The Influence of Vaccination of Broiler Chickens and Turkeys with Live E. coli Attenuated Vaccine on E. coli Population Properties and TRT Vaccination Efficacy

Colibacillosis is one of the major causes of economic losses in the poultry industry. Vaccination against E. coli is attracting increasing interest. The aim of the study was to evaluate the influence of vaccination with live, aroA gene-deleted vaccine on the structure and properties of field E. coli population and its potential impact on TRT vaccination efficacy in broiler chickens and turkeys. We performed three independent experiments on farms: (1) with antibiotic-free broiler chickens, (2) with conventional broiler chickens and (3) with broiler turkeys. In experiment 1, we have recorded an approx. 0–15% prevalence of multi-susceptible E. coli strains in the first production cycle. Starting from production cycle number two, after vaccination introduction, successive significant increases in E. coli susceptibility emerged, reaching 100% of strains at the end of production cycle 3. Increased E. coli susceptibility remained for three production cycles after vaccination withdrawal. In experiments 2 (2 production cycles) and 3 (1 production cycle), we recorded similar tendencies of E. coli susceptibility profile change. In experiments 1 and 2, the E. coli population count was lower after vaccination. In experiments 2 and 3, no negative influence of E. coli vaccination on the level of specific antibodies against TRT was recorded.

Comparative study of two forms of aro A CP4 gene in Escherichia coli

The enzyme CP4 5-enolpyruvyl shikimate-3-phosphate synthase (EPSPS; EC 2.5.1.19) from Agrobacterium tumefaciens CP4, encoded by the aroA gene, has been used for the construction of genetically modified crops resistant to total herbicide glyphosate. During the study of possible horizontal gene transfer of aroA CP4 gene from genetically modified food in gastrointestinal tract to bacterial community living in the animal gut, we have discovered and characterized truncated form of aroA CP4 within the cloning experiments in Escherichia coli. We have compared properties of the recombinant E. coli strains with both CP4 EPSPS enzyme forms.