Comparing Viremia And Antibody Response Dynamics In SPF Chickens Inoculated With Avian Leukosis Virus Subgroup J In Different Routes And Ages

Avian Leukosis Virus Subgroup J (ALV-J) is a new kind of retrovirus which infects broilers, ALV-J was first reported as a new subgroup of ALV by Payne in 1991. It seriously influnenced the development of broilers industry. We have consistently maintained that ALV-J infect mainly broilers . It induced avian myelcytomatosis (ML) in broilers. Although egg-type chickens used to infect, but few cause tumor. In recent years there are reports about egg-type chickens infected with ALV-J.It shows that ALV-J infection has spreaded from broilers to egg-type chikens. If we do not take timely measures, that ALV-J infection will seriously influnenced the development of egg-type chickens industry.Viremia, virus shedding and antibody response were successive measured after inoculation with ALV-J strain HN0001 intraperitoneally ,orally or in contact in SPF chickens at 1 day and 49 days. 50 SPF chickens are divided into 4 groups randomly at 1-day-old: the first group,10 SPF chickens, were inoculated intraperitoneally with ALV-J;the second group, 10 SPF chickens, were were inoculated orally with ALV-J;the third group ,10 SPF chickens, were in contact with the first and the second group; the fourth group,20 SPF chickens, were inoculated intraperitoneally with ALV-J and REV(1:1).We continuous detection the dynamic variety of viremia ,antibody and antigen in 26 weeks after infection. 7 SPF chickens are divided into 3 groups at 49 days: the fifth group ,3 SPF chickens, were inoculated intramuscular with ALV-J; the sixth group, 3 SPF chickens, were inoculated orally with ALV-J; the seventh group ,1 SPF chicken, were in contact with the fifth and the sixth group. We continuous detect the dynamic variety of viremia ,antibody and antigen in 19 weeks after inoculation. We still compared dynamic variety of antibody ,antigen and viremia in different days SPF chickens inoculated with ALV-J. Chickens with maternal antibody and Chickens without maternal antibody were inoculated with ALV-J. We detected the dynamic variety of viremia in 2w after inoculation. To understand dynamic variety of viremia, virus shedding and antibody responses in chickens inoculated with avian leukosis vrius subgroup J (ALV-J) and provide essential epidemiological data for prevention and eradicationo of ALV-J infection.1. The dynamic variety of viremia and antiboty responses were very different in chickens inoculated with ALV-J at different ages. Inoculation with ALV-J at 1-day-old easily induced immune tolerence, chickens inoculated demonstrated persistant viremia or p27-shedding, but no antibody reactions. Chickens inoculated with ALV-J at 49-day-old, antibody could detected 1w after inoculation, but no viremia and p27-shedding were detected. Viremia and p27 in cloaca swabs started to be detected from 2w after inoculation with ALV-J at 1-day-old . In the group inoculated intraperitoneally with ALV-J, 71% (5/7) continuously demonstrated viremia and p27-shedding. Viremia and virus shedding lasted for at least 45 w in 3 chickens. Among them, only 1 chicken showed transient antibody reaction at 16-week-old, another 2 were in tolerant viremia without any antibody reactions. In chickens intraperitoneally inoculated with ALV-J at 49-day-old , neither viremia nor p27-shedding were detected in 5 separate testing during 19w after inoculation, but antibody reaction started to be detected 1w after inoculation. In the orally inoculated chickens or the contacted control chicken, all samples were negative in vriremia, p27-shedding and antibody reactions.2. Inoculation routes significantly influenced the dynamic variety of ALV-J inoculation, intraperitoneally injection induced higher viremia levels and increased percentages with tolerant viremia when compared to oral inoculation.In the group inoculated orally with ALV-J , 11% (1/9) demonstrated persistant viremia and p27-shedding but no antibody response, 44% (4/9) showed transient viremia or p27-shedding, and then antibody responses from 8-week-old. No control bird kept in contact with inoculated birds in the same isolators demonstrated viremia or p27-shedding, and also no antibody responses. It indicated there was no horizontal infection.3. Maternal antibodies can prevent effectively the incidence of viremia in chickens inoculated with ALV-J. Inoculated with ALV-J, the chickens with maternal antibodies show no viremia in the two weeks ; but the chickens without maternal antibody shown obvious viremia.