Immunopathology of chlorpyriphos and T-2 toxin in broiler chicken

A total of 48 commercial broiler chicks were divided in to four groups of 12 birds each. Group I was kept as untreated control while Group II birds were given 45 ppm chlorpyriphos, an organophosphorus compound, Group III birds were fed 0.5 ppm T-2 toxin, a mycotoxin and Group IV birds 45 ppm chlorpyriphos + 0.5 ppm T-2 toxin in feed for 4 weeks from day of hatch. The birds were vaccinated with Newcastle disease virus vaccine F on day 5 intraocularly and HI titre against NDV was estimated on 14 and 28 days of age. Spleen was collected on 28^th day of age to assess the cell mediated immunity by lymphocyte proliferation assay. The mean ± SE HI titres were 2.88 ± 0.14, 2.18 ± 0.21, 2.15 ± 0.14 and 1.90 ± 0.12; stimulation index 1.8691 ± 0.0476, 1.1235 ± 0.0229, 1.3647 ± 0.0238 and 1.0594 ± 0.0579 in control, chlorpyriphos, T-2 and chlorpyriphos + T-2 groups respectively. Thus, chlorpyriphos and T-2 were found to exert immunosuppressive effects in commercial broiler chicken at 45 and 0.5 ppm, respectively.