Comprehensive Lipidomics Analysis Reveals the Effects of Different Omega‑3 Polyunsaturated Fatty Acid-Rich Diets on Egg Yolk Lipids

Dietary
supplementation with omega-3 polyunsaturated fatty acids
(n-3 PUFAs) for laying hens enriches eggs with these essential fatty
acids. However, the enrichment patterns and changes to intact lipids
in egg yolk have not been sufficiently revealed. Herein, egg yolk
lipids from hens fed with diets supplemented with flaxseed, Schizochytrium sp. residue, or their mixture were comprehensively
analyzed using ultraperformance liquid chromatography coupled with
quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). A total
of 335 individual lipid species covering 23 (sub)­classes were identified
and quantified. Distinct n-3 PUFA-lipid profiles were revealed among
different groups. Dietary α-linolenic acid (ALA) was mainly
deposited in the TAG fraction, whereas synthesized or preformed docosahexaenoic
acid (DHA) predominantly existed in the glycerophospholipid form.
Furthermore, different lipid species were identified and related lipid
pathways after dietary supplementation were analyzed. Collectively,
these findings provide us with new knowledge for production, nutritional
evaluation, authentication, and application of n-3 PUFA-enriched eggs.