Although tin and rubidium are essential trace elements for some bacteria and plants, their essentiality for higher animals is not fully established. This study examined the effects of low dietary levels of tin and rubidium on growth, tissue mineral concentrations and the selected plasma biochemical indices of growing rats. Compared to rats given 2μg tin/diet, rats fed a 17ng tin/g diet exhibited lower weight gain, decreased food efficiency, alopecia, altered mineral levels in some tissues and changes in plasma lipid concentrations. Compared to rats fed an 8μg rubidium/g diet, rats fed a 0.5μg rubidium/g diet showed decreased rubidium concentrations in all tissues examined, altered levels of other minerals in various tissues and an increased urea nitrogen level in plasma. These results suggest that tin and rubidium are essential for animals.
