Research Project: Control Strategies for Avian Mycoplasmosis

Location: Poultry Research

Project Number: 6064-32000-013-000-D
Project Type: In-House Appropriated

Start Date: Oct 11, 2021
End Date: Oct 10, 2026

Objective:
1. Investigate the efficacy of different strategies to displace virulent or moderately pathogenic strains of Mycoplasma gallisepticum (MG) with safer or less pathogenic, including vaccine strains, of MG as a means to reduce economic impacts to egg laying facilities. 2. Evaluate the effects of commercial-scale poultry management practices on transmission and microbial ecology of Mycoplasma. 3. Investigate the long-term efficacy of in ovo vaccination strategies to protect against disease caused by MG.

Approach:
To determine the transmissibility of Mycoplasma gallisepticum (MG) under varying conditions relevant to commercial poultry industries, layer chickens will be challenged with virulent and attenuated MG strains and then will be placed among naïve poultry. Transmissibility will be assessed by detection the MG among nonchallenged poultry. To determine the impact of housing system on the transmission rates both conventional cage and non-cage systems will be investigated. Further, among conventional cage systems, the ventilation systems will include both still air and tunnel ventilation. Among the non-cage systems, experiments will be designed to compare poultry housed over open pit, deep pit, and flush tank systems to determine any effects on MG transmissibility. To compare genetic and phenotypic differences between virulent and attenuated strains of MG, MG strains will be sequenced and their genome assembled. Further, comparative proteomics will be performed, and all associated findings will be analyzed to elucidate differences which may be applied to future means of MG control. To develop an MG in ovo vaccination protocol and test its’ potential for application towards protection of commercial flocks from MG challenge, experiments will be initially be performed to determine appropriate dosage levels. The effects of the various doses of the MG vaccine on the 18 d embryo will be determined and findings will be applied to the development of a commercially applicable high throughput automated protocol. In addition, chicks derived from the vaccinated eggs will be hatched and assessed for afforded protection.