Livestock diseases have a considerable impact on animal welfare, production efficiency and economic profitability. Improving general disease resistance is therefore of great importance. Selective breeding of animals for improved disease resistance is a promising option.
“Natural antibodies” might have an important role in this selection, because in earlier research with layer chickens they were associated with survival. However the genetic background of these antibodies, and the possibility to breed for them, are unknown.
This PhD thesis describes the investigation of the genetic background of natural antibodies in layer chickens, which found that one particular region on the genome is of big importance for the amount of natural antibodies. In this region, the disease-sensor-gene “Toll-like receptor 1A” is located, which is known for its beneficial role in inducing immune responses, and consequently disease resistance.
Also, chickens were bred for high and low levels of natural antibodies. Chickens bred for high levels of natural antibodies showed in addition to a higher defence against several antigens, an increased resistance against an “avian pathogenic E. coli”-infection at young age compared to chickens bred for low levels of natural antibodies.
The results of this thesis give a promising opportunity to improve general disease resistance in chickens in a natural way by selective breeding on natural antibodies.