introduce
The purpose of this study was to evaluate the efficacy of vaccination against infectious bronchitis virus (IBV) (Arkansas strain) before or concurrently with Mycobacterium synoviae infection.
prove
Of these, 96 SPF Leghorn pullets were divided into 8 groups, 6 of which were vaccinated with commercial IBV vaccine by eye instillation at 2, 4, or 8 weeks of age.
Then, after confirming that all mice were mycoplasma-free 14 days later, at 8 weeks of age, half of each group were inoculated with a pathogenic strain of M. synoviae (K6677), and all mice were evaluated 10 weeks later. Days were performed by air sac scoring of macroscopic lesions, histopathological examination of tracheal lesions, serology, and real-time quantitative PCR.
result
The highest mean air sac injury scores and the highest mean tracheal mucosal measurements were observed in the group vaccinated with IBV at week 8 and with M. synoviae at the same age.
The average air sac score of all birds in the K6677-vaccinated group was significantly higher than that of the group not vaccinated with M. synoviae (all of these groups had no air sac lesions).
The highest mean (genome) log copy number of M. synoviae, 10 (MCNlog10), was detected in the group vaccinated with IBV at the same age as M. synoviae at week 8, and replication of M. synoviae was significantly greater in this group. With. higher than other groups of birds vaccinated with M. synoviae and uninfected birds (P < 0.05).
Very few footpad injuries were observed, and the mean scores were not significantly different between the groups (P < 0.05).
In conclusion, although further results are yet to be published, we conclude that IBV vaccination may worsen respiratory disease, including airsacculitis, in birds infected with M. synoviae .
The results show that IBV vaccination affects the macroscopic and microscopic lesions evaluated, as well as the replication of M. synoviae in the trachea of infected birds.
Colonel M. EHSAN et al.
69 Western Poultry Farm Conference. Sacramento, 2020
Tags: #SA766 • Bronchitis Vaccine