Evaluation of the Efficacy of a Modified Live Escherichia coli Vaccine in Commercial Laying Hens Against Field Challenges at 23 or 44 Weeks of Age

• Main Authors: Untari, Tri, Betty, Yuriko, ChoewKong, Mah, Artanto, Sidna
• Format: Article PeerReviewed
• Language: English
• Published: World Veterinary Poultry Association 2019
• Subjects: Veterinary Sciences
• Online Access: https://repository.ugm.ac.id/277211/1/prosiding_WVPAC%20full-pages-1-3%2C6%2C15%2C26%2C207-208%2C488.pdf; https://repository.ugm.ac.id/277211/; http://wvpac2019.com
• Institution: Universitas Gadjah Mada

In Indonesia, colibacillosis outbreaks in commercial layer flocks characterized by acute mortality and suboptimal egg production are still common. The aim of this study with duration of 46 weeks was to evaluate the protective effects of a modified live E. coli vaccine (Poulvac® E.coli) in laying hens against two common serotype of avian pathogenic E. coli (APEC), namely O78 andO2 orlocally known as S strain. A total of 180 Isa Brown chicks raised under field condition were divided into two groups (unvaccinated controls, vaccinated twice at 10 days and 12 weeks of age, respectively). All birds were challenged with either a homologous E. coli strain (O78) or a heterologous challenge strain (S / O2) through intra-tracheal route (>109 mean CFU/dose). The challenge took place at either23or44weeksofagetomimic themost common periods of APEC infection. Efficacy was determined based on a reduction of APEC-associated lesions and mortality, and higher cumulative number of eggs produced per hen housed compared to the challenged controls. Thisstudy showed thediseasemanifestations and mortality were pronounced in the unvaccinated controls. Poulvac® E. coli has been demonstrated to provide 95%and97%protection againstO78 challenge at 23 and 44 weeks of age; 87% and 89% protection against a heterologous E. coli S/O2 strain challenge at two respective periods. The vaccinated layers yielded 11 more cumulative numbers of eggs per hen housed than the unvaccinated controls.Differencesin eggshell color and individual egg weight were also observed in the study.