پردیس کشاورزی و منابع طبیعی دانشگاه تهران Iranian Journal of animal Science 2008-4773 57 1 2026 03 21 Effect of Walnut and Green Tea Ethanolic Extract to Mitigate Methane Emission and VFA Concentration in Ewes Effect of Walnut and Green Tea Ethanolic Extract to Mitigate Methane Emission and VFA Concentration in Ewes 79 99 103337 10.22059/ijas.2025.394591.654074 FA Maryam Sahebi-Ala Department of Animal Science, Faculty of Animal Science, Urmia University, Urmia, Iran 0000-0003-4118-1779 Hamed Khalilvandi-Behroozyar Department of Animal Science, Faculty of Animal Science, Urmia University, Urmia, Iran 0000-0002-2834-6260 Rasoul Pirmohammadi Department of Animal Science, Faculty of Animal Science, Urmia University, Urmia, Iran 0000-0002-0654-3810 Ehsan Anassori Department of Internal Medicine and Clinical Pathology, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran 0000-0002-5692-4718 Journal Article 2025 05 21 This study was conducted to evaluate the effects of ethanol extracts of walnut leaves and green tea leaves on ruminal fermentation characteristics, methane and total gas production under in vitro conditions, and microbial population in lactating ewes using microbial-based methods. The experiment was arranged in a completely randomized design with four treatments: a control group (no extract) and three experimental groups receiving 100 mg extract per kg of live weight from walnut leaves, green tea leaves, or an 1:1 ratio. Extracts were administered orally twice daily for two months. At the end of the period, rumen fluid was collected from each treatment and subjected to in vitro gas production tests, including total gas production, methane production, and protozoal counts, conducted in three independent runs with four replicates per treatment. The results indicated that the control group had the highest potential gas production (A) at 373.60 mL, while the mixture of extracts showed the lowest (265.60 mL). The molar proportion of acetate decreased, and that of propionate increased significantly, with the highest propionate values observed in the mixture (34.39%) and walnut leaf (32.21%) treatments, and the lowest in the control (29.80%) and green tea leaf (29.66%) treatments. The combination of extracts led to a reduction in protozoa and methanogen populations, while fungal populations increased significantly (P < 0.02). Overall, the findings suggest that dietary inclusion of these extracts in lactating ewes may beneficially modify rumen fermentation patterns in terms of volatile fatty acid profiles, gas production, and microbial populations. This study was conducted to evaluate the effects of ethanol extracts of walnut leaves and green tea leaves on ruminal fermentation characteristics, methane and total gas production under in vitro conditions, and microbial population in lactating ewes using microbial-based methods. The experiment was arranged in a completely randomized design with four treatments: a control group (no extract) and three experimental groups receiving 100 mg extract per kg of live weight from walnut leaves, green tea leaves, or an 1:1 ratio. Extracts were administered orally twice daily for two months. At the end of the period, rumen fluid was collected from each treatment and subjected to in vitro gas production tests, including total gas production, methane production, and protozoal counts, conducted in three independent runs with four replicates per treatment. The results indicated that the control group had the highest potential gas production (A) at 373.60 mL, while the mixture of extracts showed the lowest (265.60 mL). The molar proportion of acetate decreased, and that of propionate increased significantly, with the highest propionate values observed in the mixture (34.39%) and walnut leaf (32.21%) treatments, and the lowest in the control (29.80%) and green tea leaf (29.66%) treatments. The combination of extracts led to a reduction in protozoa and methanogen populations, while fungal populations increased significantly (P < 0.02). Overall, the findings suggest that dietary inclusion of these extracts in lactating ewes may beneficially modify rumen fermentation patterns in terms of volatile fatty acid profiles, gas production, and microbial populations. https://ijas.ut.ac.ir/article_103337_942846d97f7a48f31b6e54f29e281b6b.pdf