Effect of intermittent feeding on thermoregulatory abilities of young and aged C57BL/6J mice.

At 6 mth of age, male C57BL/6J mice were subjected to an intermittent schedule of feeding (every-other-day) or continued to be maintained on an ad libitum diet (24% protein). This regimen of dietary restriction resulted in increased mean and maximum lifespan (11%) compared to the survival of ad libitum-fed mice. At 8 and 26 mth of age, different groups of mice were tested for cold tolerance during 3 h exposure to 10 degrees C. Aged mice (26 mth) fed ad libitum compared to young mice (8 mth) on the same diet had significantly lower baseline colonic temperatures prior to cold exposure, and impaired cold tolerance, as measured by the rate of decline in colonic temperature during cold exposure. Dietary restriction by intermittent feeding had no significant effect on cold tolerance in young mice or baseline colonic temperature in young or aged mice. However, the cold tolerance of aged mice subjected to 20 mth of intermittent feeding was markedly improved over that of aged cohorts maintained on an ad libitum diet and in fact was indistinguishable from that of young counterparts. Thus, it appeared that this regimen of dietary restriction when implemented in young adults prevented the age-related decline in cold tolerance observed among ad libitum fed mice of this strain.