الفهرس 
NTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
1. Introduction
It is well known that nutrition, age, and health status, as well as housing system, are key factors influencing the productive and reproductive performance of laying hens (Ahmadi and Rahimi, 2011).
In recent years the phytogenic feed additives originating from plants and consist of herbs such as chicory, spices, fruit, and other plant parts are relatively young classes of feed additive that have gained considerable attention in feed industry. The medicinal plants active components, often called phytobiotics or botanicals, are secondary metabolites in medicinal plants with positives effects on animal health and productivity (Windisch et al., 2008). These feed additives are reported to have a wide range of activities including antimicrobial, antioxidant, growth enhancer, and immune modulator. Besides these properties they are also reported to stimulate feed intake and endogenous secretion and enhance production (Upadhaya and Kim, 2017).
Phytogenic feed additive has been reported to enhance performance, feed conversion ratio, carcass meat safety and quality in animals Besides enhancing performance, also has anti-oxidant property, the effects of which are associated with essential oils and their components Phytogenic. However, has beneficial effects on nutrient utilization possibly by stimulating digestive enzymes such as lipase, amylase, or protease and improves gastrointestinal morphology, phytogenic supplementation have a positive impact