The effect of microalgal diets on growth, biochemical composition, and fatty acid profile of Crassostrea corteziensis (Hertlein) juveniles

The culture of the mangrove oyster Crassostrea corteziensis is a promising enterprise on the Pacific coast of Mexico, yet little is known about the diet and essential nutrients required to maximize growth during culture. C. corteziensis juveniles were grown for 22 days under hatchery conditions and using monospecies or binary diets of the microalgal species Chaetoceros calcitrans, Chaetoceros muelleri, Isochrysis galbana clone T-iso, Phaeodactylum tricornutum, and Tetraselmis suecica. The monospecies diet of C. calcitrans provided a superior diet for C. corteziensis juveniles, yielding a growth rate up to 272-μm shell length day− 1. The nutritional value of the microalgae tested was in the order C. calcitrans > C. muelleri > I. galbana clone T-iso > P. tricornutum > T. suecica. The reasons for the different nutritional values of the algae investigated were not related to carbohydrate, protein, or lipid content. The HUFA composition of oysters was related to their diets. C. calcitrans is characterized by high levels of arachidonic acid (ARA; 20:4n-6). The monospecies diet of T. suecica, which yielded the lowest growth rate (107-μm shell length day− 1) lacked docosahexaenoic acid (DHA; 22:6n-3) together with having low levels of ARA and eicosapentaenoic acid (EPA; 20:5n-3) that could explain the poor performance of this diet. There were significant differences in the fatty acid composition of the oysters fed different diets but the only correlation with growth was in the case of ARA. We conclude that C. calcitrans supplies the appropriate nutrient balance that C. corteziensis needs at this juvenile stage.