Japanese rock ptarmigan displays high levels of polyunsaturated fatty acid in egg yolk compared to chicken and quail.

Egg yolk from captive and wild Japanese rock ptarmigan were analyzed for fatty acid composition. Compared to commercially reared poultry species, the ptarmigan yolk samples displayed higher level of polyunsaturated fatty acids as opposed to monounsaturated fatty acids. The difference between the commercial controls and ptarmigan were larger than the difference between groups of ptarmigan, indicating that the fatty acid profile of Japanese rock ptarmigan might be partly attributed to genetic factors rather than feed, despite wild and captive birds having vastly different diets, and captive birds having been artificially bred for several generations.