Some studies on viral causes of retarded growth in broilers

ln this study:1- Isolation of IBDV from chickens suffered from poor growthwhich ranged from 33.1- 47.1 % through inoculation ofembrynated chicken eggs via CAM at age 11 day.2- Isolation of Reo virus from chickens. showed retarded growthwhich ranged from 9.9- 13.2% through inoculation ofembroynated chicken eggs via allentioc cavity at age 9day3- Experimental infection of chickens with IBDVS, and Reo.virus revealed advarce effect on body performance4- Histopathologically bursa fabricius after IBD virus infectionshowed lymphoid necrosis practically in the medullary zone andreplaced by eosinophlic necrotic debris or become atrophied andshrunken together with vesicle formation in its• coveringepithelium. Lymphocytes had pyknosis and karyorrhexis, of theirnuclei with hyperplasia of reticulo endothelial cells. Intenseheterephil in inter follicular tissues and within the cavities ofsome cystic follicles beside fibroplasia were common. Thesplenic white pulps revealed intense lymphoid depletion andnecrosis particularly in the germinal follicles and periarteriolarlymphoid sheath.