EFFECTS OF DIETARY VITAMIN E OR C ON LAYER HEN PERFORMANCE, SERUM PARAMETERS AND EGG CHOLESTEROL CONTENT

Cholesterol is one of causes of cardiovascular diseases in humans, but serum cholesterol has an important role for egg production in birds. There are conflicting hypothesis about dietary antioxidant effect on serum cholesterol, while very few experiment have been conducted on poultry. So this study was performed to evaluate the effect of dietary levels of antioxidant vitamins (vitamin E and C) on hen performance, egg quality, egg cholesterol, blood parameters including glucose, triglyceride as well as cholesterol and its components in laying hens. Total 168 Hy-Line W36 laying hens at 39 weeks of age were divided into 7 groups and 6 replicates with 4 hens in each replicate as completely randomized design. Treatments consisted of adding levels of 100, 200 and 400 mg vitamin E or C per kg of the basal diet. Vitamin E or C has not significant effect on hen performance. Yolk weight decreased (p<0.05) by increasing the level of antioxidant vitamins in the diet. Yolk cholesterol also decreased linearly with increasing dietary antioxidant vitamin. Vitamins, particularly vitamin C, caused a significant increase in serum glucose. Although, no significant differences were observed between groups in total serum cholesterol, but serum HDL cholesterol decreased, whereas LDL cholesterol increased (p<0.05) as dietary vitamin E or C increased in diets. It seems that vitamin E is more effective than vitamin C in modifying cholesterol contents. ...