Improving Fatty Acid Composition of Lipids Synthesized by Brachionus plicatilis in Large Scale Experiments

Nannochloropsis oculata and Chlorella sp. were cultivated in industrial scale bioreactors 300?L, under full sunlight and artificial light during night-time at various temperatures. The most abundant fatty acids were C18:3n-3 and C16:0 in Chlorella sp., whereas in N. oculata C16:0, eicosapentaenoic acid (EPA) and C16:1n-9 were predominant. Brachionus plicatilis cultivated in 2,500-L tanks on N. oculata, Chlorella sp. and Saccharomyces cerevisiae, was able to de novo synthesize as well as to elongate and desaturate pre-existing fatty acids in the feed. When fed with S. cerevisiae, B. plicatilis synthesized lipids containing EPA and docosahexaenoic acid (DHA), despite the fact that these fatty acids were absent in yeast lipids. Brachionus fed with Nannochloropsis synthesized DHA in non-negligible quantities. Brachionus enriched with various commercial preparations incorporated into its lipids substrate fatty acids but also synthesized new fatty acids such as C16:1n-9, C18:1n-9, C18:2n-6, EPA and DHA. Neutral lipid was the main lipid fraction while phospholipids predominated over glycolipids plus sphingolipids. The major amounts of EPA and DHA were observed in neutral lipids, noteworthy quantities of these fatty acids were also incorporated into body phospholipids. Interestingly, the high n-3 fatty acids content of rotifer lipids was retained even after the rotifers were grown in low n-3 fatty acid media.