Thyme

Thymus vulgaris L., a member of the Lamiaceae family, is a herb widely used in conventional medicine because of its various therapeutic properties. Thyme, mostly cultivated in the Mediterranean region, is used as a spice and medicine worldwide, owing to its antioxidant and antibacterial properties. This chapter focuses on data supporting the use of thyme as a productive enhancer in animal feed and as a partial or full substitute for antibiotics. The essential oils found in the aerial portions of thyme are a source of fragrance and therapeutic qualities. The main active constituents of thyme extract are thymol, carvacrol, and other mono- and sesquiterpenes. These compounds contribute to the flavor, fragrance, and antibacterial properties of thyme. The effect of thyme on animal performance is attributed to its bioactive compounds, which vary depending on several factors. Thyme supplementation has been documented to be advantageous in poultry production, with thymol reported to prevent oral bacterial infections and to influence the permeability of pathogenic bacterial cell walls, leading to cell death. Essential oils from thyme can also support digestive functions by stimulating endogenous enzyme activity, nitrogen absorption, and regulating the ammonia content and odor of excreta. The antibacterial properties of thyme are influenced by the chemical structure and lipophilic characteristics of its essential oils, allowing them to pass through bacterial membranes and affect the interior of the cell.