Natural antibodies and resilience indicators appear to be under polygenic control
Results from a Wageningen University & Research, Animal Breeding and Genomics (WUR-ABG) study published in Poultry Science suggest that both natural antibody (NAb) levels and resilience indicators are heritable and are under polygenic control in a brown layer line.
However, capturing resilience remains non-trivial and resilience indicators require further refinement for management and breeding purposes.
Breeding for (disease) resilient livestock
Resilience is the capacity of an animal to be minimally affected by disturbances or rapidly return to the state pertained before exposure to a disturbance. Given that livestock are continuously exposed to environmental disturbances, for example fluctuations in temperature or pathogens, breeding (disease) resilient livestock is important for the sustainability and profitability of livestock production. Measuring general resilience of animals is challenging. However, the increasing availability of longitudinal production data allows estimating resilience indicators based on deviations observed from expected production levels. To evaluate an animal’s general disease resistance, levels of natural antibodies (NAbs) can be used as an indicator trait.
Genome-wide association study to facilitate genetic improvement
The researchers performed a genome-wide association study (GWAS) to identify genomic regions influencing NAbs and resilience indicators in a purebred Rhode Island layer line. Results suggest that both resilience indicators and NAbs are heritable and under ‘polygenic control’, meaning that they are influenced by many genes with a small effect. This is, for example, in contrast with a White Leghorn layer line, for which researchers of WUR found an important region with a large effect of IgM Nabs in 2018. These observations provide further insight in the genetic architecture underlying resilience, which, in turn, may facilitate genetic improvement for resilience in layer lines.
Resilience: a challenging trait
The overall findings of the study suggest that both NAb levels and resilience indicators are heritable and have potential for genetic improvement of (disease) resilience. However, interpretation of none of the resilience indicators is straightforward, as demonstrated by the authors. Therefore, further refinement and validation of these indicators is important to verify their practical relevance and implement them in management and breeding practices.
This research was a collaboration with the Technical University of Munich and Hendrix Genetics B.V.