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Our experiences in enriching table eggs with n-3 PUFA

Eggs are a good source of nutrients, such as protein, vitamins and minerals. By modifying laying hens’ feed, it is possible to influence the content and profile of fatty acids in eggs, aiming to increase the n-3 polyunsaturated fatty acids (PUFA) and to enable production of eggs with increased content of desirable functional ingredients. Such eggs represent a functional foodstuff and their consumption has health benefits. Functional ingredients or nutricines, such as n-3 PUFA, are efficient in protection against chronic diseases (arthritis, psoriasis, Crohn's disease), as well as in prevention of cardiovascular diseases. Omega-3 fatty acids are polyunsaturated fatty acids with a double bond on the n-3 position, i.e. on the third C atom. In the human nutrition, the most important n-3 fatty acids are α-linolenic (ALA, C18:3), eicosapentaenoic (EPA, C20:5) and docosahexaenoic (DHA, C22:6). ALA is a precursor of long-chain PUFA. Since conventional table eggs contain high portion of n-6 PUFA and low portion of n-3 PUFA, which affects the unfavorable n-6/n-3 PUFA ratio, laying hens' feed is supplemented with forages or mixtures that have a good source of n-3 PUFA. Thus, different oils, such as linseed, rapeseed, fish and algae oils, as well as their combinations, supplemented to laying hens feed significantly increase the portion of total n-3 PUFA and reduce the portion of n-6 PUFA in egg yolks. The results of our researches show that meal composition affects the FA profile in eggs. ALA in egg yolk may increase from 1.9 to 4.4 times, EPA from 3.3 to 7 times, and DHA from 1.7 to 5.5 times. Total n-3 PUFAs can be increased from 2.2 to 2.8 times. At the same time, the ratio of n-6 / n-3 PUFAs is reduced. Supplementation of oils may have negative effects on organoleptic properties of eggs (odor and taste), which occur because of the increased n-3 PUFA oxidation due to higher number of double bonds. For this reason, there are organic or synthetic antioxidants (Se, carotenoids, vitamin E) supplemented to laying hens' feed to prevent unwanted oxidative processes in eggs, as well as the occurrence of undesirable taste and odor. In this way, produced eggs have improved nutritional value and extended shelf life. Our researches have confirmed the efficient enrichment of eggs with n-3 PUFA by supplementing linseed, rapeseed, soybean and fish oils to laying hens' feed. Individual concentrations of ALA, EPA and DHA depend on the composition of forage (fat) in laying hens' diet. Vegetable oils (linseed, rapeseed oils) affect the increase of ALA, while the fish and algae oils affect the increase of EPA and DHA in egg yolks.

DHA ; EPA ; egg ; fish oil ; vegetable oils

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