Effect of the selenized yeast added in feed on selenium-containing proteins of albumins in egg yolk

This work was aimed to study the effects of the selenized yeast added in feed on selenium-containing proteins of egg yolk. Two groups of the same little hens were given the ordinary grain feed either unsupplemented selenized yeast (Group O) or supplemented with 0.15% selenized yeast (Group Y), respectively. The water-soluble Se-containing proteins were isolated and purified from the two group eggs yolk using the same conditions. SeP1-1 and SeP1-I were purified from the yolk of Group Y and Group O, respectively. Sequences identified by HPLC-MS/MS showed that SeP1-1 was a highly homologous Se-containing protein with Se-free YGP-42 with 83% match, in which Se species include methylselenocysteine and selenocysteine. SeP1-I was a highly homologous Se-containing protein with Se-free ovalbumin with 78.2% match, in which Se species include selenomethionine and selenocysteine. It can be concluded that the selenized yeast can change the compositions and structures of Se-containing proteins in egg yolk.