Lab Rats Need Better Diets

Rodents fed all-you-can-eat diets may be skewing experimental results.

Hayley Dunning
Jul 18, 2012

Rats and mice used in toxicology testing and other studies are commonly give constant access to food, and allowed to eat as much as they want. Compared to larger lab animals that are fed regular meals, rodents on a free-for-all diet tend to have higher blood fat, higher, cholesterol, and greater incidence of heart damage and cancer, which can be problematic when investigating the toxicity of new drugs, among other inquiries. Fluctuating food intake can also promote hyperinsulinemia, a precursor for developing diabetes.

"The enhanced insulin sensitivity of the meal-fed rodent suggests that toxicology researchers using an ad libitum model are unknowingly using a diabetic-type model," said Gale Carey and Lisa Merrill from the University of New Hampshire in their new study published online May 29 in Chemical Research in Toxicology.

Reviewing more than 50 published studies from the past 40 years, Carey and Merrill say their review supports...