Histopathological changes of bursa fabric us of imported broilers and local chicks vaccinated with two types of infectious bursal disease vaccines

الملخص EN

This study was designated to investigate the Histopathological changes of bursa of Fabricius (BF) in broilers and local chicks after vaccination with two types of Infectious Bursal Disease (IBD) vaccines.

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.

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.

For histopathological examination of the bursa, 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.

Histopathological lesions in this investigation were scored from 0 to 6 based on the presence of degenerative alterations, necrosis, follicular atrophy in the bursa of Fabricius and the percentage of altered lymphoid follicles.

The present study revealed that the more pathogenic intermediate vaccine (intermediate- plus) caused severe bursa of Fabricius injury in vaccinated local chicks.

This could be explained by the lower degree of attenuation of this kind of vaccine and may be also related to the lack of maternally-derived antibody in these chicks.

It seems that there are no changes in the bursae of control groups.