Abstract
The effect of the microalgae Haematococcus pluvialis and Chorella zofingiensis, and synthetic astaxanthin on the gonad of the sea urchin Anthocidaris crassispina was studied. The basal diet was supplemented with H. pluvialis, C. zofingiensis, or synthetic astaxanthin, at two levels of astaxanthin (approximately 400 mg/kg and 100 mg/kg), to obtain the experimental diets HP1, HP2, CZ1, CZ2, AST1, and AST2, respectively, for two months of feeding experiment. The results showed that the concentrations of astaxanthin in the gonads of the sea urchins fed these experimental diets ranged from 0.15 to 3.01 mg/kg dry gonad weight. The higher astaxanthin levels (>2.90 mg/kg) were found in the gonads of the sea urchins fed the diets HP1 (containing 380 mg/kg of astaxanthins, mostly mono- and diesters) and AST1 (containing 385 mg/kg of synthetic astaxanthin). The lowest astaxanthin level (0.15 mg/kg) was detected in the gonads of the sea urchins fed the diet CZ2 (containing 98 mg/kg of astaxanthins, mostly diesters). Furthermore, the highest canthaxanthin level (7.48 mg/kg) was found in the gonads of the sea urchins fed the diet CZ1 (containing 387 mg/kg of astaxanthins and 142 mg/kg of canthaxanthin), suggesting that astaxanthins, especially astaxanthin esters, might not be assimilated as easily as canthaxanthin by the sea urchins. Our results show that sea urchins fed diets containing astaxanthin pigments show higher incorporation of these known antioxidant constituents, with the resultant seafood products therefore being of potential higher nutritive value.
Highlights
The sea urchin Anthocidaris crassispina is commonly found in the coastal waters of southern China and is an economically important species in China [1,2,3]
The results indicated that the absorption of astaxanthins by sea urchins from the alga C. zofingiensis, which contains 16.1% of astaxanthin monoesters and 81.7% of astaxanthin diesters, was much lower than that from the alga H. pluvialis, which contains 48.1% of astaxanthin monoesters and 49.1% of astaxanthin diesters, demonstrating that the accumulation of astaxanthin in the gonads was different when supplied as free, monoesters, or diesters in the diets
The present study investigated the effects of the microalgae H. pluvialis containing a large amount of astaxanthin esters, Chorella zofingiensis containing an amount of astaxanthin esters and a small amount of canthaxanthin, and synthetic astaxanthin in the gonad of the sea urchin A. crassispina
Summary
The sea urchin Anthocidaris crassispina is commonly found in the coastal waters of southern China and is an economically important species in China [1,2,3]. The quality of gonad depends on its mass and appearance, especially its color, which is one of the major factors affecting the marketability of sea urchins [6], and is determined by the composition of carotenoids accumulated in the gonads of sea urchins [7]. The red ketocarotenoid astaxanthin, 3,3′-dihydroxy-β,β-carotene-4,4′-dione, is one of the major carotenoids naturally found in sea urchins and has been added to feed to improve gonad color of the sea urchins [8,9]. The gonads of sea urchins containing astaxanthin have a higher nutritive value. H. pluvialis is the richest source of natural astaxanthin among all algal species reported [11,12,13], and C. zofingiensis is proposed as a promising producer of astaxanthin because of its capability of accumulating astaxanthin under heterotrophic conditions [14,15,16]
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