An exploratory study of the content of vitamin D compounds in selected samples of Australian eggs
- J. Liu, PhD, postgraduate student
- H. Greenfield, PhD, Adjunct Professor
- D.R. Fraser, PhD, Emeritus Professor
The aim of this study was to obtain preliminary indicative data for vitamin D3 (cholecalciferol) and 25-hydroxycholecalciferol (25OHD3) in Australian chicken egg yolk (Gallus gallus domesticus, Linnaeus, 1758), comparing data with the egg yolk of other species, crocodile (Crocodylus porosus, Schneider, 1801) and salmon (Salmo salar, Linnaeus, 1758).
Convenience samples of chicken eggs were obtained from a producer known to fortify feed with 25OHD3 as well as D3 (Brand A; n = 6), a producer with an unknown feeding protocol (Brand B; n = 6) and a producer known to use low levels of only feed vitamin D3 (University of Sydney; n = 4). Salmon roe (50 g jar) was obtained from a retail outlet and crocodile eggs (n = 2) from a commercial crocodile farm. Egg yolks and whole salmon roe were analysed for vitamin D3 and 25OHD3 by high-performance liquid chromatography.
Brand A and B chicken egg yolks contained 2.9 and 2.1 μg vitamin D3/100 g, respectively, while University of Sydney eggs contained lower concentrations (0.5 μg/100 g). Further, yolk from brand A and B chicken eggs contained 4.2 and 1.4 μg 25OHD3/100 g, respectively. Salmon roe contained 6.3 μg vitamin D3/100 g and vitamin D3 content of two crocodile egg yolks differed widely (10.9 and 0.7 μg/100 g).
The vitamin D in chicken eggs has the potential to contribute considerably to the vitamin D content of the Australian diet, up to 3.8 μg vitamin D equivalents per egg, depending on the form of feed vitamin D. Further representative samples of all edible or potentially edible Australian egg species require analysis for public health nutrition purposes.