@article{oai:ir.kagoshima-u.ac.jp:00000726,
 author = {TANAKA, Yoshito},
 issue = {2},
 journal = {鹿児島大学水産学部紀要=Memoirs of Faculty of Fisheries Kagoshima University},
 month = {2016-10-27},
 note = {The distribution of carotenoids in aquatic animals, crustacean, fresh-water red fish, marine red fish, sea sponge and starfish were confirmed in order to elucidate their metabolic pathways to their main carotenoids.
During identification of these carotenoids, three new carotenoids were isolated and their structural formulae were proposed. Two were isolated from Tedania digitata and Tethya amamensis, and their structures were proposed to be 3-hydroxy-7, 8-didehydro-β, x-carotene and 3, 4-didehydro-β, x-carotene. The other new carotenoid, an astaxanthin-like pigment,
was isolated from Onihitode, Acanthaster planci, and its structure was established to be 7, 8-didehydro-astaxanthin.
In these aquatic animals, the most abundant pigment is astaxanthin, which is the main substance of their coloration. Therefore, the present investigations were undertaken to pursue the biochemical pathways to astaxanthin through the distributions of carotenoids in tissues and feeding tests applying various kinds of carotenoids.
In these studies, it was found that aquatic animals could be classified into three types based on the biochemical oxidation pattern of carotenoids.
I. Prawn-type carotenoid oxidation: Most of crustacean belong to this type. They can oxidize carotenoids at the 3- and 3'-positions of β-ionone rings with oxo groups at the 4- and 4'-positions, and also at the 4- and 4'-positions of β-ionone rings with hydroxy groups at the 3- and 3'-positions. This implies that they can convert β-carotene, canthaxanthin and zeaxanthin to astaxanthin. Therefore, crustacean should be fed diets supplemented with β-carotene, canthaxanthin, or zeaxanthin for preventing the fading of their coloration.
II. Goldfish-type carotenoid oxidation: Most of fresh-water red fish in Japan belong to this type. They can oxidize carotenoids at the 4- and 4'-positions of β-ionone rings with hydroxy groups at the 3- and 3'-positions, but can not oxidize carotenoids at the 3- and 3'- positions of β-ionone rings with oxo groups at the 4- and 4'-positions. They can convert zeaxanthin and lutein to astaxanthin, but not canthaxanthin and β-carotene. Therefore,
these fresh-water red fish should be fed diets mixed with either zeaxanthin or lutein for maintaining or restoring their bright red color.
III. Sea bream-type carotenoid oxidation: Most of marine red fish belong to this group. They cannot oxidize carotenoids at the 3- and 3'-positions of β-ionone rings with oxo groups at the 4- and 4'-positions, and also at the 4- and 4'-positions of β-ionone rings with hydroxy groups at the 3- and 3'-positions. They cannot convert β-carotene, canthaxanthin, or zeaxanthin to astaxanthin. They can only transfer zeaxanthin, lutein, canthaxanthin, and astaxanthin from feed to their own tissues. Therefore, astaxanthin should be supplemented
to their diet for maintenance of color or improvement of faded color during culture.},
 pages = {355--422},
 title = {Comparative Biochemical Studies on Carotenoids in Aquatic animals},
 volume = {27},
 year = {}
}