The Vitamin D Potency of Egg Yolk From Irradiated Hens

Naturally enhanced eggs as a source of vitamin D: A review

“…A lot of studies were published in the 1920'ties and 1930'ties regarding how to increase the vitamin D content in eggs. It was shown that the content of vitamin D in egg yolk could be increased by adding vitamin D to the feed of laying hens (Bethke, Kennard, & Sassaman, 1927;Branion, Drake, & Tisdall, 1935;DeVaney, Munsell, & Titus, 1933;Guerrant, Kohler, Hunter, & Murphy, 1935) or by irradiating nonsupplemented hens from above (Farrell, 1924;Hart et al, 1925;Hendricks, 1931;Hughes & Payne, 1924;Hughes, Payne, Titus, & Moore, 1925;Maughan & Maughan, 1933). However, when Carson & Beall (1955) supplemented hens with approximately 29 μg vitamin D/kg feed and exposed them to UVB from above, no increase of vitamin D in the eggs were observed.…”

The Role of Environment in the Life of Birds

“…Ultra-violet radiation, either solar or artificial, also affects adult birds in a marked manner (Hughes and Payne 1924, Hughes, Payne and Latshaw 1925, Hart, Steenbock, Lepkovsky, Kletzien, Halpin, and Johnson 1925, Hendricks, Lee and Godfrey 1931, Maughan and Maughan 1933. Without the proper irradiation and with food low in anti-rachitic vitamin, the calcium and phosphorous content of the blood drops below normal, health is impaired, and hens develop lameness or paralysis of the legs and wings.…”