Preferential enrichment of liver phospholipids in docosahexaenoate relative to eicosapentaenoate in ω-3-depleted rats injected with a medium-chain triglyceride: Fish oil emulsion

The bolus intravenous injection of a novel medium-chain triglyceride:fish oil (FO) emulsion was recently proposed as a tool to provoke a rapid enrichment of cell phospholipids in long-chain polyunsaturated ω-3 fatty acids. In the present study, the enrichment of liver phospholipids and triglycerides in C20:5ω-3, C22:5ω-3 and C22:6ω-3 was assessed 60 min after the intravenous administration of FO (1.0 ml) to second-generation ω-3-depleted rats. When compared to uninjected rats, or animals injected with a control ω-3 fatty acid-poor medium-chain triglyceride:olive oil (OO) emulsion, the enrichment of liver phospholipids, and to a lesser extent liver triglycerides, attributable to the injection of the FO emulsion was more pronounced for C22:6ω-3 than C20:5ω-3, despite the presence of equal amounts of these two ω-3 fatty acids in the injected diglycerides and triglycerides. The possible determinants and potential beneficial effects of such a difference are briefly discussed.