Pigmentation of Cultured Sweet Smelt Fed Diets Supplemented with a Blue-Green Alga Spirulina maxima

Abstract

Pigmentation of cultured sweet smelt Plecoglossus altivelis was attempted by using diets supplemented with a commercial preparation of Spirulina maxima, whose main carotenoid is zeaxanthin. Addition of 3 to 6% Spirulina to diets and feeding them for 10 weeks improved successfully the color of test fish. Supplementation of 4 to 8 mg lutein A per 100 g of diet was also tried for comparison and was found to be effective. Carotenoids in the diets were accumulated not only in the integuments but in the subcutaneous tissues. The contents of the integuments and subcutaneous tissues in the test groups were 4.2 to 5.7 mg/100 g and 19.5 to 44.0 mg/ 100 g, whereas those in the control group were 2.9 mg/100 g and 12.7 mg/100 g, respectively. In the integuments major carotenoids were zeaxanthin, β-cryptoxanthin, lutein B, and diatoxanthin together with minor ones such as 3’-hydroxyechinenone, cynthiaxanthin, and β-carotene triol. No lutein A was detected in the Spirulina-fed groups. In the subcutaneous tissues appreciable amounts of β-carotene and canthaxanthin were found in addition to the carotenoids mentioned above, but no lutein B was detected. Presumed metabolic pathways of carotenoids from diets to the integuments via the subcutaneous tissues were discussed. © 1987, The Japanese Society of Fisheries Science. All rights reserved.