This study was aimed to clone the CDS of long-chain acyl-CoA synthetase 3 (ACSL3) gene in Red Steppe cattle,analyze it for bioinformatics,and detect the expression differences in different tissues of Red Steppe cattle at the mRNA and protein levels.The CDS of ACSL3 gene was obtained by RT-PCR and TA cloning methods.A variety of software and online tools were used to analyze the homology among different species and construct phylogenetic tree,analyze physical and chemical properties,potential phosphorylation locus,O-glycosylation sites,N-glycosylation sites,signal peptide,disulfide bonds,transmembrane region,subcellular localization,and the secondary and tertiary structures of ACSL3 protein.Meanwhile,the mRNA and protein expression levels of ACSL3 gene in each tissue of Red Steppe cattle were detected by Real-time PCR and Western blotting.The results showed that the CDS of ACSL3 gene was 2 163 bp in length encoding 720 amino acids with a protein molecular weight of 80.28 ku and a theoretical isoelectric point of 8.74,which was a hydrophilic protein.By NCBI BLAST comparison,the nucleotide sequence homology of ACSL3 gene in Red Steppe cattle shared 99%,97%,93%,91%,88%,88% and 78% identity with Bos taurus,Ovis aries,Sus scrofa,Homo sapiens,Mus musculus,Rattus norvegicus and Gallus gallus,respectively.The phylogenetic tree found that the Red Steppe cattle had the closest relationship with Bos taurus and Ovis aries,and the farthest relationship with Gallus gallus.The protein sequence had 7 disulfide bonds,66 phosphorylation sites,9 O-glycosylation sites,3 N-glycosylation sites,no signal peptide,but had a transmembrane region.The secondary and tertiary structures analysis showed that ACSL3 protein was connected by random coil,and the protein structure was mainly alpha helix and beta turn,which was a mixed protein.Real-time PCR and Western blotting results showed that the ACSL3 mRNA and protein were expressed in all the collected tissues,and the highest expression was found in kidney and muscle tissues,which were significantly higher than that in the other tissues (P<0.05);It was moderately expressed in stomach,liver and heart,which was significantly higher than that in spleen,lung,intestine and fat (P<0.05);While there were the lowest relative expression in spleen,lung,intestine and fat.The results showed that the differential expression levels of ACSL3 gene in Red Steppe cattle might be related to the regulation of fat deposition and lipid metabolism,which provided the basic materials for further study on the regulation of ACSL3 gene on lipid metabolism and fat deposition in Red Steppe cattle.

This study was aimed to clone neuropeptide Y (NPY) gene in Tianzhu muscovy,and analyze its transcriptional level of different tissues in Tianzhu muscovy.The mixed cDNA of Tianzhu muscovy tissues during lying was used as PCR template,then the entire CDS region of NPY gene was cloned and sequenced by RT-PCR.The homology and relationship of genetic evolution of NPY gene,the physical and chemical properties,subcellular localization,signal peptide,glycosylation site and phosphorylation site,the secondary and tertiary structures of NPY protein were analyzed by bioinformatics tools,and the transcriptional level of NPY gene mRNA in different tissues were detected.The results showed that the whole-length coding region of NPY gene in Tianzhu muscovy was 294 bp,which coded 97 amino acids.The homology alignment results of nucleotide and amino acid sequences showed that there was a certain genetic diversity of NPY gene in different species,and Tianzhu muscovy had a close relationship with Anas platyrhynchos.NPY protein were acidic and unstable protein,which had one signal peptide (1-28 amino acids),and the subcellular localization was 100% outside the cell.In addition,there were two O-glycosylation sites and abundant phosphorylation sites of NPY protein,which existed a functional domain named PAH.Spatial structure of NPY protein were mainly assembled with alpha helix and random coil.Real-time PCR results showed that the NPY gene mRNA were distributed in all tissues,there was the highest expression level of NPY gene mRNA in cerebrum,and there was the secondry highest expression level of NPY gene mRNA in pancreas and glandular stomach,which were extremely significant difference with others tussues (P<0.01),and there was the lowest expression of NPY gene mRNA in gizzard.The results would provide references for further research on the physiological regulatory functions of NPY gene on energy balance,growth and development,fat deposition,reproductive performance in poultry.

This study was aimed to clone and analyze myoblast-determining 1(MyoD1) gene in Guangxi Bama Mini-pig,and construct the eukaryotic expression vector of MyoD1 gene,which would lay the foundation on the regulation of skeletal muscle of MyoD1 gene in Guangxi Bama Mini-pig.The coding sequence of porcine MyoD1 gene was cloned by RT-PCR using the liver tissue,and the nucleotide and protein sequences were analyzed by bioinformatics.The eukaryotic expression vector was constructed and verified in C2C12 cells by PCR,double digestion and transfection.The results showed that the coding region of MyoD1 gene in Guangxi Bama Mini-pig was 960 bp of length and encoded 319 amino acids.The homology of Guangxi Bama Mini-pig with Sus scrofa,Bos taurus,Bubalus bubals,Ovis aries,Equus cabalus,Homo sapiens,Mus musculus,Rattus norvegicus and Canis lupus was 99.7%,92.8%,92.9%,92.6%,91.5%,82.9%,82.9%,82.0% and 90.9%,respectively.The phylogenetic tree analysis showed MyoD1 gene of Guangxi Bama Mini-pig was highly conservative in different species.The protein structure analysis indicated that MyoD1 protein was an extramembrane protein,and there was a MyoD family-named MyoD domain in the 4-116th amino acid.There was a very high similarity in the high structure of MyoD1 protein among the Guangxi Bama Mini-pig,Sus scrofa and Homo sapiens.The expression vector pEGFP-N1-MyoD1 with MyoD1 gene was successfully constructed in Guangxi Bama Mini-pig and expressed in C2C12 cells with a green fluorescent signal,which indicated that MyoD1 gene was successfully expressed on C2C12 cells.

This study was aimed to construct Brucella 2308 (S2308) vceA gene mutants then analyse its growth character and survival ability in human embryonic trophoblast cells (HPT-8).The upstream,downstream homologous arms of vceA gene and kan gene were amplified by PCR method with wild S2308 strain as template.The fusion PCR technology was used to fuse the three genes fragments and connected to pMD19-T vector and then electric transported to E. coli DH5α competent cells to construct S2308ΔvceA strain.The genetic stability of the mutant strain was tested by screening continuously with kanar resistance,and the growth rates between the S2308ΔvceA and S2308 strains were compared.The HPT-8 cells were infected with S2308ΔvceA and S2308 strains at a multiplicity of infection of 100:1 and the intracellular survival ability was determined by CFU counting.The results showed that the target gene fragments of upstream homologous arms (372 bp),downstream homologous arms (510 bp) of vceA gene and kan gene (1 093 bp) were amplified respectively.The mutants was successfully constructed and the virulence not recover after culture at least 10 generations.The growth curves of S2308ΔvceA and S2308 strains were similar under the same condition.These two strains reached the logarithm growth phase at 12 h,entered in platform period after 30 h.However,the survival rates of the S2308ΔvceA strain was significantly lower than its parent strain S2308 after the infection of HPT-8 cells at 12 h (P<0.05).In conclusion,This experiment successfully constructed and obtained a vceA gene deletion strain of Brucella with good genetic stability,and the growth trend of this deleted strain was similar to parent strain under the condition of in vitro culture.However,the viability of the deleted strain in HPT-8 cells was significantly weakened.

This study was aimed to investigate the effects of a new slow-release urea substituting dietary part of some soybean meal on growth performance,nutrient digestibility and blood biochemical indexes of beef cattle.Eighteen healthy 7-month-old Simmental hybrid cattle weighted (315±5) kg were randomly divided into three groups:Soybean meal group,slow-release urea group and common urea group,with 6 cattle in each group.Soybean meal group was fed a test diet containing 11.12% (15.51% crude protein (CP),48.06% dry matter (DM)) of soybean meal (concentrate to forage ratio was 4:6).According to the principle of isoenergetic and isonitrogenic,the slow-release urea and common urea groups were fed with slow-release urea and common urea accounted for 1.41% and 1.15% of the respective diets,respectively.That is,75% of the soybean meal in the soybean meal group was replaced by slow-release urea and ordinary urea in the two test groups.Pre-test period was 14 days,and formal test period was 60 days.The results showed as follows:① There was no significant difference in average daily gain (ADG) and feed:gain (F/G) among all groups (P>0.05),but the average dry matter intake (ADMI) in slow-release urea and common urea groups was significantly lower than that in soybean meal group (P<0.05).② The apparent digestibility of DM and organic matter (OM) in slow-release urea and common urea groups were significantly higher than that in soybean meal group (P<0.05);The apparent digestibility of CP in slow-release urea group was significantly lower than that in common urea group (P<0.05),but there was no significant difference between slow-release urea and soybean meal groups (P>0.05);The apparent digestibility of ether extract (EE) was the lowest in common urea group and the highest in soybean meal group,and there was a significant difference among all groups (P<0.05);There was no significant difference in the apparent digestibility of neutral detergent fiber (NDF) and acid detergent fiber (ADF) among all groups (P>0.05).③ Compared with the soybean meal group,the replacement of some soybean meal by slow-release urea in the diet did not affect the blood biochemical indicators of beef cattle (P>0.05);The albumin (ALB),alanine aminotransferase (ALT) and aspartate transaminase (AST) in slow-release urea group were significantly higher than that in common urea group (P<0.05).The results showed that some soybean meal in the diet could be replaced by slow-release urea and common urea in the production of beef cattle,and the effect of soybean meal being replaced by slow-release urea was better than that of common urea.

This study was aimed to understand the fattening performance and meat quality of hybridize first sheep from Sa×Du×Hu (a generation of Suffolk rams and Hu ewes).The lambs from different source were divided into three groups on average at random according to the body weight and age,nine 3-month-old hybrids first lambs of Dorper and Hu sheep (Du×Hu F1),nine 3-month-old hybrids first lambs of Suffolk and Hu sheep (Sa×Hu F1),nine 3-month-old hybrids first lambs of Suffolk and crossbred ewes F1 from Dorper and Hu sheep (Sa×Du×Hu F1) were selected to perform trial,and nine 3-month-old Hu sheep were selected as control.3 repetitions per group,3 sheep per repetition.After 10 days preliminary trial,all lambs were fed according to the nutritional requirements recommended by the national mutton sheep raising standard NY T/816-2004 in the next 50 days.The results showed that the average daily weight gain and economic benefit of Sa×Du×Hu F1 were extremely significantly higher than that of Sa×Hu F1,Du×Hu F1 and Hu sheep (P<0.01),the F/G of Sa×Du×Hu F1 were extremely significantly lower than that of Sa×Hu F1,Du×Hu F1 and Hu sheep (P<0.01),compared with Sa×Hu F1,Du×Hu F1 and Hu sheep,the average daily gain of Sa×Du×Hu F1 was increased by 20.89%,30.62% and 47.46%,the F/G of Sa×Du×Hu F1 was decreased by 21.76%,18.11% and 28.72%,respectively.The net meat ratio,meat-bone ratio and loin eye muscle area of Sa×Du×Hu F1 were extremely significantly higher than Sa×Hu F1,Du×Hu F1 and Hu sheep (P<0.01),compared with Sa×Hu F1,Du×Hu F1 and Hu sheep,the net meat ratio,meat-bone ratio and loin eye muscle area of Sa×Du×Hu F1 were increased by 2.94%,2.79%,3.92%,27.94%,6.76%,24.90% and 24.79%,24.55%,49.46%,respectively.The meat quality of Sa×Du×Hu F1 was better than Sa×Hu F1,Du×Hu F1 and Hu sheep.Furthermore,the performance of Sa×Du×Hu F1 was more prominent in nutritional value.In conclusion,the performance of Sa×Du×Hu F1 was outstanding in growth rate,feed conversion rate and economic efficiency,and was also of mutton quality and nutritional value,and the ternary crossbreeding with the Suffolk rams and Du×Hu F1 ewes was worthy of generalizing and utilizing.

This experiment was conducted to evaluate the effects of long-term supply of fermented complete feed (FCF) on the growth performance,fecal mephitis,serum immunity and antioxidation indexes of growing pigs.Complete feed was fermented with Bacillus licheniformis and Lactobacillus brevis.A total of 90 pigs (Yorkshire×Rongchang) with the initial weight about 22 kg were used in a 60 d experiment.The pigs were randomly allotted to 3 dietary treatment groups:Control group (antibiotic-free feed),antibiotics and fermentation groups.Each treatment consisted of six replicates with five pigs in each replicate.At the end of the experiment,the growth performance,pH and mephitis of the fresh faeces,serum immunity and antioxidation indexes was measured.The results showed that:①Fermentation extremely significantly improved the T-AOC (P<0.01) of feed.The reducing power and hydroxyl radical scavenging activity tended to rise (P>0.05).②After two months,ADFI,ADG and F/G of pigs in three groups had no significant difference (P>0.05).③The faeces pH,the contents of p-cresol,indole,skatole,acetic acid,propionic acid,butyric acid and valproic acid were not significantly different among three groups (P>0.05).The isovaleric acid of fermentation group were significantly lower than that of antibiotic group (P<0.05).④The contents of serum MDA,T-AOC and the activities of CAT,GSH-Px and SOD of three groups had no significant difference (P>0.05).Compared to control group,the serum IgM level of pigs from fermentation group showed a rising tendency (P>0.05),and the complement protein 4(C4) content was significantly higher (P<0.05),but these two indexes had no significant differences compared to antibiotics group (P>0.05).In conclusion,long-term supply of FCF to growing pigs had no significant effect on the growth performance,feces pH and content of the main malodorous gases,serum antioxidant indexes and IgM,IgG levels,the advantage of short-term feeding did not last.

In order to study the latest progress of nutriton and feed researches in Yellow-feathered broilers,provide some references,for the safety and efficiency of breeding in Yellow-feathered broilers industry,the authors consulted and summarized the domestic and foreign literature on feed nutrition of Yellow-feathered broilers from 2017 to 2018,mainly reviewed the nutrition requirements of Yellow-feathered broilers,technology of additive application,technology of the safe and efficient use of unconventional feed resources and the evaluation for the nutritive value of feed ingredients.The following points should be paid attention to the application and research:The contents of mineral elements and vitamins in feed materials should be ascertained in order to reduce the waste of vitamins and mineral elements.Chinese herbal medicine had many active ingredients such as polysaccharides,alkaloids,saponins,and organic acids.It was suggested to combine Chinese herbal medicine with different functions in a reasonable way.Probiotics additive was an effective and green additive for Yellow-feathered broiler chickens,in which Bacillus and yeast were effective,and the combination of two probiotics was more effective.In general,the efficient breeding techniques of Yellow-feathered broilers still should be developed.The utilization rate could be improved by improving the production process of plant feed raw materials.It was a trend to develop new animal protein raw materials.Insect animal protein such as fly maggot and black soldier fly had the advantages of safety,environmental protection,and which was the preferred choice of new animal protein feed materials.In general,the efficient breeding technology of Yellow-feathered broiler needs to be further improved,it included the following aspects:perfecting the breeding standards of Yellow-feathered broiler and breeding chickens;More extensive researches on the safe and efficient use of feed resources of Yellow-feathered broiler chickens;Study on the effects of maternal nutrition on the offspring of Yellow-feathered broiler chickens.

The in vitro gas production technique experiment with a single-factor design was conducted to compare the effect of the low-dose (T1,1.14×10¹⁰CFU/kg) and high-dose (T2,2.27×10¹⁰ CFU/kg) Bacillus subtilis on 12 and 48 h kinetic parameters of rumen gas production and rumen fermentation parameters of TMR (ratio of concentration and rough was 60:40),and the values of metabolizable energy (ME),organic matter digestibility (OMD)and yield of microbial protein (MCP) were also evaluated according to 24 h gas production.The purpose of the study was to provide a theoretical basis for Bacillus subtilis rational application in ruminants.The results indicated that both T1 and T2 had a significant effect (P<0.05) on 24 and 48 h gas production compared to control group (CON),and the gas production of T2 group was higher than that of T1 group (P<0.05).Moreover,T1 significantly increased the content of CH₄ compared to CON(P<0.05),while T2 had no significant effect on content of CH₄ (P>0.05).For rumen fermentation parameters,T2 increased the concentration of NH₃-N of 12 h (P<0.05),and had no significant effect on other fermentation indexes (P>0.05).Moreover,T1 decreased the content of butyric acid and valeric acid of 48 h (P<0.05),and T2 significantly reduced pH and increased the total volatile acid content (P<0.05).Both T1 and T2 had no significant effect on other indexes (P>0.05).In addition,the values of OMD,ME and MCP of T1 and T2 groups were significantly higher than those of CON,and the values of OMD and ME in T2 were significantly higher than those in T1 group (P<0.05).In conclusion,both low-and high-concentration Bacillus subtilis had a certain improvement effect on the fermentation parameters of the fermentation substrate (TMR,60:40),and high concentration (2.27×10¹⁰ CFU/kg) was better.

The study was aimed to investigate the effects of fermentation preparation of compound Chinese herbal medicine on growth performance,immune function and serum biochemical indexes in weaned piglets.A total of 144 Duroc×Yorkshire×Landrace health piglets weaned at 35 days of age with the same genetic background and (9.54±0.08) kg body weight were randomly divided into three groups with 4 replicates in each group and 12 pigs in each replicate (half male and female).The control group (groupⅠ) was fed basal diet,group Ⅱ was fed basal diet supplemented 0.4% compound Chinese herbal medicine and group Ⅲ were fed 0.4% fermentation preparation of compound Chinese herbal medicine.The trial lasted for 30 d.The results showed as follows:①Compared with the control group,the average daily gain (ADG) of the group Ⅱ increased to a certain extent,but the difference was not significant (P>0.05),the average daily feed intake (ADFI) and F/G decreased significantly (P<0.05);compared with group Ⅱ,the ADG of group Ⅲ increased (P>0.05),while the F/G decreased to a certain extent (P>0.05),and the ADFI decreased significantly (P<0.05).②There was no significant difference in IgA,IgG and IgM between the control group and group Ⅱ (P>0.05),but the levels of IgA,IgG and IgM increased significantly in group Ⅲ compared with control group,and the levels of IgA and IgM were higher than that in group Ⅱ (P<0.05).③ Compared with the control group,serum ALT,AST,TP,ALB,GLO,GLU,CHO and TG in group Ⅱ had no significant change (P>0.05),while BUN decreased significantly (P<0.05).Compared with group Ⅱ,ALT activity,contents of TP and GLO in group Ⅲ increased significantly (P<0.05).In conclusion,supplementing compound Chinese herbal medicine could improve growth performance,increase serum TP,ALB and GLO contents,and enhance immune function in weaned piglets.

The purpose of this study was to investigate the effects of different enzyme preparations on fermentation quality of whole corn silage to improve its utilization efficiency.The whole corn that castrating during wax maturity were used as materials and assigned into 7 groups which were control group and 6 treatment groups with 3 repeats per group.The six treatment groups were added 5 g/kg cellulase,xylanase,pectinase,α-galactosidase,β-mannanase and β-glucanase,respectively.Then the sensory evaluation,fermentation quality and nutrient composition of different processed corn silage were compared after 56 d of silage.The results showed that the whole corn in cellulase,xylanase and β-glucanase groups had better silage effect on sensory evaluation.Compared with control group,cellulase,xylanase and β-glucanase could significantly increase carbohydrate and lactic acid contents in whole corn silage (P>0.05),and significantly reduce ammonia nitrogen/total nitrogen (P<0.05),so that the silage had a significant improvement in fermentation quality.The DM content in cellulase group was higher than that of control group and other treatment groups.The content of CP treated with cellulase and α-galactosidase was higher;The ADF content in cellulase group and contents of NDF and ADF in β-glucanase group were significantly lower than that in control group (P<0.05).In summary,under the experimental condition,cellulase,xylanase and β-glucanase were more suitable as additives for whole corn silage.

In order to explore the etiology,diagnosis and treatment of the disease characterized by skeletal muscle damage in yak,mineral concentrations were determined on inductively coupled plasma atomic emission spectroscopy in soil,forage and tissue of yaks.Blood parameters,biochemical indicators and antioxidant indicators were determined on automatic hematology analyzer,biochemical analyzer and visible spectrophotometry.The results showed that concentrations of selenium in the soil and forage samples from the affected area were extremely significantly lower than those from the unaffected areas (P<0.01).The mean concentration of selenium in blood,liver and hair samples from the affected yaks were extremely significantly lower than those in unaffected yaks (P<0.01).The concentrations of Hb and RBC from the affected yaks were extremely significantly lower than those from the unaffected yaks (P<0.01).MDA,CPK,GPT,GOT,ALP,LDH,FT₄,T₄ and TSH from the affected yaks were extremely significantly higher than those from the unaffected yaks (P<0.01).SOD,CAT,GSH-Px,FT₃ and T₃ from the affected yaks were extremely significantly lower than those from the unaffected yaks (P<0.01).Treatment of affected yaks by injecting 0.1% sodium selenite and 5% vitamin E compound sterilized solution,the concentration of selenium in blood samples and blood serum antioxidant indexes from the treated group yaks were gradually returned to normal.The clinical symptoms disappeared.It indicated that yaks' muscle injury disease in this region was caused by selenium deficiency,mainly due to the low selenium content in soils and forage.The above results were important for further diagnose of yaks' selenium deficiency.

Proteomics is a new subject that studies the function of life structure,physiology and life activities rule comprehensively,it has become an important part of post-genomics research,which has been extensively concerned in many fields,it also provides brand new research ideas and technical means for the development and innovation of animal science.At present,proteomics is involved in animal growth,reproduction,nutrition,disease and meat quality in livestock and poultry,and a batch of proteins related to the important economic traits have been mined through various methods,which contributes important theoretical reference for production.Post-translation modifications (PTMs) is an important branch of proteomics research,which plays an important role in increasing protein diversity and studying complex physiological regulatory process.The author reviews the advances and applications of proteomics and PTMs in animal husbandry.

The objective of the study was to explore the codon usage feature of protein disulfide isomerase A4 (PDIA4) gene in pig,the codon usage differences and evolutionary relationship between pig and other reference species.In this research,the coding region of the PDIA4 gene was amplified by RT-PCR using the uterus of pig as experimental material.The PDIA4 gene sequences of 18 species were downloaded as conferences from NCBI database.At the same time,the differences of codon usage bias between pig and four different kinds of model organisms were compared.The results showed that the complete coding region of PDIA4 gene of pig was 1 941 bp in length,which coded 646 amino acid residues.The results of molecular identification showed that the identity between PDIA4 gene cloned in this study with the known sequences of Sus scrofa in NCBI database (GenBank accession No.:NM_001267834.1) was 99%.The PDIA4 in pig preferred to use G-or C-ending codons and had 27 preferred codons (RSCU>1).Moreover,the three codons with the highest frequency were CTG (RSCU=3.69),GCC (RSCU=2.31) and CGC (RSCU=2.29),respectively.Comparing the codon usage feature of the PDIA4 gene among 19 species,there were significant differences in the related data and most of them tended to use G/C-ending codons.These related data included the effective number of codons (ENc),codon adaptation index (CAI),GC contents,contents of T,C,A,G and GC on the 3rd site (T3s,C3s,A3s,G3s and GC3s).Although there were differences between cluster analysis based on the relative synonymous codon usage and the results of phylogeny derived from coding region,and the molecular phylogenetic tree rooted in the PDIA4 CDS region was more consistent with the true classification system of the 19 species.The differences in codon usage frequency between pig PDIA4 gene and genome of Mus musculus were less than those in other three kinds model organisms' genome.Mus musculus might be the best receptors for genetic transformation and heterologous expression of PDIA4 gene in pig.

This study was aimed to investigate the expression of the silent information regulator family (SIRT1-7) sirt2geneof different tissues inXiangcunBlackpig,analyzetheassociation between sirt2 gene polymorphism and meat quality traits,and find the molecular markers associated with meat quality traits in Xiangcun Black pig.The PCR-RFLP method and gene sequencing technology were used to analyze the polymorphism of sirt2 gene in Xiangcun Black pig.Real-time PCR was used to analyze the relative expression of sirt2 gene in eight tissues including heart,liver,spleen,lung,kidney,pancreas,hind leg muscle and longissimus dorsi.At the same time,the different genotypes of sirt2 gene mutation site and muscle color value,pH_{45 min},pH_{24 h},drip loss,water loss rate,intramuscular fat,tenderness and loin eye muscle area were analyzed by SAS 9.4 software.The results showed that a mutation (C to T) was found at 240 bp in the amplified fragment of sirt2 gene exon 8 in Xiangcun Black pig,and the encoded amino acid changed from arginine (Arg) to cysteine (Cys).The mutation type was a missense mutation and formed three genotypes of CC,CT and TT,CC genotype was the dominant genotype,and C was the dominant allele.The χ² test indicated that the mutation site deviated from Hardy-Weinberg equilibrium.The homozygosity of this locus was higher,the number of effective alleles was 1.301,and the polymorphic information content was 0.205,which was low polymorphism (PIC<0.25).Correlation analysis between gene polymorphism and meat quality traits showed that the muscle L^* value and drip loss of TT genotype were significantly lower than that of CC and CT genotypes (P<0.05).The water loss rate of CC genotype was significantly higher than that of CT and TT genotypes (P<0.05).sirt2 gene was expressed in 8 tissues of Xiangcun Black pig,and the relative expression was the highest in longissimus dorsi,which was not significantly different with lung (P>0.05),but was significantly higher than heart,liver,spleen,kidney,pancreas and hind leg muscle (P<0.05),and the relative expressions in heart,liver,spleen,kidney and pancreas were not significant (P>0.05).The results showed that sirt2 gene had a certain effect on the development of meat quality traits in Xiangcun Black pig,which could be used as a candidate gene affecting the meat quality in Xiangcun Black pig.

The accurate separation of chromosomes is completed under the correct assembly of spindles and the monitoring of spindle assembly checkpoint (SAC).For the mammalian oocytes,the spindle formation and SAC are the important factors to ensure the accurate separation of chromosomes.If the chromosome is separated incorrectly,it will directly lead to spontaneous abortion or other birth defects.After the oocyte centrosome is deleted,the cells can still form a bipolar spindle by antiparallel arrangement of microtubules which are nucleated around the chromosome independent of the centrosome,that is self-assembled spindle.The microtubules are gathered by the microtubule organization center (MTOC),the maturation promoting factor (MPF) maintains the formation process of the spindle during the two meiosis,and the cytostatic factor (CSF) maintains the metaphase structure,so that the spindle remains stable when the chromosomes do not all converge on the equatorial plate.The heavy volume of sites is prone to aneuploidy,and the particularity that sites don't contain centrosomes leads to a dispute over whether SAC exists on site for a long time,but now SAC is one of the mechanisms to ensure accurate chromosome separation from sites.There is a kind of adhesion between chromosomes in meiosis metaphors,and the ‘wait-later’ signal produced by the cell inhibits SAC activity so as to retain the adhesion stable until all chromosomes complete the connection with the spindle,and the ‘wait-later’ signal is inactivated,SAC starts to inactivate the adhesion between chromosomes,and then chromosomes are separated under the action of the spindle.This paper reviews the specific assembly process of spindles and the composition and mechanism of spindle checkpoints during meiosis,which enriches our understanding of meiosis and provides a basis of the formation mechanism of aneuploid during meiosis.

The aim of the experiment was to explore the buffalo estrus and provide theoretical references for buffalo production by studying the change laws of estradiol (E₂) and progesterone (P₄) concentrations during estrus cycle of salivary and serum,investigating the salivary ferning and the development of ovaries in buffalo.The concentrations of E₂ and P₄ were determined by the enzyme linked immunosorbent assay (ELISA) in estrus cycle,and the correlation between the serum and saliva hormones were analyzed.The results show that the concentrations of E₂ and P₄ varied fluctuantly.The concentration of saliva P₄ was maintained from 6.50 to 7.10 ng/mL at the beginning of estrus,and reached 11.09 ng/mL at 13 d of estrus,then fell fast.The concentration of saliva E₂ had two peaks,respectively at 3-5 d (178.53 pg/mL) and 14-17 d (179.10 pg/mL) of estrus.The change trends of E₂ and P₄ levels in salivary and serum had the same change trends,the concentrations of salivary P₄ and E₂ had significant correlations with that in serum (P<0.05),while the salivary E₂ concentration also had a extremely significant correlation with the salivary P₄ concentration (P<0.01).Saliva showed a typical fern-like crystallization patterns at 0 d of estrus,with significantly lower fractal dimension values compared with the other days of estrus (P<0.05).The results were also showed the basic synchronization between saliva crystallization and ovarian follicle.In conclusion,saliva crystallization could be used as a reliable index for monitoring estrus and predicting ovulation in buffalo.

Methionine (Met) is an important methyl donor in the growth and metabolic process of animal.At the same time,as the only sulfur-containing amino acid in the essential amino acid,it is the first or second restrictive amino acid with lysine to synthesize corn-soybean meal feed or microbial protein.In addition,Met serving as a feed additive plays an important role in animal production performance,autoimmunity and disease prevention.With the development of epigenetics in the field of animal studies,as an important nutrient,Met can be used to carry out epigenetic modifications (DNA methylation,histone modification,chromatin remodelling and non-coding RNA,etc.).DNA methylation is one of the ways of epigenetics,and it has an important role in the study of phenotypic traits,making it a connection between genes and phenotypes.This paper introduces the mechanism of DNA methylation and the regulation of methionine metabolism,which will provide references for understanding the relationship between the Met and epigenetic modification and further revealing the molecular mechanism of phenotypic traits.In addition,through genomics,further prospect and analysis of how Met affects the changes of animal phenotypic traits at the molecular level can also help grasp the individual differences in animal Met demands,determine the individual nutritional requirements,and realize the real "gene breeding" model.

To investigate the distribution of major serotypes and virulence factors of Streptococcus suis (SS) strains in parts regions of Guangxi,116 samples of suspected streptococcal infections (brain,lung,lymph nodes,etc.) collected from different swine farms from January to June in 2018 were examined in this study.The serotypes and some virulence genes were identified by bacterial isolation,morphological observation,PCR amplification.The positive rate of Streptococcus suis in 116 samples was 27.59% (32/116).The main serotypes of positive samples were SS2 (40.63%,13/32) and SS9 (43.75%,14/32),and other serotypes accounted for 15.63% (5/32).The test results of virulence factors demonstrated that the detection rates of SLY,MRP,EPF and SBP2' factors were 81.25% (26/32),59.38% (19/32),50.00% (16/32) and 71.88% (23/32),respectively.Among the 32 strains of Streptococcus suis,SLY⁺MRP⁺EPF⁺SBP2'⁺(13 strains),SLY⁺MRP^-EPF^-SBP2'^-(5 strains) and SLY⁺MRP⁺EPF^-SBP2'⁺(5 strains) were the main virulence genotypes.And SS2 could be detected three or more virulence genes.SS9 was the prevalent type in Yulin and Liuzhou.SS2 was the prevalent type in Nanning and Baise.It was discovered that there were differences in the distribution of virulence factors in the four regions of Guangxi.The distribution of streptococcal virulence factors in different serotypes or the same serotype was different,and the detection rate of virulence gene of SS2 was higher than other serotypes.This study could provide a theoretical basis for the future research of Streptococcus suis vaccine and pathogenesis,and provide guidance for the selection of serotypes of Streptococcus suis vaccine in Guangxi.

In January 2017,a diarrhea epidemic occurred in calves of a cattle farm in Bole,Xinjiang.The purpose of this study was to investigate the etiology and formulate corresponding prevention and control measures.Anal swabs and stool samples from 6 diarrhoeal calves were collected,rotavirus,coronavirus,Cryptosporidium and Escherichia coli F5 (K99) were detected by Speed V-Diar 4^TM test paper.Then the samples were isolated,identified and molecular clustering,the pathogenicity and drug resistance of the isolated bacteria were detected.The test results of all stool samples were negative.6 strains of Escherichia coli and 1 strain of Edwardsiella tarda were obtained from 6 samples.Phylogenetic PCR analysis showed that 6 strains of Escherichia coli A group accounted for 83.3%(5/6),F group accounted for 16.7%(1/6).Half the lethal dose result showed that only one strain of Escherichia coli (strain XJ-B1) was pathogenic,and could cause diarrhea and death in mice.The results of drug sensitivity test showed that 7 isolates had different degrees of resistance to the 18 antibiotics,and Escherichia coli XJ-B1 was the most serious drug-resistant strain.It was multidrug-resistant to beta-lactams,sulfonamides and polypeptide antibiotics.Therefore,this pathogenic Escherichia coli might be one of the causes of this diarrhea in calves,and it was also the first group F Escherichia coli isolated from cattle.The multi-drug resistance of the bacteria increased the difficulty of clinical treatment.This results provided a basis for the cattle farm to treat the calf diarrhea.

In order to quantitatively analyze the virus content of clinical live pseudorabies (PR) vaccine in Guizhou province,a pair of specific primers was designed according to the sequence of pseudorabies virus (PRV) gB gene in GenBank (accession No.:M17321.1),a Real-time quantitative PCR method was established,and the virus content of live PR vaccine from 6 different manufacturers was analyzed.The results showed that a Real-time quantitative PCR method was successfully established for detection of PRV.There was a good linear relationship between the number of plasmid copies diluted in the standard curve and Ct value,the standard curve equation was Y=-0.97X+33.66 (R²=0.999).The method had a minimum detection virus content of 3.19×10¹ copies/μL,high sensitivity,good repeatability and specificity.The Real-time quantitative PCR method was applied to detect the viral content of live PR vaccine produced by 6 manufacturers in Guizhou province.The results showed that the virus content of 6 live PR vaccine (A-F) sold in 6 markets were 1.67×10⁷,4.83×10⁵,2.64×10⁶,4.27×10⁷,3.39×10⁶ and 3.68×10⁵ copies/μL,the viral content of the vaccine from different manufacturers was significantly different,the biggest difference could be 116 times.Two kinds of live PR vaccine from A and D manufacturers had higher viral content.The Real-time quantitative PCR method established in this experiment could be used for rapid detection and evaluation of the viral content of live vaccine against porcine PR,it had a certain guiding significance for the quality control of the live vaccine of PR and the selection of clinical vaccine.

To investigate the molecular epidemiology and genetic diversity of porcine circovirus type 2 (PCV2) in Jiangxi province,1 082 tissue samples were collected during 2013 to 2017 from suspected pigs in 10 regions (including Nanchang,Yichun,Xinyu,Ganjiang,Ji'an,Jiujiang,Shangrao,Fuzhou,Jingdezhen and Yingtan cities) of Jiangxi province were detected for PCV2.And PCV2 isolates complete genome sequences were amplified,cloned and sequenced.The results showed that 610 of 1 082 samples were detected to be positive of PCV2 and the total positive rate was 56.4%.The positive rates from 2013 to 2017 were 52.7%,48.8%,58.5%,71.0% and 67.4%,respectively.The 83 of 89 PCV2 isolates belonged to PCV2b,and 53 and 30 of 83 isolates were grouped into PCV2b-1C and PCV2b-1A/1B,respectively,and 6 isolates belonged to PCV2a.The homology of nucleotides and the deduced amino acid sequence of ORF2 between sequenced strains and reference strains were 88.9% to 100.0% and 86.0% to 100.0%,respectively.Analysis of Cap acid amino sequences showed that there were 20 amino acid mutation sites.This research indicated that the dominant genotype of PCV2 in pigs in Jiangxi was PCV2b,and PCV2b-1C was a dominant subgenotype.At the same time,a small amount of PCV2a subgenotype also existed.

This experiment was conducted to investigate the effects of recombinant E.coli expressing heat-stable enterotoxin (STa) on jejunum inflammation of 7 days old piglets.Twenty-four 7 days old piglets were allotted to four treatments:Control group (artificial milk),STa group (artificial milk+2×10⁹ CFU E.coli LMG194-pBAD-STa),LMG194 group (artificial milk+2×10⁹ CFU E.coli LMG194),and K88 group (artificial milk+2×10⁹ CFU E.coli K88),six piglets each group.The pigs were treated with E.coli on the 5th day and slaughtered on the 7th day.The results showed that compared with control group,the jejunum villi of STa and K88 groups were significantly atrophied and shortened with obvious damage or even falling off.Compared with control group,the concentrations of IL-10,IL-8 and IL-6 in the serum of STa,LMG194 and K88 groups were significantly increased (P<0.05),and the concentrations of iFABP in the blood and intestinal tract of LMG194 and K88 groups were significantly decreased (P<0.05);The concentrations of TNF-α in serum of STa and K88 groups were significantly decreased,the concentration of NF-κB was significantly increased (P<0.05);The concentration of NF-κB in LMG194 group was significantly decreased,and the concentration of TNF-α was significantly increased (P<0.05).Compared with control group,the expression levels of CCL2 and CXCL9 genes in STa and LMG194 groups were significantly up-regulated (P<0.05),and the expression level of VNN1 gene was significantly down-regulated (P<0.05),the expression level of IFN-γ in STa and LMG194 groups was significantly increased and decreased,respectively (P<0.05);The expression of CXCL9 and IFN-γ genes was significantly down-regulated in K88 group (P<0.05),and the expression level of VNN1 gene was significantly up-regulated (P>0.05).There was no significant difference in CCL2 gene expression level (P>0.05).These results suggested that recombinant E.coli expressing type Ⅰ heat-stable enterotoxin STa was almost as toxic as E.coli K88,which could cause damage to intestinal mucosa of 7-day-old piglets,induce serious inflammatory reaction,lead to diarrhea in piglets,and could be used as a candidate strain for piglet diarrhea model.

To investigate the effect of murine recombinant UBC13 protein on lipopolysaccharide (LPS)-induced acute inflammation in mice,twenty-four SPF female mice were randomly divided into 4 groups:PBS group,LPS model group,UBC13 high and low dose groups (100 and 25 μg per mouse,respectively),with 6 mice in each group.LPS model group and each protein dose group were intraperitoneally injected with 20 mg/kg LPS,and the PBS group was intraperitoneally injected with equal volume of PBS.After 1 h of injection,each protein group was injected subcutaneously with recombinant UBC13 protein at the corresponding dose,PBS group and LPS model group were injected equal volume PBS.The mice were sacrificed 24 h after the administration of the protein.The lung,spleen,thymus and liver tissues of the mice were collected,the organ indexes were calculated.The histopathological changes were observed by HE staining and the relative expression of IL-1β, TNF-α and IL-6 mRNA in lung,spleen,thymus and liver and iNOS mRNA in lung were detected by Real-time PCR.The results showed that compared with PBS control group,the indexes of lung,spleen and liver in LPS model group were significantly or extremely increased (P<0.05; P<0.01),and the lung,spleen,thymus and liver tissues showed pathological changes.The results of Real-time PCR showed that the relative expressions of IL-1β,TNF-α and IL-6 mRNA in lung,spleen,thymus and liver of LPS model group were extremely significantly increased compared with PBS control group (P<0.01).The relative expression of iNOS mRNA in lung was also extremely significantly increased (P<0.01).Compared with LPS model group,the pathological changes in lung,spleen and liver were significantly improved in high dose group of UBC13 protein;The expressions of IL-1β,TNF-α and IL-6 mRNA in lung,liver and spleen were extremely significantly decreased (P<0.01),and the expression of iNOS mRNA in lungs was also extremely significantly decreased (P<0.01);The expression of TNF-α mRNA in thymus was significantly decreased (P<0.05),the expression of IL-6 mRNA and IL-1β were extremely significantly decreased (P<0.01).It indicated that murine recombinant UBC13 protein could down-regulate the expression of inflammatory factors and alleviate LPS-induced acute inflammatory response in mice.

The purpose of this study was to investigate the effect of Chinese medicine compound Jiangong powder on some blood and metabolic indexes of dairy cows with metritis,explore the mechanism of Chinese medicine compound on postpartum uterus,and provide a theoretical basis for early prevention of dairy cows.Eighteen dairy cows with similar age,weight and parity were divided into 3 groups according to clinical symptoms,vaginal secretions and B-ultrasound:Diseased group (with no treatment for metritis),normal group (with no metritis) and treatment group (treatment with metritis),6 heads in each group.The treatment group was given the traditional Chinese medicine Jiangong powder,the diseased and normal groups were given normal saline.The filling period was 7 d.Blood was collected before,during and 1,4,7,11,15,and 20 d after treatment.The blood and metabolic indexes of the three groups of dairy cows before and after treatment were detected by ELISA.The results showed that Jiangong powder could significantly increase the number of red blood cells,hemoglobin and lymphocytes in the blood (P<0.05),significantly reduce the number of white blood cells,granulocytes,β-hydroxybutyric acid,urea nitrogen,aspartame and aminotransferase content in the blood (P<0.05).It indicated that the traditional Chinese medicine Jiangong powder could regulate some blood and metabolic indexes,improve the body's anti-inflammatory,immune ability and metabolic function,and better prevent and treat metritis.

In order to diagnose the pathogen which caused disease of one duck farm in Shangqiu in Henan province,the brain,liver,spleen,and lungs of diseased ducks were collected,and AIV-H9,DTMUV,DRV and NDV were tested according to PCR detection methods of nucleic acid.Isolation and identification of bacteria was operated by serum-agar plates and conventional PCR detection methods.The serotype of the isolated strain was identified by glass agglutination,and the animal regression test was conducted.In order to screen sensitive drugs of the pathogen,31 kinds of antibacterials were chosen in the drug sensitivity test.The results showed that the detections of AIV-H9,TMUV,DRV and NDV were negative,which means these four viral diseases was initially excluded.The liver and brain tissues were cultured in serum nutrient AGAR medium aseptically and there were a translucent colonies at the size of a needle on culture medium.PCR amplification of purified culture broth showed that 338 bp specific bands of RA were amplified which was identified as RA serotype 7.The animal regression test showed that the isolated strain could be successfully replicated in clinical practice and could show obvious clinical infection symptoms of infectious serositis.The drug sensitivity test results showed that the isolates were sensitive to cefixime,cefazolin,cefradine,ceftriaxone,spectinomycin,doxycycline,levofloxacin,florfenicol,lincomycin and ampicillin (sulbactam).In conclusion,the pathogen causing the disease in the duck farm was Riemerella anatipestifer serotype 7 and some antibacterials could be used such as cephalosporin antibiotics.

The aim of this study was to elucidate antibacterial mechanism of the fungal defense Plectasin derived peptide NZ2114 against Staphylococcus aureus (S.aureus) that caused cow mastitis and its effect on inhibiting drug resistance of S.aureus in vitro.16S rRNA gene identification and disc diffusion method were used to identify the pathogenic bacteria of 55 mastitis milk samples and test their drug resistance,microdilution method was used for determining the antimicrobial activity of NZ2114 to S.aureus.The effect of NZ2114 on S.aureus cell membrane integrity and cell morphology were observed by flow cytometry and scanning electron microscope.The methods of gel retardation and circular dichroism spectrum were used to analyze the effect of NZ2114 on S.aureus genome DNA.The effect of NZ2114 on the drug resistance S.aureus was studied by incubating NZ2114 with S.aureus.The effect of NZ2114 on the drug resistance genes of S.aureus was further identified by PCR.The results showed that 10 strains of S.aureus were obtained,which were resistant to 9 antibiotics such as penicillin,and 50% of them were multidrug resistant.NZ2114 showed strong inhibitory activity against 10 strains of S.aureus,and the minimum inhibitory concentrations (MIC) were 0.5 to 1.0 μg/mL.NZ2114 could cause micromorphological change of S.aureus S7,including cell surface shrinkage,cell contents leakage,and cell lysis and propidine iodide (PI) cell membrane penetration rate was up to 5%.Additionally,NZ2114 could bind to S.aureus S7 genomic DNA and change its structure.S.aureus and 1/4×MIC NZ2114 were incubated together for 12 h,the result demonstrated that except amoxicillin and sulfanilamide,the resistance to other antibiotics of S.aureus had decreased to different extent (10% to 40%) and the elimination rate of NZ2114 to blaZ and braRS genes were 28.57% (2/7) and 22.22% (2/9),respectively.The above results proved that NZ2114 had strong inhibited activity against multidrug resistant S.aureus,and its mechanism of interfering with the membrane and intracellular DNA,which laid the cytological foundation for its low drug resistant bactericidal mechanism.At the same time,NZ2114 had elimination effect on the drug resistance and related drug resistant genes of S.aureus.Thus,NZ2114 was a promising antibiotic alternative for treatment of cow mastitis caused by S.aureus.

The target,gene enrichment and pathway of aspirin and eugenol were investigated by network pharmacological method in order to speculate the action mechanism of aspirin eugenol ester (AEE) on preventing and curing canine cardiovascular diseases.From methodology,aspirin and eugenol were searched from DrugBank database to obtain their target,and then the compound-target network,the canine protein-protein interaction (PPI) network and target-pathway network were constructed.Then the targets were uploaded to the STRING database,the species was selected as canine,and the PPI network diagram was obtained.Finally,the targets acting on canine were uploaded to the DAVID database,and the species was selected as canine.Gene enrichment and KEGG pathway with false discovery rate <0.01 were screened out.These networks were used to speculate the mechanism of action of AEE on preventing and curing canine cardiovascular diseases.The results showed that there were 15 known targets related to aspirin and eugenol,of which 8 were corresponding with canine.Key targets included TP53 gene,NF-κB,androgen receptor and prostaglandin G/H synthetase 1.There were 4 gene function enrichment (GO) entries,including 2 molecular functions,involving steroid binding and transcription factor activity,sequence specific DNA binding,and 2 biological processes,involving DNA transcription template and its positive regulation.There were 2 KEGG pathways involved in prostate cancer and cancer signaling pathways.This study suggested that AEE might regulate TP53 gene,NF-κB,androgen receptor,prostaglandin G/H synthetase 1,etc.Gene functions were enriched in DNA template transcription,steroid binding,transcription factor activity and specific DNA sequence binding,and positive regulation of DNA template transcription.AEE could use prostate cancer and other cancer signaling pathways to treat canine cardiovascular disease.

To evaluate the epidemicity and antimicrobial resistance of Staphylococcus aureus in the milk of mastitis cows,70 samples from Xinjiang and 50 samples from Inner Mongolia were collected from April to May in 2018.Staphylococcus aureus was cultivated,separated and purified.Antibiotic susceptibility test of purified isolates with KB paper and PCR analysis for the drug resistance gene were carried out.The results showed that the separation rate of Staphylococcus aureus in Xinjiang and Inner Mongolia was 28.6% and 54.0%,respectively.Penicillin G (75.0%) was the highest resistant antibiotic for Staphylococcus aureus isolated from Xinjiang,followed by sulfis oxazole (60.0%),lincomycin (55.0%).For the isolates from Inner Mongolia,penicillin G (70.4%) was also the highest resistant drug,followed by lincomycin (63.0%) and clindamycin (51.9%).The results of the resistance gene test showed that multi-resistance genes were detected in more than 88.9% of the isolates.The highest frequency resistance genes of isolated were ermA (30.0%) and dfrS1(30.0%) in Xinjiang and lnuA (46.2%) in Inner Mongolia,respectively.

To determine the pathogen caused a serious mortality of racoon dog in Hebei province,and one Gram-negative bacterium was isolated from the the lung samples of diseased racoon dog.The isolate received morphological obsrvation,16S rRNA sequence analysis and biochemical test.Basis on this,the serotype characteristics,pathogenicity tests,drug sensitivity test were completed.The isolated strain was confirmed as not K1/K2 Klebsiella pneumoniae,named as CLKp18.16S rRNA gene sequence analysis results showed that the bacterium was 99% homologous with many strains of Klebsiella accessed in GenBank.The Vitek automatic bacterial identification results showed that the similarity between the strain and Klebsiella pneumoniae standard was 99%.Pathogenicity test results showed that the mice in the experimental group began to develop clinical symptoms 6 h after the challenge.The lung,liver,spleen and kidney of the dead mice were aseptically removed,and the bacteria were isolated by scribing and plating.It indicated that the infected strain could invade many tissues and organs in mice after infection,which caused different degrees of lesions,especially liver and lung lesions,the LD₅₀ in mice was 2.17×10⁷ CFU.Drug susceptibility test results showed that the strain resistant to monocyclic lactam,chloramphenicol,aminoglycosides,tetracyclines,sulfonamides and most cephalosporins,and sensitive to amikacin,amoxycillin/clavulanic acid,imipenem and ceftazidime.This study confirmed that K1/K2 Klebsiella pneumoniae didn't cause the pathogens,and the strain with strong pathogenicity in mice and multi-drug resistance.The results provided a reference for clinical treatment of pneumonia caused by the strain.

The aim of this study was to optimize the fermentation medium and fermentation conditions of Bacillus subtilis BL0006 and improve the titer of antimicrobial peptide.Through the single factor experiment,the optimum carbon source,nitrogen source and inorganic salt were selected as glucose,peptone and K₂HPO₄.The path of steepest ascent was undertaken to approach the optimal region of the three significant factors.Box-Behnken design and response surface analysis were adopted to get the best formula of culture medium that could improve the titer of antimicrobial peptide.The fermentation conditions,temperature,inoculation quantity and rotational speed were optimized by shaking flask single factor test.The optimized fermentation medium was glucose 47.7 g/L,peptone 29.0 g/L,K₂HPO₄ 3.3 g/L.The optimized fermentation process was inoculum size 30 mL/L,pH 7.5,220 r/min and 37℃.Under the optimized conditions,the titer of antimicrobial peptide was 4.25×10⁴ U/mL and was 3.51 times as high as before optimization.In conclusion,the selected medium and the optimized fermentation process could achieve high yield,reduce cost and shorten fermentation time.

Respiratory disease seriously threats the livestock industry,which has caused high morbidity and mortality so that resulted in huge economic losses.Actinobacillus pleuropneumoniae (A.pleuropneumoniae),Pasteurella multocida (P.multocida),Streptococcus suis (S.suis) and Haemophilus parasuis (H.parasuis) are the material reasons for the respiratory tract diseases which caused by the bacterial infected.Cefquinome,the fourth generation of cephalosporins soly for animals,which is characterized as quick absorption,high bioavailability,high stability to β-lactamases and low toxicity to mammals.It can effectively treat porcine respiratory diseases and prevent resistance.The article described the physicochemical properties,bactericidal mechanism and pharmacokinetics of cefquinome,and compared the pharmaceutical parameters of cefquinome in different animals,indicating that cefquinome had a short peak time and high peak concentration in pigs,elimination half-life was longer,could quickly exert high-efficiency antibacterial effect and maintain antibacterial effect for a certain period of time.The in vitro antibacterial activity and clinical treatment effect of cefquinome on the main pathogens of respiratory tract in pigs were systematically introduced.It was found that the clinical pathogens of respiratory tract had high sensitivity to cefquinome and had a promising clinical application.However,there are some problems in the clinical application of this drug.The unreasonable use of cefquinome leads to the emergence of drug resistance.Through the research of PK-PD synchronization model and the establishment of drug resistance determination criteria,it can provide a scientific basis for the rational application of the drug.

To study the pharmacokinetics behavior of florfenicol nanoemulsion in rats,florfenicol solution was chosen as the contrast medicine,the medicine was taken oral and intramuscular dose of 30 mg/kg body weight,and sampled at 0.5,1,2,4,8,12,24,36,48 and 72 h.The concentrations of florfenicol in plasma samples were detected by a high performance liquid chromatography (HPLC) method.The data were analyzed with the pharmacokinetic program DAS 2.0.The results showed that the concentration-time course of florfenicol solution and florfenicol nanoemulsion in plasma fitted a 2-compartment open model.The parameters of FFNE and FFSol under compartmental model after oral administration,AUC_(0-∞) were 1 085.047 and 2 176.490 mg/L·h,half-life were 10.566 and 13.687 h,the relative bioavailability of florfenicol nanoemulsion was 187.4%.The parameters of FFNE and FFSol under compartmental model after intravenous administration,AUC_(0-∞) were 1 530.55 and 3 243.338 mg/L·h respectively,the half-life were 7.533 and 13.335 h,respectively,and the relative bioavailability of florfenicol nanoemulsion was 211.9%.The results indicated that FFNE had an adequate distribution in rats after intramscular and oral administration,however,elimination rate was faster by oral administration than by intramuscular of most rats.The prepared florfenicol nanoemulsion promoted absorption of florfenicol,and the bioavailability of florfenicol nanoemulsion was significantly improved.

This trial was aimed to preliminarily locate clinically isolated Escherichia coli (E.coli) resistant genes in pigs.Using conventional bacterial isolation and culture,16S rRNA PCR amplification and sequence analysis,the pathogens were isolated and identified from the uterus pus sent from three large-scale pig farms in Jiangxi province,the drug resistance genes of clinical isolates were preliminarily located by plasmid extraction,transformation of E.coli DH5α competent cells and drug susceptibility test.The results showed that 3 strains of E.coli were isolated and identified,among which JX-22 was only sensitive to ofloxacin and spectinomycin,and JX-26 was only sensitive to four drugs,such as streptomycin and ofloxacin,JX-28 was only sensitive to three drugs such as ofloxacin,all were multi-drug resistant bacteria.Three strains of E.coli could be purified to obtain plasmids of different molecular masses.The results of drug sensitivity test of isolates and plasmid transformants and E.coli DH5α competent cells showed that resistance genes of three strains of E.coli to streptomycin,lincomycin,metronidazole,ampicillin,amoxicillin,spectinomycin and amikacin,JX-22 and JX-26 isolates to doxycycline,florfenicol and cotrimoxazole,JX-22 isolate to ceftriaxone,and ceftriaxone,cefotaxime and norfloxacin genes of JX-28 isolate were located on a bacterial plasmid.Resistant to doxycycline,florfenicol and cotrimoxazole genes of JX-28 isolate,norfloxacin gene of JX-22 isolate and ceftriaxone and cefotaxime genes of JX-26 isolate were all located on their chromosomes.None of the three isolates had the ofloxacin resistance gene.In this experiment,most of the multidrug resistance genes of three multi-drug resistant E.coli were preliminarily located on the plasmid,which laid a foundation for further study on the drug resistance mechanism and effective control measures of E.coli.