Breeding for improved disease resistance in chickens

In poultry housing systems, animals have frequent contact with each other. This enables pathogens to spread quite easily through flocks. Therefore, the livestock industry has for long time been searching for a strategy to improve general disease resistance. By improving general disease resistance, chickens become less sensitive for several types of pathogens, such as bacteria and viruses.

Breeding for natural antibodies

Animals have so-called 'natural antibodies', which are a part of the immune system. Natural antibodies recognize pathogens in healthy animals, without (a previous) exposure of the animal to this pathogen. The antibodies slow down and prevent spreading of the pathogen from in the body. In addition, they warn and activate other parts of the immune system. The involved researchers of Wageningen University & Research bred layer chickens for different levels of natural antibodies to investigate if this would result in improved disease resistance.

Disease resistance by natural antibodies

To get better insight in how natural antibodies can give general protection, the layer chickens were selected for six generation for either high or low natural antibody levels. Subsequently, the disease resistance against Escherichia coli (also known as APEC) was measured. Main researcher Tom Berghof explains: "We have investigated mortality and internal damage of the E. coli-disease in a controlled setting. We found that the high line has a two to three times lower mortality AND less organ damage induced by the E. coli-infection in comparison to the low line." Berghof continuous: "This gives us a great and unique opportunity, because the natural antibodies are not specific for E. coli, but probably have a broad recognition of pathogens. Breeding for higher natural antibody levels might improve a broad and general disease resistance!"

Applications and future plans

At this moment the physiological consequences of the selection for natural antibodies is being investigated to get a better understanding how they improve general disease resistance. In addition, follow-up studies to get more insight in the genetic background of natural antibodies and E. coli-resistance have been set-up in collaboration with Hendrix Genetics. Ultimately this will result in livestock animals with an improved general disease resistance with less need for antibiotic use, lower economic costs for the farmer, and a higher animal welfare.

Read the complete article at Developmental & Comparative Immunology for more information.

Hendrix Genetics supplied animals for this research.

This research is part of the research programme "Divergent selection for natural antibodies in poultry" (with project number 12208), which is financed by the Netherlands Organisation for Scientific Research (NWO).