Metabolic Interdependence of Vitamin B 1 and Manganese. Reciprocal Neutralization of Their Toxic Effects. ∗

Abstract

Summary and Conclusions

In rats fed normal adequate diets an excess of vitamin B, in amounts exceeding 30 or 40 times the minimal requirement results in an interference with the capacity of the mother to rear her young and with the nursing instinct. With an excess of 400 gamma this manifestation was pronounced in the parent generation but became progressively worse in the F₁ and F₂ generation. The young were neglected and eaten in over 90% of the litters in the F₂ generation.

The toxic manifestations of an excess of vitamin B₁ were found to be dependent on the ratio of manganese to vitamin B₁ in the diet. The addition of manganese to the diet in amounts of 2 mg per rat per day completely neutralized the unfavorable effects of the excess of vitamin B₁ (400 gamma daily). Practically no interference with lactation or rearing of the young was observed in animals which received both the excess of vitamin B₁ and manganese as addition to the normal diet during 3 successive generations. Apparently manganese in amounts of 1/2 mg is even more effective.

Supplements of manganese alone in amounts of 2 mg a day result in interference with lactation and cannibalism, particularly marked after one generation.

It is inferred that manganese acts as an essential catalyst in oxidative processes in which vitamin B₁ is concerned. The vitamin B₁ requirement of an animal varies with the manganese content in its diet.