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 30gkg1 fish oil. Two other groups were given the same diet further supplemented with olive leaves at 5 (OL5) and 10 (OL10) gkg1 respectively, while the diet of the fourth group was supplemented with -tocopheryl acetate (TOC) at 200mgkg1. Eggs were analysed for lipid hydroperoxide and malondialdehyde (MDA) contents, fatty acid profile, -tocopherol content and susceptibility to iron-induced lipid oxidation. RESULTS Neither OL nor TOC supplementation affected (0.05) the fatty acid composition. Dietary supplementation with OL10 or TOC reduced (P0.05) the lipid hydroperoxide content but exerted no (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 (P0.05) MDA levels than the control but lower (P0.05) than the OL10 group. Eggs from the TOC group presented lower (P0.05) 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.