Humoral immune response to different lasota strain vaccines in chicken

Seventy-six broiler chicks were divided into six groups. Among that five groups namely group A, B, D, E and F were given LaSota vaccine code-A, B, D, E. (Clone 30 selected strain vaccine) and F (lab adapted vaccine), respectively on 7th day. Group C was kept as unvaccinated control. Among these five vaccines, the HA (haemagglutination) titres of code-B was below 640 while remaining all had more than 640 titre. The birds from each group were bled at weekly intervals to 49 days to assess humoral immune response and five birds from each group were challenged on 21 st day after vaccination. On the basis of HI (Haemagglutination-inhibition) and challenge infection, vaccine code A and B showed poor performance, while vaccine code-D, E and F resulted in adequate inul1une response to the challenge infection.