• lipid oxidation;
  • fish oil;
  • n-3 eggs;
  • olive leaves;
  • α-tocopheryl acetate;
  • fatty acids



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.


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.


The results of this study suggested that dietary supplementation with both OL10 and TOC could protect n-3 fatty acids in eggs from deterioration.