为了研究预防和控制家禽EHEC病的措施,观察该疾病的感染过程和发展以及各种器官的病理变化。在这项研究中,采用不同给药途径感染不同剂量肠出血性大肠杆菌(EHEC)O157:H7,建立EHEC肉鸡模型。将195只14日龄肉鸡随机分为13组:对照组,灌肠滴注组(1010、1011、1012、1013CFU大肠杆菌O157:H7),灌胃组(P.O)(1011、1012、1013、1014CFU大肠杆菌O157:H7),和腹膜内注射组(I.P.)(108、109、1010、1011CFU大肠杆菌O157:H7)。大肠杆菌(E.大肠杆菌)使用灌肠滴注,灌胃或腹膜内感染。然后是饲料摄入量,体重变化,实验期间记录小鸡的粪便和临床症状。大肠杆菌感染后7d,从颈静脉收集血液并进行血清学检查。肝脏,脾,脾并提取小鸡的结肠以获得器官指数,细菌负荷,和他们的组织病理学变化。感染大肠杆菌后,一些小鸡的粪便是绿色或红色的水汪汪的粪便,有时伴有泡沫,I.P.组肉鸡的料重比显著增加(P<0.05),108CFU组是对照组的1.3倍.三种造模方法均可导致血脂代谢和肝功能指标异常(AST升高,TBA,T-Bil和TC水平;ALB降低,TG,和TP水平)。通过所有3种方法感染O157:H7的小鸡导致其在肝脏中的检测,脾,脾和结肠。三种造模方法显著降低肝脏指数,肝脏可见炎性细胞浸润和充血。灌胃和灌肠滴注可显著降低大肠杆菌肉仔鸡的脾脏指数,观察到脾充血和小动脉周围透明变性。I.P.组肉鸡脾脏呈紫黑色球体肿大,脾脏组织学改变较严重。灌胃组和灌肠滴注组肉鸡的肠绒毛较薄,更容易破裂,肠道固有层充血,和炎性细胞浸润。此外,粘膜上皮杯状细胞数量增加。大肠杆菌O157:H7可以诱导肝脏,脾脏和肠道损伤,降低雏鸡的生长性能。通过比较这三种方法,我们发现通过管饲法感染O157:H7的小鸡有更严重的肝脏和肠道损伤,灌肠滴注法造成最严重的肠道损伤,和I.P.方法显著损害了鸡的肝脏和脾脏。
In order to study the prevention and control EHEC disease measures in poultry, the infection process and development of this disease and the pathological changes of various organs were to be observed. In this study, chickens were infected with different doses of enterohemorrhagic Escherichia coli (EHEC) O157:H7 using different routes of administration to establish EHEC broiler model. A total of 195 14-day-old broilers were randomly divided into 13 groups: including control group, Enema-drip groups (1010, 1011, 1012, 1013 CFUs E. coli O157:H7), gavage groups (P.O) (1011, 1012, 1013, 1014 CFUs E. coli O157:H7), and intraperitoneal injection group (I.P.) (108, 109, 1010, 1011 CFUs E. coli O157:H7). Escherichia coli (E. coli) was given using enema-drip, gavage or intraperitoneal infection. Then the feed intake, weight changes, stool and clinical symptoms of the chicks were recorded during the experiment. 7 d after E. coli infection, blood was collected from the jugular vein and serological tests were carried out. The liver, spleen, and colon of the chicks were extracted to get the organ index, bacteria load, and their histopathological changes. After infection with E. coli, some chicks feces were green or red watery stool, sometimes accompanied by foam, and the material to weight ratio of broilers in I.P. group increased significantly (P < 0.05), the 108 CFUs group were 1.3 times as large as control group. Three modeling methods can result in abnormal serum lipid metabolism and liver function indexes (increase of AST, TBA, T-Bil and TC level; decrease of ALB, TG, and TP level). Infection of chicks with O157:H7 by all 3 methods resulted in its detection in the liver, spleen, and colon. Three modeling methods significantly decreased liver index, and inflammatory cell infiltration and hyperemia were observed in liver. The spleen index in E. coli broilers by gavage and enema-drip was significantly decreased, splenic hyperemia and periarteriolar hyalinosis were observed. The spleen was enlarged with purplish-black spheroids in I.P. group broilers, and the spleen histological changes was more serious. The colon villi of broilers in gavage and enema-drip groups were thinner, more prone to rupture, intestinal lamina propria hyperemia, and inflammatory cell infiltration. Moreover, the number of goblet cells in the mucosal epithelium increased. E. coli O157:H7 can induce liver, spleen and intestinal damage and reduce growth performance of chicks. By comparing these 3 methods, we found that chicks infected with O157:H7 by gavage had more severe liver and intestinal damage, the enema-drip method caused most serious intestinal damage, and I.P. method significantly damaged the liver and spleen of chickens.