α-Tocopherol in Some Atlantic Fish and Shellfish with Particular Reference to Live-Holding Without Food

Abstract

Muscle tissue from four species of Atlantic fish (cod, dogfish, mackerel, and flounder) and one species of Pacific fish (sablefish) was examined for total lipid and α-tocopherol content. The values for α-tocopherol in both lean and fat major muscle tissues fell in the range 210–330 μg/g lipid. Lipids from cod and mackerel livers showed slightly higher values (430 μg/g lipid). These results are interpreted as the result of a lipid integration process in which the tocopherols produced by phytoplankton are redistributed with lipid through various lower life forms and small fish until similar levels are reached in the principal fats of larger fish. The metabolically active dark (lateral line) muscle of cod was twice as rich (630 μg/g) in α-tocopherol in proportion to lipid as white muscle tissue from cod. Lobster muscle was exceptionally rich (> 1200 μg/g) in α-tocopherol. Examination of starved cod indicated that large amounts of α-tocopherol remained after lipid depletion. Frozen flounder fillets showed no significant amount of α-tocopherol after 4 to 8 months frozen storage.Eight species of Atlantic shellfish were examined in toto. Oysters and quahogs lost their α-tocopherol after several weeks of live-holding without food. In the oysters this was accompanied by muscle weakening and an objectionable odour. Most filter feeding species in the normal environment had 1–2.5% lipid and α-tocopherol values of 300–600 μg/g lipid, but a high proportion of organic detritus in the diet of mussels from one area reduced this level. The quahogs examined were extremely low (~0.60%) in lipid and therefore relatively high in α-tocopherol in proportion to lipid (> 1000 μg/g). Herbivorous periwinkles and accompanying predatory dogwinkles had the highest α-tocopherol contents on a fresh weight basis (35 and 21 μg/g tissue) and high values in proportion to lipid (~850 μg/g).