Abstract
Dunaliella salina is one of several carotenoid sources that have been considered to enhance gonad coloration in sea urchins, although its relatively high cost may limit routine use in commercial echinoculture. Identifying the minimum feeding duration required to achieve optimal results may offer a cost-effective strategy. This study evaluated a cold-extruded diet supplemented with 1.5% D. salina (DUN) as a finishing diet for Paracentrotus lividus , compared with a non-supplemented control diet (CTRL). Two finishing durations (4 and 8 weeks) were tested to assess dietary effects on carotenoid deposition, gonad color and texture. A consumer sensory evaluation was conducted at week 8 using the Rate-All-That-Apply method with 30 untrained panelists. DUN significantly enhanced gonad coloration in females through increased carotenoid deposition, with marked improvements observed as early as week 4. By week 8, female gonad color matched or exceeded high quality reference standards. Male gonads also showed improved coloration by week 8, although color saturation remained below values associated with high-quality reference samples. Still, regardless the sex, consumers rated DUN-fed gonads as visually more appealing, with no negative effects on flavour or mouthfeel. Finishing duration modulated carotenoid accumulation and gonad visual quality in a sex-dependent manner. A 4-week feeding period was sufficient to achieve marketable gonadosomatic index, texture and coloration in females, whereas males required a longer feeding duration to reach desirable gonad size and color. Overall, an 8-week finishing period with the DUN diet was optimal for maximizing gonad quality, while a 4-week may represent a cost-effective option when targeting female gonad production.