【摘要】 为了研究在不同感染率下雏鸡白痢沙门杆菌的水平传播特性及其对组织器官病理变化的影响,将240只3日龄SPF鸡均分成6组,1组为对照组,口服生理盐水,0.5 mL/只;2~6组分别按照20%,40%,60%,80%,100%的比例随机选取8,16,24,32,40只,每只分别口服1×108cfu/mL鸡白痢沙门杆菌悬液,0.5 mL/只。分别在攻毒后1,3,7,14,21,28天对未攻毒雏鸡进行泄殖腔采样来检测不同感染率组的感染情况,同时对0和100%感染率组进行组织学和血清学检测。结果表明:攻毒后1天(1DPI)时,感染率为0,85.71%,91.41%,97.14%,97.14%,100%;3DPI时,全部感染。各组的死亡率分别为0,5.40%,11.43%,28.57%,22.86%和35.00%。血清TNF-α在1DPI(P<0.05)和3DPI(P<0.01)时差异显著或极显著。器官载菌量为盲肠﹥肝脏﹥脾脏;组织病理学变化出现在3~7DPI,以肝脏、心脏和肺脏的病变最典型。说明鸡白痢沙门杆菌水平传播对雏鸡早期感染危害较大,特别是感染后1~7 d为细菌侵染的关键时间。更多还原

【Abstract】 To study the horizontal transmission characteristics of Salmonella pullorum under different infection rates and its effects on the pathological changes in the tissues and organs,two hundred and forty three- day- old SPF chickens were randomly divided into 6 groups of 40 each.The group 1 was the control group,in which each chicken was orally given 0. 5 mL saline. 8,16,24,32 and 40 chickens were randomly selected from the other five groups according to 20%,40%,60%,80%,and 100%,respectively; each chicken was orally inoculated with 0. 5ml of the bacterial suspension containing 1 × 108 cfu S. Pullorum. The samples were collected from the cloaca of the chickens without challenge at 1,3,7,14,21,and 28 d before post infections,and were used to detect the infections in the groups with different infection rates. And then the histological and serological detections were carried out in the groups with 0 and 100% infection rates. The results showed that the infection rates of the six groups were 0,85. 71%,91. 41%,97. 14%,97. 14%,100% at 1d post- infection( 1DPI),respectively; all chickens in the six groups were infected at 3d post infection( 3DPI). Mortality in each group was 0,5. 40%,11. 43%,28. 57%,22. 86% and 35. 00%,respectively.There were significant differences( P < 0. 05) and highly significant differences( P < 0. 01) on the levels of serum TNF- α at 1 DPI and 3 DPI,respectively. The amount of bacteria in the organs,in descending order,was cecum,liver and spleen. The histopathological changes appeared within 3 ~ 7 DPI,and the lesions in the liver,heart and lung were most typical. The results indicate that the horizontal transmission of Salmonella pullorum is harmful to the early infection in chickens,especially the period of 1 to 7 DPI is the crucial time for the invasion and infection of bacteria.更多还原