Effect of diet on the biochemical composition of Paracentrotus lividus (Echinodermata: Echinoidea) under natural and rearing conditions (effect of diet on biochemical composition of urchins)

The biochemical composition (expressed as % dry weight) of the test, gut and gonad of Paracentrotus lividus was estimated. Sea urchin biochemical composition was studied in two natural populations of a coastal Mediterranean lagoon and in two rearing stations, one in open sea and one inland. Artificials feeds were administered to the reared urchins in order to evaluate variations in the biochemical composition of this species when provided different food resources. The results reveal that, for the natural populations examined in this study, the biochemical composition of the gonad, gut, and test do not depend on food availability and, hence on the quantity of food consumed. The comparison between wild and reared sea urchin biochemistry reveals that organ biochemical composition is strongly influenced by the quality of the feed. The use of artificial feed containing fish meal (rich in protein), favours a storage of reserves in the gonad, the gut, and even in the test in the form of lipids and/or carbohydrates. This is true for both open sea and inland rearing.