The status of circulating vitamins A and E was studied in captive and free-ranging bottlenose dolphins. Blood samples were collected from eight captive animals, four from each of two facilities and 32 free-ranging dolphins. The primary circulating vitamin A form in animals is retinol. The animals housed at Brookfield Zoo's Seven Seas facility had elevated retinol levels (mean = 6.1 mcg/100ml) compared to those at the Hawk's Cay facility (mean = 3.6 mcg/100ml) and the free-ranging dolphins (mean = 3.5 mcg/100ml). A review of diets showed that the animals at Seven Seas were receiving high levels of supplemental vitamin A compared with those at Hawk's Cay. However, all the values appear low when compared with other mammals and fish-eating animals. Free-ranging dolphins showed levels of circulating carotenoids (lutein and beta-carotene) while the captive animals did not. Animals depend on dietary intake for carotenoids. Some fish contain unchanged lutein as well as considerable levels of beta-carotene. Lutein and beta-carotene contain vitamin A activity in a number of animals. It is not known whether dolphins can utilize carotenoids. Additional carotenoids were analyzed but not found in any dolphin (Cryptoxanthin, lycopene, Gama carotene). Retinyl palmitate, the predominate storage form of vitamin A, also was not found.

Forms of vitamin E that are naturally present in foods include alpha and gamma-tocopherol. In animal tissues, alpha-tocopherol is the predominant active form. Dolphins had similar alpha-tocopherol levels: Seven Seas (mean 1114 mcg/100ml), Hawks Cay (mean = 1127 mcg/100ml), free-ranging (mean 1131 mcg/100ml). These values appear elevated when compared to other mammals but is within the range of that reported for fish-eating birds. None of the captive dolphins had circulating gamma- tocophero 1. In contrast, 21 of the 32 free ranging dolphins possessed gamma-tocopherol.