Journal of the Faculty of Fisheries and Animal Husbandry, Hiroshima University Volume 12 Issue 1
1973-06-30 発行

養殖マダイの体色改善に関する研究 : I. アメリカザリガニ甲殻カロチノイドの投与効果

Natural Coloration of Cultured Red Sea Bream,Pagrus major (T. & S.) : I. Feeding Effects of Crayfish Carapace Carotenoids
Kayama, Mitsu
Nakagawa, Heisuke
Yamada, Hisashi
Murakami, Yutaka
When applying an artificial diet in the rearing of red sea bream, Pagrus major (T. & S.), one of the main problems is that the brilliant-redish-natural color of the skin and fins fades away slowly and turns dark. Hereupon, in order to improve the color appearance of cultured red sea bream, a feeding experiment of crayfish (Cambarus clarkii) carapace carotenods, in which astaxanthin in free and ester forms, astacene and β-carotene are major component, added to a basal diet (Nippai No. 6 P for trout) was experimented.

Red sea breams of 5 months (A) and 13 months (B) of age were grouped according to the kind of addition and raised during 8 weeks for the former, and 2 months for the latter as follows: β-carotene (A-1), carophyll red (10% canthaxanthin) (A-2), carotenes (A-3) and xanthophylls (A-4) separated from the unsaponifiable matter of crayfish carapace lipid, crayfish carapace lipid (A-5), crayfish carapace powder (A-6, B-1), and control (A-7, B-2) of basal diet.

The effects of the diet on the fish pigmentation were determined by naked eye observation, the total carotenoid content and the measurement of astaxanthin esters in the integument, muscle and liver of red sea breams. The group A-5 was significantly better colored, A-6 or B-1 came after, whilst the other groups remained almost similar in appearance to the control group, but A-2 indicated a little effect. Analytical examination of the integument showed significant increase in the level of total carotenoids as well as the deposition of astaxanthin esters in the group A-5 and A-6 or B-1.

It may therefore be concluded that when red sea breams are fed on ordinary rations plus astaxanthin either in the forms of free, ester with fatty acids or crustacyanin, they will absorb and deposit astaxanthin mainly in the form of esters in the integument of the fish. Moreover, the metabolic ability of red sea bream in the conversion of carotenoids was compared with that of other fish, such as fancy carp and goldfish, or crustacea, and was discussed.