Wird die Wirksamkeit der Immunisierung von Küken mit Salmonella-Lebendimpfstoffen durch maternale Antikörper beeinflusst?

In the progeny of breeder birds which had been vaccinated with live Salmonella Typhimurium and inactivated Salmonella Enteritidis vaccines, the caecal and systemic colonisation by a live Salmonella Enteritidis and a live Salmonella Typhimurium vaccine was studied. The efficacy of the oral immunisation of chicks from vaccinated and non-vaccinated breeders with a live Salmonella Enteritidis vaccine on day 1 of age was studied by an experimental challenge with Salmonella Enteriticlis on day 30 of age. Antibody production of isotypes IgG, IgA and IgM was determined in sera and jejunum of the birds. Vaccination of parent birds resulted in an increase of the antibody concentration in sera and jejunum of the chicks. Own antibody production after administration of the live Salmonella vaccine to the day-old chicks was not detected until day 21 of life. Compared to controls, the number of vaccine organisms in the caeca of the progeny of vaccinated breeder birds was reduced by 0.5-1.5 log(10) units. The reduction of the Salmonella Enteritidis vaccine was more pronounced than that of the Salmonella Typhimurium vaccine. However, the reduced colonisation by the live Salmonella vaccine strain did not impair the efficacy of the immunisation of the chicks. To ensure efficacy of the active oral immunisation of chicks from vaccinated parent birds with attenuated live Salmonella vaccines also in case where amounts of maternally transferred antibodies are even higher, it should be guaranteed that chicks take in via drinking water the recommended dose of the vaccine strain. In this connection, factors like the low intake of drinking water by very young chicks, the concentration of the vaccine organisms in the water and the survival of the vaccine should also be considered