Seaweed inclusion in artificial diet of purple sea urchin Paracentrotus lividus: effects on somatic and gonadal development

This work evaluated the inclusion of seaweed in artificial diet of Paracentrotus lividus sea urchins weighing between 11 and 14 g to test its effect on growth and gonadal yield. Initially, multiple-choice feeding preference assays were conducted using 20% fresh and dried specimens of Laminaria digitata, Sargassum muticum, and Ulva lactuca seaweeds incorporated into an artificial diet. Then, over the course of 20 weeks, experiments comprised of four different diets were carried out, including one for each seaweed incorporated into the artificial diet. Afterwards, sea urchins were weighed to evaluate somatic growth. From the eighth week onwards, animals were selected for gonadosomatic index and gonad coloration analyses. In the feeding preference test, fresh and dried L. digitata showed the best results. In test with seaweed incorporated into the artificial diet, the preference was for diets containing L. digitata and S. muticum. Both diets also promoted a higher gonadosomatic index than that of the control at the end of the experiment. Therefore, it can be concluded that the inclusion of L. digitata and S. muticum in the artificial diet of sea urchins can act as a food stimulant to improve growth performance.