Ensiling in acid — A method to stabilize astaxanthin in shrimp processing by-products and improve uptake of this pigment by rainbow trout (Salmo gairdneri)

Abstract It has been demonstrated that astaxanthin is stable in an acid silage of shrimp processing waste, but for a slow conversion of its diester to the corresponding monoester. The digestion by rainbow trout of the astaxanthin present in this waste material was improved by ensiling, to about 71% as compared to 45% in the corresponding fresh or dried material. Also the rate of accumulation of the pigment in the fish muscle was markedly higher in fish fed the silage diet than those given fresh or dried shrimp waste.