Suitability of Tisochrysis lutea at different growth phases as an enrichment diet for Brachionus plicatilis sp. complex
- PDF / 682,101 Bytes
- 15 Pages / 595.276 x 790.866 pts Page_size
- 89 Downloads / 195 Views
Suitability of Tisochrysis lutea at different growth phases as an enrichment diet for Brachionus plicatilis sp. complex rotifers Hideaki Matsui 1
&
Modesto Melden Briones Intoy 2 & Viliame Waqalevu 3 & Manabu Ishikawa 1,3 & Tomonari Kotani 1,3
Received: 18 May 2020 / Revised and accepted: 22 July 2020 # Springer Nature B.V. 2020
Abstract In larviculture of marine finfish, Tisochrysis lutea cultured cells have a potential to be a sustainable enrichment diet for rotifers due to its de novo synthesis of docosahexaenoic acid (DHA). To improve its effectiveness in rotifer enrichment for later larviculture, we determined which growth phase of T. lutea can enhance DHA in polar lipids (PLs) in Brachionus plicatilis sp. complex rotifers without reducing their vigor. Tisochrysis lutea was harvested at logarithmic growth phase, deceleration growth phase, and stationary phase. The ambient concentrations of phosphorus (P) and nitrogen (N), and fatty acid composition of microalgae were measured. P was limited between logarithmic and deceleration growth phases, followed by N starvation in stationary phase. Total lipid DHA was lowest in logarithmic growth phase, whereas DHA levels increased in deceleration growth phase and maintained at high levels even in stationary phase. PL-DHA also increased during deceleration growth phase, although its abundance dropped during stationary phase. In a rotifer enrichment trial, T. lutea harvested in each phase were fed to B. plicatilis sp. complex rotifers for 12 h. The highest PL-DHA value for cells in deceleration growth phase reflected the concentrations of the rotifers. No significant differences were found in rotifer growth rate and egg ratio. Rotifers fed cells in deceleration growth phase exhibited higher swimming speeds than those fed the other cells, potentially linking to increased larval capture success. Therefore, we recommend the deceleration growth phase as an optimal timing for T. lutea harvest for the effective enrichment of B. plicatilis sp. complex rotifers. Keywords DHA . Enrichment . Growth phase . Polar lipids . Rotifer . Tisochrysis
Introduction The euryhaline rotifer Brachionus is commonly used as a live feed in the initial feeding period during larviculture in numerous marine finfish species (Watanabe et al. 1978; Koven et al. 1990; Castell et al. 2003; Tomoda et al. 2004; Park et al. 2006; Thépot et al. 2016). In larval rearing fields, the enrichment of rotifers with docosahexaenoic acid (DHA) is critical, since DHA is an essential fatty acid for embryonic development and larval growth in marine finfish (Fernández-Palacios * Hideaki Matsui [email protected] 1
Faculty of Fisheries, Kagoshima University, Shimoarata 4-50-20, Kagoshima 890-0056, Japan
2
Institute of Aquaculture College of Fisheries and Ocean Sciences, University of the Philippines Visayas, 5023 Miagao, Iloilo, Philippines
3
The United Graduate School of Agricultural Sciences, Kagoshima University, Korimoto 1-21-24, Kagoshima 890-0065, Japan
et al. 1995). However, DHA concentrations of
Data Loading...
