Mycotoxins in ruminants are thought to be bio-transformed in the rumen and so have minimal impacts on the animal. However, any factors that affect the functioning of the rumen, e.g., that lower the activity of fibre digesting bacteria or affect the bio-transforming bacteria, will result in more mycotoxins entering the small intestine and causing ill effects. Mycotoxins also impair rumen function due to their negative effects on rumen bacteria causing a decrease in ruminal motility, poor feed digestion, lower VFA production and reduced flow of metabolisable protein.
While ruminants are better able to deal with mycotoxins than other species due to bio-transformation in the rumen, the effect of mycotoxins (example deoxynivalenol) on ruminant cells is more sever than in a pig. Low levels of mycotoxins increase gut permeability and increase inflammation that has a high energy cost resulting in loss of production. The synergistic actions of mycotoxins (e.g. Deoxynivalenol plus Fumonisin) makes them more potent than by themselves with resulting loss in production and increasing risk of mastitis and laments. The effects of LPS endotoxins was also discussed.
The majority of mycotoxin effects are subclinical (including facial excema). Rumen detoxification is a useful tool to minimise these effects. Enzymic biotransformation is useful agains the tricothecenes due to its action on the hypoxic ring.
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