Two microalgae Crypthecodinium cohnii and Phaeodactylum tricornutum as alternative source of essential fatty acids in starter feeds for seabream (Sparus aurata)

Abstract

Despite oils extracted from algae and other microorganisms that may constitute excellent sources of HUFAs, few studies havedetermined the nutritional value of different microalgal species for young marine fish. Six thousand gilthead seabream (Sparusaurata) postlarvae (73 mg body weight) were fed for 57 days diets containing either fish oil as a single lipid source or 2 and 4% ofCryptecodinum cohniior 5%Phaeodactylum tricornutum. Fish oil substitution byC. cohniiresulted in improved fish survival anda very good growth performance, in agreement with a higher proportion of DHA in diets and in total lipids of fish. Incorporation ofDHA and other fatty acids was proportional to their contents in diet suggesting the good nutritional utilization of homogenizedC. cohnii. Lower survival rates were found in fish fedP. tricornutumand could be related to an epithelial degeneration observed inthe anterior intestine. This degeneration could be related to a higher lipid content in these fish or to the strong hornlike cornutateprocesses found in the valves of the diatomP. tricornutum.