Chemistry and utilization of plankton. XXI. Pigmentation of coho salmon cultured in sea net pens with Antarctic krill and littoral mysid.

Abstract

The pigmentation of the flesh of cultured coho salmon Oncorhynchus kisutch was examined on a practical scale by feeding diets supplemented mainly with Antarctic krill and littoral mysid both of which are rich in a red carotenoid, astaxanthin. Approximately 10, 000 and 6, 000 juvenile freshwater coho salmon weighing 160-180g were acclimatized to sea water and then maintained in two net pens for feeding. Diets No.1 and 2 that contained carotenoids at concentrations of 0.1-0.4mg end 1.1-4.1mg/100g, respectively. On the 127th day the fish from Diet No.1 group and as early as on about 50th day those from Diet No.2 group accumulated carotenoids in the flesh to 0.6mg/100g, the flesh color being fairly close to that of wild coho salmon. In the case of the fish from Diet No.2 group the content of carotenoids reached 1.0mg/100g on the 127th day, which is almost the same as that of wild fish.