Effects of different levels of iron, iodine and vitamin B12supplementation on egg quality and antioxidant capacity of eggs at different times of storage in laying hens

The experiment was carried out to evaluate the effects of adding different levels of iron salts, iodine and vitamin B12 on yield, quality traits and antioxidant capacity of eggs in laying hens. A total of 320 laying hens (HyLine Variety White, 28 wk old) in a 2x2x2 factorial experiment were randomly assigned to 8 groups, and each group consisting of 40 hens (5 replicates of 8 hens each) for a period of approximately 13 weeks in a completely randomized design. Hens in the control group received a basal diet with no supplementation whereas hens in treat 2 received basal diet supplemented with 400 mg Fe/kg as FeSO4, treat 3 (basal diet + 450 mg I/kg as KI), treat 4 (basal diet + 0.1 mg B12vit/kg), treat 5 (basal diet + 400 mg Fe/kg as FeSO4 + 450 mg I/kg as KI), treat 6 (basal diet + 400 mg Fe/kg as FeSO4 + 0.1 mg B12Vit/kg), treat 7 (basal diet + 450 mg I/kg as KI + 0.1 mg B12Vit/kg), treat 8 (basal diet + 400 mg Fe/kg as FeSO4 + 450 mg I/kg as KI + 0.1 mg B12Vit/kg), respectively. The results showed that the use of iodine and vitamin B12 increased the shell thickness of eggs (P