Organic selenium in the nutrition of laying hens: Effects on egg selenium content, egg quality and transfer to developing chick embryo

Studies were conducted to compare the effects of feeding laying hens organic sources of selenium, selenium yeast (Se yeast), vs. sodium selenite (Na2SeO3) on egg selenium content, egg quality and rate of transfer of selenium to developing embryos.;In Experiment 1, hens were fed practical diets with 0.3 ppm Se added as Se yeast or Na2SeO3. Using Se yeast resulted in higher deposition of Se in the egg (16.3 mug vs. 9.8 mug Se).;In Experiment 2, hens were fed corn-soy diets alone or supplemented with 0.1, 0.2 or 0.3 ppm Se as Na2SeO3 or Se yeast. Fertile eggs collected after 33 days of feeding were incubated for 0, 5, 10, 15 or 20 days. Higher embryonic Se resulted from use of Se yeast vs. Na2SeO 3 and from higher levels of supplemental Se. In all treatments embryo Se concentration increased markedly between days 10 and 15 of incubation.;In Experiment 3, hens were fed corn-soy diets supplemented with 0.1 or 0.3 ppm Se as Na2SeO3 or Se yeast. Fertile eggs collected after 31 days of feeding were incubated for 10, 11, 12, 13, 14 or 15 days. Higher embryonic Se resulted from use of Se yeast vs. Na2SeO 3 and from higher levels of supplemental Se. In all treatments embryo Se concentration increased after 12.25 days of incubation.;In Experiment 4 hens were fed a corn-soy diet alone or supplemented with 0.3 ppm Se as Na2SeO3 or Se yeast. Eggs were stored under different conditions. Feeding hens Se yeast for 42 days, produced eggs with increased eggshell strength (ES). Dietary treatment did not affect interior egg quality (IEQ).;In Experiment 5 hens were fed a corn-soy diet alone or supplemented with 0.1, 0.2 or 0.3 ppm Se as Na2SeO3 or Se yeast. Eggs were refrigerated for increasing periods of time. ES was higher for eggs stored for 28 days but was not affected by dietary treatment. IEQ decreased as storage time increased.;Feeding Se yeast (vs. Na2SeO3) to hens increased the Se content of eggs and developing embryos. The effect of Se source on IEQ and SS was not clearly defined.