Garlic : A Promising Alternative to Antibiotics in Poultry Diet

The use of synthetic antibiotics as a growth promoter to improve the production performance in poultry is gaining popularity worldwide. However, the abusive use of antibiotics negatively impacted human health due to residues in chicken meat, milk, and eggs. Hence, the European Union's ban on synthetic antibiotics in feed has prompted animal nutritionists to search for alternative natural growth boosters such as prebiotics, probiotics, organic acids, and medicinal herbs. Garlic (Allium sativum) is a well-known species and herbal medicine for preventing and treating various diseases. It is also used as condiment and medicament, antioxidant, anticoagulant, antihypertensive, hypolipidaemic, antiplatelet, antifungal, antimicrobial, and heavy metal detoxifier. The major active compound of garlic is its organosulfur compounds, such as S-allyl cysteine sulfoxide (alliin), diallyl thiosulfonate (allicin), and diallyl sulfides. Garlic has been known to effectively improve the immune response of broiler chickens against Newcastle disease and the avian influenza virus. Moreover, garlic powder has been recommended as a growth promoter alternative to synthetic antibiotics without adverse effects on poultry production performance and carcass characteristics. The diverse effects of garlic in broiler chickens might be due to the variable quantities and forms incorporated into the diet. The purpose of this review is to discuss the phytochemical components of garlic,antimicrobial activity, and its effect on the production performance and carcass characteristics of poultry