Nutritional Influences on Aging of Fischer 344 Rats: I. Physical, Metabolic, and Longevity Characteristics

Abstract

The aims of this research were (a) to compare food restriction initiated in adult life of male Fischer 344 rats with that limited to early life or involving most of the life span on physical, metabolic, and longevity characteristics and (b) to study a similar level of protein restriction without caloric restriction on these characteristics. Food restriction (60% of the ad libitum intake) initiated at 6 months of age markedly increased life span as did a similar restriction started at 6 weeks of age, but food restriction limited to early life (6 weeks to 6 months of age) and protein restriction caused only a small increase in longevity. Food restriction does not act by reducing the intake of calories or other nutrient per gram of body mass, a finding not in accord with classic views. A progressive decrease in spontaneous locomotive activity with age occurred in ad libitum fed but not restricted rats.

The effects of graded levels of calorie restriction: IX. Global metabolomic screen reveals modulation of carnitines, sphingolipids and bile acids in the liver of C57BL/6 mice

“…The 12AL group was used as the control. We initiated CR at 20 weeks; this was performed to avoid any effect of CR on development while retaining effectiveness of increasing lifespan (Yu et al ., 1985). Mice were fed CR (or AL) diets for 12 weeks, before being sacrificed at 32 weeks of age.…”

Evidence for only two independent pathways for decreasing senescence in Caenorhabditis elegans

“…If a single cause of senescence, such as free radicals generated by mitochondria, exists, then all these life-extending manipulations may have one mechanism in common. To determine if there is a single pathway by which senescence is retarded, we have examined four separate manipulations that have been shown to increase lifespan in C. elegans: dietary restriction (DR), cold-/hypothermic-induced longevity (CHIL), decreased insulin signaling, and mutations influencing mitochondrial respiration (Ball et al 1947;Conti et alDietary restriction has been shown to extend lifespan by up to 50% in mammals (Davis et al 1983;Yu et al 1985;Weindruch and Walford 1982). In several different worm models of dietary restriction, evidence has revealed that DAF-16, a forkhead box O (FOXO) transcription factor that is required for lifeextension via the insulin pathway, is not required for the life-extending effects of dietary restriction (Houthoofd et al 2003;Lakowski and Hekimi 1998).…”

Significance of hepatic xanthine oxidase and uric acid in aged and dietary restricted rats

“…All rats were fed adlibitum until 6 weeks of age, at which time they were separated into two groups: ad libitum-fed (AL) control and diet-restricted (DR) group, whose food intake was restricted of 60% of the food intake of control. Detailed maintenance of animals and dietary procedures are published previously (23).…”