The ferret as a model for evaluation of the bioavailabilities of all-trans-beta-carotene and its isomers.

The objective was to develop the ferret as a model for evaluation of the bioavailabilities of natural and synthetic beta-carotenes in foods. For these studies, a low carotenoid purified diet was formulated that produced excellent food intake and adequate growth. After consuming the diet for 16 d, ferrets were randomly assigned to one of three groups. For a 10-d period, they ingested a standardized amount of all-trans-beta-carotene (18 mumol/L) from either carrot juice, a test beverage of beta-carotene beadlets dispersed in fruit juices, or a control beverage of beta-carotene beadlets dispersed in water. Accumulations of all-trans-beta-carotene in the sera, livers and adrenals of ferrets that consumed the carrot juice were significantly lower (P < 0.02) compared with those of ferrets that consumed the test or control beverages. The content of a cis-isomer component relative to that of all-trans-beta-carotene was higher in each beta-carotene beadlet-fortified beverage than in the liver and adrenal tissues of ferrets that ingested the beverage; the cis-isomer was not measurable in sera. The content of all-trans-beta-carotene relative to that of all-trans-alpha-carotene, a structural isomer, was higher in carrot juice than in sera of ferrets that ingested the juice. We conclude that: 1) all-trans-beta-carotene is less bioavailable from carrot juice than from beta-carotene beadlet-fortified beverages, and 2) there are apparent bioavailability differences between isomers of beta-carotene in ferrets.