## 5 Conclusions  
In conclusion, the findings of this study highlight the in vitro potential of SAG, PIN, and CLO as effective interventions to reduce greenhouse gas emissions, specifically methane, during ruminal fermentation. The addition of these essential oils resulted in a significant decrease in gas production and methane production, which can be attributed to their antimicrobial properties and the inhibition of methane-producing microorganisms in the rumen. However, it is imperative to acknowledge the limitations of in vitro research and the necessity for validation through in vivo studies. Future work should prioritize translating these findings into practical applications. Moreover, the inclusion of essential oils led to a substantial reduction in carbon dioxide emissions, indicating their potential to mitigate overall greenhouse gas emissions. Additionally, the study demonstrated that essential oils, particularly CLO, effectively reduced the concentrations of atherogenic and thrombogenic fatty acids, such as C14:0 and C16:0, while promoting the accumulation of beneficial fatty acids, such as _cis-9_, _trans-11_CLA and _trans-_11 C18:1. Since some essential oils exert their effects at high dose levels, we encourage researchers to consider novel techniques, such as nano-encapsulation, to enhance the effectiveness of plant chemical compounds in the rumen, even at lower doses, in their future studies. Overall, these findings provide valuable insights into the modulation of ruminal fermentation processes and the bioconversion of fatty acids, emphasizing the potential of essential oils as sustainable strategies to address environmental concerns without compromising the nutritional value of ruminant-derived products.  
Conceptualization, M.B. and T.G.; Data curation, M.B.; Formal analysis, M.B.; Funding acquisition, A.T. and I.J.E.; Investigation, M.B.; Methodology, M.B. and A.T.; Project administration, M.B. and T.G.; Resources, M.B. and I.J.E.; Software, M.B.; Supervision, M.B.; Validation, M.B., T.G. and A.T.; Visualization, M.B. and A.T.; Writing--original draft, M.B.; Writing--review and editing, M.B. and I.J.E. All authors have read and agreed to the published version of the manuscript.  
The funding for this work was provided by Glopex through the research grant for innovation (project no. GP-BioMed2023). The authors would like to convey their sincere appreciation to Glopex ([[https://glopex.kr/](https://glopex.kr/)]([https://glopex.kr/](https://glopex.kr/)), accessed on 20 October 2023), whose kind financial assistance made this study feasible. We would also like to thank our coworkers and collaborators for their suggestions and criticism throughout the course of this project. We also thank the editorial staff and reviewers for their insightful criticism and recommendations, which considerably raised the caliber of this work. We warmly thank Glopex for their dedication to science and their conviction that this research is crucial.  
All experimental procedures involving animals were conducted in compliance with the International Guidelines for research involving animals (Directive 2010/63/EU) and were approved by the Animal Welfare and Ethics Committee of Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran (approval number: N.T. 20/1225).  
Not applicable.  
Data Availability Statement: Data are available upon a reasonable request.  
**Acknowledgments:** The authors wish to thank the Gorgan University of Agricultural Sciences and Natural Resources Research Council and the academic members of the Animal Science Department.  
**Conflicts of Interest:** The authors declare no conflict of interest.