抄録
Besides astaxanthin, the existence of lutein and taraxanthin-like compound was confirmed as the carotenoids of red pigments in sea breams. The contents of astaxanthin in the cultured sea breams at the Ushine Fish Farm, Kagoshima, were only one-twentieth of those in the natural sea breams of the same size, caught around the Kagoshima Bay, so it was clarified that the faded color of the cultured sea breams at the Ushine Fish Farm was caused by the extremely small amount of astaxanthin contained in them.
It has commonly considered that fish, with all other animals, do not possess any ability to synthesize carotenoids de novo, but they can alter alimentary carotenoids by oxidation and can store the resulted products, therefore the contents of the stomach of natural sea breams were examined, and the half digested Squilla oratoria and other Crustacea were found in them. It was assumed that the most of astaxanthin in natural sea breams was brought about their foods.
The dried Euphausiacea, used as foods to the cultured sea breams at the Ushine Fish Farm, contained only a trace of astaxanthin in them. Most of their astaxanthin was assumed to have been oxidized and destroyed during the unsuitable storage. The bait containing more amounts of astaxanthin, like fresh Euphausiacea, should be given to the cultured sea breams at a fish farm as the foods.
