Effect of artificial diets on growth, lipid utilization, and gonad biochemistry in the adult sea urchin Psammechinus miliaris

Three artificial extruded diets of high protein and varying lipid content w ere manufactured from dried kelp Fronds and commercially available raw mate rials. The diets were fed to replicate groups of Psammechinus miliaris (Ech inodermata: Echinoidea) over a 14-wk period. Survivorship, weight gain, gon ad index, and gonad biochemistry were monitored over the duration of the tr ial. The diets proved palatable to the urchins and were sufficiently stable in seawater for the urchins to consume in tank-based trials. All of the ar tificial diets enhanced gonad growth as compared to a reference group fed L aminaria saccharina fronds. The satisfactory performance of urchins fed a h igh-protein diet with a vegetable oil lipid source, composed mainly of olei c and linoleic fatty acids, suggests that P. miliaris is able to utilize ef fectively diets low in polyunsaturated fatty acids (PUFAs). This has positi ve implications for the manufacture of cost-effective urchin diet by exclud ing expensive raw materials (i.e., fishmeal, fish oil).