The phospholipid (PL) and triglyceride (TG) content and fatty acid (FA) pattern are altered in several organs of rats depleted in long-chain polyunsaturated ω3 fatty acids (ω3D rats). The present study extends these findings to brain lipids. Sixteen control rats (C) were compared to 18 non-injected ω3D rats (ω3-NI). Two groups (n = 29-30) of ω3D rats were injected intravenously 60-120 min before sacrifice with 1.0 ml of either a medium-chain triglyceride-fish oil emulsion (ω3-FO) or a control medium-chain triglyceride-olive oil emulsion (ω3-OO). The total FA content was 17 % lower and that of C22:5ω3 and C22:6ω3 10 times lower in the PL of ω3-NI vs C. As judged from both the C18:2ω6/C20:4ω6 and C20:4ω6/C22:4ω6 ratios, the metabolism of ω6 FA was more efficient in ω3D rats. The Δ9-desaturase activity appeared unaffected (C16:0/C16:1ω7) or decreased (C18:0/C18:1ω9). The total FA content of TG (µg/g wet wt.) was not significantly different in ω3-NI vs C rats. The TG C18:0/C18:1ω9 ratio was lower in ω3-NI than in C. The sole significant differences between ω3-FO vs ω3-OO or ω3-NI consisted in a slightly higher C22:5ω3 content of PL in ω3-FO vs ω3-OO and ω3-NI and a slightly higher FA content of PL in ω3-FO vs ω3-OO. In addition to the expected changes in ω3 and ω6 FA, the present findings reveal an unexpected decrease of brain PL content in ω3D rats, the lack of ectopic lipid deposition and opposite changes of C18:0/C18:1ω9 ratio in PL vs TG.
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