鼻气管鸟杆菌对SPF雏鸡的致病性

Pathogenicity of Ornithobacterium rhinotracheale on SPF chicks

通过气管、消化道和肌肉注射接种鼻气管鸟杆菌(Ornithobacterium rhinotracheale,ORT)人工感染SPF雏鸡,观察试验鸡的发病情况及症状,并检测各试验组和对照组的体质量;利用建立的PCR检测方法对试验组和对照组的排菌情况进行动态观察;于感染后不同时间随机剖杀试验组和对照组鸡只,采集心脏、肝脏、肺脏和气管等组织固定、切片、H.E.染色,观察各器官病理组织学变化,利用建立的IFA方法对ORT在雏鸡体内的分布进行研究,并进行血常规和血液生化指标检测。结果表明,ORT接种后,主要引起雏鸡的呼吸困难、咳嗽等症状,增重明显降低;病理组织学变化以肝脏、心脏组织细胞变性,气管和肺脏广泛性出血和炎性细胞浸润为特征;IFA阳性信号主要分布于肺脏和气管;从感染后2～8d一直可持续排菌;HGB、WBC、RBC、BUN和AST发生显著变化。这表明ORT感染主要引起雏鸡的呼吸系统病变,气管接种比消化道和肌肉注射接种对雏鸡致病性强,肺脏和气管是ORT侵害的主要靶器官。

To study the pathogenicity of Ornithobacterium rhinotracheale on SPF chicks, the SPF chicks were artifi- cially infected through the trachea, digestive tract and intramuscular challenge. The incidence and clinical symptoms of chicks were observed. And the body weight gain of chicks of each test group and negative control group were re corded. Dynamical observation of detoxification conditions of the experimental group and negative control group were done using the established PCR detection methods. The chicks of experimental group and the negative control group were killed randomly at different time of infection. The heart, liver, lungs and trachea were collected to be fixed and stained by conventional H. E. staining. Then the histopathological changes of these organs were observed. The distri- bution of the ORT in chicks issue was studied with IFA（indirect fluorescent antibody test） ;Their bloods were col- lected to be carried out the routine blood test and the detection of blood parameters. The results showed that the chicks manifested dyspnea, coughing and other symptoms. And the weight gain of these chicks significantly decreased. Histopathological changes were characterized by denaturization in liver, heart extensive hemorrhage and inflammatory cell infiltration in the trachea and lungs. IFA positive signals were mainly distributed in the lungs and trachea. The exhaust bacteria stage continued from 2 d to 8 d post challenge. The indexes of HGB,WBC,RBC,BUN, and AST significantly changed. Challenge of ORT was mostly associated with trachea problem. The tracheal had stronger pathogenicity than the digestive tract and intramuscular challenge. The main target organs of ORT were lung and trachea.