Effects of dietary n−3 fatty acid‐enriched chicken eggs on plasma and tissue cholesterol and fatty acid composition of rats

Abstract

The purpose of this study was to examine the effects of feeding n-3 polyunsaturated fatty acid (PUFA)-enriched chicken eggs on plasma and liver cholesterol levels and fatty acid composition in rats. Eggs were collected from laying hens fed diets containing 10% flax seed (Hn-3), 12% sunflower seed (Hn-6), or wheat and soybean meal control (CON). Yolk powders were prepared and fed at the 15% level to weanling female Sprague-Dawley rats for 28 days. Consumption of n-3 PUFA-enriched yolks significantly reduced both plasma and liver total cholesterol. Liver total lipids and phospholipids of rats fed Hn-3 diet were enriched with linolenic, eicosapentaenoic, and docosahexaenoic acids with a concomitant reduction of arachidonic acid in liver phospholipids. The plasma cholesterol of rats fed yolk powders enriched with n-6 PUFA (mainly linoleic acid) was reduced to the same extent as in those fed the n-3 enriched, but the liver cholesterol was significantly increased, indicating differential effects of dietary n-3 and n-6 PUFA. The results demonstrated that the cholesterolemic and tissue lipid modulating properties of chicken eggs could be modified in a favorable way by altering the fatty acid composition of yolk lipids through manipulation of laying hen diets.

Lipid composition of liver in rats fed diets supplemented with egg yolks of modified composition

“…If eggs of group FO laying hens are considered as n-3 enriched eggs, then our findings regarding the content of linoleic acid in the total liver lipids of rats differ somewhat from the findings of Jiang and Sim (1992). The liver of males in group F had a higher content of linoleic acid compared to groups C and L, but not in relation to group P which had the highest content of linoleic acid -even 13.66% ( Table 4).…”

“…Obvious difference between males end females was found in group L. In the males of this group there were no significant differences in concentration and content of total cholesterol in the liver comparing to control group ( Figure 6), but these differences were very clear in females ( Figure 5). Consumption of egg yolks enriched with n-3 polyunsaturated fatty acids not only reduced the pool of cholesterol in the body, but, more importantly, enriched total lipids and phospholipids in the liver with linoleic, eicosapentaenoic (C20:5n-3), docosapentaenoic (C22:5n-3) and docosahexaenoic (C22:6n-3) acid (Jiang and Sim, 1992). The greatest enrichment of yolks with n-3 polyunsaturated fatty acids was achieved after supplementation of diet for laying hens with flax seeds and oil (Jiang and Sim, 1992) and with fish oils (Hargis et al, 1991).…”

“…In addition, the contents of free and total cholesterol in the liver, but not in the heart, were significantly lower in rats fed mixtures with egg yolk powder. The same authors (Jiang and Sim, 1992) later found that feeding the yolks enriched with n-3 polyunsaturated fatty acids (PUFA) in rat's diet significantly reduced cholesterol in plasma and liver compared with the yolks of normal composition. Different fish oils and meals (Hargis et al, 1991), flax seed and oil (Jiang and Sim, 1991), or linolenic acid (Ahn et al, 1995) and rapeseed oil (Lewis et al, 2000) in the diet for laying hens increased the content of n-3 PUFA in egg yolks.…”

Healthy Pork Production through Dietary n6:n3 Ratio Regulation

“…Previous reports showed that consumption of n-3 polyunsaturated fatty acid (n-3 PUFA) significantly reduced plasma triacylglycerol, cholesterol and blood pressure (Jiang & Sim, 1992;Oh et al, 1994;Baik et al, 2010), and decrease atherogenic oxidative stress in vivo (Casós et al, 2010). In addition, Wan et al (2010) indicated that the aortic lesion area was significantly reduced with lower ratio of n-6:n-3 fatty acids.…”

The effect of dietary fat on the fatty acid composition and cholesterol content of Hy-line and Warren hen eggs

“…An alternative way to reduce the potential cholesterolaemic effect of eggs is to modify the fatty acid composition of the yolks (Elkin, 2006). The cholesterol-lowering effects of polyunsaturated fatty acids (PUFA) have been recognized for some years (Naber and Biggert, 1989), and feeding egg layers a diet rich in PUFA results in higher relative and absolute concentrations of PUFA in yolk total lipids (Jiang and Sim, 1992). In chickens, yolk cholesterol can be influenced by breed or strain (Chowdhury et al, 2002) or age of the hen (Vorlova et al, 2001); nonetheless, information on the influence of strain and age on egg fatty acid composition throughout the laying cycle is controversial (Elkin, 2006).…”