Effect of experimental aflatoxicosis and E. coli infection on humoral and cell mediated immune response in broiler chickens

The present paper describes the immunosuppressive effect of aflatoxin feeding and E. coli infection in young chicks using RDF as an indicator of humoral immune response and DNCB to assess the cell mediated immune response. A total of 240 unvaccinated day-old broiler chicks, were divided into four groups of 60 chickens each. Group ‘A’ was fed with aflatoxin @1 ppm level from 7th day to 7th week of age. Group ‘B’ chicks were infected with E. coli (strain 02) at 14th day of age through oral route with sublethal dose having 1 × 10⁶ cfu/ml. The combined group ‘AB’ was given aflatoxin and simultaneously infected with E. coli. Group ‘C’ served as control. A lowered RD-HI antibody titres in all the groups A, B and AB suggest a mild suppression of humoral immune response. The CMI response was also affected in chicks of group A and AB as evidenced by decreased mean skin thickness and DTH reaction induced by DNCB at the challenge site.