Effects of Yarrow (Achillea millefolium) Essential Oil Compared with Growth Promoter Antibiotic and Probiotic on Growth Performance, Meat Quality, and Immune Response of Broiler Chickens

Introduction: Application of growth-promoting antibiotics in poultry nutrition improves growth, feed intake, feed conversion ratio and reduces mortality. But, due to their persistent effects and increased drug resistance to pathogenic bacteria and the transmission of bacteria to humans through the food chain, the European Union banned their use. One of the natural alternatives is medicinal plants. Because plant products for reasons such as availability, ease of use, reduction of side effects, antibacterial and antioxidant properties, were used to treat some diseases in humans and animals. Among these medicinal plants we can mention yarrow with the scientific name of Achillea millefolium. This plant in addition to high antimicrobial and antioxidant properties; has antifungal properties, stimulates appetite, improves digestion and feed intake, improves the condition of the gastrointestinal tract, etc. This plant also accelerates digestion and shortens the passage of food through the gastrointestinal tract by increasing bile production and enzymatic activity. On the other hand, probiotics are living microorganisms of a nonpathogenic and nontoxic in nature that improve gastrointestinal health and improve performance in birds by improving intestinal microbial balance. According to these cases, this study was performed to evaluate the effect of yarrow essential oil in comparison with a growth-promoting antibiotic and probiotic on performance of broiler chickens.Materials and Methods: A total of 200 day-old male broiler chicks (Ross 308) were studied in a completely randomized design with five treatments, and four replicates. Experimental diets were: 1) basal diet (control), 2 and 3) basal diets supplemented with 100 and 200 mg/kg of yarrow essential oil, respectively, 4) basal diet supplemented with 200 mg/kg probiotic, and 5) basal diet supplemented with 500 mg/kg antibiotic (flavophospholipol). Body weight and feed intake were measured at the end of each growing period and were used to calculate Performance parameters such as body weight gain, and feed conversion ratio. At the end of the experiment, one bird per each replicate was slaughtered for meat quality tests, including measurements of TBARS, pH, water holding capacity, dripping loss and antibody titer. For TBARS, the amount of fat oxidation of the sample was measured by measuring the amount of malondialdehyde and the microtiter hemagglutination method was used to determine the antibody titer produced against sheep erythrocytes.Results and Discussion: During the whole experimental period, birds received yarrow essential oil at 100 mg/kg diet, showed significantly higher body weight and lower FCR compared to the control group(P