Evaluation of immune response of broiler chicks against Salmonella Gallinarum infection

The present study was performed to evaluate the pattern of immune response of susceptible broiler chicks after Salmonella Gallinarum infection. Experimentally infected birds with positive strains of Salmonella Gallinarum which remained alive were used. Immune responses in them were studied on day 14th, 21st and 28th days post-infection. Six (6) control chicks were also examined. Total lymphocyte count: The method described by Chauhan and Verma (1983) was used. Peripheral blood was collected from the wing vein of 8 recovered and 6 control chicks. Two ml of diluted blood was layered slowly over 1 ml of Ficoll-paque and kept in a glass tube of 8 mm diameter. The tubes were centrifuged at 400 g for 30 min in a refrigerated centrifuge. The lymphocytes and monocytes formed a white layer, which was separated completely with a Pasteur pipette and the volume of suspended fluid was measured. The number of cells per unit volume of the suspension was counted with haemocytometer and was expressed as lymphocyte count per microlitre (μl) of blood. The counts from recovered and control chicks were made on 14th, 21st and 28th days post-infection.