**5. Conclusions**

Replacing MH with SFPs affected the composition of methanogenic bacteria in the rumens of the lambs and consequently reduced methane emissions, thus helping to reduce the environmental burden of methane and minimizing the adverse effects on animal health. From this point of view, the use of SFPs can be very useful in good agricultural practice. This study, to the best of our knowledge, is the first on the effect of SFPs on the ruminal microbiome and the abomasal histopathology of lambs loaded with parasites.

**Author Contributions:** Conceptualization, Z.V. and D.P.; methodology, D.P.; software, S.S.; vali- ´ dation, D.P., D.B. and M.K. (Martyna Kozłowska); formal analysis, A.Ł. and W.F.; investigation, D.P.; resources, D.P. and M.K. (Michaela Komáromyová); data curation, A.C., M.S.-S. and S.K.; writing—original draft preparation, D.P.; writing—review and editing, Z.V.; supervision, Z.V.; project administration, Z.V. and M.V.; funding acquisition, M.V. All authors have read and agreed to the published version of the manuscript.

**Funding:** This study was supported by funds from the Slovak Research and Development Agency (www.apvv.sk accessed on 1 July 2019) (APVV 18-0131), the SAS Programme for PhD student grants (www.doktogrant.sav.sk accessed on 1 June 2020) (DoktoGrant APP0162) and the Polish Ministry of Science and Higher Education "Regional Initiative Excellence" program 2019–2022, Project No. 005/RID/2018/19.

**Institutional Review Board Statement:** The study was conducted according to the guidelines of the Declaration of Helsinki and approved by the Ethical Committee of the Institute of Parasitology of the Slovak Academy of Sciences on 22 November 2020 (protocol code 2020/21).

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Data are available upon reasonable request to the corresponding author.

**Acknowledgments:** The English has been revised throughout the manuscript by a native English language editor, William Blackhall. The authors are grateful to Valéria Venglovská, Peter Jerga, and Gabriel Benkovský for their technical support.

**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.
