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ARS Home » Southeast Area » Mississippi State, Mississippi » Poultry Research » Research » Publications at this Location » Publication #336452
Title: Layer chicken embryo survival to hatch when administered an in ovo vaccination of strain F Mycoplasma gallisepticum and locations of bacteria prevalence in the newly hatched chick

Author
item ELLIOTT, K E C - Mississippi State University
item Branton, Scott
item Evans, Jeffrey - Jeff
item GERARD, P - Mississippi State University
item PEEBLES, E - Mississippi State University

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/15/2017
Publication Date: 8/3/2017
Citation: Elliott, K., Branton, S.L., Evans, J.D., Gerard, P.D., Peebles, E.D. 2017. Layer chicken embryo survival to hatch when administered an in ovo vaccination of strain F Mycoplasma gallisepticum and locations of bacteria prevalence in the newly hatched chick. Poultry Science. 96:3879-3884.

Interpretive Summary: Mycoplasma gallisepticum (MG) is a bacterial pathogen of poultry that in layer chickens causes production losses. To combat MG, multi-age layer facilities currently vaccinate pullets by either spray or eye drop vaccination which is labor intensive. The purpose of this study was to determine if layer chicken embryos could survive to hatch when administered a live attenuated strain F (FMG) vaccine in ovo at 18 days of incubation. Eighteen day old layer chicken embryos were either not-injected, or hand-injected with a diluent injection, or a high, medium, low, or low-low dosage of an FMG vaccine. Hatch success and residual egg embryonic mortality was noted after 23 days of incubation. Hatch of embryonated eggs was decreased by the medium and high doses (P=0.02), with embryonic mortalities occurring as dead pips (P=0.004). No FMG was detected in any site in the control; however, FMG was detected at all dosages and sites with greater amounts of positive chicks in the higher FMG dosage treatments. These findings indicate the potential practicality of in ovo vaccinating layer embryos with FMG based on hatch success at lower dosages.

Technical Abstract: Mycoplasma gallisepticum (MG) is a bacterial pathogen of poultry that in layer chickens causes production losses. To combat MG, multiage layer facilities vaccinate pullets by either spray or eye drop vaccination. The purpose of this paper is to evaluate if in ovo vaccination of MG is a potential alternative vaccination route for MG in layer chickens, beginning with testing if embryos could survive to hatch once administered a live attenuated strain F (FMG) vaccine in ovo. Layer embryos at 18 days of incubation were either not-injected, or hand-injected with a diluent injection, or a high, medium, low, or low-low dosage of an FMG vaccine. Hatch success and residual egg embryonic mortality was noted after 23 days of incubation. Six hatched chicks per treatment were swabbed for the detection of FMG at four different sites (trachea, mouth and esophagus, yolk sac membrane, and the lumen of the duodenal loop) via real-time PCR. Embryos were found to be administered 106 colony forming units (CFU) per dose in the high treatment, 104 CFU/dose in the medium treatment, 102 CFU/dose in low, and between 5.06 and 5.93 CFU/dose in the low-low treatment. Hatch of embryonated eggs was decreased by the medium and high doses (P=0.02), with embryonic mortalities occurring as dead pips (P=0.004). 40 No FMG was detected in any site in the control and diluent injected chicks. However, FMG was 41 detected at all dosages and sites with greater amounts of positive chicks in the higher FMG 42 dosage treatments. These findings indicate the potential practicality of in ovo vaccinating layer 43 embryos with FMG based on hatch success at lower dosages, and that the bacteria, once injected 44 into the amnion, is present in the upper respiratory and gastrointestinal tracts as well the yolk sac membrane and the small intestine of hatchlings. Future research will need to ascertain any post hatch mortality effects of in ovo administered FMG and its implications on post-hatch immunity.