Influence of one selectedTisochrysis luteastrain rich in lipids onCrassostrea gigaslarval development and biochemical composition

Abstract

Effects of a remarkably high overall lipid Tisochrysis lutea strain (T+) upon gross biochemical composition, fatty acid (FA), sterol and lipid class composition of Crassostrea gigas larvae were evaluated and compared with a normal strain of Tisochrysis lutea (T) and the diatom Chaetoceros neogracile (Cg). In a first experiment, the influence of different single diets (T, T+ and Cg) and a bispecific diet (TCg) was studied, whereas, effects of monospecific diets (T and T+) and bispecific diets (TCg and T+Cg) were evaluated in a second experiment. The strain T+ was very rich in triglycerides (TAG: 93-95% of total neutral lipids), saturated FA (45%), monounsaturated FA (31-33%) and total fatty acids (4.0-4.7 pg cell À1 ). Larval oyster survival and growth rate were positively correlated with 18:1n-7 and 20:1n-7, in storage lipids (SL), and negatively related to 14:0, 18:1n-9, 20:1n-9, 20:4n-6 and trans-22-dehydrocholesterol in membrane lipids (ML). Surprisingly, only the essential fatty acid 20:5n-3 in SL was correlated positively with larval survival. Correlations suggest that physiological disruption by overabundance of TAG, FFA and certain fatty acids in larvae fed T+ was largely responsible for the poor performance of these larvae. 'High-lipid' strains of microalgae, without regard to qualitative lipid composition, do not always improve bivalve larval performance.

Use of a lipid rich strain reveals mechanisms of nitrogen limitation and carbon partitioning in the haptophyte Tisochrysis lutea

“…At steady state of this experiment in chemostat, the mutant strain limited by nitrogen accumulates 2 to 3-fold more storage lipids than the WT strain and membrane lipid were quite similar. Alkenones were very low in the mutant strain as previously observed [92]. The 2.2fold down-accumulated in 2Xc1 of the Very-long-chain 3-oxoacyl-CoA, putatively involved in alkenone biosynthesis, could have led to the lower concentration detected.…”

Understanding the mechanisms involved in the high sensitivity of Pecten maximus larvae to aeration

“…Holbach et al (2017) demonstrated that aeration had detrimental effects in small-volume (5 L) systems. Conversely, flow-through systems (without aeration) appeared to be a promising technique, though only at lower densities (10 larvae/mL) than those (e.g., 300 larvae/mL) that were successfully tested for professional purposes in oysters (Da Costa et al 2016;Robert et al 2017). Holbach et al (2017) also demonstrated that coupling a flow-through system with aeration, which may allow for higher larval density, increased P. maximus larval mortality, which reinforces the adverse effects of the hydrodynamic forces generated by aeration on this species.…”

Development of a screening procedure for the characterization of Botryococcus braunii strains for biofuel application

“…The system solvent used for the pre-run and run was composed of methyl acetate:isopropanol:chloroform:methanol:KCl aqueous solution of 0.25% (10:10:10:4:3.6, v:v:v:v:v). This method, routinely used and adapted to marine animal matrices (mainly bivalves) [37][38][39], allowed the separation of not only the different phospholipid classes present in these matrices, cardiolipin (CL), sphingomyelin (SM), lysophosphatidylcholine (LPC), phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS), and phosphatidylinositol (PI), but also some particular microalgae glycolipids such as monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG). However, two PL classes, present in the microalgae B. braunii, sulfoquinovosyldiacylglycerol (SQDG) and phosphatidylglycerol (PG), were co-eluted with PE (Fig.…”