Effects of selenium, alone and in combination with silver or arsenic, in rats

In two experiments, Sprague-Dawley rats were administered elemental selenium (Se; 10 ppm), silver (Ag; 1000 ppm) and arsenic (As; 50 ppm), either alone or in combination (Ag+Se or As+Se). Administration was via drinking water. Body weight, fluid intake, and food consumption were monitored weekly and measures of forelimb and handlimb strength were taken. Se depressed body weights in both experiments, as did As+Se. Food consumption relative to body weight tended to be increased by Se alone; none of the other treatments affected body weight, except for As+Se. Water consumption was depressed in all cases, which was attributed to a palatability effect. Limb strength was not affected by any treatment. The addition of Ag to the drinking water containing Se appeared to reduce the toxic effect of Se. However, As appeared to interact in a potentiating fashion with Se. There was 1 death in the Se alone group, none in the As group, but 7 out of 10 animals receiving As+Se had died by the end of the 18 week dosing period.