Toxicological Sciences, Vol 52, 24-34, Copyright © 1999 by Society of Toxicology
KP Keenan, GC Ballam, KA Soper, P Laroque, JB Coleman and R Dixit
The diet can significantly alter the results of toxicity and
carcinogenicity studies. Ad libitum (AL) overfeeding of excessive calories
to sedentary adult rodents is one of the most poorly controlled variables
affecting the current rodent bioassay. AL-overfed rodents develop an early
onset of adverse metabolic events, endocrine- disruptive degenerative
diseases, and tumors that result in early morbidity and mortality. AL food
consumption is extremely variable, but has a strong correlation with adult
body weight, obesity, and survival. AL feeding of diets with modified
protein, fiber, and energy content are not as effective as simple, moderate
dietary (caloric) restriction (DR) in controlling these study variables.
Moderate DR (70-75% of adult AL) is operationally simple and controls adult
body weights, prevents obesity, and improves health and survival by
reducing or delaying diet- related endocrine, renal, and cardiac diseases.
Moderate DR provides a uniform rodent model, increases treatment exposure
time, and increases the statistical sensitivity of these chronic bioassays
to detect true treatment effects. Feeding a balanced diet by a moderate DR
regimen of 70-75% of the maximum, unrestricted adult AL food intake is
recommended for conducting well-controlled toxicity and carcinogenicity
studies.
ARTICLES
Diet, caloric restriction, and the rodent bioassay
Department of Safety Assessment, Merck Research Laboratories, West Point, Pennsylvania 19486, USA. kevin_keenan@merck.com
![]()
CiteULike
Connotea
Del.icio.us What's this?