Life span of mice fed enriched or restricted diets during growth

¹ Department of Pathology, Washington University, School of Medicine, Saint Louis, Missouri

Longevity was studied in male mice of the inbred strain C₅₇BL Jax 6 fed during the period of growth a stock diet enriched with 25% lard or the stock diet restricted to two-thirds of the ad libitum intake. The findings were compared with those obtained in controls kept on the stock diet ad libitum through life. Consumption of the fat-enriched diet ad libitum significantly lowered juvenile mortality and correspondingly increased the mean life span of mice thus fed. Underfeeding, on the other hand, significantly increased juvenile mortality and thus decreased the mean life span of the animals irrespective of whether they had been underfed jointly or individually. Mice underfed in groups retained a high mortality even beyond the period of growth. However, the life span of all other mice, once they had reached adulthood (200 days of age), was not affected by the changes in dietary regimen during growth; their mean life spans and the maximum ages reached were not significantly different from one another.