US – Researchers evaluating the use of a novel live vaccine to prevent necrotic enteritis in broilers have found it does provide partial protection against the disease.
The research was funded by USPOULTRY and the USPOULTRY Foundation, and was led by Dr Joan Smyth at the University of Connecticut.
Necrotic enteritis is a disease produced by a bacterium called Clostridium perfringens, which may grow in the intestinal tracts of chickens and turkeys and produce toxins which cause illness and mortality in flocks.
It is a serious and often fatal disease of chickens and turkeys, with up to 50 per cent mortality reported before effective control measures were introduced. A less severe, but economically important, form of this disease has also been identified and is frequently called subclinical NE.
The disease can be controlled by incorporation of antibiotic growth promoters (AGPs) in the feed. AGPs are effective in preventing NE, but they have been banned in many countries and their use is rapidly being phased out in the US.
NE is expected to become a much bigger problem in the US, as has been the experience in other countries following the cessation of use of AGPs. Alternative preventative measures are needed, and vaccination is a good alternative strategy.
Dr Smyth used a novel isolate of the clostridium organism, which does not cause the disease as a live oral vaccine in young chickens.
She showed the inoculated birds developed antibodies to clostridium and some vaccine formulations provided partial protection against the disease.
Although the vaccine does not provide full protection, this research supports the concept of using a live vaccine to protect against necrotic enteritis and will stimulate further research to improve the effectiveness of this live vaccine.
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