High performance liquid chromatography-tandem mass spectrometry of phospholipid molecular species in eggs from hens fed diets enriched in seal blubber oil

The total lipid fraction of eggs from hens fed diets enriched in seal blubber oil (1.25–5.0% SBO)was directly analysed with normal-phase high performance liquid chromatography coupled on-line with electrospray ionization ion-trap tandem mass spectrometry (HPLC-ESI-MS–MS) for the identification of the molecular species of phospholipids (PLs). The species of phosphatidylethanolamine (PE) and phosphatidylinositol (PI) were all detected as the [M−H]− ions. The phosphatidylcholine (PC), sphingomyelin (Sph) and lysophosphatidylcholine (LPC) classes, were detected as formate adducts [M + HCOO]−. Tandem MS of PE and PI showed the loss of the carboxylate anions, and, for PI, also the loss of water and inositol. Product ion spectrum of PC, LPC and Sph contained only the [M−CH3]− ion fragment. Feeding different levels of SBO for 5 weeks resulted in a significant increase of PE, PC and PI molecular species carrying eicosapentaenoic acid (C20:53, EPA), docosapentaenoic acid (C22:53, DPA) and docosahexaenoic acid (C22:63, DHA), but not Sph nor LPC. The highest increase of the omega3/omega6 ratio occurred for PE and PC. On the contrary, PI was less affected by the increase of SBO in the die

Positional analysis of egg triacylglycerols and phospholipids from hens fed diets enriched in refined seal blubber oil

The effect of feeding laying hens with refined seal blubber oil (SBO, containing 22.2% ω3 polyunsaturated fatty acids) on the fatty acids composition and regiospecific distribution of fatty acids in triacylglycerols (TAG) and phospholipids (PL) of egg produced was investigated. The hens were fed four diets containing 0 (control), 1.25, 2.5 or 5% SBO for 5 and 9 weeks. Comparison of the total fatty acids composition indicated that a 5 week feeding period was sufficient to obtain the highest amount of total polyunsaturated fatty acids in the eggs. The fatty acids composition of the egg lipids reflected the fatty acids composition of the diet. The substantial reduction in the ω6/ω3 ratio (ie 8.5 to 2.6) is of interest, and is in line with the recommendations of health authorities in several countries, where it has been suggested that the human diet should contain a ω6/ω3 ratio of 3–4. The greatest reduction of the ω6/ω3 ratio occurred for diet A (control) and diet B (1.25% SBO). Principal component analysis analysis of the fatty acids composition of egg lipid showed four clusters representing: (i) the control diet; (ii) the diet containing 1.25% SBO as well as samples obtained from feeding 2.5% SBO for 9 weeks; (iii) the diet with 5% SBO; and (iv) samples obtained from hens fed 2.5% SBO for 5 weeks. More ω-3 polyunsaturated fatty acids (ω3 PUFA) were incorporated in phosphatidylethanolamine and phosphatidylcholine than in TAG. Although ω3 were predominantly linked in the position Sn-1,3 of TAG in SBO, they were esterified in the Sn-2 position of the TAG and PL of eggs obtained after feeding laying hens with enriched diets