Metabarcoding assessment of the progressive bacterial and fungal community shifts during the maturation of hornmanure (Preparation 500) used in biodynamic agriculture.. HORNMANURE01

Hornmanure (Preparation 500) is a product used in the practice of biodynamic agriculture. It isobtained by an underground fermentation of cow faecal material incubated for some months intocow horns. The product is used as spray treatment meant to increase soil fertility. In the presentreport we analysed the successional shifts in bacterial and fungal communities throughout theprocess of hornmanure maturation (100 days) by metabarcode pyrosequencing of ribosomal 16S(bacterial) and ITS (fungal) amplicons. Clear trends of relative abundance substitution were seeninvolving a general decrease from a Firmicutes-dominated material to a product transiently enrichedin Proteobacteria and later in Actinobacteria, mostly within the Nocardioidaceae family. The fungalcommunity evolution showed particularly interesting clues. The most abundant taxon in the startingfaecal material resulted a member of the Onygenales order, which is known to specifically degradekeratin. Its abundance in the intestine is explained by the fact that keratin is not only the structuralcomponent of hairs and horns but is found in all epithelial layers, including the gut mucosa. Thisoccurrence suggests a justified link between manure and horn, and provides an interpretive groundto explain an otherwise seemingly odd practice, reconciling it with a scientific rationale.