Abstract: To investigate effects of ALV-J infection on production performance and immune responses in Wuhua chicken, excellent local breed in Anhui province, the antibody-positive and antibody-negative chickens at laying peak were studied in 18 weeks, on the basis of ALV-J serologic survey. The results showed that antibody-positive Wuhua chicken (infected or had been infected) had not significant increase in morbidity and mortality. And the serum antibody level to New Castle disease virus(NDV), H5 and H9 avian influenza virus didn't show obviously drop. However, to a certain extent, the effects on the egg-laying rates and the average egg weight of the chickens were observed. The laying rate and average egg weight of control group were 56% and 0.055 kg, while the positive group were 53.37% and 0.051 kg. Feed-to-egg ratio of the negative and positive groups were 3.49 and 3.92, respectively. Although ALV-J infection in Wuhua chickens didn't cause significant pathogenesis, death, and immune suppression, but the effects on the production performance were obvious. Therefore we should attach great importance to original breeding, and purification and preventive measurements should be carried out early.

Key words: Wuhua chicken; avian leukosis subgroup-J; production performance; immune performance