Journal Article
Inclusion of Dunaliella salina in cold extruded and softly dried diets as a promising way to enhance the quality of Paracentrotus lividus gonads
Paula Canada; Inês Garrido; Luís F. Baião; Tiago Sá; Helena M. Amaro; A. Catarina Guedes; Tânia Tavares; Isabel Costa; F. Xavier Malcata; Filipa Amaro; Joana Pinto; Paula Guedes de Pinho; Luísa M. P. Valente
Journal of Applied Phycology · Vol. 37, Issue 3 · pp. 1633-1658 · 2025
Abstract
The unicellular alga Dunaliella salina is a good source of β-carotene whereas the macroalga Porphyra sp . is rich in flavor-enhancing amino-acids such as glycine. Therefore, this study focused on the development of new dietary formulations for Paracentrotus lividus, including D. salina, Porphyra or glycine, aimed at improving roe color and flavour. Five isonitrogenous and isoenergetic diets were produced by cold extrusion and soft drying, meant to protect carotenoids. Sea urchins were fed these diets every 2 days in a recirculating aquatic system, at 18ºC. At the end of 8 weeks all diets proved equally effective in promoting growth and improving the gonadossomatic index. However, there were differences in the feed conversion ratio, which was lower in sea-urchins grown upon a diet based on commercial macroalgae mix and supplemented with D. salina at 1.5% (D2). Notable differences were found between males and females on carotenoids deposition in both gut and gonads, gonadal proximal composition, volatile compounds and anti-oxidant activity. This suggests sex-related differences in both nutrient assimilation and several metabolic processes. Gut carotenoids were influenced by both sex and diet, but gonads carotenoids were only affected by sex. All diets supplemented with Dunaliella improved gonad colour, resulting in redder and darker gonads when compared to a control (non-supplemented) diet. In particular D2 allowed to produce gonads with a higher colour saturation ( C* ) and the lowest hue angle ( h* ), comparable to a gourmet reference. Glycine supplementation and Porphyra led to an increase of sweet tasting amino acids in P. lividus roe. Dunaliella salina and Porphyra also increased umami tasting amino acids. The overall results point to D2 as the most promising formulation for P. lividus grow-out, as it allowed to obtain good colour roe at a lower feed conversion ratio.