Evaluation of immunomodulatory activities of clove oil in broiler

The present study was planned to evaluate the immunomodulatory effects of clove(Syzygium aromaticum) oil in broiler. Total of 60 chicks were divided randomly to 5 groups. Group I served as control and given basal diet without clove oil and vitamin E and selenium. Group II served as standard control and given vitamin E and selenium containing proprietary product in water. Groups III, IV and V were given clove oil at the dose rate of 200, 400 and 800 mg/kg feed for 35 days, respectively. Cutaneous basophil hypersensitivity (CBH) response was carried out to assess the cell mediated immunity on 14^th day of age. Blood was collected on 7^th, 21^st and 35^th day of age and serum was separated to estimate antibody titers against Newcastle Disease Virus vaccine by haemagglutination inhibition (HI) test and biochemical parameters like serum total protein, serum albumin, serum globulin and albumin to globulin ratio (A/G). On 35^th day, thin blood smears were prepared to determine differential leucocyte counts microscopically. At the end of the experiment, birds were sacrificed for histopathological examinations. Chicks supplemented with clove oil at 200, 400 and 800 mg/kg feed and vitamin E & selenium showed significantly higher CBH response. Birds supplemented with clove oil at 200, 400 and 800 mg/kg feed and vitamin E & selenium showed significantly increased antibody titre as compared to control birds. The result indicates clove oil has beneficial effect in terms of augmenting the cell mediated as well as humoral immune response in broiler. Clove oil supplementation significantly increased the serum total protein, serum globulin and significantly decreased albumin to globulin ratio. It shows stimulatory effect of clove oil (200, 400 and 800 mg/kg) on humoral immune response in broiler birds. Birds supplemented with clove oil (400 and 800 mg/kg) in feed showed significantly decreased heterophil to lymphocyte ratio suggesting its beneficial effect on cell mediated immune response. Histopathological evaluation of bursa of fabricius and thymus showed lymphoid cell proliferation in birds supplemented with clove (400 and 800 mg/kg feed) suggesting immune-potentiating activity of clove oil. Result of the present study revealed that supplementation of clove oil at given doses in feed was possesses immunostimulant effects in broiler.