Veterinary World, EISSN: 2231-0916 1139 Veterinary World, EISSN: 2231-0916 Available at www.veterinaryworld.org/Vol.17/May-2024/23.pdf RESEARCH ARTICLE Open Access Effects of herbal plant supplementation on rumen fermentation profiles and protozoan population in vitro Antonius Antonius 1 , Roni Pazla 2 , Ezi Masdia Putri 1 , Muhammad Ichsan Alma’i 3 , Erika Budiarti Laconi 4 , Didid Diapari 4 , Anuraga Jayanegara 4 , Laily Rinda Ardani 2 , Leni Marlina 5 , Riris Delima Purba 1 , Ruslan Abdul Gopar 1 , Windu Negara 1 , Sharli Asmairicen 1 , and Putut Suryo Negoro 1 1. Research Center for Animal Husbandry, National Research and Innovation Agency (BRIN), Jl. Raya Jakarta Bogor Cibinong 16915, Indonesia; 2. Department of Animal Nutrition, Faculty of Animal Science, Andalas University, Jl. Limau Manis, Padang 25163, West Sumatra, Indonesia; 3. Edufarmers International Foundation, Government Relations Manager, Edu Farmers International Foundation, Jl. MT. Haryono Kav. 16, Jakarta 12810, Indonesia; 4. Department of Nutrition and Feed Technology, Faculty of Animal Science, IPB University, Jl. Agatis Kampus IPB Dramaga Bogor, 16680, Indonesia; 5. Research Center for Agroindustry, National Research and Innovation Agency (BRIN), Jl. Puspitek Tangerang Selatan, 15314, Indonesia. Corresponding author: Roni Pazla, e-mail: ronipazla@ansci.unand.ac.id Co-authors: AA: antoniuschaniago02@gmail.com, EMP: ezim002@brin.go.id, MIA: ichsanalmai21@gmail.com, EBL: erika_laconi@apps.ipb.ac.id, DD: dididdi@apps.ipb.ac.id, AJ: anuraga.jayanegara@gmail.com, LRA: ardanilaily@gmail.com, LM: leniirsyah@gmail.com, RDP: riri005@brin.go.id, RAG: rusl005@brin.go.id, WN: windu.negara@brin.go.id, SA: asmaraicen@gmail.com, PSN: putu006@brin.go.id Received: 21-01-2024, Accepted: 26-04-2024, Published online: 17-05-2024 doi: www.doi.org/10.14202/vetworld.2024.1139-1148 How to cite this article: Antonius A, Pazla R, Putri EM, Alma’i MI, Laconi EB, Diapari D, Jayanegara A, Ardani LR, Marlina L, Purba RD, Gopar RA, Negara W, Asmairicen S, and Negoro PS (2024) Effects of herbal plant supplementation on rumen fermentation profiles and protozoan population in vitro, Veterinary World, 17(5): 1139–1148. Abstract Background and Aim: In the livestock sector, particularly ruminants, an approach to minimize methane emissions can be carried out through a feeding strategy involving herbal plants containing bioactive compounds that can reduce protozoa and decrease methane gas emissions. The aim of this in vitro study was to analyze the effects of herbal plant supplementation on rumen fermentation, total gas, and methane production, in vitro dry matter digestibility (IVDMD), in vitro organic matter digestibility (IVOMD), and protozoa populations within the rumen. Materials and Methods: Two experiments were conducted in this study. Experiment 1 was conducted to determine the most promising herbal plants capable of increasing total gas production and reducing protozoan populations. Three potential herbals selected in Experiment 1 were continued in Experiment 2 as supplements in the palm kernel meal (PKM)-based ration (70% PKM + 30% herbal plants). Results: Experiment 1 revealed that Eurycoma longifolia (EL), Cola acuminata (CLA), and Cassia alata (CSA) were potential herbal candidates for enhancing total gas production and the percentages of IVDMD and IVOMD. In Experiment 2, supplementation with EL, CLA, and CSA significantly increased IVDMD from 62.84% to 70.15%, IVOMD from 61.61% to 53.18%, and NH 3 from 13 mM to 17 mM, as well as reduced partial volatile fatty acids and total gas production. In addition, the methane gas and protozoan populations were reduced. Conclusion: The utilization of EL, CLA, and CSA effectively increased the production of total gas, IVDMD, and IVOMD while reducing methane gas protozoa populations in rumen fermentation compared with the control. Keywords: feed digestibility, methane emissions, plant herbs, protozoa. Introduction At present, humans are facing major environ- mental problems such as global warming. This issue is associated with several greenhouse gases, includ- ing chlorofluorocarbons (CFCs), methane (CH4), nitrogen oxide (N 2 O), and carbon dioxide (CO 2 ), that accumulate in the atmosphere at high rates due to increased human activities [1]. The agricultural sector is one of the main contributors to the largest emissions of anthropogenic methane (CH 4 ) in the world, with ruminants being the main producers. However, meth- ane emissions are expected to increase by up to 30% by 2050 if they are not controlled immediately [2]. In addition, data from the FAO in 2017 indicate that the 100-year global warming potential for non-CO 2 greenhouse gas (GHGs) from the livestock sector contributes approximately 15.6%–18.9% of all annual GHG emissions worldwide [3]. Methane gas (CH 4 ) in ruminants results from the anaerobic fermentation of carbohydrates by metha- nogenic microorganisms (methane–producing bac- teria). The gas is then released into the atmosphere by erupting (belching). Methane production can decrease energy utilization in the bodies of rumi- nants by 7%–12% [4]. The relationship between rumen protozoa and methane production has also Copyright: Antonius, et al. Open Access. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/ by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http:// creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.