Abstract
This study was carried out at the farm of the Agricultural Institute techniques located in Gheran, using two hundred and forty Ross broiler chicks which were divided into four groups (500, 1000, 1500 and 0 ppm in the water ) for five days at the 3rd week of age. The statistical model includes the effect of oxytetracycline. The results of analysis of variance showed that the levels of antibiotic had no significant effect (p>0.05) on all investigated traits. The live weight ranged from 2048 to 2141.50 gm at the end of the 6th week, the body weight gain ranged from 366.25 to 570.00 gm.w-1. It was concluded that oxytetracycline supplementation had no effect on the traits of the broiler performance, but there were no mortalities or infected cases recorded after treatment in all groups.