Vitamin E Supplementation Reduces Dexamethasone–induced Oxidative Stress in Laying Hens

The objective of the present study is to research the effect of dietary vitamin E (Vit E) on the antioxidative status and lipid peroxidation in laying hens as well as in egg yolks under experimentally induced oxidative stress conditions via Dexamethasone (DEX) administrations. A total of 60 Egyptian local strain (Gimmizah) laying hens at 36 weeks of age were housed in individual cages in an open-sided building under a 16 hr light: 8 hr dark lighting schedule. Birds were randomly divided into four experimentally treatments [DEX (4 mg/hen/day), Vit. E (200 mg/kg diet), DEX+Vit. E (4 mg/hen/day+ 200 mg/kg diet; respectively) and control, n= 15]. Birds were provided with commercial feed and water ad libitum. All treatments lasted for 7 successive days. Oxidative stress induced by DEX injections significantly reduced egg production and egg weight. Vit. E recovered this reduction when supplemented to stressinduced hens, compared to DEX treatment. Highly yolk lipid oxidation was associated with oxidative stress treatment and it was reduced by Vit E supplementation. The same trend was observed in lipid peroxidation in plasma and liver. It could be concluded that super-nutritional levels of Vit E (200 mg/kg diet) may contribute in enhancing laying performance and antioxidative properties of laying hens under stress conditions.