Total carotenoids of the copepod Acartia clausi Giesbrecht, 1889 from the Caspian Sea at different growth stages fed different microalgal diets

In the Caspian Sea, the calanoid copepod Acartia clausi, a potential food for fish fry, obtains its carotenoids from plant sources. To determine the effects of microalgal diets containing Isochrysis galbana and Chaetoceros calcitrans on total carotenoids of nauplii, copepodites and adults of A. clausi, they were cultured under three microalgal treatments: I. galbana, C. calcitrans, and a mixture of these microalgae (5000, 15 000 and 30 000 cells/ml). Total carotenoids were measured separately using methanol and ethanol. The highest level of total carotenoids was observed in the copepodites fed 30 000 cells/ml of both C. calcitrans and the microalgal mixture, which were different from nauplii and adults fed 5000 and 15 000 cells/ml (p <= 0.05). The nauplii fed I. galbana showed higher total carotenoids than copepodites and adults (p <= 0.05). Ethanol and methanol worked differently for carotenoid extraction from A. clausi fed C. calcitrans compared with the other treatments (p <= 0.05). These solvents showed dissimilarities with 5000 cells/ml of C. calcitrans and I. galbana, as well as with 30 000 cells/ml of I. galbana and mixed microalgal diets. A mixed microalgal diet of 30 000 cells/ml is recommended for mass production of this species. The use of methanol is suitable for optimized extraction of total carotenoids.