The continuous use of pesticide even in normal recommended doses may have deleterious effects on physiological function of various systems of the body which might range from lowered immunity reduced production performance. Pesticides like endosulfon mainly leads to imunosuppression and this property of pesticide is one of the important causes of vaccine failure and disease outbreak. The effect of endosulfan on humoral immune response in 66 two week old chicks was studied for a period of 2 months using “No Observable Adverse Effect Level” (NOAEL) dose (@ 30 ppm in feed). Chicks were divided into two groups (Group I & group II) and vaccinated with New Castle Disease vaccine. Group I served as control and group II birds were subjected to endosulfan treatment. B-lymphocyte blastogenesis assay using lipopolysaccharide as mitogen and ELISA were performed to assess Humoral immune response. There was significant reduction in specific antibody titers against ‘New Castle Disease’ vaccine and reduction in B lymphocyte blastogenesis was also significant in pesticide fed birds indicating immunosuppressive effect of endosulfan. The immunosuppressive action of insecticides is due to their detrimental action on lymphoid organs.
