Evaluation of Immune Status of the Chicken using Morphometry and Histology of the Bursa of Fabricius

The outbreaks of IBD (infectious bursal disease) are frequently observed among correctly vaccinated broiler flocks in Algerian Nord-East region. The present study aimed to search for the immunosuppression state as possible consequence of IBD. Our investigation focused on 17 broilers flocks whom one suffering from IBD. Total of 400 bursa Fabricius were collected from broiler chickens during the rearing period or at slaughtering. The parameters of the bursa Fabricius are evaluated: body weight ratio, index bursal, morphometric characteristics and the histopathological observations. The results obtained show that the weight and diameter of bursa Fabricius are not proportional to the age and weight of chickens. The weight and size of the bursa Fabricius were found lower than the accepted standards. According to the evaluation system in effect, 58 % of examined chickens belong to the poor category and 29 % to the excellent category. Such results indicate bursa atrophy and confirm state of immunosuppression which was suspected because of poor performances recorded in some broiler flocks. In conclusion, the bursa characteristics (body weight ratio, morphometric and histopathological studies) are practical and not expensive tools for any field investigation to evaluate the immune status of broilers.