Department of Poultry and Fish Diseases, Faculty of Veterinary Medicine, Damanhour University, Elgomhoria st. Damanhour, Elbehira 22511, Egypt.
Department of Nutrition and Veterinary Clinical Nutrition, Faculty of Veterinary Medicine, Damanhour University, Elgomhoria st. Damanhour, Elbehira 22511, Egypt.
Poult Sci. 2019 Jan 1;98(1):105-111. doi: 10.3382/ps/pey324.
Ornithobacterium rhinotracheale (ORT), a bacterium causing respiratory tract infection, has led to a significant problem in the intensive poultry production in Egypt. Polymerase chain reaction-amplified 784-bp specific ORT DNA fragments were found in 7 ORT isolates from lungs, air sacs, and tracheas of commercial broilers or layers in Egypt in 2015. The objective of this study was to investigate the role of the live variant IBV 4/91 with ORT infection. A total of 120 14-d-old broiler chickens (Cobb 500) were equally divided into 4 groups for experimental infection in a complete randomized design. Group 1 was infected with ORT strain and live infectious bronchitis vaccine (IBV 4/91) simultaneously; group 2 was infected with the bacterial strain alone; group 3 was vaccinated only with IBV 4/91, and group 4 was the non-vaccinated and non-infected control group. The respiratory signs, post-mortem lesions (tracheitis and pneumonia) and histopathological findings of lungs, trachea, and air sacs in the experimentally infected broiler chickens appeared to be more prominent in the chickens of group 1 than group 2. With respect to body weight, weight gain, feed conversion rate, and Ornithobacterium re-isolation, there was a difference (P ≤ 0.05) among the chickens of group 1 and the other groups. This reveals that the use of live infectious bronchitic vaccines, which is a common practice in the local Egyptian field of production, may concomitantly increase the pathogenicity of ORT in broiler chickens.
嗜鸟分枝杆菌（ORT）是一种引起呼吸道感染的细菌，它在埃及集约化家禽生产中造成了严重问题。2015 年，从埃及商业肉鸡或蛋鸡的肺部、气囊和气管中分离出的 7 株 ORT 分离株中发现了 784bp 的特异性 ORT DNA 片段。本研究旨在探讨活变体 IBV 4/91 与 ORT 感染的关系。采用完全随机设计，将 120 只 14 日龄的肉鸡（Cobb 500）等分为 4 组进行实验感染。第 1 组同时感染 ORT 株和传染性支气管炎活疫苗（IBV 4/91）；第 2 组单独感染细菌株；第 3 组仅接种 IBV 4/91，第 4 组为未接种和未感染的对照组。实验感染肉鸡的呼吸道症状、剖检病变（气管炎和肺炎）以及肺、气管和气囊的组织病理学发现，第 1 组的鸡比第 2 组更为明显。就体重、增重、饲料转化率和嗜鸟分枝杆菌再分离而言，第 1 组的鸡与其他组之间存在差异（P≤0.05）。这表明，在埃及当地生产领域普遍使用传染性支气管炎活疫苗可能会同时增加 ORT 在肉鸡中的致病性。
