Serum retinol, alpha-tocopherol, and lipids in four species of adult captive pinnipeds

The sera of adult aquarium-held pinnipeds from four species (family Phocidae: harbor seals (Phoca vitulina) and gray seals (Halichoerus grypus); family Otariidae: northern fur seals (Callorhinus ursinus) and California sea lions (Zalophus californianus)) were analyzed for vitamin A (retinol), vitamin E (alpha-tocopherol), total cholesterol, triglycerides, phospholipids, and fatty acids. Each subject animal was healthy at the time of blood collection, was fasted for at least 12 hr prior to sampling, and was maintained on a constant diet and supplement regime throughout the study. Retinol values for the four species ranged from 0.16 to 0.92 mug/mL, with the lowest concentrations seen in the harbor seals and the highest in the northern fur seals. Vitamin E values ranged from 10.55 to 43.58 mug/mL, with northern fur seals showing the highest and gray seals the lowest levels. Vitamin E/lipid ratios (cholesterol, triglyceride, phospholipid, and total lipids) were also examined. A significant correlation was seen between vitamin E and total lipids (P<0.05) and phospholipid (P<0.01). Statistical analysis of the retinol, tocopherol, triglyceride, and phospholipid levels showed significant differences between phocid and otariid seals. Otariids had significantly lower tocopherol and phospholipid values (19.36 mug/mL, 4.29 mg/mL) and the phocids had significantly lower retinol and triglyceride levels (0.29 mug/mL, 124 mg/dL). There was no significant difference in serum cholesterol. Zoo Biol 22:83-96, 2003. (C) 2003 Wiley-Liss, Inc.