The present project was designed to investigate the effect of organic and inorganic selenium with and without combination of vitamin E on the immune system of broiler chickens. For this purpose 130 (one day old) broiler chicks were taken and divided into three different groups i.e. A, B and C. Group A and B consisted of 60 chicks each while group C consisted of 10 chicks. Group A was further sub divided into six sub groups Al, A2, A3, A4, A5 and A6 which were fed on organic selenium at the dose rate of 0.25, 0.25, 0.5, 0.5, 1.0 and 1.0 mg/kg and vitamin E at the dose rate of 0, 200, 0, 200, 0 and 200 lU/kg respectively. Group B was further sub divided into six sub groups Bi, B2, B3, B4, B5 and B6, which were fed on inorganic selenium at the dose rate of 0.25, 0.25, 0.5, 0.5, 1.0 and 1.0 mg/kg and vitamin E at the dose rate of 0, 200, 0, 200, 0 and 200 lU/kg respectiyely. Group C received no selenium and vitamin E and served as control group.

Immunomodulatory effects of selenium and vitamin E were evaluated by measuring haemagglutination inhibition antibody titre against Newcastle Disease Virus (NDV). Pathological examination of lymphoid organs, lymphoid organs weight/body weight ratio, growth traits and economy were also studied. Highest immune response was observed in sub groups A6 and B6 as compared to control group that had the lowest immune response. There was no effect of organic and inorganic selenium with and without combination of vitamin E on the pathology of bursa of Fabricius, spleen and thymus as compared to control group. Lymphoid organs weight/body weight ratio was also highest in sub groups A6 and B6 while lowest in control group. Body weight gain was highest in sub groups A6 and B6 as compared to control group. Feed Conversion Ratio (FCR) was also best in sub groups A6 and B6 as compared to control group.

To summarize, the immunomodulatory effects of supplementation of organic selenium with and without combination of vitamin E were better than supplementation of inorganic selenium with and without combination of vitamin E. Moreover, the effects of organic or inorganic selenium with combination of vitamin E were better than the supplementation of organic or inorganic selenium without combination of vitamin E. It can be concluded that feeding of organic/inorganic selenium with and without combination of vitamin E is not only beneficial for health status of birds but also economical and cost effective for the farmers.