Efficacy of broth-grown Pasteurella multocida bacterins in ducklings
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Abstract:
Pasteurella multocida (PM) isolates produced dense growth in tryptic soy broth and modified tryptose broth (MTB) when the media were continuously shaken or aerated. In carboys containing 15 liters of aerated MTB, the growth exceeded an absorbance of 0.9 and contained about 10(10) colony-forming units per ml. Bacterins prepared from PM isolates grown in MTB were injected subcutaneously into ducklings at 2 and 3 weeks of age. Such ducklings experienced significantly less mortality than unimmunized controls following homologous challenge at 4, 5, or 6 weeks of age. Similar protection was provided against challenge by a heterologous isolate (same serotype). Six-week-old ducklings given a single injection of an oil-emulsified PM bacterin developed immunity that lasted for 8 weeks.
Insights
Developing an effective Pasteurella multocida (PM) bacterin involved optimizing growth media and aeration. Vaccinated ducklings showed significantly reduced mortality against PM challenge, demonstrating vaccine efficacy.
Area of Science:
- Veterinary Microbiology
- Immunology
- Bacteriology
Background:
- Pasteurella multocida (PM) is a significant pathogen in poultry.
- Effective vaccines are crucial for controlling PM-related diseases in ducklings.
Purpose of the Study:
- To optimize growth conditions for Pasteurella multocida (PM) isolates.
- To evaluate the efficacy of a PM bacterin in ducklings.
Main Methods:
- PM isolates were cultured in aerated tryptic soy broth and modified tryptose broth (MTB).
- Bacterins were prepared from PM grown in MTB and administered to ducklings.
- Vaccinated and control ducklings were challenged with homologous and heterologous PM isolates.
Main Results:
- Optimized aeration in MTB yielded dense PM cultures (approx. 10(10) CFU/ml).
- Ducklings vaccinated with PM bacterin exhibited significantly lower mortality rates post-challenge.
- A single dose of oil-emulsified PM bacterin provided immunity lasting at least 8 weeks.
Conclusions:
- Optimized culture conditions facilitate high-yield PM antigen production for bacterin development.
- PM bacterins are effective in protecting ducklings against homologous and heterologous challenge.
- Oil-emulsified bacterins offer sustained protection against Pasteurella multocida infections.