BIOLOGICAL CONTROL OF SALMONELLA
You may associate salmonella food poisoning with poorly cooked eggs, but increasing evidence shows the major source of this foodborne infection is broiler meat. Broilers are young chickens slaughtered by the time they are six weeks old. At this age, their immune systems are not well developed and they frequently succumb to infection by pathogenic salmonella, particularly under intensive rearing conditions. Facing stiff competition from Asian and South American producers, the European poultry industry desperately needs a cost-effective way of dealing with salmonella in young broilers so that it can produce assured pathogen-free meat at a competitive price. A consortium of veterinary research institutes and companies is being funded by the Sixth Framework Programme (FP6) to investigate strategies for biological control of salmonella, including the promising avenue of live 'designer' vaccines for newly hatched chicks.
With only weeks to live, the bacterial community in the gut of a broiler does not have long to establish itself. It is possible, under extremely hygienic conditions, to produce pathogen-free broilers, but this method is currently too costly to be commercially viable.
Vaccines are increasingly popular for controlling disease in livestock, but broilers are so immature that ordinary vaccines are not fully effective. In a previous European project, some partners in this Specific Targeted Research or Innovation Project studied the use of live salmonella vaccines in new chicks. Live vaccines are strains of pathogenic bacteria that are weakened and, thus, no longer pathogenic. Unlike dead vaccines, they actually colonise the intestine. The scientists discovered that, in addition to stimulating an immune response, live salmonella vaccines have two additional effects on a young chick. First, they inhibit colonisation by similar bacteria, such as pathogenic salmonella and, secondly, they induce chick immune cells to enter the gut, thereby improving immune protection.
GENETICALLY ENHANCED VACCINES
This project, lasting three and a half years and known as SUPASALVAC, aims to use biotechnology to enhance these effects of live salmonella vaccines. Scientists will test strains of salmonella to see which are best at inhibiting colonisation by similar strains, and find out which genes are involved in the inhibition. They will also identify the genes that draw chick immune cells to the gut in response to the live vaccine. Their results should pave the way to producing a highly effective live vaccine designed for young chicks - based on the best inhibiting strains - with the genes to promote chick immunity.
The team will investigate other methods of preventing colonisation of chick intestines by salmonella, exploring dietary additives or methods of inhibiting bacterial genes active during colonisation. It may be possible to eliminate bacteria of all kinds from the broiler gut prior to slaughter, using live vaccines genetically programmed to commit suicide. This would help alleviate public concerns about genetically modified micro-organisms in the food chain, an issue the project will address directly through a series of workshops.
Finally, three of the partners, including a Dutch company, have expertise in the evolving science of using bacteria-killing viruses known as bacteriophages to target particular bacteria. They will develop phages to destroy salmonella, both in broilers and in carcasses. Overall, the project will help reduce the burden of salmonella in poultry meat, and enhance Europe's Potential in the fast developing market for biological disease-control agents.
List of Partners
- Institute for Animal Health (UK)
- Institut National de la Recherche Agronomique (France)
- Universiteit Gent (Belgium)
- Bundesforshcungsanstalt für Viruskrankheiten (Germany)
- Veterinary Research Institute (Czech Republic)
- Veterinary Medical Research Institute (Hungary)
- Lohmann Animal Health (Germany)
- Institut voor Dierhouderij en Diergezondheid (The Netherlands)
- University of Bristol (UK)
- Exponential Biotherapies (Germany)
- Full title:
- Salmonella-free broilers by live vaccine-induced innate resistance to colonisation and invasion and novel methods to eliminate vaccine and field strains
- Contract n°:
- Project co-ordinator:
- P. A. Barrow, Institute for Animal Health, firstname.lastname@example.org
- EC Scientific Officer:
- Jean-Charles Cavitte, email@example.com
- EU contribution:
- € 2.4M
- Specific Targeted Research Project