Higher Dietary Arachidonic Acid Levels Improved the Growth Performance, Gonad Development, Nutritional Value, and Antioxidant Enzyme Activities of Adult Sea Urchin (Strongylocentrotus intermedius)

Abstract

The gonads of sea urchins (Strongylocentrotus intermedius) are characterized by high levels of arachidonic acid (ARA, 20:4n-6) and eicosapentaenoic acid (EPA, 20:5n-3). However, to our knowledge, little information is available regarding the physiological response of adult sea urchins to dietary ARA. In the present study, four dietary feeds were formulated with graded ARA (0, 0.5%, 1%, and 2% dry diet). Each diet was randomly allocated to three cages during a 56-day feeding experiment. The results showed that the sea urchin weight gain rate (WGR) and the gonadosomatic index (GI) significantly increased as ARA was equal to or above 1.0% of dry diet (P 0.05), but was significantly lower than those fed with kelp (P < 0.05). These results suggested that relatively higher levels of ARA (1% dry diet) significantly promoted growth, gonad development, activities of antioxidant enzymes, as well as nutritional values (TEAA, TEAA/TNEAA, and PUFA) of adult S. intermedius.