Metabolism of inorganic selenium in rumen bacteria

Abstract

In vitro and in vivo experiments demonstrated that rumen bacteria were capable of metabolizing inorganic 75Se and incorporating the element into the microbial protein. The fixation of 75Se into bacteria in vitro was inversely proportional to the previous dietary intake of selenium by the host sheep. In sheep fed a purified diet low in selenium and vitamin E, selenium supplementation caused a marked alteration of the rumen microorganisms. Characterization of the 75Se-containing compounds in the rumen bacteria protein hydrolysates revealed the presence of 75Se-selenomethionine and 75Se-selenomethionine selenoxide.