Comprehensive Fatty Acid Profiling of Diets and Tissues

Fatty acid profiles of mouse diets and tail and colon tissues were analyzed by gas chromatography (GC), as described previously [18 (link),97 (link)]. Briefly, tissue or food samples were ground to powder under liquid nitrogen and subjected to total lipid extraction and fatty acid methylation by 14% boron trifluoride (BF3)-methanol reagent (Sigma-Aldrich) at 100 °C for 1 h. Fatty acid methyl esters were analyzed using a fully automated HP5890 gas chromatography system equipped with a flame-ionization detector (Agilent Technologies, Palo Alto, CA, USA). The fatty acid peaks were identified by comparing their relative retention times with the mixed commercial standards (NuChek Prep, Elysian, MN, USA), and the area percentage for all resolved peaks were analyzed by using a PerkinElmer M1 integrator. The fatty acids examined as total n-6 PUFA with GC include: Linoleic acid (C18:2n6), Gamma-linolenic acid (C18:3n6), Eicosadienoic acid (C20:2n6), Dihomo-gamma-linolenic acid (C20:3n6), Arachidonic acid (C20:4n6), Docosadienoic acid (C22:2n6), Adrenic acid (C22:4n6) and Docosapentaenoic acid (22:5n6). The fatty acids examined as total n-3 PUFA with GC include: α-Linolenic acid (C18:3n3), Eicosatrienoic acid (C20:3n3), Eicosapentaenoic acid (C20:5n3), Docosapentaenoic acid (C22:5n3), and Docosahexaenoic acid (C22:6n3).