Interactions between gut microbiome and nematode parasites in sheep

Abstract

Traditionally, research in host–helminthic interactions has focused on the host´s immune system and the parasite. Over the last decade, the development of the next generation DNA sequencing tools allow usto add a third player, the host gut microbiome. The aim of the present work was to investigate in vivo, the interaction between sheep gastrointestinal (GI) parasites and the gut microbiome. In this line, we used 15 naturally infected sheep in order to explore how the nemabiome and gut microbiome compositions influenced each other before and after treatment with monepantel (MNP) and the broad-spectrum antibiotic oxytetracycline (OXT). We wait for microbiome stabilization and 17 days post treatment, abomasum and colon content and worm samples were taken. As we expected, adult parasites were not observed in the GI tract of the MNP treated animals, with the exception of Oesophagostomum in colon. High-throughput Illumina sequencing of the bacterial 16S rRNA V3-V4 region showed that the abomasum relative abundance of the methanogenic archaebacteria and cyanobacteria changes in the MNP treated animals (log2FC= 2.09, Padj=0.045; log2FC=-1.39, Padj=0.046, respectively). No statistical differences between groups were observed in the colon bacteria content. OXT treatment did not affect the parasite content of the animal GI tract. To conclude, the results here presented showed that the lack of parasites or the direct effect of the MNP, impact in the microbial composition of the sheep abomasum, particularly in the Archaea content, rumen microorganismsthat produce methane, a gasthat has been implicated in global warming.