| Salmonellosis has always been one of the bacterial infectious diseases affecting the poultry industry, including pullorum disease, fowl typhoid and paratyphoid infections. It seriously affects the survival rate of chick, is also one of the important causes of laying hens production-cut and its contamination in the products may arise food safety issues. The contents of the study including:1. Compare the sensibility of three products of stained polyvalent antigen produced by Peking Zhonghai Animal Health Company, China Institute of Veterinary Drug Authority and LOHMANN ANIMAL HEALTH INT respectively, and the accuracy of whole blood plate agglutination (WBPA) test with sera plate agglutination (SPA) test;2. Investigate the epidemiology of Salmonellosis farms with breeding hens of different ages, chicks with wet-anus, death embryos at21days of incubation and the distribution of Salmonella in pullorum-gallinarum antibody positive and negative hens, with the purpose of providing the scientific foundation for the prevent and control of the diseases.According to Detection of Antibodies Against (Pullorum Disease)-Protocol of Whole Blood Plate Agglutination Test, issued by Entry&Exit Inspection and Quarantine Bureau of The people’s republic of China, totally1109sera samples, originated from four chicken breeder farms were detected with products of stained polyvalent antigen produced by three companies at the same time. Results showed that the quantity of positive samples detected with Zhonghai antigen, China antigen and LOHMANN antigen respectively were273,235and238, the quantity of positive sera detected with all three products of antigen was201;300positive sera samples and303negative sera samples detected by WBPA text with Zhonghai antigen were rechecked by SPA test, the positive rates were13%and1.0%with the correspondence of13%and99%respectively.Samples of110-day-old,168-day-old,258-day-old breeding hens,4-27-day-old chicks with wet-anus and dead embryos at21days of incubation from three un-eradicated farms were used for the isolation and identification of Salmonella. Firstly, samples of visceral organs and cloacal swabs were cultured for Salmonella, suspected bacterial colonies were detected with A-F Salmonella Diagnose Sera by slide agglutination test. Secondarily, positive bacterial strains were then confirmed by PCR. Finally, Salmonella isolates were further classified by Salmonella Diagnose Sera, move-ability test and biochemical test. The results showed that the positives of Salmonella isolated by cloacal swab, visceral organs of antibody-positive, antibody-negative birds were1%(1/100),46.7%(14/30) and0%(0/15) respectively, and in the positive birds, ovary, oviduct and spleen were the most prevalent organs of Salmonella in vivo (64.3%,9/14); The positive of visceral organ samples of133chicks with wet-anus and80dead embryos were12%(16/133) and62.5%(50/80), respectively. Totally81Salmonella strains were identified in the study and they were Salmonella pullorum (91.3%,74/81), Salmonella gallinarum (7.4%,6/81) and Salmonella paratyphoid(1.3%,1/81).The results of the study demonstrated that:1. The pullorum-gallinarum polyvalent stained antigen produced by Peking Zhonghai Animal Health Company is the most sensitive one and that by China Institute of Veterinary Drug Authority is the most accurate one of three antigens in the study;2. Sera plate agglutination test is more accurate than whole blood plate agglutination test especially for the positive result;3. In the Salmonella infected breeding hens, ovary, oviduct and spleen were the most prevalent organs of Salmonella, while the cloacal swab sample is the lowest;4. In the un-eradicated farms, the positive of Salmonella isolated in the dead embryos was high to62.5%;5. Most of the Salmonella spp prevailing in the un-eradicated farms in the study are Salmonella pullorum and Salmonella gallinarum. These results will provide useful data for the further eradication of pullorum-gallinarum on the farms. |
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