The Vitamin A Requirement of the Mouse

Abstract

Albino mice of the Swiss-Webster strain, depleted of tissue stores of vitamin A from birth, received graded doses of vitamin A just prior to the development of a vitamin A deficiency. It was found that vitamin A at a level of 1 I.U. per day gave as good growth as was obtained at levels of 210 to 300 I.U. daily. This level was also sufficient for the maintenance of life over long periods of time and was adequate in preventing the appearance of internal and external macroscopic symptoms of vitamin A deficiency. The normal red blood cell counts and hemoglobin levels and the similar white blood cell counts encountered on all levels of vitamin A intake would indicate that 1 I.U. daily supports a normal hemopoietic functioning, and protects against the infections to which chronically vitamin A-deficient mice are susceptible. The reproductive function in the male is particularly sensitive to a deficiency of vitamin A; 1 I.U. daily allows for a completely normal exercise of this function. Vitamin A at a level of 1 I.U. per day allows for significant storage in the adult mouse, indicating that this level is definitely in excess of the needs of the adult animal. The fact that storage occurred in mice even during the period of rapid growth would suggest that 1 I.U. daily is somewhat in excess of the needs of the growing animal.