COMPARATIVE BIOAVAILABILITY OF DIET-BASED, OIL-BASED AND EMULSION-BASED PREPARATIONS OF VITAMIN-A AND BETA-CAROTENE IN RAT

The bioavailability of vitamin A and beta-carotene delivered from the diet, from an oily solution or from a lipid emulsion was studied in fe male and male rats both in moderate and in severe vitamin A-deficient states. Weaning rats were fed a vitamin A-free diet for 3 or 5 weeks a nd were thereafter supplemented with vitamin A or beta-carotene by ora l gavage with oil- or emulsion-based solutions or by diet. Vitamin A r epletion, as judged by growth rate and by vitamin A accumulation in ti ssues, was improved when aqueous- preparations of both micronutrients were selected, as compared with other treatments. The vitamin A equiva lence of beta-carotene ranged from 3.75 to 8.83 when emulsion- and oil - mediated supplementations were respectively achieved. Both vitamin A bioavailabity and vitamin A activity of beta-carotene were shown to b e related to the vitamin A status of the animal. No sex effect was obs erved on the measured parameters.