Protective Efficacy of Live LaSota Strain Newcastle Disease Virus Vaccine in Layer-type Chickens

Abstract

The purpose of this study was to evaluate the protective efficacy of live LaSota strain Newcastle disease virus (NDV) vaccine administered with different routes against a NDV challenge in layer-type chickens. Fifty male layer-type chickens were divided into 3 groups. There were 20 chickens/group for the vaccinated groups (Groups 1 and 2) and 10 chickens for the non-vaccinated control group (Group 3). Chickens in Groups 1 and 2 received the vaccine individually at 4 weeks old by eye drop and oral drop, respectively. All chickens received NDV challenge individually by oral drop at 7 weeks old or 3 weeks post-vaccination (PV). At 3 weeks PV, the results reveal that the haemagglutination-inhibition (HI) titer of the vaccinated Group 1 was significantly higher than that of the vaccinated Group 2 (p<0.05) and they were significantly higher than that of the non-vaccinated Group 3 (p<0.05). The protection rate of the vaccinated Groups 1 and 2 were 100 and 60 percent, respectively. There was no protection in the non-vaccinated Group 3. The results of this study indicate that single vaccination with live LaSota strain NDV vaccine is adequate in protection against a NDV challenge in layer-type chickens if the chickens receive the appropriate route of vaccine administration.