Biosynthesis of LC-PUFA in Ruditapes philippinarum: Cloning and tissue distribution of Fad and Elovl, and effects of microalgae diets varied in LC-PUFA composition on their expressions and fatty acids profile of this bivalve

To reveal the biosynthetic pathway of long-chain polyunsaturated fatty acids (LC-PUFA) in Ruditapes philippinarum , herein, two acid desaturases (Fads, including one Δ5 Fad and Δ6 Fad-like) three elongases very (Elovls, Elovl2/5 Elovl4-like) genes were firstly cloned from this bivalve their tissue distributions examined. Results showed that newly Fads Elovls contained corresponding conserved functional domains clustered closely with orthologs, respectively. Meanwhile, they expressed significantly higher digestive glands intestine. Subsequently, to further understand LC-PUFA biosynthesis R. effects dietary on Elovl expressions (FA) profile investigated by feeding microalgae varied compositions [including Chlorella sp. (rich 18:2n-6 18:3n-3), Chaetoceros calcitrans eicosapentaenoic acid, EPA), Isochrysis galbana docosahexaenoic DHA]. that, throughout experiment, up-regulated visceral mass (digestive intestine) fed sp., while no significant changes or slightly decreases observed those I. . Furthermore, C. not changed, whereas but then restored its initial level at end experiment. These results suggested could modulate adapt composition. The FA analysis a amount DHA EPA was found respectively, which reflected well FA. However, exhibited decrease 18:3n-3 increase products such as 20:3n-6 22:5n-3, indicating had certain capacity for biosynthesis. Collectively, study provided valuable insights into