Olive leaves ( Olea europaea L.) versus α ‐tocopheryl acetate as dietary supplements for enhancing the oxidative stability of eggs enriched with very‐long‐chain n ‐3 fatty acids

BACKGROUND Ninety‐six brown Lohmann laying hens were equally assigned into four groups with six replicates. Hens within the control group were given a corn/soybean‐based diet supplemented with 30 g kg −1 fish oil. Two other groups were given the same diet further supplemented with olive leaves at 5 ( OL5 ) and 10 ( OL10 ) g kg −1 respectively, while the diet of the fourth group was supplemented with α ‐tocopheryl acetate ( TOC ) at 200 mg kg −1 . Eggs were analysed for lipid hydroperoxide and malondialdehyde ( MDA ) contents, fatty acid profile, α ‐tocopherol content and susceptibility to iron‐induced lipid oxidation.RESULTS Neither OL nor TOC supplementation affected ( P  > 0.05) the fatty acid composition. Dietary supplementation with OL10 or TOC reduced ( P  ≤ 0.05) the lipid hydroperoxide content but exerted no ( P  > 0.05) effect on the MDA content of fresh eggs compared with controls. Eggs submitted to iron‐induced lipid oxidation from the OL5 group presented higher ( P  ≤ 0.05) MDA levels than the control but lower ( P  ≤ 0.05) than the OL10 group. Eggs from the TOC group presented lower ( P  ≤ 0.05) MDA levels compared with all groups at all incubation time points.CONCLUSION The results of this study suggested that dietary supplementation with both OL10 and TOC could protect n ‐3 fatty acids in eggs from deterioration.