Morphological investigation of bursa of fabricius of imported broilers and local chicks vaccinated with two types of ibd vaccines.

This study was designated to investigate the morphology of bursa of Fabricius (BF) in broilers and local chicks. Eighty Hubbard broilers and one hundred local, one-day-old chicks were reared on litter floor for 35 days. They were divided into six groups, A, B and C for broilers, and D, E and F for local chicks. Two types of Infectious Bursal Disease (IBD) vaccine were used. Chicks of group A, and D were vaccinated with an intermediate type vaccine (Bursine ® -2) at 14th day, whereas group B and E were vaccinated with an intermediate-plus vaccine (Bursine ® plus) at 14th day also (Fort Dodge Animal Health, Fort Dodge, Iowa, USA). Chicks of group C and F were acted as control. Five chicks were sacrificed from A, B, D and E groups at 21st, 28th and 35th day and at 1st, 7th, 14th, 28th and 35th day from C and F control groups. Body weights, bursa weights, diameters and relative weight of bursa were measured. The results showed a non significant difference (P>0.05) between group A and C, whereas group B showed a significant reduction (P<0.05) of bursal index at 21st day compared with group C. Different levels of significancy of bursal index (BI) were noticed in local chicks. Reduction of bursal weight of vaccinated groups may be associated with the proliferation of the virus vaccine in the bursal tissues. This study also revealed that intermediate-plus vaccine caused severe BF injury in vaccinated local bird. The present study indicated a significant correlation between bursa diameter and the injury produced by the vaccination process in broiler chicks, on the other hand the same trend was also recorded in the local chicks. The present study was also revealed a clinical signs and mortality up to 66.6% due to highly virulent IBD vaccine in group E of local chicks, because of their high susceptibility to this vaccine. [ABSTRACT FROM AUTHOR]