Impact of Escherichia coli vaccine on parent stock mortality, first week mortality of broilers and population diversity of E. coli in vaccinated flocks

TY - JOUR

T1 - Impact of Escherichia coli vaccine on parent stock mortality, first week mortality of broilers and population diversity of E. coli in vaccinated flocks

AU - Olsen, Rikke Heidemann

AU - Christensen, Henrik

AU - Ewers, C.

AU - Bisgaard, Magne

PY - 2010

Y1 - 2010

N2 - In the present investigation 20,000 broiler parents were vaccinated during rearing with Nobilis Escherichia coli vaccine and were placed in two out of four identical houses, with the remaining two houses on the same farm accommodating 20,000 unvaccinated control birds. During the production period a total of 335 dead birds (including 171 vaccinated and 164 control birds) randomly selected from the four houses were subjected to post-mortem examination. Although the overall mortality between the vaccinated and control flocks did not differ, mortality due to E. coli infections made up only 8.2% in vaccinated birds compared with 24.6% in unvaccinated birds. All E. coli isolates recovered from internal organs were assigned to the same phylogenetic group (B2), but a major genetic diversity was outlined by multilocus sequence typing. Only a single isolate was demonstrated to harbour a gene encoding the P-fimbriae variant F11, a key component of the Nobilis vaccine. Significant differences in average first week mortality, calculated average weight at 38 days and food conversion rate among broiler flocks originating from vaccinated and control birds, respectively, were not found. Further investigations are needed to explain the protection observed and the impact on the genetic diversity of E. coli.

AB - In the present investigation 20,000 broiler parents were vaccinated during rearing with Nobilis Escherichia coli vaccine and were placed in two out of four identical houses, with the remaining two houses on the same farm accommodating 20,000 unvaccinated control birds. During the production period a total of 335 dead birds (including 171 vaccinated and 164 control birds) randomly selected from the four houses were subjected to post-mortem examination. Although the overall mortality between the vaccinated and control flocks did not differ, mortality due to E. coli infections made up only 8.2% in vaccinated birds compared with 24.6% in unvaccinated birds. All E. coli isolates recovered from internal organs were assigned to the same phylogenetic group (B2), but a major genetic diversity was outlined by multilocus sequence typing. Only a single isolate was demonstrated to harbour a gene encoding the P-fimbriae variant F11, a key component of the Nobilis vaccine. Significant differences in average first week mortality, calculated average weight at 38 days and food conversion rate among broiler flocks originating from vaccinated and control birds, respectively, were not found. Further investigations are needed to explain the protection observed and the impact on the genetic diversity of E. coli.

U2 - 10.1080/03079457.2010.495744

DO - 10.1080/03079457.2010.495744

M3 - Journal article

C2 - 20706885

SN - 0307-9457

VL - 39

SP - 287

EP - 295

JO - Avian Pathology

JF - Avian Pathology

IS - 4

ER -