| As a unique poultry in Tibet Plateau,breeding Tibetan chickens can not only bring fresh meat and egg products to plateau herdsmen,but also bring good economic benefits to scale breeding,which is of great significance for rural revitalization.However,with the rapid development of Tibetan chicken breeding industry and the continuous expansion of feeding scale,the impact of the occurrence and prevalence of Tibetan chicken epidemic diseases on the healthy development of Tibetan chicken breeding industry is prominent.Salmonella is the pathogen of zoonosis,which can cause infection in Tibetan chickens,leading to pullorum disease in chicks,high morbidity and mortality,and the growth and development and egg production performance of surviving chickens are seriously affected.Because Salmonella can be transmitted through eggs,it not only seriously affects the fertilization rate and hatching rate of eggs,but also causes food poisoning in humans through egg-borne routes,so it has important public hygiene significance.In this study,the etiological investigation was carried out on the low performance of breeders and the survival rate of chicks in a Tibetan chicken nursery farm in Aba Prefecture,and the diagnosis of Salmonella infection was confirmed.The prevention and control plan was formulated and implemented through a series of studies,and the following results were obtained:1.Salmonella infection was the main cause of the low performance of breeders in the Tibetan chicken nursery farm.In this study,venous blood was randomly collected from 360 breeders from 3000 200 chickens,quarantined with typhoid plate agglutination test,60 dead embryos and30 shelled chicks were collected as sick materials,inoculated with SS medium,and cultured at 37 ℃ for 24 h to identify the dominant bacteria.The results showed that the positive rate of plate agglutination test was 16.67%,Salmonella was identified in SS agar plate colony morphology,biochemical identification of intestinal bacteria and PCR,and 60 strains were isolated from 20 dead embryos and shelled chicks,with a positive rate of 66.67%,of which the isolation rates of chicken embryos and chicks were 68.33% and 63.33%,respectively.According to the results of quarantine and bacterial isolation and identification,combined with the low production performance of the Tibetan flock such as egg production rate,fertilization rate and fledging rate,salmonellosis can be diagnosed.2.The antibacterial drugs and disinfectants sensitive to Salmonella were selected.In order to understand the drug resistance of bacteria in this Tibetan chicken farm,30 Salmonella isolates were randomly selected in this study,and the susceptibility to 8antibiotics including amoxicillin(AML),lincomycin(MY),gentamicin(FFC),fluorobenzonicol(NA),cephalexin(CL),amikacin(AK),ampicillin(AMP),and sulfadiazine(SDZ)was tested by K-B method,while the minimum inhibitory concentrations of 4 disinfectants including oxofujian(glutaraldehyde solution),chlorine dioxide fast-acting effervescent tablets,Luankang(potassium persulfate complex),and neogilaldehyde on the isolated strains were determined by broth microdilution method.The results showed that Salmonella was sensitive to amoxicillin and gentamicin,sensitive to glutaraldehyde sunflower methyl ammonium bromide solution and new Gilamine solution,and sensitive to chlorine dioxide fast-acting effervescent tablets.In summary,amoxicillin,gentamicin and Aofujian,new Gilamine solution sensitive,chlorine dioxide fast-acting effervescent tablets can be used as alternative antibacterial drugs and disinfectants in prevention and treatment.3.Demonstration and popularization of comprehensive control measures.In order to effectively prevent and control salmonellosis in Tibetan chickens,on the basis of previous studies,comprehensive prevention and control measures were formulated for quarantine and elimination of breeder chickens,drinking water with sensitive drugs every 1 month for 3-5 days,spraying disinfection with sensitive disinfectants 2-3 times a week for enclosures,hatching rooms,brooding rooms,and utensils,and adding sensitive disinfectants to drinking water.The results showed that the positive rate of quarantine in demonstration Tibetan flocks decreased from 21% to5%,the egg production rate increased from 45.74% to 59.06%,the fertilization rate increased from 77.21% to 81.08%,the fledging rate increased from 85.16% to94.37%,and the dead embryo rate decreased from 12.78% to 5.45%;the positive rate of quarantine in popularized Tibetan flocks was 3.23,and the egg production rate was65.32%.In summary,the production performance of Tibetan chicken flocks has been significantly improved after the adoption of comprehensive control programs. |
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