Effects of Sage (Salvia Officinalis), Thyme (Thymbra Spicata), Mentha (Menthae Piperitae) Extracts and Vitamin E Supplementation at Different Levels Into Diets of Hens on Performance, Egg Quality and Yolk Tbars Values

This experiment was conducted to investigate the effects of sage, thyme, mentha extracts and vitamin e supplementation at different levels into diets of hens on performance egg qualty traits and the contents of cholesterol and triglyceride in yolk and serum. a total of 216 lohmann white layers, 36 weeks of age, were randomly allocated three tier battery cages, each having 6 replicate cages as subgroups, comprising of four hens. experimental treatments were applied two factors (4x3) plot design. the first factor consist of sage, thyme, mentha and vitamin e groups, the second factor was three different levels ( ppm 0, 150 and 300) of these plant extracts and vitamin e. while the experimental groups did not affect egg weight, feed conversion rate, shape index, shell tickness, yolk colour, albumen index and haugh unit, but they increased egg production, shell weight, shell stiffness (p<0.01) and decrased cracked egg rate (p<0.01). also, extract and vitamin e supplementation increased the content of serum cholesterol compared to level of 0 ppm (p<0.05). the extract and vitamin e supplementation reduced the values of tbars in egg stored at 21 and 42 days (p<0.01). in conslusion, sage and thyme from aromatic plant extracts used as alternative to antioxidants had possitive effects on some performance and egg quality parameters and can be used instead of vitamin e as preventing lipid oxidation. also, high level of these extracts (300 ppm) can be used as a hipocholesterolemic agent in layers.