Larval development, survival and fatty acid profile of purple sea urchin (Paracentrotus lividus Lamarck, 1816 (Echinodermata: Parechinidae) fed with Phaeodactylum tricornutum diatom

Abstract

In this work, the effect of this microalga on the larval rearing of sea urchin Paracentrotus lividus was evaluated, and its use alone (D3) was compared with the application of multi-species diets (D1- Skeletonema costatum + Rhodomonas spp.+ P. tricornutum; D2- S. costatum + Rhodomonas spp.). To evaluate the success of the three diets, the development and survival of larvae fed the three diets was analyzed over 18 days. It was found that larvae fed the D3 diet grew and developed significantly faster than the other two diets (D1 and D2), but survival was significantly lower. To better understand the relationship between the larvae and their food, the fatty acid profile of the larvae fed the three diets was analyzed. The fatty acid profile of the three microalgae used was also analyzed. A correlation between the constitution of the larvae and their food was found, and the biosynthesis of some polyunsaturated acids, such as 20:5ω3 (EPA), 20:4ω6 (ARA), and 16:4ω3, was also verified. Despite the high nutritional value of P. tricornutum, it was found that this alga has a high EPA/ARA ratio, a ratio that may reduce larval survival. However, the association of this microalgal species with other species may contribute to improve the overall success of larval rearing.