H9N2 Avian influenza (AI) is an infectious disease which considered to have low pathogenic virulence, but in the case of coinfection with other pathogens it has the potential to become a major threat to the poultry industry. Infectious bronchitis (IB) and Newcastle diseases (ND) are other common problems to the poultry industry, which there are an extensive vaccination program against these viral pathogens. To investigate the effects of administration of infectious bronchitis and Newcastle disease live vaccines (IBLVs and NDLVs) in the presence of H9N2 AI infection on the immune system and some production parameters, 180 one-day-old broiler chicks were randomly allocated into six groups with different vaccination programs including H120 IBLV, 4/91 IBLV, B1 NDLV and LaSota NDLV. At the age of 20 days, all birds of the experimental groups except the negative control group, were inoculated intra-nasally (at dose of 106 EID50) with H9N2 AIV. After the inoculation, gross and microscopic lesions of the immune organs, serological changes and some production parameters were examined. The findings of this study showed that coinfection of H9N2 AI with NDLVs exacerbated the gross and microscopic injuries in the immune organs; especially the bursa of Fabricius. LaSota + AIV group had the most severe lesion in the bursa of Fabricius, spleen and thymus. Furthermore, the birds of LaSota + AIV group consumed the least amount of feed and water and their final body weight were significantly (P ≤ 0.05) lower in comparison with the other groups. Interestingly, in the context of this experiment both 4/91 and H120 IB live vaccines enhanced the HI antibody titers against H9N2 AIV, but the 4/91 showed the most significant (P ≤ 0.05) increase compared to the other experimental groups.

中文翻译：

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新城疫和传染性支气管炎活疫苗对实验感染H9N2禽流感肉鸡免疫系统和生产参数的影响。


H9N2禽流感（AI）是一种传染性疾病，被认为具有低致病力，但在与其他病原体混合感染的情况下，有可能成为家禽业的主要威胁。传染性支气管炎 (IB) 和新城疫 (ND) 是家禽业的其他常见问题，针对这些病毒病原体有广泛的疫苗接种计划。为了研究 H9N2 AI 感染时接种传染性支气管炎和新城疫活疫苗（IBLV 和 NDLV）对免疫系统和一些生产参数的影响，将 180 只 1 日龄肉鸡随机分为 6 组，不同的疫苗接种计划包括 H120 IBLV、4/91 IBLV、B1 NDLV 和 LaSota NDLV。 20日龄时，除阴性对照组外，所有实验组鸡均鼻内接种H9N2 AIV（剂量为106 EID50）。接种后，检查免疫器官的肉眼和微观损伤、血清学变化和一些生产参数。这项研究的结果表明，H9N2 AI 与 NDLV 的共感染加剧了免疫器官的肉眼和微观损伤；尤其是法氏囊。 LaSota+AIV组法氏囊、脾脏和胸腺损伤最严重。此外，LaSota + AIV 组的鸡消耗的饲料和水量最少，其最终体重显着低于其他组（P ≤ 0.05）。有趣的是，在本实验中，4/91 和 H120 IB 活疫苗均增强了针对 H9N2 AIV 的 HI 抗体滴度，但与其他实验组相比，4/91 显示出最显着的增加（P ≤ 0.05）。