Lipid oxidation in fresh and stored eggs enriched with dietary w3 and w6 polyunsaturated fatty acids and vitamin E and A dosages
AbstractTwo experiments were planned to study the influence of dietary fat sources (fish oil (FO) or sunflower oil (SO)) and dietary doses of -tocopheryl acetate (-TA) (0, 60 and 120 mg/kg of feed) and vitamin A (0 IU, 10000 IU and 20000 IU) on lipid oxidation of stored eggs in three stages of 0 or fresh, 1 and 2 months of storage time. In the first experiment, 96 hen layers in six treatments including two oil sources (FO and SO) and two dietary [0, 60 and 120 mg/kg doses of -tocopheryl acetate (-TA)] were fed for 75 days. In the second experiment, 96 hen layers in six treatments including two sources of w3 and w6 (FO and SO) and three doses 0, 10000 and 20000 IU of vitamin A were fed for 75 days. The results showed
that using -TA supplementation, lipid stability of enriched eggs increased and was very effective throughout the stored period of the eggs. Yolk TBA value was higher in fish oil than sunflower oil groups (p < 0.01). The treatments that contained 120 mg/kg of -TA in diets, showed lower lipid
peroxidation than other groups in stages of 2 and 3 storage time (30 and 60 days). The degree of lipid oxidation in fresh, 1 and 2 months of storage eggs was measured by the lipid TBA values. The results showed that TBA value in fresh and stored eggs was higher in groups containing fish oil than other groups (p < 0.01). The MDA value in stage 1 was higher in fish oil group and in 2 and 3 stages was lower in FO + A1. Therefore, addition of Vitamin E and A as natural antioxidants in diets containing oil source for the prevention of lipid oxidation is recommended.