TY - JOUR

T1 - Protective potential of an autogenous vaccine in an aerogenous model of escherichia coli infection in broiler breeders

AU - Kromann, Sofie

AU - Olsen, Rikke Heidemann

AU - Bojesen, Anders Miki

AU - Jensen, Henrik Elvang

AU - Thøfner, Ida

N1 - Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

PY - 2021

Y1 - 2021

N2 - In poultry, Escherichia coli is a common cause of high-cost infections. Consequently, au-togenous vaccines are often used despite limited and conflicting evidence on their effectiveness have been presented. The present study aimed to investigate the efficacy of a commonly used autogenous vaccine, previously deemed ineffective, in an aerosol model of colibacillosis. Methods: Broiler breeders (n = 47) were randomly allocated to one of four groups (vaccinated and unvaccinated birds receiving an autogenous vaccine or sterile saline intramuscularly) and challenged with either aerosolised E. coli or vehicle at 29 weeks of age. Two days following inoculation, the birds were euthanised, thoroughly necropsied, and samples for bacteriology and histopathology were collected. Results: Vaccinated birds had a significantly lower bacteriology score compared to the unvaccinated group challenged with E. coli (p < 0.01) and a lower overall air sac lesion score (p < 0.05). Overall lung and spleen lesion scores only differed significantly between the unvaccinated E. coli challenged group compared to the vehicle inoculated groups. The overall gross pathology score was 2.8 and 1.95 in the unvaccinated and vaccinated E. coli challenge groups, respectively, whereas the vaccinated vehicle group had a score of 0.9 and the unvaccinated vehicle group a score of 1. Conclusions: A protective effect of an autogenous vaccine was found utilising an aerogenous model of colibacillosis through multiple methods of evaluation. The findings encourage the continued use of autogenous vaccines and underlines the necessity of discriminative experimental models with high predictive validity when evaluating vaccine interventions.

AB - In poultry, Escherichia coli is a common cause of high-cost infections. Consequently, au-togenous vaccines are often used despite limited and conflicting evidence on their effectiveness have been presented. The present study aimed to investigate the efficacy of a commonly used autogenous vaccine, previously deemed ineffective, in an aerosol model of colibacillosis. Methods: Broiler breeders (n = 47) were randomly allocated to one of four groups (vaccinated and unvaccinated birds receiving an autogenous vaccine or sterile saline intramuscularly) and challenged with either aerosolised E. coli or vehicle at 29 weeks of age. Two days following inoculation, the birds were euthanised, thoroughly necropsied, and samples for bacteriology and histopathology were collected. Results: Vaccinated birds had a significantly lower bacteriology score compared to the unvaccinated group challenged with E. coli (p < 0.01) and a lower overall air sac lesion score (p < 0.05). Overall lung and spleen lesion scores only differed significantly between the unvaccinated E. coli challenged group compared to the vehicle inoculated groups. The overall gross pathology score was 2.8 and 1.95 in the unvaccinated and vaccinated E. coli challenge groups, respectively, whereas the vaccinated vehicle group had a score of 0.9 and the unvaccinated vehicle group a score of 1. Conclusions: A protective effect of an autogenous vaccine was found utilising an aerogenous model of colibacillosis through multiple methods of evaluation. The findings encourage the continued use of autogenous vaccines and underlines the necessity of discriminative experimental models with high predictive validity when evaluating vaccine interventions.

KW - APEC

KW - Bacterin vaccine

KW - Challenge study

KW - Colibacillosis

KW - Disease prevention

KW - Poultry disease

U2 - 10.3390/vaccines9111233

DO - 10.3390/vaccines9111233

M3 - Journal article

C2 - 34835164

AN - SCOPUS:85118199237

VL - 9

JO - Vaccines

JF - Vaccines

SN - 2076-393X

IS - 11

M1 - 1233

ER -