The health promoting omega-3, -7, and -5 fatty acids, α-linolenic acid (ALA), docosahexaenoic acid (DHA), rumenic acid (RmA), and α-eleostearic acid (α-ESA)/punicic acid (PunA), are not currently combined in frequently consumed food items. We have evaluated the impact of supplementing laying hens' feeds with flaxseeds combined with oil derived from seeds of either Ricinodendron heudelotii, an α-ESA source, or Punica granatum, a PunA source, on the egg fatty acid profile. The supplemented diets increased the egg content in ALA, DHA, RmA, as well as α-ESA or PunA. The combination of dietary lipids did not affect the conversion rate of ALA into DHA. Hens fed on R. heudelotii or P. granatum seed oil both accumulated RmA in egg yolk, indicating an efficient conversion from the α-ESA or PunA precursors through a Δ-13 reductase activity. The accumulation of PunA in eggs was largely higher than that of α-ESA.

Long-term feeding trials examining the incorporation of conjugated linolenic acids (CLnA) into the diet of laying hens are lacking. In the present study, we compared two diets in sixty-six red Sex-Link hens (33 hens/treatment), fed for 26 weeks. The control diet was high in oleic acid, while the test diet was high in α-linolenic acid (ALA) and punicic acid (PunA). No significant differences were observed between treatments for hens’ performance, egg weight and yolk weight. In contrast, dietary ALA and PunA resulted in a significant increase in n-3 PUFA, rumenic acid (RmA) and PunA contents in egg yolk, as well as in the liver, heart, muscle and adipose tissue of the hens. Other conjugated dienes resulting from the metabolism of PunA or RmA also accumulated in the egg yolk and tissues. Unlike DHA, which was exclusively distributed in phospholipids, ALA, RmA and PunA were preferably distributed in triglycerides.

Alpha-linolenic acid (ALA), docosahexaenoic acid (DHA), rumenic acid (RmA), and punicic acid (PunA) are claimed to influence several physiological functions including insulin sensitivity, lipid metabolism and inflammatory processes. In this double-blind randomized controlled trial, we investigated the combined effect of ALA, DHA, RmA and PunA on subjects at risk of developing metabolic syndrome. Twenty-four women and men were randomly assigned to two groups. Each day, they consumed two eggs enriched with oleic acid (control group) or enriched with ALA, DHA, RmA, and PunA (test group) for 3 months. The waist circumference decreased significantly (−3.17 cm; p < 0.001) in the test group. There were no major changes in plasma insulin and blood glucose in the two groups. The dietary treatments had no significant effect on endothelial function as measured by peripheral arterial tonometry, although erythrocyte nitrosylated hemoglobin concentrations tended to decrease. The high consumption of eggs induced significant elevations in plasma low-density lipoprotein (LDL)- and high-density lipoprotein (HDL)-cholesterol (p < 0.001), which did not result in any change in the LDL/HDL ratio in both groups. These results indicate that consumption of eggs enriched with ALA, DHA, RmA and PunA resulted in favorable changes in abdominal obesity without affecting other factors of the metabolic syndrome.