of bovine viral diarrhea disease and vaccine research and development in this area.

Foot-and-mouth disease (FMD) is a highly contagious disease infected with cloven-hoofed animals,caused by Foot-and-mouth disease virus (FMDV).The disease has the characteristics of multiple transmission routes and fast transmission speed,so as to cause huge economic losses to global livestock farming.Therefore,FMD is classified as the top of category A in animal infectious diseases by the World Organization for Animal Health (WOAH).The authors review the updated research on the genomic structure,the mechanism of proliferation and immune evasion of FMDV,which revealed the mechanism of invading cells and replicating and expression for FMDV in the host depending on the integrins receptor,the heparan sulfate receptor,as well as a third "receptor" that has not yet been discovered,and illustrating the mechanism of evading the natural immunity of the host that has been evolved during the striving of FMDV and host with each other.It is also found that multiple structural and non-structural proteins have participated in the inhibition of the activation of natural immunity signaling pathways.By studying the mechanisms of cell proliferation and immune escape of FMDV,elucidating the pathogenic mechanism of FMDV can provide ideas for improving the prevention and control of FMD in the future.

【Objective】 This study was aimed to investigate the effects of Eimeria tenella (E.tenella) infection on production performance,immune organs as well as cecum morphology and structure of Yellow-feathered broilers.【Method】 Seven half-sibling genealogies of Yellow-feathered broilers were screened for resistant and susceptible lines according to the coccidia susceptibility index after E.tenella infection to form resistant and susceptible groups,which were compared and analysed for differences in production performance,immune organs and intestinal morphology and structure between the different groups during the infected period and the recovery period,respectively.【Result】 The results showed that the average weight and daily gain of chickens in resistant and susceptible groups were extremely significantly lower than those of control group during E.tenella infection period and recovery period (P＜0.01),and the F/G was both extremely significantly higher than that in control group (P<0.01). Seven immune and intestinal organ indices of chickens,including thymus and spleen and so on,had no significantly different among resistant,susceptible and control groups at different periods of infection (P＞0.05),but the immune organ indices were higher in the recovery period than those in the infection period.In addition,pathological changes such as necrosis of cecum mucosa,incomplete and broken muscle layer were observed in chickens in both resistant and susceptible groups during the infection period,and coccidian gametes could be seen in the epithelium of cecum of chickens in susceptible group,while resistant group’s tissue structure of cecum of chickens gradually recovered to normal during the recovery period,all layers of cecal tissue of chickens in susceptible group were still showing significant degeneration or necrosis.【Conclusion】 Both resistant and susceptible chickens showed reduced performance and altered intestinal morphology after infection with E.tenella,regardless of whether they were infected or recovered,but during the recovery period,resistant chickens were able to gradually return to a healthy state,whereas susceptible chickens showed irreversible damage to cecum.The results of the study provided a reference for delve into the effects of E.tenella infection on the production performance and intestinal tract of chickens in infection period and recovery period.

【Objective】 This study was aimed to understand the current epidemiological dynamic status of main viral pathogens that cause calf diarrhea in some large-scale farms in 4 dominant cattle production areas in Xinjiang,so as to provide epidemiological investigation basis for formulating precise prevention and control measures.【Method】 In this experiment,367 diarrhoeic anal swab samples were collected from some large-scale farms in prefectures of Bole,Ili,Kashgar and Changji of Xinjiang,5 diarrhea causing viruses,namely,Bovine viral diarrhea virus (BVDV),Bovine norovirus (BNoV),Bovine rotavirus (BRV),Bovine nebovirus (BNeV) and Bovine coronavirus (BCV) were detected by using PCR with the analysis of the difference between seasons,areas and the calf breeds.【Result】 The results showed that BVDV had the highest detection rate of 26.7%.A total of 11 mixed infections were detected,including 5 kinds of double infection,mainly BVDV+BNoV mixed infection (11.4%).There were 5 kinds of triple infection,mainly BVDV+BRV+BNoV mixed infection (3.5%).The quadruple infection was only BVDV+BRV+BNoV+BNeV mixed infection (0.2%).The detection rates of BVDV,BRV and BNoV in spring and summer were significantly higher than those in autumn and winter (P＜0.05),while the detection rates of BCV and BNeV were significantly lower than those in autumn and winter (P＜0.05).Five pathogens were detected in both Ili and Changji regions,with the highest detection rate of BVDV (92.3%) in Ili region,followed by BNoV (52.7%).The detection rate of BNoV was the highest (19.5%) in Changji area,followed by BVDV (17.8%).The detection rate of BNeV in dairy calves was higher than that in beef calves (P<0.05),and BNoV infection was predominant in dairy calves (18.6%).Beef calves were mainly infected with BVDV (31.1%).【Conclusion】 It was concluded that there were significant seasonal,regional and breeds differences in the infection of 5 calf diarrheic causing viruses in Bole,Ili,Kashgar and Changji of Xinjiang.The result of this study provided a scientific basis for comprehensive prevention and treatment of calf diarrhea in Xinjiang.

Porcine deltacoronavirus (PDCoV),a novel enteric coronavirus,primarily infects suckling piglets,causing clinical symptoms such as diarrhea,vomiting and dehydration with a morbidity rate of up to 100%.PDCoV poses a significant threat to the health of newborn piglets and has become one of the primary pathogens causing diarrhea in swine.PDCoV enters host cells through membrane fusion and receptor-mediated endocytosis,with the S protein being the major structural protein for cell entry.Aminopeptidase N and caveolin on the cell surface have been identified as critical entry sites.Additionally,aminopeptidase N is currently considered a crucial determinant of PDCoV cross-species transmission.Host cells initiate an antiviral response through the expression of interferon (IFN) genes,cholesterol metabolism,and N protein ubiquitination.PDCoV evades the host immune response by interfering with IFN expression and inducing apoptosis of infected cells through its structural,accessory and non-structural proteins.Commercial vaccines or antiviral drugs for the prevention and control of PDCoV infection are currently in the experimental or early market stages,their clinical efficacy in preventing and controlling PDCoV infection still requires market validation.In particular,the development of antiviral drugs or vaccines targeting viral replication,immune evasion,and host factors against PDCoV provides new research directions and a solid foundation for the development of novel vaccines or antiviral drugs.By elucidating the infection and anti-infection mechanisms between PDCoV and the host,and investigating the potential mechanisms of various antiviral drugs in inhibiting PDCoV infection,this review provides a reference for studying the pathogenesis of PDCoV,antiviral therapy and the development of new drugs.

【Objective】 The purpose of this experiment was to investigate the classification,genetic diversity and incidence of Theileria of sheep in Keping and Aatii counties,Aksu region,Xinjiang.【Method】 A total of 78 sheep blood samples from farms in Keping and Awati counties were tested for the pathogen of ovine theileriosis by PCR,and the positive samples were sequenced,and the sequences obtained were analyzed for similarity and genetic diversity with 18S rRNA sequences of Theileria species in GenBank.【Result】 The overall PCR positive rate of ovine theileriosis was 84.6% (66/78) in the two counties,with rates of 73.3% (22/30) in Keping county and 91.7% (44/48) in Awati county.The similarity of 6 representative sequences obtained by sequencing was more than 93%,and their similarity with 18S rRNA sequences of Theileria ovis in GenBank database was more than 97%.The genetic evolution tree revealed independent clades for 9 species of Theileria ovis,Theileria annulata and Theileria cervi,and so on.Theileria ovis was closely related to Theileria annulata,and was closely related to isolates from Turkey,Iraq and Saudi Arabia.Haplotype analysis of 50 18S rRNA gene sequences from seven countries including China,Iraq,Turkey,Saudi Arabia showed that these sequences were distributed in 16 haplotypes.Five sequences from this study were grouped into Hap_1 along with sequences from Henan and Gansu provinces in China,and the other one was isolated as Hap_16.Population structure analysis using a total of 47 sequences from China,Iraq,Turkey and Saudi Arabia indicated a separation site in all four countries.Strains from Iraq exhibited high nucleotide diversity,while that of isolates from China,Turkey and Saudi Arabia was low.Strains from Turkey had the highest average difference number,indicating large genetic differences within the population compared to the other three countries where genetic differences were small.Haplotype diversity for isolates from Turkey,Iraq and Saudi Arabia was more than 0.5,with Iraqi isolates showing the highest value reflecting high genetic diversity,whereas Chinese strain value was 0.250 indicating low genetic diversity.Tajima’s D value for all four countries above were less than 0,suggesting that the population had shifted its genetic balance state,possibly due to population expansion.【Conclusion】 The data of this study showed that Theileria infection was prevalent in Keping and Awali counties,Aksu,and Theileria ovis was the main pathogen. Theileria uilenbergi and Theileria luwenshuni were not detected,and Theileria ovis had a distant genetic relationship with them.Theileria ovis populations from different regions were characterized by high haplotype and genetic diversity,and population expansion was occurring.The results of this study could provide a reference for the comprehensive control of ovine theileriosis and the healthy development of local aquaculture in Aksu.

【Objective】 Streptococcus agalactiae was one of the main pathogens causing mastitis in dairy cows,and it was of great significance to clarify the resistance,virulence and genomic properties of Streptococcus agalactiae for the study of the resistance mechanism of Streptococcus agalactiae.【Method】 The test was carried out by inoculating milk samples on blood plates for isolation and purification by plate scribing method,and the isolates were identified by morphological observation,Gram staining microscopy and molecular biology methods.The minimum inhibitory concentration (MIC) of the isolates was detected by micro broth dilution method,8 drug resistance genes and 14 virulence genes of the isolates were detected by PCR method,and the isolates were analyzed for drug resistance,virulence genes,and genome function using whole-genome sequencing technology.【Result】 In this study,two strains of bacteria were successfully isolated from 36 samples,which showing white,round,smooth and raised colonies on blood agar plates,and purple spherical Gram-positive organisms were seen on microscopic examination.The biochemical identification showed that the isolates were β-hemolytic and the contact enzyme test was negative,and the PCR amplification showed two bands of 1 500 bp in size as expected,and the sequencing result showed that the similarity with Streptococcus agalactiae ATCC 13813 was ＞99.93%,so the isolates were identified as Streptococcus agalactiae at the molecular level,and were designated as S1 and S2.The results of serotyping and molecular typing showed that the serotype of S1 strain was type Ⅱ and molecular typing was ST312,whereas the serotype of strain S2 was type Ⅲ and molecular typing was ST309.Drug sensitivity tests showed that strains S1 and S2 exhibited high sensitivity to ampicillin,amoxicillin/clavulanic acid,oxacillin,cefphalothin,sulfisoxazole and compound sulfamethoxazole.However,strain S1 was resistant to tetracycline and clindamycin,whereas S2 was resistant to tetracycline,erythromycin and clindamycin.In addition,tetO and ermB resistance genes were detected in strain S2,whereas other resistance genes were not found.In terms of virulence genes,cfb,bca,iagA,bibA,cspA,pavA,sip, hylB and fbsA were detected in both strains S1 and S2.Genomic analysis showed that strain S1 had a circular chromosome of 2.44 Mb in size,with a GC content of 36.34%,and were predicted to contain 2 448 genes.Strain S2 had a ring chromosome of 2.56 Mb in size with a GC content of 36.59% and was predicted to contain 2 576 genes.By constructing a homologous phylogenetic tree,it was found that strain S1 had the highest consistency with the Streptococcus agalactiae NCTC13947 strain from UK; S2 was most closely related to Streptococcus agalactiae NCTC8184 strain from UK.【Conclusion】 In this study,two strains of Streptococcus agalactiae S1 and S2 were isolated from 36 samples of dairy cows with mastitis and found to be sensitive to a variety of antibiotics,but also showed resistance.Genomic analysis revealed their resistance and virulence genes,providing valuable data for further studies on the resistance and virulence of Streptococcus agalactiae.

Bisphenol A (BPA),as an endocrine disruptor with estrogenic activity,is widely used in daily products such as food packaging,medical equipment,and children’s toys due to its high heat resistance and durability.BPA accumulates in soil,water and other environments,and enters the human body through diet,skin contact,and other pathways.BPA binds to estrogen receptors,interferes with hormone balance in the body,and poses a potential threat to human health.Among them,BPA has the most significant damage to the reproductive system.To this end,human have developed various BPA alternatives such as BPS and BPF,but these BPA alternatives have also been detected globally,and their environmental and health impacts cannot be ignored.In recent years,BPA and its substitutes have been widely found in animal manure and excrement,breeding environments,as well as animal products such as meat,eggs,and milk in intensive scale livestock and poultry farming.The manure and urine produced by intensive livestock and poultry farming are important sources of BPA and its substitutes in the environment,which pose a threat to human health through diet and contact pathways.Human have developed various detection methods and clearance strategies for BPA and its alternatives,while research on intensive livestock and poultry farming is relatively scarce.The authors summarize the population distribution,toxicokinetics,environmental risk assessment,impact on the reproductive system,detection methods,and clearance strategies of BPA and its substitutes in livestock and poultry breeding environments,aiming to provide theoretical basis for the prevention and control of bisphenol compound pollution in large-scale livestock and poultry breeding.

【Objective】 This study was aimed to understand the infection,drug resistance and virulence genes of the main causative organisms and Mycoplasma of bovine respiratory diseases in a large-scale ranch in Inner Mongolia,and provide medication basis for the prevention and treatment of bovine respiratory diseases in this ranch.【Method】 The lung tissues of dead cattle were collected for isolation and culture of pathogenic bacteria,biochemical identification,16S rRNA gene sequencing,PCR identification,drug susceptibility test,drug resistance genes and virulence genes detection.【Result】 One strain of Pasteurella multocida type A and one strain of Mannheimia haemolytica type A6 were isolated from the TSA plate,which showed rounded,grayish-white,transparent or translucent colonies,and the amplification of specific and serotypic genes was in accordance with the expected bands.One strain of Mycoplasma bovis was isolated from the solid medium of PPLO,which appeared in the solid medium of PPLO,and showed the appearance of omelette in the microscopic examination,and the amplification of specific genes was in accordance with the expected bands.The 16S rRNA sequencing and aligning results showed that the three pathogens had similarities of over 99% with Pasteurella multocida,Mannheimia haemolytica and Mycoplasma bovis,respectively.The results of drug resistance analysis and virulence gene detection showed that Pasteurella multocida and Mannheimia haemolytica were highly sensitive to oxfloxacin,and sensitive to kanamycin,amikacin,gentamicin and other antimicrobials.Pasteurella multocida carried resistance genes strA,strB,tetA,tetB,qnrA and bla_ROB,and 22 virulence genes such as exbB,exbD,ompA and psl.Mannheimia haemolytica carried resistance genes strA and strB,and four virulence genes such as gcp,gs60,lktC and tbpB.Mycoplasma bovis was resistant to streptomycin,erythromycin,clindamycin,intermediary to ciprofloxacin,amikacin and kanamycin,and sensitive to gentamicin,ofloxacin,enrofloxacin and tetracycline,carrying resistance genes strA,strB,mph and msr-E,and the virulence genes of VspX,VspY2,VpmA and P81.【Conclusion】 The respiratory disease of sick and dead cattle in this ranch was caused by Pasteurella multocida,Mannheimia haemolytica and Mycoplasma bovis,and the isolated strains carried a variety of virulence genes,it was recommended to use oxfloxacin as the main therapeutic antimicrobial drug for the treatment of bovine respiratory disease in the clinic and the use of antimicrobial drugs such as erythromycin and clindamycin were not recommended.

【Objective】 This study was aimed to explore the conditions and methods of the infection mice model induced by Streptococcus equi subsp. equi from horse/donkey,and lay a foundation for the development of new drug of horse/donkey strangle and related research.【Method】 100 Kunming mice were selected and infected with different concentrations of hourse source Streptococcus equi Xinjiang strain (SEE-M) and donkey source Streptococcus equi Xinjiang strain (LXY019),the minimum complete lethal dose (MLD) was determined.Then 30 Kunming mice were randomly divided into 3 groups (Model Ⅰ:SEE-M strain infection;Model Ⅱ:LXY019 strain infection;Control:Normal saline),10 mice in each group.Mice were infected with the corresponding strain of 80% MLD to establish the model of strangle infection,and the death of mice was observed.By detecting the organ coefficient,visceral bacterial load,serum inflammatory factors,and histopathology of mice,the construction of the mouse infection model was verified.【Result】 The results showed that the MLD of mice infected with horse/donkey derived Streptococcus equi subsp.equi was 1.875×10⁹ and 8.750×10⁸ CFU,respectively.The horse/donkey strangle model was established by infecting mice with 80% MLD horse/donkey Streptococcus equi subsp. equi.The mortality rates were 60% and 70% respectively,and the body weight showed a downward trend.The experimental results of mice infection model showed that compared with control group,the liver,lung and kidney organ indexes of mice in model Ⅰ and model Ⅱ groups were significantly increased (P＜0.05).All organs of the mice in model Ⅰ and model Ⅱ groups showed Streptococcus equi subsp.equi infection positive,and the bacterial load in liver,spleen,lung and kidney was significantly higher than that in heart and brain (P＜0.05).The levels of tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) in serum of mice in model Ⅰ and model Ⅱ groups were extremely significantly increased (P＜0.01).Pathological section results showed that the organs of mice in model Ⅰ and model Ⅱ groups showed obvious pathological changes such as inflammatory cell infiltration,bleeding,structural destruction,and necrosis and shedding of visceral cells.【Conclusion】 Infection of mice with 1.5×10⁹ CFU of Streptococcus equi subsp.equi from horses and 7×10⁸ CFU of Streptococcus equi subsp.equi from donkeys could successfully establish equine strangle animal model. All the organs of infected mice were infected by pathogenic bacteria,especially lungs,livers,spleens and kidneys.The results laid a foundation for the prevention and treatment of equine strangle and the development of targeted drugs.

【Objective】 Clostridium perfringens type D was a Gram-positive anaerobic bacterium,which could cause enterotoxaemia in animals such as goats,sheep and cattle,which had a great impact on the health of ruminants.The aim of this study was to understand the drug resistance of Clostridium perfringens type D in Wushen county, Inner Mongolia, and provide a scientific basis for the treatment of diseases caused by Clostridium perfringens type D in this region.【Method】 The isolated strain was initially identified by culture characteristics and Gram staining microscopy.The suspected strain was further identified by 16S rRNA sequence comparison and PCR amplification of toxin gene.And the drug sensitivity test was carried out by K-B paper slide method,and PCR was used to detect the drug resistance gene of the isolated strain.【Result】 The isolated strain grew black round colonies in TSC medium,and the Gram staining microscopy showed that the bacterium was thick and short,and became a single or double arrangement of Gram-positive rectobacteria,and the morphological and microscopic results were consistent with the characteristics of Clostridium perfringens.The results of 16S rRNA sequence alignment showed that the similarity of the isolated strain and 16S rRNA gene sequences of Clostridium perfringens published in NCBI database was more than 99%,and the strain was identified as Clostridium perfringens.The PCR detection results of toxin genes showed that cpa and etx genes were amplified,indicating that the strain was Clostridium perfringens type D.The results of drug sensitivity tests showed that the isolated strain was resistant to 16 antimicrobials including ceftriaxone,cefuroxime and gentamicin.The results of resistance gene detection showed that 4 resistance genes,bla_CTX-M,bla_SHV,qnrA and aac(6')-Ⅰb-cr,were detected,and 2 resistance genes,bla_TEM and qnrS,were not detected.【Conclusion】 In this experiment,a strain of Clostridium perfringens type D,which was multi-drug resistant,was successfully isolated from sheep.The results of this study provided a reference basis for the diagnosis,epidemiological investigation,and treatment of Clostridium perfringens type D infected sheep.

【Objective】 A pilot study was conducted to investigate the protective effect and mechanism of catechu extract (TCE) on the colon of young piglets infected with Porcine epidemic diarrhea virus (PEDV) using 7-day-old piglets.【Method】 Eighteen young piglets of similar body weight were randomly divided into three groups:Control group,PEDV group and TCE＋PEDV group,with six pigs in each group.The experimental period lasted for 11 days,with the initial adaptation period spanning from 0 to 3 days and the subsequent formal experimental period extending from 4 to 11 days.In the formal experimental period,piglets in control and PEDV groups were fed with artificial milk,and piglets in TCE＋PEDV group were fed with artificial milk and TCE (0.01 g/kg BW).The study involved the feeding of 3 mL of 10⁶ TCID₅₀/0.1 mL PEDV to piglets in both the PEDV and TCE＋PEDV groups on the 8th day.The same volume of DMEM was administered to piglets in control group.On the 11th day,all piglets were anesthetized and slaughtered,and colon tissues were collected to determine the effects of TCE on the colonic morphology and structure,antioxidant capacity,inflammatory factors,and ion channel related gene expression of piglets infected with PEDV.【Result】 Compared with control group,the colon tissue morphology of piglets in PEDV group was damaged,and the crypt depth was significantly increased (P＜0.05).Oral administration of TCE could effectively alleviate colonic damage in piglets caused by PEDV infection.Compared with PEDV group,the colon crypt depth of piglets in TCE＋PEDV group was significantly shallower (P＜0.05).Compared with control group,the activity of glutathione peroxidase (GSH-Px) in colon of piglets infected with PEDV was significantly increased (P＜0.05).Compared with PEDV group,the activities of GSH-Px,total superoxide dismutase (T-SOD),catalase (CAT) and myeloperoxidase (MPO) in colon of piglets in TCE＋PEDV group showed no significant changes (P>0.05).After PEDV infection,PEDV M,N and S genes expression could be detected in colon tissues of piglets,and the expression of interferon (IFN) signaling pathway related genes ISG15 and IRF7,inflammatory factor genes IL-1β,IL-8,REG3G,and ion channel related genes AQP10,APOB and MMP13 were significantly upregulated (P＜0.05),while the expression of IFN-β gene was significantly downregulated (P＜0.05).Compared with PEDV group,the expression of PEDV M,N,S genes,and ISG15, IL-1β, IL-8,REG3G,IRF7,APOB and MMP9 genes in colon of piglets in TCE＋PEDV group were significantly downregulated (P＜0.05),while the expression level of IFN-β gene was significantly up-regulated (P＜0.05).【Conclusion】 PEDV infection caused mucosal damage in colon tissue of young piglets,which could be alleviated by feeding 0.01 g/kg BW of TCE.

【Objective】 The purpose of this experiment was to explore the drug resistance and virulence gene carrying of Staphylococcus aureus (S.aureus)in a large-scale dairy farm in Xinjiang,so as to provide a certain reference for the prevention and control of S.aureus in this farm.【Method】 In this study,milk samples were collected from the large-scale dairy farm,the bacteria were isolated and purified by plate scribing method,the strains were identified by S.aureus-specific primers,the antibiotic resistance phenotype of the isolate was analyzed by Kirby-Bauer method,and the antibiotic resistance and virulence genes were detected by PCR method.【Result】 The average isolation rate of S.aureus in 262 milk samples was 15.27% (40/262),of which 28.57% (10/35) in clinical mastitis milk samples,and 11.41% (17/149) and 16.67% (13/78) in recessive mastitis milk samples and healthy milk samples,respectively.5.00% (2/40) of the isolates were not detected with housekeeping genes (arcC,aroE,glpF,gmK,pta,tpi and yqil genes).The detection rate of virulence genes clfA,clfB and coa was high.There were 16 different virulence gene combinations.77.50% of the isolates were multidrug-resistant strains,and one strain was resistant to 14 drugs including vancomycin.The detection rates of lincoamide resistance gene linA (52.50%),quinolone resistance gene qnrA (50.00%),aminoglycoside resistance gene aacA-aphD (45.00%),erythromycin and clindamycin resistance gene ermC (40.00%) were higher in isolates.The antibiotic resistance phenotypes of five kinds of antibiotics such as chloramphenicol had a high degree of overlap with antibiotic resistance genes,while the antibiotic resistance phenotypes of three kinds of drugs,including β-lactams,had a low degree of overlap with the corresponding resistance genes.【Conclusion】The results indicated that the milk-derived S.aureus from the farm was generally antibiotic resistant,and the phenomenon of multiple antibiotic resistance was more serious.The results of this study provided a reference for the prevention and control of S.aureus in the farm.

【Objective】 This experiment was to investigate the effect of cold stimulation on lung injury of piglets induced by Actinobacillus pleuropneumoniae (APP) infection and the role of silent information regulator 1 (SIRT1) in this process.【Method】 12 healthy 4-week-old male weaned Landrace piglets with similar body weight (8.0 kg±0.5 kg) were randomly divided into 4 groups:Control group (Control),cold stimulation group (Cold),APP infection group (APP) and cold stimulation with APP infection group (Cold＋APP),with 3 piglets in each group.After 1 week of pre-feeding,piglets in Control group were fed at room temperature.Piglets in Cold group were subjected to continuous cold stimulation at (4±1) ℃ for 6 h.Piglets in APP group were infected with APP by nasal drip (2×10⁹ CFU/mL),and 1.5 mL was injected into each of the left and right nostrils.Piglets in Cold＋APP group were first infected according to the APP group method,and then exposed at (4±1) ℃ for 6 h.After the experiment,the piglets were slaughtered and lung tissue samples were collected.The pathological changes of lung tissue were observed by hematoxylin-eosin (HE) staining and the fibrosis of lung tissue was observed by Masson staining.The contents of malondialdehyde (MDA) and glutathione (GSH) in lung tissues were determined by ELISA.The mRNA expression level of the inflammatory factors interleukin-6 (IL-6),IL-1β,and tumor necrosis factor-α (TNF-α) genes in lung was detected by Real-time quantitative PCR.Western blotting was used to detect the expression levels of nuclear factor E2-related factor 2 (Nrf2),Kelch-like ECH-associated protein 1 (Keap1),heme oxygenase-1 (HO-1),SIRT1,and acetylated nuclear factor κB subunit p65 (Ace-NF-κB p65) proteins. 【Result】 HE staining results showed that compared with APP group,there was a large number of inflammatory cell infiltration in lung tissues,capillary dilation and congestion in piglets in Cold＋APP group.Masson staining showed that,compared with APP group,a large number of diffuse collagen fiber deposition appeared in the lung tissues of piglets in Cold＋APP group.ELISA results showed that compared with APP group,MDA content in lung tissues of piglets in Cold＋APP group was significantly increased (P＜0.05),and GSH content was significantly decreased (P＜0.05).The results of Real-time quantitative PCR showed that compared with APP group,the mRNA relative expression levels of IL-6,IL-1β and TNF-α genes in lung tissues of piglets in Cold＋APP group were significantly increased (P＜0.05).Western blotting test results showed that compared with APP group,the relative expressions of Nrf2,HO-1 and SIRT1 proteins in lung tissues of piglets in Cold＋APP group were significantly decreased (P＜0.05)，the relative expression levels of Keap1 and Ace-NF-κB p65 proteins were significantly increased (P＜0.05).【Conclusion】 Cold stimulation could enhance the oxidative stress and inflammatory response of piglet lung tissues induced by APP infection.SIRT1 could aggravate the lung injury of piglets after APP infection under cold stimulation by regulating the acetylation of NF-κB p65.

【Objective】 The purpose of this study was to analyze the correlation between drug resistance and virulence genes of Escherichia coli with polycolistin resistance gene mcr-1 from chickens in Fujian province,and study the plasmid transfer characteristics of mcr-1 resistance gene.【Method】 The sensitivity of 87 strains of chicken Escherichia coli with mcr-1 gene to 11 kinds of antibiotics was detected by microbroth dilution method.PCR was used to detect the drug resistance gene,virulence gene and plasmid type of the isolates,and to analyze the drug resistance phenotype and drug resistance gene of mcr-1 gene positive bacteria,and the correlation between drug resistance gene and virulence gene.Plasmid conjugation test was used to investigate the transfer of mcr-1 gene.【Result】 The results of drug susceptibility test showed that 96.55% (85/87) isolates were multi-drug resistant bacteria,among which the resistance to tetracyclines was the most serious,and the resistance rates of doxycycline and tetracycline were 88.51% (77/87) and 82.76% (72/87),respectively.11 drug resistance genes were detected in the isolates,among which tetracyclines resistance gene tet(A) had the highest detection rate of 95.40% (83/87).A total of 18 virulence genes were detected,among which invasiin-type mat was the dominant virulence gene,with a detection rate of 85.06% (74/87).Some resistance genes and phenotypes,resistance genes and virulence genes were correlated.The isolates carried 12 germplasm,and the main type was IncFIB (77.01%,67/87).The conjugation test results showed that 42 isolates were successfully conjugated,and the conjugation transfer rate was 48.28% (42/87).IncI2,IncHI2 and IncX4 plasmids were successfully transferred to conjugons,and the detection rate of IncI2 plasmid was the highest (57.14%).【Conclusion】 The 87 strains of Escherichia coli with mcr-1 gene from chicken had severe multiple drug resistance,high detection rate of drug resistance genes,various types of virulence genes,and some of the drug resistance genes were correlated with drug resistance phenotype and virulence genes.The mcr-1 gene of 48.28% (42/87) strains could be transmitted by plasmids IncI2,IncHI2 and IncX4.The results provided a scientific basis for further understanding the multi-drug resistance,virulence characteristics and transmission mechanism of mcr-1 gene positive Escherichia coli from chickens in Fujian province.

【Objective】 The purpose of this experiment was to identify the pathogen of goats suspected to be suffering from pseudotuberculosis in a farm in Yiliang,Yunnan province,and explore its drug resistance and pathogenicity,so as to provide theoretical basis for the diagnosis and treatment of the disease.【Method】 According to the clinical symptoms of the infected goats,the cause of the disease was preliminarily determined,the disease material was collected aseptically,and the pathogenic bacteria were isolated and purified to identify the morphological characteristics,culture characteristics and biochemical characteristics.The 16S rRNA gene sequences of the isolate was amplified by PCR and analyzed by sequencing.The drug resistance and pathogenicity of the isolate were investigated by drug susceptibility test,drug resistance gene test and pathogenicity test in mice.【Result】 The isolate grew well on the blood agar plate,the colonies were yellowish-white and opaque,and did not grow well in the common nutrient agar and the common nutrient broth.Gram staining microscopy showed that the bacteria were spheroidal or rod-shaped and Gram-positive bacteria.The results of biochemical identification showed that glucose and urea tests were positive,while lactose,maltose,mannitol,sucrose,Simon’s citrate,hydrogen sulfide,indigo matrix,nitrate reduction test,methyl red (MR) test and VP test were negative.16S rRNA sequence alignment results showed that，the 16S rRNA gene sequence similarity between the isolated and Corynebacterium pseudotuberculosis in NCBI database was more than 99%,and it was identified as Corynebacterium pseudotuberculosis.Drug sensitivity test results showed that，the isolate showed intermediation to streptomycin,gentamicin and neomycin,and resistance to amtronam,ceftazidime and polymyxins.The results of drug resistance gene detection showed that the isolate carried drug resistance genes Sul2,Sul3,bla_TEM and bla_CTX-M. The results of animal pathogenicity test showed that abdominal and subcutaneous inoculation with 4.4×10⁸ CFU/mL isolated bacteria could cause death of mice,and the mortality rate was 100%.Subcutaneous abscess appeared 96 h after subcutaneous inoculation,and Corynebacterium pseudotuberculosis could be isolated from the pus.【Conclusion】 In this experiment,a strain of Corynebacterium pseudotuberculosis of goats origin was successfully isolated and identified,and the pathogen of the infected goats was identified.The strain was highly pathogenic to mice.The results provided reference for the diagnosis,epidemiological investigation and treatment of Corynebacterium pseudotuberculosis infection in goats.

【Objective】 The objective of this experiment was to extract Polygonum viviparum L.polysaccharide by water extraction and alcohol precipitation,and optimize the extraction parameters by response surface methodology,and further analyze the composition of monosaccharides.【Method】 The effects of extraction temperature,liquid-solid ratio,extraction time and ultrasonic power on the extraction yield of Polygonum viviparum L.polysaccharide were investigated by single factor test.With the extraction rate of polysaccharide as the response value,the Box-Behnken experimental design method was used to design the 4-factor and 3-level test and optimize the response surface to determine the relationship between the influencing factors and the extraction rate of polysaccharide.The polysaccharide was deproteinized and purified by Sevag method,and the monosaccharide composition of Polygonum viviparum L.polysaccharide was determined by gas chromatography-mass spectrometry (GC-MS).【Result】 The influencing factors on the extraction rate of Polygonum viviparum L.polysaccharide was extraction temperature ＞ ultrasonic power ＞ extraction time ＞ liquid-solid ratio.The optimal extraction conditions were as follows:Extraction temperature was 50 ℃,liquid-solid ratio was 8∶1,extraction time was 90 min and ultrasonic power was 500 W.Under the optimized conditions,the extraction rate of Polygonum viviparum L.polysaccharide was 6.619%.The results of GC-MS assay showed that the Polygonum viviparum L.polysaccharide was mainly composed of D-arabinose, D-mannose,glucose and D-galactose with a molar ratio of 0.63∶0.57∶6.3∶2.5.【Conclusion】 Response surface methodology was used to optimize the extraction process of Polygonum viviparum L.polysaccharide,and the monosaccharide composition was preliminarily determined.The results provided technical support for the industrial extraction of Polygonum viviparum L.polysaccharide.

【Objective】 This study was conducted to investigate the biological functions of superoxide dismutase A (SodA),thioredoxin A (TrxA) and TrxC genes of Streptococcus suis type 2 in regulating oxidative stress and participating in pathogenic processes.【Method】 The regulation of stress resistance and virulence of 3 mutant strains of Streptococcus suis type 2,ΔSodA,ΔTrxA and ΔTrxC,were compared.The anti-oxidative stress ability of SodA,TrxA and TrxC genes to different oxidative stress treatments (0.04% hydrogen peroxide (H₂O₂),10 mol/L paraquat (PQ)) and the anti-temperature stress ability at different temperatures (4 and 43 ℃) were tested by stress survival test.Different gene deletion strains were co-cultured with porcine intestinal epithelial cells (IPEC-J2) and mouse macrophages (RAW264.7) to explore the effects of the 3 genes on cell adhesion and anti-phagocytosis.The effects of SodA,TrxA and TrxC genes on the anti-oxidative stress and the pathogenesis were investigated by testing the bacterial load,serum antioxidant enzymes and liver function in mice.【Result】 The results of anti-stress test showed that under different oxidative stress and different temperature stress conditions,the survival ability of ΔSodA and ΔTrxC strains was extremely significantly lower than that of wild strain (P＜0.01),and the survival ability of ΔTrxA strain was extremely significantly lower than that of wild strain under high temperature stimulation at 43 ℃ (P＜0.01).The results of cell adhesion test showed that the deletion of SodA and TrxA genes reduced the adhesion ability of bacteria by 55%-65%,which was extremely significantly lower than that of wild strain (P＜0.01).The results of anti-phagocytosis test showed that the survival rate of ΔSodA,ΔTrxC and ΔTrxA strains in phagocytosis cells was extremely significantly or significantly lower than that of wild strain (P＜0.01 or P＜0.05).The results of animal challenge test showed that the virulence of ΔSodA,ΔTrxA and ΔTrxC strains decreased extremely significantly compared with wild strain (P＜0.01).The mortality of ΔSodA,ΔTrxA and ΔTrxC strains were 10%,50% and 20%,respectively,and the tissue bacterial load was 3.6 lg CFU/g-4.4 lg CFU/g,4.2 lg CFU/g-5.1 lg CFU/g and 3.1 lg CFU/g-4.1 lg CFU/g,respectively.In the wild strain group,the mortality was 90%,and the tissue load was 6.4 lg CFU/g-7.8 lg CFU/g.The activities of superoxide dismutase (SOD),catalase (CAT) and total antioxidant capacity (T-AOC) in serum of mice infected with ΔSodA,ΔTrxC and ΔTrxA strains were extremely significantly higher than those of wild strain (P＜0.01).The activities of aspartate aminotransferase (AST),alanine aminotransferase (ALT) and alkaline phosphatase (ALP) were extremely significantly lower than those of wild strain (P＜0.01).【Conclusion】 SodA and TrxC genes of Streptococcus suis type 2 counteracted the damage caused by oxidative stress by neutralizing superoxide ions in bacteria and maintaining protein homeostasis,thus mediating bacterial virulence.TrxA might be a regulatory gene involved in antioxidant stress response.

【Objective】 The aim of this study was to screen probiotics with excellent probiotic properties from Kele pigs feces,and to provide reference for screening candidate strains of microecological preparations for livestock and poultry.【Method】 Fresh Kele pigs feces were collected,and bile salt-tolerant strains were initially screened with 0.3% bile salt.After isolation and purification,colony morphology and 16S rDNA sequencing were used to identify the isolates.The biological characteristics of its growth,tolerance characteristics,enzyme production characteristics,drug sensitivity characteristics and animal safety were analyzed.【Result】 A strain of bile salt-tolerant Bacillus velezensis was isolated and screened,named W1.The isolate was round,milky white and opaque on LB solid medium,with a wrinkled and dry surface and untidy edges.Gram-stained microscopic examination showed positive brevibacterium,and the bacteria were short rod shaped by scanning electron microscope.The isolates entered the logarithmic phase after 4 h in LB liquid medium,and entered the stationary phase after 28 h.The survival rate was 78.44% and 86.62%,respectively,after 2% of the inoculated liquid was placed in artificial gastric fluid and artificial intestinal fluid for 1 h.The diameter of transparent circles formed by isolate in cellulase,amylase and protease screening media was (15.44±2.27),(25.11±0.69) and (29.69±1.76) mm,respectively.The results of drug sensitivity test showed that the isolate was sensitive to tetracycline,kanamycin,gentamicin,azithromycin,norfloxacin and ciprofloxacin,and was intermediate to penicillin,amoxicillin and erythromycin.The results of animal safety test showed that the mice in control and the experimental groups were in good growth condition by gavage of 0.1 mL 1×10⁹ CFU/mL isolated bacterial solution for 20 d,and no visible lesions were observed in the organs by anatomy.The average daily gain of mice in experimental group was significantly higher than that of control group (P＜0.05),and there was no significant difference in blood routine indexes between the two groups (P ＞ 0.05).【Conclusion】 A strain of Bacillus velezensis with good biological characteristics was isolated and screened.It had certain tolerance to artificial gastric and intestinal fluids,produced cellulase,amylase and protease,and was not toxic to mice.It was expected to be a candidate strain for livestock and poultry microecological prearations.

【Objective】 The purpose of this study was to investigate the effect of piceatannol (PIC) on liver injury induced by deoxynivalenol (DON) in mice.【Method】 Eighteen 5-week-old SPF grade C57BL/6J male mice with an initial weight of (19.3±0.8) g after 7 d of adaptive feeding were randomly divided into 3 groups based on the body weight：Control (CON),DON and PIC＋DON groups,with 6 mice in each group in a single cage.The experiment lasted for 14 d.Mice in CON group were given 0.2 mL PBS solution every day for 14 d.The mice in DON group were given 0.2 mL PBS solution continuously on days 1 to 7,and 0.2 mL DON (3 mg/kg BW) continuously on days 8 to 14.The mice in PIC+DON group were given 0.2 mL PIC (40 mg/kg BW) from days 1 to 7,and 0.2 mL DON (3 mg/kg BW) from days 8 to 14.Liver tissue and blood samples were collected after the experiment.The activities of glutathione peroxidase (GSH-Px) and catalase (CAT),total antioxidant capacity (T-AOC) and the content of malondialdehyde (MDA) in liver,the contents of total cholesterol (TC) and triglyceride (TG),and the activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in serum were determined.The changes of liver histomorphology were observed by HE staining.Real-time quantitative PCR was used to detect the relative mRNA expression of interleukin-6 (IL-6),IL-1β,B-cell lymphomato-2-associated X protein (Bax),Caspase-3,Caspase-9,Caspase-1,microtubule associated protein 1 light chain 3β (LC3B),nuclear factor-κB (NF-κB),tumor necrosis factor-α (TNF-α),B-cell lymphoma-2 (Bcl-2) and nuclear factor E2-associated factor 2 (Nrf2) in liver.【Result】 Compared with CON group,the body weight of mice in DON group was significantly decreased (P＜0.05),and the liver index was significantly increased (P＜0.05).Compared with DON group,the body weight of mice in PIC＋DON group was significantly increased (P＜0.05),and the liver index was significantly decreased (P＜0.05).The pathological section results showed that the arrangement of liver cords was disordered,hepatocyte swelling and degeneration,endothelial cell shedding and inflammatory cells increased in DON group.After PIC treatment,the degree of lesion was significantly improved.Compared with CON group,GSH-Px,CAT activities and T-AOC of liver in DON group were significantly decreased (P＜0.05),MDA content of liver,TC and TG contents,AST and ALT activities of serum were significantly increased (P＜0.05).Compared with DON group,GSH-Px,CAT activities and T-AOC of liver in PIC＋DON group were significantly increased (＜0.05),MDA content of liver,TC and TG contents,AST and ALT activities of serum were significantly decreased (P＜0.05).Real-time quantitative PCR results showed that compared with CON group,the relative expressions of IL-6,Bax,Caspase-3, Caspase-9,Caspase-1,IL-1β,LC3B,NF-κB and TNF-α genes in DON group were significantly increased (P＜0.05)，and the relative expression of Bcl-2 and Nrf2 genes were significantly decreased (P＜0.05).Compared with DON group,the relative expressions of IL-6,Bax,Caspase-3, Caspase-9,Caspase-1,IL-1β,LC3B,NF-κB and TNF-α genes in PIC＋DON group were significantly decreased (P＜0.05)，and the relative expression of Bcl-2 and Nrf2 genes were significantly increased (P＜0.05).【Conclusion】 PIC could improve the liver injury induced by DON by increasing the activity of antioxidant enzymes and decreasing the expression of inflammatory factors.