Mentha herbs and their bioactive molecules on biological functions, production performance, health, and product quality in poultry and livestock.

The use of in-feed antibiotics in livestock systems, particularly in poultry, has raised concerns about the increased prevalence of antibiotic-resistant human pathogens and the presence of antibiotic residues in animal products. Consequently, natural feed additives, including herbs and their bioactive compounds, are becoming preferred alternatives. Different species and varieties of mentha herbs contain varying essential oil components and concentrations, which influence their biological functions due to their antioxidant, antimicrobial, and immunomodulatory properties. Thus, mentha herbs, their extracts, or individual molecules have been used in both non-ruminants and ruminants to assess growth performance, blood constituents, antioxidant status, gut morphology, microbiota composition, and carcass quality. There are discrepancies in studies regarding growth and laying performance in poultry, but it appears that Mentha herbs may be more effective under stressful conditions, such as heat stress and disease prevalence. While results on ruminal fermentation are inconsistent, menthol has been shown to stimulate calcium absorption in the rumen. Additionally, mentha herbs enhance meat preservation quality due to their antioxidant and antimicrobial properties. This review highlights the effects of mentha herbs, their extracts, and bioactive components on various biological properties, performance, health metrics in farm animals, and the quality of meat preservation.