Immunogenicity of a commercial Salmonella enteritidis vaccine in layer birds

Abstract

Background: The aged birds are known to induce good immunity against Salmonella enteritidisas compared to young. To judge this hypothesis layer birds at 42 and 49 days old were vaccinated with AVI Pro®109SE4 vaccine and immune response in terms of antibody titers was measured.

Methods: A composition of antibody production in vaccinated chicken was performed following a usual vaccination schedule with a newly suggested vaccination schedule. To study the immunogenicity of vaccine a total of 15 chickenswere divided into three groups. Each group comprised of 5 layer chicken. Chicken in group A and B were vaccinated with AVI Pro®109SE4 vaccine with a dose of 0.5ml/bird through SC route. Primary vaccination was performed at 42 days and 49 days of age respectively and booster vaccination was given at 72 days and 79 days of age respectively. Blood samples were collected to obtain sera from each chicken at every 7 days interval up to 93 days post vaccination for the determination of antibody titer using microplate agglutination test.

Results: Highest mean antibody titers were recorded as179.20±70.11and 307.20±114.49 in birds of group A and B respectively. The highest mean antibody titer was recorded as 307.20±114.49 in chicken at 21 days post vaccination with AVI Pro®109SE4 vaccine using newly suggested schedule as compared to usual schedule of vaccination.

Conclusions: Primary vaccination at birds at 49 days (newly planned vaccination schedule) of age induced better immune response as compared to birds vaccinated at 42 days of age.