Serum alpha- and gamma-tocopherols, retinol, retinyl palmitate, and carotenoid concentrations in captive and free-ranging bottlenose dolphins (Tursiops truncatus)

Concentrations of retinol, retinyl palmitate, p-carotene, a-carotene, crypt oxanthin, lutein, lycopene, cc-tocopherol, and gamma-tocopherol were measur ed in blood samples collected from 15 captive and 55 free-ranging bottlenos e dolphins (Tursiops ti truncatus). From June 1991 to June 1994, blood samp les were collected from captive animals residing at two locations; at Seven Seas (Brookfield Zoo, Brookfield, IL) and Hawk's Cay (Marathon Key, FL). B lood samples were collected from free-ranging animals from June 1991 to Jun e 1996. Retinol levels were not significantly different between captive dol phin groups. However, Seven Seas animals had higher (P < 0.01) serum retino l concentrations compared to free-ranging animals (0.061 vs 0.041 mu g/ml). Retinyl palmitate was not detected in the serum of captive or free-ranging dolphins. Alpha-tocopherol levels were significantly (P < 0.05) higher for Seven Seas dolphins (16.4 mu g/ml) than for Hawk's Cay (13.0 mu g/ml) and free-ranging dolphins (12.5 mu g/ml). Gamma-tocopherol concentrations were similar among captive and free-ranging dolphins. Free-ranging dolphins show ed levels of circulating carotenoids (lutein and beta-carotene) while the c aptive animals did not. Additional carotenoids (lycopene, alpha-carotene an d cryptoxanthin) were analyzed but not detected in any samples. Serum vitam in differences between captive and free-ranging dolphins may reflect the na tural diet or indicate some potential biological or nutritional status sign ificance. (C) 1999 Elsevier Science Inc. All rights reserved.