Immune response in weaning pigs after vaccination with two kinds of food and mouth disease vaccine: 6PD50 and 3PD50

Abstract

FMD vaccines are classified into: Standard potency FMD vaccine (3PD50) and high immune response vaccine (6PD50). The high immune response vaccine (6PD50) can improve the protective effect against other FMD virus strains with different topotypes. Realtime RT-PCR technique is the standard technique, commonly used in testing and diagnosing FMD. Based on the quantitative principle of realtime RT-PCR technique, the study analyzed the Ct index of realtime RT-PCR testing results for two popular commercial FMD vaccines at present in Viet Nam, such as: 6PD50 and 3PD50 vaccines. The 6PD50 vaccine had a significantly (P<0.05) lower Ct index compared to that of the 3PD50 vaccine. However, after the first vaccine injection with
either 6PD50 or 3PD50 FMD vaccine for the post weaning piglets, a very low percentage of pigs (32.5% and 40.0%) induced specific antibodies against FMD virus for both 6PD50 and 3PD50 FMD vaccines, respectively. A high maternal antibody could interfere to the efficacy of immune response after the first FMD vaccine injection for the post-weaning piglets. Both vaccines only induced immune response in pigs for protecting at a level of more than 70% after second vaccine injection in 4 weeks interval between the first and second vaccine injection, with 92% of piglets were injected with 6PD50 vaccine and 75% of piglets were injected with 3PD50 vaccine.