Cobalt-selenium interactions in the nutrition of the rat.

An interaction between dietary cobalt and selenium was revealed when groups of female weanling rats were fed standard rations, containing different concentrations and ratios of the two trace elements, continuously over a 15 week period. It was found that the levels of selenium in the heart and skeletal muscle were positively related to dietary selenium and negatively related to dietary cobalt, and that the levels of selenium in liver and kidney were positively related to dietary selenium and negatively related to an interaction between dietary selenium and cobalt. Dietary selenium did not influence the cobalt level of heart muscle. Bodyweight gains and histological appearance of the major tissues of rats fed either or both of the trace elements in concentrations as high as 8-6 p.p.m. in the ration were not affected except for some minor liver changes in those on the ration containing 8-6 p.p.m. cobalt and low levels of selenium. It was suggested that cobalt/selenium interactions probably occurred in the gut with effects on absorption rather than in the tissues studied.