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Lookup NU author(s): Kawa Merkhan, Dr Abdul ChaudhryORCiD
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
© 2026 The AuthorsObjectives: Using phytogenic feed additives (PFA) could be a promising strategy for mitigating enteric methane (CH4) emissions from ruminants. This study aimed to evaluate the efficacy of specific phytogenic additives on rumen fermentation, methanogenesis, microbial community, and functional pathways. Methods: This 2 x 4 x 3 factorial study was conducted using an in vitro rumen fermentation system for a period of 72 h. Treatments included two silage-to-concentrate ratios (60:40 and 40:60), four PFA (great burnet leaves, GBL; oregano leaves, OL; cumin seeds, CS; and garlic bulbs, GB), and three inclusion levels (0, 10, and 20 g kg−1 DM) for each PFA. Results: The GB addition proved the most potent anti-methanogenic additive, reducing CH4 by up to 32.8% at 20 g kg−1 DM, followed by GBL with a 28.5% reduction at 10 g kg−1 DM, without impairing total volatile fatty acid production. Methane suppression was associated with a lower acetate-to-propionate ratio, decreased abundance of methanogenic archaea (particularly Methanobrevibacter), and reduced expression of the key methanogenesis gene mcrA and fmdB. While GB exhibited a strong anti-protozoal effect, OL effectively reduced ruminal ammonia concentrations. Additionally, metagenomic analysis identified Porcincola was among the core and most abundant genera in our bovine rumen dataset. Conclusion: Optimising the inclusion of specific phytogenic additives can selectively manipulate the rumen microbiome, concurrently reduce methane production and influence nitrogen metabolism. Further research is warranted to evaluate potential synergistic interactions among these additives to enhance fermentation efficiency of ruminant diets.
Author(s): Merkhan K, Chaudhry AS
Publication type: Article
Publication status: Published
Journal: Anaerobe
Year: 2026
Volume: 98
Online publication date: 09/04/2026
Acceptance date: 17/02/2026
Date deposited: 21/04/2026
ISSN (print): 1075-9964
ISSN (electronic): 1095-8274
Publisher: Academic Press
URL: https://doi.org/10.1016/j.anaerobe.2026.103046
DOI: 10.1016/j.anaerobe.2026.103046
Data Access Statement: Data will be made available on request
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