Vitamin E deficiency has been documented and experimentally produced in captive pinnipeds consuming un-supplemented fish diets commonly fed in zoos and aquariums. A recommendation of l00 IU vitamin E/kg fish has been suggested as the level necessary to prevent deficiency diseases in piscivorous species. Thus vitamin E is commonly supplemented in the diets of captive pinnipeds. The concentrations of supplements provided to pinnipeds at 20 North American institutions were found to range from 50 to 4000 IU/day. Levels of vitamin E in whole fish will vary with species, age, diet, season and reproductive state and are often lower than recommended dietary levels indicating a need for supplementation.

This study investigates the absorption, metabolism and clearance of alpha tocopherol in captive male harbor seals consuming a single oral dose (100 ma) of d₆alpha-tocopherol acetate. Blood samples drawn over a 7 day period were analyzed for do (unlabeled) and d₆ (labeled) alpha tocopherol by gas chromatography/mass spectroscopy (GC/MS) after purification by high performance liquid chromatography (HPLC). A time versus concentration curve was generated from the data and the curve fitting program SAAM II was used to fit the curve and generate the time of apparent maximum absorption, mean sojourn time (MST) and disposal rate (DR). The amount of time vitamin E spends in the body before irreversible utilization (MST) was 244 ± 92 hours. The rate of loss of vitamin E from the body (DR) was 97 ± 25 IU/day. Dietary requirements for vitamin E in most animal species range from 5 to 50 IU/kg diet (NRC, 1987), but deficiencies have been recognized in captive wildlife consuming these levels, resulting in recommendations of l00 to 250 IU/kg dry diet (Robbing, 1993).