The efficacy of inactivated Escherichia coli autovaccines against the E. coli peritonitis syndrome in layers.

The efficacy of inactivated Escherichia coli autovaccines against the E. coli peritonitis syndrome in layers. Avian Pathol. 2017 Jun 26;:1-28 Authors: Landman WJM, van Eck JHH Abstract Autogenous Escherichia coli vaccines to prevent the E. coli peritonitis syndrome (EPS) in laying hens are often used in the field, although their effectiveness has not been demonstrated yet. Therefore, in this study, which consisted of two experiments, their efficacy was assessed. In the first experiment, the EPS inducing ability of three E. coli isolates originating from bone marrow of hens that died due to EPS and with different Pulsed-Field Gel Electrophoresis patterns, was examined by intravenous inoculation of the isolates in 17 week-old brown layers. Based on the results one isolate was chosen for the preparation of the vaccines and for homologous challenge and another one for heterologous challenge performed in the second experiment. In named experiment, groups of laying hens which had been vaccinated intramuscularly at 14 and 18 weeks of age with inactivated vaccine either formulated as aqueous suspension or as water-in-oil emulsion were homologously or heterologously challenged per aerosol at 30 weeks of age. The vaccines contained ≥10(8.2) formaldehyde inactivated colony forming units (cfu) of E. coli per hen dose in 0.5 ml. The estimated E. coli challenge dose uptake ranged from 10(5.8) to 10(6.5) cfu per hen. Groups consisted of 18 hens e...
Source: Avian Pathology - Category: Pathology Authors: Tags: Avian Pathol Source Type: research