comparison of the effects of propolis and virginia mycine on performance and immune response of broiler chicks

three hundred and sixty male day- old ross 308 broiler chicks were randomly assigned to four dietary treatments in order to evaluate the effect of propolis as growth promoter on the performance and the immune response of the broiler chicks to the nd vaccine. each treatment contained three replicates of 30 chicks. dietary treatments were as follow: a corn - soy meal diet (control diet).control diet + 3000 ppm (starter) and 2000 ppm (grower and finisher) propolis.control diet + 6000 ppm (starter) and 4000 ppm (grower and finisher) propolis. control diet + 100 ppm virginiamycine.the chick performance was evaluated by recording the body weight gain, feed intake, feed conservation ratio, and productive efficiency index at 21 and 42 days of age. prior to the administration of nd vaccine (day 17) and 10 days post-vaccination, the blood sample was taken for hi test. the chicks fed diet supplemented with virginiamycin showed higher bwg, fi, pei when compared with other treatments. however, those chick provided with dietary treatment 2 (3000 and 2000 ppm) had lower fcr. propolis had no effect on antibody titer against nd vaccine. in this experiment propolis don't act as an immunostimulant, but appeared to be promising a potential growth promoter.