Effects of dietary form of selenium on its distribution in eggs.

The objective of this experiment was to investigate the selenium distribution in eggs from hens fed diets supplemented with Se from sodium selenite (SS) or selenium-enriched yeast (SY). One-day-old female chickens of Hy-Line Brown breed were randomly divided into four groups according to dietary treatments and, for the subsequent 9 months, were fed diets which differed only in the form or amount of Se supplemented. During the whole experiment, group 1 (control) was fed basal diet (BD) with only background Se level of 0.13 mg/kg dry matter (DM). Diets for groups 2 and 3 consisted of BD supplemented with an Se dose of 0.4 mg/kg DM either in the form of SS or SY, respectively. Group 4 was fed BD supplemented with 0.9 mg Se/kg DM from SY. After 9 months of dietary treatments, the Se levels in egg yolk and albumen from hens fed unsupplemented diet were almost identical whereas eggs from hens given diet supplemented with SS showed significantly higher Se deposition in yolk than in albumen (P < 0.01). On the other hand, the feed supplementation with Se doses 0.4 or 0.9 mg/kg DM from SY resulted in significantly higher Se concentration in albumen than in yolk (both P < 0.001). The total Se amounts in whole eggs from hens in groups 1, 2, 3 and 4 were 5.1, 14.4, 22.7 and 31.6 μg Se/egg thus demonstrating the significantly higher (P < 0.001) selenium deposition in eggs from hens given feed enriched with SY than from birds fed diet with equivalent SS dose. Regardless of dose and source, the selenium supplementation to feeds for groups 2, 3 and 4 resulted in significantly increased α-tocopherol concentration in egg yolk compared to control group 1 (P < 0.001). The presented results demonstrate the different pattern of Se distribution in egg mass when laying hens are fed diets supplemented with inorganic or organic selenium sources.