Published online by Cambridge University Press: 12 January 2017
Se supplementation in feed can be used to increase human Se intake, and this has showed significant progress in the area of healthy nutrition in recent years. It has been proven that the antioxidant function of Se is likely to contribute to better shelf life in animal products. Egg freshness can be monitored by assessment of albumen and yolk pH, fatty acid profile, malondialdehyde content, yolk vitelline membrane strength, carbonyl content and yolk pigment stability. It has been proven that Se reduces oxidation processes inside the egg and hence the pH of its contents does not increase too rapidly when stored. Several studies have reported that the rate of fatty acid oxidation and the production of lipid oxidation products (malondialdehyde, MDA) are lower in Se enriched eggs compared to non-enriched eggs. These results have been explained by an increase in gluthation peroxidase (GSH-Px) levels and activity in eggs after supplementation of laying hens with Se, which is an essential component of GSH-Px. Se has a positive effect on the stability of yolk pigments, which is linked to the oxidation stability of yolk lipids. According to several studies, Se decreases the carbonyl, which is a marker of protein oxidation. The yolk vitelline membrane consists of a high amount of protein incorporating Se, which explains the increased vitelline membrane strength after Se supplementation.