Effects of Dietary Peppermint and Thyme Powders on Growth, Immunity, Rumen Fermentation, Carcass, and Meat Quality in Sanjabi Fattening Lambs

Khamisabadi, Hassan

doi:10.22034/jmpb.2025.370516.2039

Effects of Dietary Peppermint and Thyme Powders on Growth, Immunity, Rumen Fermentation, Carcass, and Meat Quality in Sanjabi Fattening Lambs

Articles in Press

Document Type : Research Paper

Author

Hassan Khamisabadi

Animal Science Research Institute of Iran (ASRI), Agricultural Research Education and Extension Organization (AREEO), Karaj, Iran

10.22034/jmpb.2025.370516.2039

Abstract

Medicinal herbs have attracted considerable attention as natural edibles to enhance growth performance and meat quality in ruminants. This study was conducted to evaluate the impact of dietary supplementation with medicinal herbs, peppermint (Mentha piperita) or thyme (Thymus vulgaris), on production performance and meat quality in Sanjabi fattening lambs. The experimental diets were control diet without medicinal herbs, basal diet contained 3% peppermint powder, and basal diet contained 3% thyme powder. Results showed that peppermint supplementation in lambs improved average daily gain (298.15 g/day), while the control group showed the lowest daily gain (228.70 g/day, P < 0.05). Dietary supplementation with peppermint and thyme powders lowered rumen pH and reduced ammonia-nitrogen concentrations compared to the control group (P < 0.05). The peppermint-supplemented group exhibited significantly higher final live weight, rumen capacity, and both hot and cold carcass weights compared to the thyme and control groups (P < 0.05). Overall, incorporating peppermint and thyme powders into the diet enhanced growth performance, decreased ruminal ammonia-nitrogen levels, and improved carcass traits and meat quality in Sanjabi fattening lambs. These findings highlight the potential of medicinal herbs as effective natural feed additives to boost small ruminant production efficiency.

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