中国中部地区传染性鼻炎的流行病学调查及屎肠球菌对提高疫苗免疫效果的影响

Epidemiological Investigation of Infectious Coryza in Central China and the Effect of Enterococcus faecium on Improving Vaccine Immunity.

作者信息

Cui Weitao, Wang Chun, Wu Yaxin, Wang Tao, Wang Zhaoyang, Zhang Wei, Hu Ting, Zhang Wanpo, Hu Sishun, Zhou Hongbo, Li Zili, Zhou Zutao

机构信息

College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China; Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Huazhong Agricultural University, Wuhan 430070, China.

Hubei Provincial Center for Animal Disease Control and Prevention, Wuhan 430070, China.

出版信息

Poult Sci. 2025 Jul 29;104(10):105622. doi: 10.1016/j.psj.2025.105622.

DOI:10.1016/j.psj.2025.105622

PMID:40769017

Abstract

Infectious coryza is a major respiratory disease of chickens induced by Avibacterium paragallinarum. Understanding the prevalent serovars of the bacterium is fundamental for effective prevention and control of the disease. Moreover, improving the immune efficacy of the infectious coryza vaccine for laying hens under modern production systems is critical for disease management. Enterococcus faecium is a probiotic bacterium. However, the impact of E. faecium on infectious coryza vaccine efficacy has not been investigated. In this study, we isolated and identified Av. paragallinarum strains from chickens with suspected infectious coryza in farms in central China between 2019 and 2022. Serotyping was performed based on the haemagglutinin HMTp210 gene sequence. Seventy-two strains were isolated, including 19 strains of serovar A-1, 44 strains of serovar C-4, and six strains of serovar B. Three strains were non-serotypable. Av. paragallinarum loads in palatine clefts of the flocks were detected using qPCR targeting the recN gene which revealed increasing loads with age that stabilized at 31 weeks of age (5.59 × 10³ CFU/g). Healthy Hy-Line Grey laying hens were immunized with the infectious coryza vaccine at six weeks of age, and E. faecium TC3 was added to feed at a concentration of 10 CFU/g. Blood samples were collected 28 days post-immunization to assess antibody titers, cytokine levels, and other immune parameters. Immunoprotective efficacy was evaluated by challenge with serovar A-1 and C-4 isolates. Addition of E. faecium significantly increased infectious coryza vaccine antibody levels and enhanced protective efficacy against A-1 and C-4 strains by 6.72 % and 7.07 %, respectively. Furthermore, morbidity rates decreased by 33.53 % and 24.77 % in A-1 and C-4 strains, respectively. These findings indicate that E. faecium improves infectious coryza vaccine efficacy and strengthens the health of chicken flocks.

摘要

传染性鼻炎是由副鸡禽杆菌引起的鸡的一种主要呼吸道疾病。了解该细菌的流行血清型是有效预防和控制该病的基础。此外，提高现代生产系统下蛋鸡传染性鼻炎疫苗的免疫效果对疾病管理至关重要。屎肠球菌是一种益生菌。然而，屎肠球菌对传染性鼻炎疫苗效果的影响尚未得到研究。在本研究中，我们于2019年至2022年期间从中国中部农场疑似患有传染性鼻炎的鸡中分离并鉴定了副鸡禽杆菌菌株。基于血凝素HMTp210基因序列进行血清分型。共分离出72株菌株，其中包括19株A-1血清型菌株、44株C-4血清型菌株和6株B血清型菌株。3株无法分型。使用靶向recN基因的qPCR检测鸡群腭裂中副鸡禽杆菌的载量，结果显示载量随年龄增加而增加，在31周龄时稳定下来（5.59×10³CFU/g）。健康的海兰灰蛋鸡在6周龄时用传染性鼻炎疫苗免疫，并以10⁶CFU/g的浓度将屎肠球菌TC3添加到饲料中。免疫后28天采集血样，以评估抗体滴度、细胞因子水平和其他免疫参数。通过用A-1和C-4血清型分离株进行攻毒来评估免疫保护效果。添加屎肠球菌显著提高了传染性鼻炎疫苗的抗体水平，并分别将针对A-1和C-4菌株的保护效果提高了6.72%和7.07%。此外，A-1和C-4菌株的发病率分别降低了33.53%和24.77%。这些发现表明屎肠球菌可提高传染性鼻炎疫苗的效果并增强鸡群健康。