Journal of Biological Sciences1727-30481812-5719Asian Network for Scientific Information10.3923/jbs.2003.1095.1100Rahat Ali M. Ashraf Syed Muzaffar Hussain Bukhari 122003312Present study was initiated to evaluate the effect of Tylosin and Zinc Bacitracin (at low level) on weight gain and immune response of vaccinated and non-vaccinated Broiler Chicks. For this purpose a 240-day-old chicks were divided into 3 groups, A (fed on Tylan Premix), B (fed on Albac) while C was non-medicated and non-vaccinated control group. These were further subdivided into two groups on the basis of vaccination against NDV. Results of this project revealed that low level feeding of Tylosin (Tylan Premix) and Zinc Bacitracin (Albac) did not interfere with development of the birds and their immune status.]]>Constantinescu, V., E. Onet, E. Suteu and N. Slavacoie,1981314650Farooq, M.U.,199445459461Harold, C.B., H.C. Ferrester, W.M. Lyeria, B.R. Velleca and J.D. Roberts,19751975Khalid, M.C.,19911991King, D.J.,198630724727Kobe, A.,19831983Kulkarni, V.B., A.N. Mulbagal, B.L. Parajape J.B. Khot and A.V. Manadec,197350235237Muneer, M.A., J.A. Newman, I.O. Farah and S.M. Goyal,1988144288301Naqvi, S., A. Sahin, G. Wagner and J. William,19844514251429Onifade, A.A. and G.M. Babatunde,199764337342Rizvi, A.R. and A.R. Shakoori,1992245358Saeed, Z.A., A.R. Shabbir and M. Ajmal,198512224Jianzhong, S., X. Xilling, Z. Balei, S.X. Xiao and B.L. Zhu,199521100103Steel, R.D.G. and J.H. Torrie, 19823rd Edn.,