Potassium requirement of the growing rat.

On the basis of maximum weight gain in weanling male rats fed a semipurified diet for 21 days, the requirement for potassium was found to be 0.23% of the diet. This compares with the NRC requirement of 0.18%. The higher requirement is believed to be due to the greater rate of growth, 6.6 to 7.0 g/day, compared with that obtained in older studies on which the NRC estimate was based. The higher potassium level also improved efficiency of food utilization.