| Salmonella can so easily cause food poisoning for humans that it is significant for public health to investigate,study and prevent the occurrence of related diseases to salmonella.In this study,the samples were collected from different cultivars of chicken in some areas,salmonella was isolated from these samples and the research was conducted from the pathogen and serology at the beginning.Then,a representative strain of Salmonella enteritidis SDBL-1 were selected to explore its biological characteristics.Finally,the above strain of Salmonella enteritidis SDBL-1 was utilized to infect SPF chicken and initially explore the infected pathways and pathogenicity of SDBL-1 isolates in SPF chickens,which laid the scientific basis for the prevention of salmonella enteritidis.Comparision of Salmonella Antibody Diagnostic Antigen with Different Diagnostic Methods for Salmonella Antibody Tests.210 samples were randomly selected,including 154 samples of serum samples and 56 samples of yolk samples.Four batches of pullorum disease and fowl typhoid polyvalent antigen from the same company were used to detect the antibodies of pullorum disease and fowl typhoid by slide agglutination and find the difference among four batches of these kits.Additionally,36 samples of serum samples were randomly selected from the same batch of different antigens to determine the antigens by slide agglutination.And 91 samples of serum samples were randomly selected and tested with three kits: laboratory homemade domestic salmonella enteritidis antigen,and domestic and imported salmonella antibody ELISA kit to find the difference among them.The results showed that the anastomosis rate changed from 65.6% to 89.6%,and the anastomosis rate of egg yolk antibody fluctuated between 98.2% and 100%.The coincidence rate between the commercialization diagnostic antigen and the laboratory homemade diagnostic antigen was61.1%.The coincidence rate of the laboratory homemade antigen with the domestic and imported Salmonella antibody ELISA kit was 69.2%.The results suggest that there are differences between the different diagnostic antigens and different diagnostic methods,and the methods can not be completely replaced.The investigation of Salmonella epidemiology form different cultivars of chicken.8 chicken flocks in different areas were selected and utilized to collect 2971 serum samples to detect salmonella antibodies with antigen antibody plate agglutination.And 1658 samples of chicken embryos at 20 days and organs were collected from 17 chicken flocks to isolate and identify Salmonella by the self-optimizing salmonella isolation method.The results showed that the positive rate of pullorum disease and fowl typhoid in 2971 serum samples was 31.8%.The positive rate of pullorum disease and fowl typhoid Serum changed from6.2% to 71.9%.There were 80 positive samples in 1658 chicken embryos and organ samples,and 8 positive chickens in 17 chickens.The positive rate of different flocks changed from0% to 31.5%.The results suggest that the detection of chicken flocks infection by salmonella.The research of pathogenicity and transmission route of Salmonella enteritidis SDBL-1 isolates.The biological characteristics of salmonella enteritidis SDBL-1 isolates were explored in this study,including their growth curve,drug susceptibility and virulence.6-week SPF chicken were randomly divided into three groups: control,air transmission group and infected group with SDBL-1 isolate of salmonella enteritidis.The body weight,blood routine index,lymphocyte Subgroup indicators and antibody changes and infection of chickens detoxification laws,and the environment(feed,drinking water,mosquitoes,etc.)were detected every two days after the infection finished.The results showed that the LD50 of the SDBL-1 strain of salmonella enteritidis was 1.905 × 109 CFU,which was effective against penicillin,oxacillin,kanamycin,erythromycin,midecamycin,nitrofurantoin,vancomycin,clarithromycin(P> 0.05),The lymphocyte ratio decreased significantly at 2,4,6 and 8 days(P <0.05),and the granulocyte ratio and granulocyte was significantly higher than that control group at 2,4,6 and 8 days(P <0.05).The granulocyte ratio was significantly higher than that control group at 4,6 and 8 days(P <0.05).The percentage of CD4+and CD8+induced by SDBL-1 isolates was significantly increased at 2 and 4 days(P<0.05),firstly appeared to decline and reached the botom at 6 days after infection.air transmission group had the same trend,but the time delayed 2d.Furthermore,antibodies of salmonella were detected at 4 days after infection in the infected group and in the air transmission group.The results suggest that salmonella enteritidis SDBL-1 isolates infected with SPF chicken,caused inflammation of the body,resulted in immune dysfunction and caused different degrees of organ damage.Salmonella can be transmitted through the air and infected chickens can discharged bacteria through the feces,mouth and cloaca.In conclusion,it was significantly various for the diagnosis of Salmonella among different diagnostic antigens and different diagnostic methods.The chicken flocks from different areas were infected with Salmonella,most of which was salmonella enteritidis.SDBL-1 can cause SPF chicken infection,resulted in bodies damage,continuously discharged bacteria,polluted environment and infected other chicken flocks. |
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