Abstract: Based on the severe situation of avian leukosis virus infection in local chicken breeds, in this study, four generationws of four Jianghan chicken populations were tested and purified for avian leukemia. The results showed that different samples were collected from different developmental stages and different sex groups for four consecutive years for detection and purification, the average positive rate of ALV p27 antigen in cock semen before pure breeding （40-45 weeks old） decreased from 30.54% in 2015 to 0.23% in 2018. The average positive rate of ALV p27 antigen in hen egg white samples decreased from 26.98% in 2015 to 0.05% in 2018. It can be seen that the detection of ALV p27 antigen at three time points before the end of brooding, the start of production and pure breeding can eliminate positive individuals, and the purification effect of avian leukemia is obvious, which can provide reference for the purification of avian leukemia in other places.

Key words: Jianghan chicken, avian leukosis, p27 antigen, purification