A Comparison of the Effect of Raw Corn and Tortillas (Lime-Treated Corn) with Niacin, Tryptophan or Beans on the Growth and Muscle Niacin of Rats

A niacin-deficient, low-tryptophan basal ration containing 18.5% of crude protein has proved useful for studying niacin deficiencies in rats. Weanling rats of this laboratory placed on such a diet failed to grow and developed mild-to-acute alopecia within 21 days. Daily oral administration of 1 mg of niacin per rat or increasing the tryptophan content of the basal ration to 0.40% restored the growth of the rats but had no influence on the alopecia. When either raw or lime-treated corn was substituted for the zein and sucrose of the basal ration the rate of growth was significantly improved and the growth of hair returned. The results confirm the increased growth rate of rats fed lime-treated corn (tortillas) compared with those fed raw whole ground corn. Beans fed at a level calculated to be equivalent to that consumed by part of the rural population of Guatemala produced a slight further improvement in growth and significantly increased the muscle niacin of depleted rats. Continuous infra-red or ultra-violet light had no apparent effect on the skin of shaved areas of niacin-depleted or supplemented rats. The addition of niacin, however, lessened the sensitivity of the depleted rats to the light as manifested by a tendency to huddle.