Selection of chickens with increased disease resistance one step closer

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Research could lead to animals with improved disease resistance and, thus, less antibiotic use, lower economic losses for farmer and improved animal welfare.

Chickens selected for higher levels of natural antibodies have a stronger immune response, according to researchers with Wageningen University & Research (WUR) in the Netherlands. This provides insight into possible mechanisms for these natural antibodies in general disease resistance.

Selection of chickens with increased disease resistance is one step closer to practice and ultimately can result in reduced antibiotic use and animals with improved well-being, WUR said.

In poultry housing systems, birds frequently come in contact with each other. A possible pathogen, once present in a house, can spread relatively easily among the flock. For a decade already, the poultry industry has requested robust birds with good resistance to diseases. One possibility for achieving such a robust chicken is to breed animals with an increased disease resistance, WUR said.

Animals have natural antibodies that are part of the immune system. Natural antibodies recognize pathogens in healthy animals without previous exposure to that pathogen. They block and prevent further spread of pathogens but also warn and activate other parts of the immune system, WUR explained.

Earlier studies showed promising results, finding that natural antibody levels are heritable and can, therefore, be altered by breeding, the researchers said. Also, higher natural antibody levels were associated with a increased survival rates.

WUR researchers put this to the test and selected layer chickens for high or low natural antibody levels for two generations. The layer hens in the second generation were vaccinated with one of three different vaccines.

Tom Berghof, main investigator of this study, explained, “We used vaccines that cause different immune responses: one immune response is directed against bacteria, one immune response is directed against viruses and one immune response was specific for our selection on natural antibodies.”

Compared to animals with low levels, birds with high natural antibody levels had a higher antibody response against the bacterial vaccine, but not to the other vaccines.

“This suggests that animals with higher natural antibodies might have better protection against bacterial diseases,” Berghof said.

According to WUR, this study offers hope for the possibility of breeding chickens with higher natural antibody levels to improve general disease resistance, especially towards bacteria.

“First, we want to know more about the selection for natural antibodies, so we will continue the selection for a couple of generations more,” Berghof said. “In addition, we will investigate if the lines also respond differently to real bacterial pathogens and if they differ in other forms of protection against, for example, viruses.”

Eventually, this research could lead to animals with improved general disease resistance and, thus, less antibiotic use, lower economic losses for the farmer and improved animal welfare, WUR said.

Hendrix Genetics supplied animals for this research. This study is part of the research program “Divergent Selection for Natural Antibodies in Poultry.”