Undesirable compounds in silage grass

“Fungal spoilage and mycotoxin contamination are one of the greatest risks of silage making.
It is hypothesized that a high content of ergosterol and polyphenols in silage prove a progressive deterioration of forage quality. Therefore, ergosterol (ERG) has been suggested as a potential indicator of fungal contamination with polyphenols concentration analysis allowing accurate prediction on silage safety. In this sense, it is necessary to identify reliable biochemical indicators to assess the risk of mould contamination in silage.

Ergosterol (ERG) is a primary metabolite which shares a biosynthetic pathway of deoxynivalenol and nivalenol. This sterol is the principal component of fungal membranes and represents between 10 to 80% of its constitution. Several studies demonstrated that the ERG was a significant correlation with mycotoxin concentrations found in various forage crops. Besides has been proposed ​as an indicator of fungal contamination for various matrices such as solid plant substrates, foods and raw materials.
Phenolic compounds are secondary plant metabolites, synthesised in the shikimate pathway (which provides phenylpropanoids), or via acetate/malonate pathway, producing simple phenols. Besides, the monomeric and polymeric phenols and polyphenols can be products of both pathways. Whilst these compounds are considered natural antioxidants; their oxidation leads to browning and production of toxic compounds oxidation, resulting in rancidity and deterioration of nutritional quality, colour, flavour, texture, and hygiene of silage compromising in that way the ruminant health. .”