Location: Poultry Research
2024 Annual Report
Objectives
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.
Progress Report
Studies to were completed to determine the impact of sampling schedule on in vivo MG populations and 3 anatomical sampling sites were compared. An autogenous and electron-beam killed bacterin-based vaccine has been produced and is ready for assessment as a means of protection against MG challenge among layer chickens. Vaccine stabilizers were assessed for applicability to in ovo-based vaccination delivery systems. A new incubator facility was brought online to expand research capabilities to test in ovo vaccination routes for MG protection. The HVAC system in the disease isolation facility was updated to allow for maintenance of broilers and layers independent of age. Further, biological isolation units were procured from ADOL (recently closed sister-lab in MI) and used to replace older units in 1 room of the disease isolation facility. A chick rearing facility was renovated and brought online for research subject development. The feed mill was renovated and brought back online after 2 years of renovations.
Accomplishments
1. Mycoplasma gallisepticum in vivo population. Sampling impact on in vivo Mycoplasma gallisepticum (MG) populations. General bio-surveillance and the timely monitoring of treatment effects on MG populations requires elucidation of sampling related impacts to clearly discern treatment-related effects. Various sampling schedules were compared by ARS researchers at the Mississippi Statue University location, to determine the minimal window between events. This knowledge will be applied to future studies to discern treatment effects on MG.
2. Electron Beam Killed Vaccine for a moderately pathogenic Mycoplasma gallisepticum (MG). A moderately pathogenic Mycoplasma gallisepticum (MG) was irradiated utilizing Electron Beams to produce a vaccine which will be applied to control of the poultry pathogen.
3. Research Facility Upgrades. Poultry Disease related facilities were renovated and improved by ARS researchers at the Mississippi State University location. Improvements included enhanced environment and updating biological isolation units, incubator/hatching facilities, chicken rearing facilities, and the feed mill.
4. Vaccine stabilizers for in ovo-based delivery. Vaccine stabilizers were assessed by ARS researchers at the Mississippi State University location, for applicability to in ovo-based vaccination delivery systems.
Review Publications
Mousstaaid, A., Fatemi, S.A., Collins Elliott, K.E., Levy, A.W., Miller, W.W., Gerard, P.D., Alqhtani, A.H., Peebles, E.D. 2022. Effects of the in ovo and dietary supplementation of L-ascorbic acid on the growth performance, inflammatory response, and eye L-ascorbic acid concentrations in Ross 708 broiler chickens. Animals. 12(19). Article 12192573. https://doi.org/10.3390/ani12192573.
Leigh, S.A., Evans, J.D. 2024. Genetic comparison of the Mycoplasma gallisepticum 6/85 vaccine strain and 6/85-like field isolates. Veterinary Microbiology. 291. Article 110008. https://doi.org/10.1016/j.vetmic.2024.110008.
Fatemi, S.A., Alghtani, A., Collins Elliott, K.E., Bello, A., Zhang, H., Peebles, E.D. 2021. Effects of the in ovo injection of VitD3 and 25-hydroxyvitamin D3 in Ross 708 broilers fed commercial or calcium and phosphorus-restricted diets. I. Performance, carcass characteristics, and incidence of woody breast myopathy. Poultry Science. 100:101220. https://doi.org/10.1016/j.psj.2021.101220.
Fatemi, S.A., Collins Elliott, K.E., Bello, A., Peebles, E.D. 2021. Effects of the in ovo injection of vitamin D3 and 25-hydroxyvitamin D3 in Ross 708 broilers subsequently challenged with coccidiosis. I. performance, meat yield and intestinal lesion incidence. Poultry Science. 100:101382. https://doi.org/10.1016/j.psj.2021.101382.