Inhibitory Effect of Transfer Factor on Avian Reticuloendotheliosis Virus Infection in Chicks

Reticuloendotheliosis virus (REV) has multiple transmission routes and can induce severe immunosuppression upon infection. Three application scenarios were set up to explore transfer factor's (TF's) potential in controlling REV. These scenarios involved using TF in chicks infected with REV during incubation, in 1-day-old chicks post-infection, and in chicks prior to REV infection. The application value of TF in controlling REV was evaluated based on various indices, including weight gain, organ development, and virus replication. The results all indicate that the use of TF could effectively alleviate the developmental delay, hepatomegaly, and thymic atrophy caused by REV infection through different routes, as well as significantly reduce the mortality rate. It could also effectively inhibit REV replication in vivo and cloacal virus shedding. Notably, TF had apparent advantages in inhibiting cloacal virus shedding through the egg in the chicks infected with REV. The functions of TF are dose-dependent, where increasing the dose or frequency of use is beneficial for enhancing its effect. This study observed the role of TF in controlling REV infection under different application scenarios, providing necessary auxiliary means to reduce the harm of REV infection.