Abstract

This study was conducted to investigate the effect of feeding two forms (powder and extract) of green tea and marigold as well as α-tocopheryl acetate on performance, egg quality, egg yolk and also serum cholesterol concentrations of laying hens. A total of 150 hens, aged 64 weeks were divided into six groups with five replicate cages containing five hens each for each treatment. Dietary treatments were as following: control, two diets including 0.5% extract of green tea (Gteaext) or marigold (Marext), two diets including 1.5% powder of green tea (Gteapow) and marigold (Marpow) and an α-tocopheryl acetate (α-TA) diet (200 mg/Kg). Feeding α-TA significantly (p<0.05) improved feed intake, egg production, yolk weight, and yolk index. Feeding Gteaext decreased feed consumption and feed conversion ratio. Compared to control, serum low-density lipoprotein (LDL) and cholesterol concentrations were reduced by diets containing Gteaext, Marext, Gteapow or α-TA, significantly (p<0.05). Also, feeding Gteaext reduced serum triglycerides and increased ratios of HDL to cholesterol and LDL in comparison to control. Egg yolk cholesterol was greater in hens on Marpow and control compared to other diets. In general, incorporating antioxidant components derived from herbal plants (green tea and marigold) in laying hens diets as alternative options for α-tocopheryl acetate can be effective based on cost and availability.

Key words: Natural antioxidants, yolk cholesterol, laying hens, egg quality, green tea extract, marigold extract.