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) To evaluate effects of various stress factors on immune response and growth performance of broiler chicks, a total of five experiments using 2000 broiler chicks were conducted. In each experiment, chicks were divided into five groups (A, B, C, D and E), and each group consisted of 80 day-old-chicks. In each experiment, the chicks were exposed to stress factors, such as temperature, stocking density, feed deprivation, water restriction and light. Each chick in groups A, B, C, and E was vaccinated against IBV, NDV, IBDV and HPSV, but chicks in group D were kept as unvaccinated controls. Blood samples from each group were collected on 36th day of age, at 18 hrs for determining TLC, DLC and H/L ratio. The antibody titers of chicks in different groups were analyzed using HI test at days 36th and 56th. The cellular response was analyzed by injecting PHA-P in the wattles of bird during post stress period. The effects of each stress on lymphoid organs were determined. The potential to resist virulent NDV challenge and effect of stress factors on body weight gains and FCR of chicks was also determined.

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Dr. Muhammad Yasser Mustafa Butt(Yasser Saleem Mustafa) earned Ph.D in Microbiology from the University of Veterinary and Animal Sciences. He passed his Matriculation from Govt Central Model High School and Intermediate from Government College University, Lahore, Pakistan. He published 30 Research articles in National and International Journals.

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