Iron content of eggs from hens given diets containing organic forms of iron, serine and methyl group donors, or phytoestogens

Abstract

1. This investigation included three experiments to determine whether the iron content of egg yolks could be enriched by supplementation of the laying diet with iron bound to organic compounds (Experiment 1), serine and methyl group donors methionine and choline (Experiment 2) or phytoestrogens (Experiment 3).

2. Hens at 34, 54 and 56 weeks of age were given experimental diets for 6, 4 and 4 weeks, respectively, in Experiments 1–3. Yolks from eggs laid over three successive days in the final week of feeding were pooled for each hen for analysis of iron by inductively coupled plasma mass spectrometry.

3. Iron concentration in egg yolk averaged 68–70, 66–71 and 62–69 µg/g in the respective experiments.

4. The addition of bloodmeal (1·22 mg Fe/egg) or phytoestrogens (1·25 mg Fe/egg) increased the total iron content of yolks by over 15% compared with the control diet (1·10 mg Fe/egg), and although this increase was not statistically significant it suggests that the iron content of eggs could be sufficiently manipulated to justify a nutritional claim of iron enrichment.

Acknowledgements

The skilled technical assistance of Derek Schultz, Evelyn Daniels, Cathrine Davies, and Cassie Matthews is gratefully acknowledged. The iron content of egg yolk was analysed by Waite Analytical Services with the cooperation of Teresa Fowles. The Australian Egg Corporation Limited provided funding for this work (UA-56A).