Influence of a prepared diet and a macroalga (Ulva sp.) on the growth, nutritional and sensory qualities of gonads of the sea urchin Paracentrotus lividus

This study evaluated the growth of the purple sea urchin Paracentrotus lividus, fed with two diets, in sea- and land-based systems compared to wild populations. The experiments investigated the effects of the feeding regimes on gonad yield, nutritional traits and overall quality. Sea-based trials were performed by the CNR of Taranto (Trial S), whereas land-based trials were performed in the facilities of the University of Cagliari (Trial L). Urchins fed with a laboratory prepared pelletized diet (P), and a mix diet PU (50% of P-Diet and 50% of fresh Ulva sp.) were compared to wild urchins (W). In both trials the experimental diets supported a gonad growth when compared to wild population (p < .05). Sensory characteristics, assessed by 6 panel experts for each trial, highlighted significant differences in gonad colour and taste in both trials, while only in Trial S for texture (p < .05). The changes in the biochemical composition of sea urchins' gonads caused significant variations in the nutritional profile. Sea urchins fed with the experimental diets contained higher levels of total protein and lipids and PUFAs than wild sea urchins, although EPA, DHA and n-3/n-6 ratio, were lower in urchins fed with artificial diets. In Trial L, total free amino acids showed an increase respect to W gonads (p < .05), whereas in Trial S, total free amino acids showed a decrease only in sea urchin fed with P-Diet (p < .05). The results presented in this study provide evidence of the good performance of the formulated diet assuming its application for the development of Mediterranean echinoculture.