Body weight suppression in broilers naturally infected with avian leukosisvirus subgroup J

Broiler progeny were hatched from avian leukosis virus (ALV)-negative and A LV subgroup J (ALV-J)-positive breeders. ALV-J infection in progeny was ide ntified by p27 antigen capture enzyme-linked immunosorbent assay and revers e transcripcase-polymerase chain reaction specific for ALV-J performed on s erum or plasma samples obtained at hatch. Hatch weights did not differ betw een ALV-negative broilers and ALV-J-positive broilers. Body weights of ALV- J-positive broilers were 64.4% of those of ALV-negative broilers ac 1 wk of age. At 8 wk of age, weights of broilers with congenital ALV-J infection w ere still only 63.8% of chose of ALV-negative broilers. No other concurrent pathogen was detected in either group of broilers. These findings indicate that congenital ALV-J infection is associated with significant weight supp ression in broilers in the absence of other pathogens.