Bioavailability of selenium and zinc supplied to the feed for laying hens in organic and inorganic form

Standard DJ feed mixture for laying hens (ISA Brown) was supplemented with organic or inorganic forms of selenium and zinc. The organic forms consisted Saccharomyces cerevisiae yeast enriched with Se (Y-Se) and Zn (Y-Zn). The inorganic forms were sodium selenite (Na-Se) and zinc oxide (ZnO). The concentrations of elements in the experimental feed were (mg·kg-1): selenium 1.414 (Y-Se) and 1.393 (Na-Se); zinc 79.3 (Y-Zn) and 78.9 (ZnO). After 6 days of feeding treatment, for the next 5 days there were collected droppings and eggs to determine Se and Zn concentrations with the use of ICP method. It was stated that in hens availability of elements (as apparent absorption) was respectively (%): Y-Se 63.65, Y-Zn 38.5, Na-Se 61.12 and ZnO 35.41. In eggs content of Y-Se hens the increase of Se was proved if compared to Na-Se eggs (p<0.05).