Examination of the qualitative ability of some cold water marine teleosts to synthesise ascorbic acid

Activity of L-gulonolactone oxidase (GLO), which is involved in ascorbic acid (AA) synthesis, was measured in kidney and liver tissues of seven teleosts, Atlantic sterlet, Acipenser ruthenus, and Atlantic dogfish, Squalus acanthias. GLO activity was also measured in liver and kidney tissues of Atlantic halibut, Hippoglossus hippoglossus, and Atlantic salmon, Salmo salar, fed AA unsupplemented and AA supplemented diets. AA synthesis was not detected in both tissues of the seven teleosts but was found in the kidneys of sterlet and dogfish. The respective GLO activities were 240 and 513 mu g AA synthesised g(-1) kidney tissue h(-1). Cold water marine teleosts such as herring, Clupea harengus, eel, Anguilla anguilla, salmon, cod, Gadus morhua, mackerel, Scomber scombrus, halibut, and turbot, Scophthalmus maximus, lack GLO activity and therefore dietary AA supplementation is required in their culture. AA deficient as well as AA supplemented diets did not induce GLO activity in salmon or halibut. (C) 1998 Elsevier Science Inc. All rights reserved.