Dietary beta-carotene absorption and metabolism in ferrets and rats

The ability of the ferret (Mustela putorius furo) to absorb dietary beta-carotene was studied to determine its appropriateness as a laboratory animal model for studies on beta-carotene metabolism. At baseline, the mean serum beta-carotene level in ferrets was 0.6 micrograms/dl and no beta-carotene was present in liver or adipose tissue. After the ferrets were fed 4 or 20 mg of beta-carotene/kg body wt daily for 2 wk, serum levels were 15.3 and 41.5 micrograms/dl, liver values were 0.9 and 4.1 micrograms/g and adipose tissue values were 0.1 and 0.2 microgram/g of beta-carotene, respectively. Thus, like humans, ferrets are able to absorb dietary beta-carotene intact. Further, these animals can store quantifiable amounts of dietary beta-carotene in their liver and, to a lesser extent, in adipose tissue. In contrast, serum beta-carotene levels in rats fed the two levels of beta-carotene were very low (0.5 to 0.6 microgram/dl) and no beta-carotene was found in liver or adipose tissue. Thus, the ferret is a more appropriate animal model for studying the intestinal absorption of beta-carotene and its storage and metabolism in body tissues.