effect of chicory plant (cichorium intybus l.) extract on performance and blood parameters in broilers exposed to heat stress with emphasis on antibacterial properties

the antimicrobial effectiveness of different extracts of chicory (cichorium intybus l.) plant including methanolic, ethylic acetate, chloroformic, and aqueous extracts was evaluated by disk diffusion method. the ethylic acetate extract showed higher antibacterial activity against e. coli compared with others. then, effects of different levels of ethylic acetate extract on growth performance and blood parameters of broilers subjected to high ambient temperature was investigated. the treatments were; a control diet, 3 levels of the chicory ethylic acetate extract (150, 250, and 350 mg/kg feed) and one level of probiotic with 4 replicates of 20 broiler chicks in each. the temperature was increased to 35°c with 50% relative humidity for 5 h daily, starting from 11 d until 42 d of the experimental period. results indicated that inclusion chicory extract at 350 mg/kg and probiotic increased body weight gain and improved feed conversion ratio during 11-24 d and 0-42 d (p < 0.05). there were no significant differences in feed intake of broilers treated with chicory extract and probiotic compared with control. the serum concentrations of triglyceride and very low-density lipoprotein significantly decreased in birds received chicory extract at the levels of 250 and 350 mg/kg feed compared with the other treatments (p < 0.05).  no significant difference was observed between treated groups and control for serum high-density lipoprotein and low-density lipoprotein concentrations. it seems that dietary supplementation of chicory ethylic acetate extract at levels higher than 250 mg/kg feed has growth promoting effect which can result in improving growth performance and decreasing blood lipids of broilers exposed to heat stress condition.