Lipidomic characterization of phosphatidylcholine and phosphatidylethanolamine species of egg yolk lipid derived from hens fed flaxseed oil and marine algal oil

Authors: NEIJAT, MOHAMED - University Of Manitoba; ZACEK, PETR - Charles University, Czech Republic; Picklo, Matthew; HOUSE, JAMES - University Of Manitoba

Submitted to: Prostaglandins Leukotrienes and Essential Fatty Acids
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/9/2020
Publication Date: 9/19/2020
Citation: Neijat, M., Zacek, P., Picklo, M.J., House, J.D. 2020. Lipidomic characterization of phosphatidylcholine and phosphatidylethanolamine species of egg yolk lipid derived from hens fed flaxseed oil and marine algal oil. Prostaglandins Leukotrienes and Essential Fatty Acids. 161. Article 102178. https://doi.org/10.1016/j.plefa.2020.102178.
DOI: https://doi.org/10.1016/j.plefa.2020.102178

Interpretive Summary: Intake of long chain n-3 (aka omega 3) polyunsaturated fatty acids (LCn-3) is associated with a reduced risk of cardiovascular disease, but many foods are not naturally enriched in LCn-3. Providing laying hens with LCn-3 or with their plant-based n-3 fatty acid precursor (alpha-linolenic acid; ALA) may enrich LCn-3 in the resulting eggs. However, LCn-3 supplementation versus ALA supplementation in hens does not yield the same enrichment of LCn-3 in the resulting eggs. In order to understand these differences, we examined, at a very fine molecular level, the specific egg yolk fats that are changed with either LCn-3 or ALA supplementation. Our data show that LCn-3 and ALA are incorporated into specific, but different, molecular types of fat in the egg yolk at different concentrations. This work will assist with efforts to increase LCn-3 enriched foods in the marketplace and provides fundamental data for egg producers and animal nutritionists.

Technical Abstract: Membrane phospholipids, including phosphatidylcholine (PC) and phosphatidylethanolamine (PE), consist of distinct fatty acids occupying the sn-1 and sn-2 positions, reflecting the highly regulated nature of lipid biosynthesis. However, little is known about the influence of dietary lipids on the positional nature of fatty acids in tissues, including the enrichment of omega-3 polyunsaturated fatty acid (PUFA) in chicken egg yolk phospholipids. This study was undertaken to characterize the PC and PE species in egg lipids derived from Lohmann hens (n=10/treatment) randomly allocated to either a control (no supplementation), a flaxseed oil (FO) or a marine algal oil (MA) diet. Each of the FO or MA diets supplied three levels of total omega-3 PUFA (0.20, 0.40 and 0.60% of diet) that were provided for 6 weeks. A combination of multiplexed mass spectrometry (MS) experiments was used to determine total, isobaric, and position molecules for PC and PE in egg yolk. The distribution of phospholipids in the yolk was predominantly PC over PE (~72 vs. 23%, respectively) across treatments. The most abundant PC species in the yolk were PC 16:0/18:1 and PC 16:0/18:2, and the PE was mainly arachidonic acid-containing species (PE 18:0_20:4). The latter decreased (P < 0.0001) with increasing dosage of dietary omega-3 PUFA. MS analyses of PCs revealed several isobaric species for PC 36:5 (i.e., 16:1/20:4, 16:0/20:5, 18:3/18:2), PC 38:6 (16:0/22:6, 18:2/20:4, 18:1/20:5), and PC 38:5 (16:0/22:5, 18:1/20:4, 18:2/20:3, 18:0/20:5) containing eicosapentaenoic acid (EPA, 20:5). In PE, EPA was only attached to 16:0 (i.e., 16:0_20:5) and increased as a function of omega-3 PUFA intake. These results may assist to elucidate potential aspects regulating the limited enrichment of omega-3 PUFA, particularly EPA and docosahexaenoic acid (22:6) in chicken eggs. In addition, this study may provide further insight on how the manipulation of dietary omega-3 PUFA impacts the health of the developing chick embryo and hatchling.