Vitamin A in the diet of laying hens: enrichment of table eggs to prevent nutritional deficiencies in humans

The concentration of vitamin A in egg yolk is directly related to its inclusion in the diet of laying hens. The vitamin A concentration of the egg yolk is 79 μg/100 g or 263 UI/100 g, and the concentration in 60 g eggs increased from 59 to 75 μg in response to an increase in dietary vitamin A supplementation. Currently, the level of vitamin A recommended for laying hens is 900 UI/day or 9,000 UI/kg feed and 15,000 UI/kg of egg mass. The bioavailability of preformed vitamin A in the egg ranges from 90 to 100%, accounting for about 15% of the daily recommended dietary intake for humans, while bioavailability may vary from 10 to 67%. The table egg is a functional food for humans that can be enriched with vitamin A, and its consumption could be an alternative to prevent and reduce the prevalence of deficiencies, especially in risk groups, such as children and the elderly.