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November 1, 2022 | by Sam Shafer
New research suggests poultry breeders can boost immune system function in birds by updating their prediction models to include “non-additive” genetic effects. The new study, published in The Journal of Applied Poultry Research, was carried out in Japanese quail and led by a research team based in Iran.
Japanese quail (Coturnix coturnix japonica) are closely related to chickens and are prized for their ability to grow to maturity and be ready for harvest between six and eight weeks old. They are also a useful model organism and have been harnessed for immune system research around the world.
Of course, a model organism like the Japanese quail isn’t useful unless researchers have a robust way to analyze animal genetics. For the new study, the researchers were especially interested in how to weigh “additive” and “non-additive” genetic effects in breeding programs. Additive genetic effects come about when multiple genes influence the expression of a trait in a linear or additive way. Non-additive effects include genetic dominance of a gene or genes across a specific section of DNA.
It has been common for researchers to discount non-additive genetic effects when looking at genome-wide markers to predict complex traits in health and breeding research.
The new study shows that factoring in non-additive effects may improve humoral immunity (antibody protection) in flocks. In data from six generations of Japanese quail, the researchers found that adding non-additive genetic effects to breeding models could improve predictions for antibody production, though not for IgY, the most common type of antibody found in quail and chickens.
The new study also offers a rare window into the importance of maternal antibodies in a bird’s early days. Maternal antibodies are passed along to chicks through the yolk sac of the eggs and can give newly hatched chicks a way to jump-start their immune protection. The new research shows this maternal immunity is also relevant for predicting the future production of most antibody types—though not IgY.
Overall, the researchers found that factoring in non-additive genetic effects could reduce the usual variation seen in estimated breeding values. “Our results showed the non-additive genetic effects, and maternal genetics (except for IgY) is significant on humoral immune traits and must be included in genetic evaluation models,” they write.
What does this study mean for producers?
The full paper, titled “Additive and non-additive genetic effects of humoral immune traits in Japanese quail,” can be found in The Journal of Applied Poultry ResearchⓇ and online here.
Categories: Interpretive Summary