Abstract
Avian leukosis is caused by various avian retroviruses which induce a variety of benign and malignant neoplasm in chickens with subsequent economic losses to the poultry industry. A survey of avian leukosis in hatchable eggs of apparently healthy chickens was carried out in an attempt to determine the prevalence of avian leukosis virus (ALV) in exotic breeders and free-range indigenous chickens in Oyo state. A total of 188 (76 exotic breeders and 112 free-range chickens) albumen of hatchable eggs were obtained from 3 different commercial breeder farms and 12 free-range indigenous chicken farms. Eggs were tested by an antigen capture enzyme-linked immunosorbent assay (ELISA) technique. Eleven out of the 76 albumen obtained from eggs of exotic breeders tested positive to ALV antigen which represents 14.5% while 37 of the 112 albumen from free-range indigenous eggs were confirmed as positive representing 33%. Overall prevalence rate of 25% was recorded for all eggs sampled with the highest prevalence of ALV antigen detected in free-range indigenous chickens than the exotic chickens. The results emphasizes the control of the Avian Leukosis transmission by including both exotic and free-range indigenous birds as wells as the use of ALV free eggs in hatcheries