Caloric-Restricted (CR) Colony

In the CR colony, rats are $12.00 per month of age. These prices apply to both CR and ad libitum (AL) controls from this colony. Both CR/AL controls are individually housed. CR controls are initiated at 14 weeks of age at 10 percent restriction, increased to 25 percent restriction at 15 weeks of age, and to 40 percent restriction at 16 weeks of age, where it is maintained throughout the life of the animal. CR/AL rats are sold only by age in months (i.e., 4 months or 24 months), not by weight or age in weeks. Survival curves, food intake curves, and body weights of NIA strains have been published (Turturro, et al., J Gerontology 54A: B492–B501, 1999).

Feeding instructions are provided with the CR animals. If ordering food, indicate how long the animals will be maintained so the contractor can calculate how much food is needed. When food is shipped by Harlan Truck, there is a flat rate freight charge of $12.00 per type of food (AL or CR). Food shipped by air freight or common carrier is subject to prevailing rates of the carrier. NIH31/NIA Fortified (for CR feeding) is available in weighed pellets at 0.5 gram intervals from 2.5 grams to 5.0 grams, at $10.00/kg. NIH31 (for AL feeding) is only available in "random weight chunk" formula, at $2.00/kg. Formulation of the diets is available from the Office of Biological Resources and Resource Development.