AUTHOR=Dayras Paul , Bialais Capucine , Sadovskaya Irina , Lee Min-Chul , Lee Jae-Seong , Souissi Sami 

TITLE=Microalgal Diet Influences the Nutritive Quality and Reproductive Investment of the Cyclopoid Copepod Paracyclopina nana

JOURNAL=Frontiers in Marine Science

VOLUME=8

YEAR=2021

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2021.697561

DOI=10.3389/fmars.2021.697561

ISSN=2296-7745

ABSTRACT=<p>Copepods represent an interesting alternative or a complement live food to brine shrimps and rotifers commonly used in aquaculture. They constitute the natural prey of many fish species and therefore do not require a potential nutritional enrichment. But an optimization of the microalgal diets used to feed copepods is essential to improve their mass culture. This study examined the effects of seven microalgal diets, namely single-species diets of <italic>Rhodomonas salina</italic> (R), <italic>Tisochrysis lutea</italic> (T), and <italic>Pavlova lutheri</italic> (=<italic>Diacronema lutheri</italic>) (P), two-species diets (R + T, T + P, and R + P), and a three-species diet (R + T + P), on the fatty acid and monosaccharide composition of the cyclopoid copepod <italic>Paracyclopina nana</italic> as well as its reproductive investment. Experiments were run during 15 days in 10-L beakers; starting with nauplii collected from a large 300-L batch culture. Copepods fatty acid contents were studied, particularly the relative amounts of docosahexaenoic acid (DHA) and eicosa-pentaenoic acid (EPA). The R + T, R, and T diets induced the highest total fatty acid amount in copepods. R + T and R also generated the lowest DHA/EPA ratios in copepods due to high EPA contents. The highest value of total monosaccharides was found in copepods fed with R + T + P. Diets R + T and R induced the greatest prosome volumes and clutch volumes in ovigerous females. Both prosome volume and clutch volume in <italic>P. nana</italic> ovigerous females were correlated to the individual EPA amount. The results demonstrated that all diets including <italic>R. salina</italic> enhanced the productivity of <italic>P. nana</italic> in mass culture, particularly when combined with <italic>T. lutea</italic>. <italic>R. salina</italic>, and <italic>T. lutea</italic> induced complementary fatty acid and monosaccharide profiles, confirming that R + T represents the best microalgae combination for productive culture of <italic>P. nana</italic>. Conversely, <italic>P. lutheri</italic> did not enhance the nutritional profile nor the fecundity of <italic>P. nana</italic> in the culture. This study is the first to demonstrate that <italic>R. salina</italic> is a suitable microalga for productive mass culture of <italic>P. nana</italic> for use as live food in aquaculture.</p>