Studies On Safety And Antibody Response In Meat-type Breeders Inoculated With An Attenuated Reticuloendotheliosis Virus

Two studies were done for valdate the an attenuated reticuloendotheliosis virus,strain REV-C99,in safty and antibody response and the antibody's effect.Test 1:A group of meat-type parent breeders in a commercial farm was pre-infected with an attenuated reticuloendotheliosis virus(REV),and its influence on growth,egg production and immune reactions to other inactivated vaccines was studied.At the same time,antibody to REV in chicken sera at different intervals after vaccination was measured and vertical transmission of the virus was checked in chicks from vaccinated breeders.The results indicated that vaccination of 18-week-old parent breeders with the attenuated REV did not give any negative influence on growth rate,egg-productivity,egg fertility and hatchability.Antibody titers against Newcastle disease virus(NDV) and avian influenza virus(AIV) was also not affected after re-vaccination with inactivated vaccines to NDV,AIV-H5 or H9 in REV vaccinated birds compare to the control.No vertical transmission of REV was detected in eggs or their REV-vaccinated breeders.REV-antibody in breeder sera could last at least for 280 days post vaccination.And the maternal antibody to REV provided by vaccination of breeders lasted at least for 7 days.Test 2:This study is an effect observation of the REV live vaccine's semi-works production in a scale field trial during February to December 2006.Through the trial,the details about mortality,production performance and hatchery result were recorded and analysed.This experiment is done in about 164 thousand birds of grandparent breeders at a big scale farm in Shandong provcine.The result show that no bad effect of REV semi-works production to the breeder's performance.When the antibody of REV was monitered after 10 dpi,it's 100%positive which can be foresee and this antibody can transmission to chicken through hatched eggs and into chicken's cri.system. Female's serum antibody of REV can keep all her life.The safty and antibody response of REV live vaccine was also authenticated.Conclusion:This Strain REV-C99 is valuable for vaccine.