What question did this study set out to answer?

This study aims to evaluate the protective efficacy of various commercial infectious bursal disease vaccines in broiler chickens post-challenge.

April 25, 2026Open Access

Protective efficacy of commercial infectious bursal disease vaccines in broiler chickens following challenge: Clinical, gross pathological, and histopathological evaluation

Key Points

This study aims to evaluate the protective efficacy of various commercial infectious bursal disease vaccines in broiler chickens post-challenge.
A total of 250 Ross 308 broiler chicks were divided into five groups: four vaccinated with different IBD vaccines and one unvaccinated control.
At 16 days of age, vaccinated groups were challenged with a local field isolate of IBDV, and clinical responses were monitored.
Evaluation included clinical symptoms, mortality rates, gross pathological, and histopathological assessments of the bursa of Fabricius and kidneys.
The unvaccinated group exhibited the highest mortality rate at 56%, while group 1 showed only 4% mortality, group 2 12%, group 3 18%, and group 4 14%.
Control group displayed the most severe gross and microscopic lesions in the bursa of Fabricius, whereas the vaccinated groups showed reduced pathology.
Group 1 demonstrated the greatest preservation of bursal and renal architecture, indicating the highest level of protection.

Abstract

The impact of the avian disease/virus (due to its acute clinical disease) on broiler production continues to be a significant viral challenge to global production and opens the door to potential industry-wide outbreak due to its association with high mortality and bursal degeneration and consequent immunosuppression. This study compared the relative protective efficacy of four commercially available infectious bursal disease vaccines for broiler chickens after a challenge from a local field isolate of IBDV. Clinical, mortality, gross pathologic, and histopathologic indicators were used to evaluate relative protection among vaccinated broiler groups. A total of 250 Ross 308 broiler chicks were divided into five groups (50 birds/group), with four groups receiving a different type of vaccine against Infectious Bursal Disease (IBD) and one group not receiving a vaccine at all. At 16 days of age, each of the four vaccinated groups was exposed orally to a previously verified field isolate of IBDV (IBDV virus), and the groups' response to the virus was evaluated according to clinical symptoms and signs, mortality, gross anatomical changes, and histopathological changes found in the bursa of Fabricius and in the kidneys of the birds. The vaccinated group had less severe clinical signs and lower mortality than the unvaccinated group. The unvaccinated control group experienced the highest mortality rate, 56%, while the vaccinated groups had lower mortalities via group 1 at 4%, group 2 at 12%, group 4 at 14%, and group 3 at 18%. The most severe lesions were found on both gross and microscopic examination of the bursa of Fabricius in the control group, while the vaccinated groups had various degrees of markedly reduced pathology. Group 1 had the least severe lesions and the greatest bursal and renal architecture preservation. To conclude, all tested commercial vaccines for Infectious bursal disease virus (IBDV) elicited varying levels of post-challenge protection; Group 1 produced the most significant overall level of protection under the experimental conditions assessed. Overall, vaccination resulted in reduced clinical severity, reduced mortality, and reduced tissue lesions.

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