| As sex linked K is widely used in chicken production, the phenomenon that the late feathering chicken are both more sensitive to avian leucosis and quickly more difficult to purify than fast feather chicken was observed. Slow feathering K gene carrying endogenous avian leukemia virus ev21 may cause different immune effect to avian leukemia virus(ALV) infection. In this study, we intend to explore the innate immunity as the starting point, trying to investiage the difference of the innate immune response to ALV infection between the late feathering chicken and the early feathering chicken. We first observed the avian leukosis(AL) status of fast and slow feathering chicken in the three farms of Guangdong Province, with the detecting of viremia feather chicken inoculated with ALV-J and detecting of the expression of innate immune molecule interferon(IFN alpha, IFN beta and gamma, interleukin(IL10, IL12 and IL18), tumor necrosis factor(TNF- alpha) and antiviral genes(Mx, PKR and OAS). The slow feathering chicken infection rate of AL was significantly higher than the fast feathering chicken infection rate(P<0.0001). All the slow feathering chicks Dwarf White and the Dwarf Partridge strains carry ev21, but all the fast feathering chicks of the Dwarf Yellow and Dwarf strains don’t. Meanwhile, the two exogenous ALV-J was isolated and named as M180 and K243, and their homology is to 96%.On the other hand, the strain M180 isolated from the slow feathering chicken was not homologous with the endogenous avian leukemia virus ev21. SCAU-HN06 strains are increased rapidly in the amount of replication which happened 6d earlier in the slow feathering chickens than in early feathering chicken. The expression of interferon and antiviral genes showed the following rules: 4d after the rapidly increase of virus replication, slow feathering group showed differential expression of interferon, interleukin and TNF- alpha with the fast feathering group. In vivo viral replication, the expression of the above genes was increased in the same time or as early as viral replication increased, and protein levels were only significantly different in the fast feathering group. The antiviral genes PKR and OAS of the fast feathering group affect significantly innate immunity than that of the slow feathering group, and the Mx gene of both all feathering chicken inhibits the replication of the virus. In summary, expression of each innate immune factors is later in the slow feathering chickens than in the fast feathering chicken, and the intensity is less in the slow feathering chickens than in the fast feathering chicken. The ability of the slow feathering chicken against ALV-J innate immune response is weaker than the fast feathering chicken. It provides a theoretical basis to further understand molecular genetic mechanisms of ALV infection innate immune response of early feathering chicken and slow feather chicken and it is advantaged to cultivate a good fast and slow feathering chicken with resistance performance leading fast and slow feathering lines better applying to breeding. |
