Abstract

SAUME, Elsy; SOGBE, Elio; CASTRO, María J  and  ASCANIO, Marisela. Comparative study of three vaccine strains of the virus that affect the bursa in broilers. Zootecnia Trop. [online]. 2007, vol.25, n.2, pp.129-134. ISSN 0798-7269.

The virus that infects the bursa In broilers (IBDV) causes one of the most important immunosuppressive diseases in commercial poultry. The present study was designed to compare the effect on the broiler’s bursas of three vaccines made with three different viral strains, mild, intermediate and intermediate plus, of IBDV. It was evaluated by means of comparing the bursa/body weight ratios and bursa histopathological changes. The experiment was conducted with 200 cobb x cobb broiler chickens, divided in 4 groups of 50 chickens each. Each group consisted of 5 replicates of 10 chickens each. The groups were: (A) no vaccinated (control); (B) vaccinated with the mild strain, (C) vaccinated with the intermediate strain, and (D) the vaccinated with the intermediate plus.strain. The chicks received a first vaccination at ten days old. Chicks were slaughtered at 8, 16, 22, and 32 days post vaccination (PV), and body and bursal weights were recorded and bursa tissues were examined for histopathological changes. At 32 days PV only the intermediate plus vaccine produced atrophy of the bursa and significant histopahological differences (P<0.05) with the other groups. For the D, there were observed larger microscopic lesions and low reactivity at 8 and 32 d PV. These results suggest that the intermediate plus IBDV vaccine is more invasive as evidenced by smaller bursas and larger microscopic lesions.

Keywords : bursa infection; vaccinal strains; bursa.