effects of clove essential oil on growth performance, carcass characteristics and immune system in broiler chicken

in this experiment two hundreds one day old broiler chicks (ross 308) in 5 treatments and 4 replicates were used based a completely randomized design. experimental treatments were: control treatment (basal diet), clove essential oil (ceo) at different levels (100, 300 and 500 mg/kg + basal diet) and 600 mg/kg flavophospholipol antibiotics (fpa) + basal diet. results showed that feed intake was negatively affected by increasing ceo as the lowest and the highest feed intake was observed when the broilers received 500 mg/kg ceo and antibiotic (p<0.05) respectively. also, the highest weight gain at antibiotic treatment and at the level of 300 mg/ kg ceo and the lowest of weight gain was observed at control treatment and at the level of 500 mg/kg ceo (p<0.01). the best and the worst feed conversion rate was observed at the level of 300 mg/kg ceo and control treatment (p<0.001) respectively. carcass and thigh proportional weights of broilers were increased at ceo oil and antibiotic treatments compared with control treatment (p<0.01). gastrointestinal and bursa of fabricius proportional weights of broilers were significantly decreased at ceo and antibiotic treatments compared with control treatment (p<0.05). none of white blood cell, red blood cell, heterophil, lymphocyte, hematocrit, hemoglobin and antibody titers was affected by dietary treatments. in this experiment, the best performance was observed at the level of 300 mg/kg ceo.