Nutritional deficiency and resistance to infectionThe effect of caloric and protein deficiency on the susceptibility of rats and mice to infection withSalmonella typhi murium

Abstract

1. The effect of either or both caloric and protein deficiency on the susceptibility of rats and mice to peroral infection withSalmonella typhi muriumwas studied.2. Moderate restriction of food intake (80% of normal diet) for a period of 5 weeks was without influence on the infection susceptibility of rats, even when the diet fed was low in protein.3. Long-term restriction of food intake (10 weeks) led to a marked lowering of the resistance of rats to the infection, there being a direct relation between the magnitude of the intake restriction and the extent of the resulting loss of resistance.4. The infection resistance of rats was lowered more markedly by a given total restriction of food intake, when the latter was imposed in the form of a gradually reduced ration, than when it was imposed in a uniformly restricted ration. The effect so produced was independent of the protein content of the diet.5. The effect of gradual food restriction was diminished by gradual supplementation of the diet with non-proteins and was augmented by gradual supplementation of the same diet with protein.6. In mice kept on a restricted diet loss of resistance toS. typhi muriumhas been shown to be due to a deficiency of both calories and protein.