Microalgae are widely used for mass culture of the rotifer Brachionus plicatilis in aquaculture. Since the nutritional value of the rotifer is closely related to its food, the nutritional value of its food should be known in detail. Chlorella ellipsoidea and Nannochloris oculata are representative food organisms for rotifers that are easily cultured. Therefore, the nutritional values of these micro algae were examined for ultrasmall, small, and large rotifers and Artemia nauplii. Chlorella ellipsoidea contained seven times more total fatty acids than N. oculata. The three types of rotifer fed N. oculata contained more amino acids than those fed C. ellipsoidea. However, the total fatty acids of the rotifers fed each microalga species differed according to the type of rotifer. Newly hatched Artemia nauplii contained more protein and had a higher dry weight than those fed microalgae for 6 h. As with the rotifers, the Artemia nauplii fed N. oculata contained more protein and amino acids than those fed C. ellipsoidea, while the reverse was true for the total fatty acid content. Our results suggest that N. oculata is a good supply of protein, while C. ellipsoidea is a good source of lipids as food organisms for rotifers and Artemia nauplii in aquaculture.
