Effects of selenium feed supplements on functional properties of eggs

The aim of the present study was to assess the effects of selenium feed supplements on the functional properties of eggs. The hens in experimental groups were fed diets supplemented with 0.2 mg/kg selenium from sodium selenite (Group 1), selenium-enriched yeast (Group 2), synthetic L-selenomethionine (Group 3), or hydroxy analog of selenomethionine (Group 4). The Control Group (Group C) was fed with basal feed without supplementation. The highest values of albumen gel firmness were shown in Group C eggs; differences with all experimental groups were significant (p < 0.001 to p = 0.009). It was ascertained that albumen gel firmness correlated with albumen pH (r_s = 0.490; p < 0.001), which was highest in eggs from non-supplemented hens. Group 1 eggs and Group C eggs showed lower albumen foaming capacity (p < 0.001) compared to eggs from other groups. Both albumen foaming capacity and albumen foam stability were higher in Group 2 eggs than in Group C eggs (p < 0.001). The highest yolk foaming capacity was found in Group 2 eggs (p < 0.001). Sponge cakes baked with Group C eggs had a smaller volume than those baked with eggs from Group 2 (p = 0.005), Group 3 (p = 0.004) and Group 4 (p = 0.024). The results of the study confirmed that selenium added to the laying hen feed significantly affected the monitored functional properties of both albumen and yolk. The most distinctive effect of selenium was shown in eggs from the group supplemented with selenium-enriched yeast, for which the results of albumen foam capacity and stability and yolk foaming capacity were the best.