September 2013 – Do we need to worry about Mycotoxins this season?

The simple answer to the question posed above is I don’t know yet. At the time of writing, I have greater confidence in the integrity of the UK crop for the 2013/14 season than I had this time last year – or for a few years for that matter – but there’s still a little way to go.

It’s worth considering why there’s no room for complacency with mycotoxin contamination, particularly in the breeding herd where it can cause serious performance losses by interfering with reproductive hormones.

Present in practically all agricultural commodities worldwide, they come from various species of mould and fungi. It’s important to realise that moulds (fungi) form an entire biological ‘kingdom’. There are about 72,000 species identified ranging from large mushrooms to microscopic yeasts.

In agriculture, we’re only interested in certain “classes” of fungi, but even this narrowing process means we’re still looking at a wide range of organisms. The major classes that concern us are: Aspergillus, which give rise to Aflatoxin and Ochratoxin; Claviceps, which are responsible for Ergot; Fusarium, which is responsible for Fumonosin, Trichothecenes (DON) and Zearlenone (ZON); Penecillium, which gives rise to Ochratoxin; and Neotyphoidium, which gives the grass Tall Fescue toxins in the form of ergot alkaloids.

Aflatoxins are generally found in warmer climates and affect some plants more than others, like Aflatoxin B1 in maize grown in Spain or Brazil. Aflatoxin B1 is regulated in the EU as it is known to pass from feed and be expressed in milk. Fusariums prefer the northern European climate, so are more of a concern during the growing season. They produce DON and ZON, and there are legal limits in wheat samples intended for human consumption, but only guideline levels for animal feed. Penicillium species affect poorly stored grain, giving rise to Ochratoxin.

All the toxins are expressed in many different ways and can be clearly identified by the problems seen on farm.
The HGCA has published excellent guidance on controlling the incidence of mycotoxin contamination. For example, wet and warm conditions during the flowering stage or a delayed harvest because of prolonged rain could mean that Fusariums are an issue. Storing grain at more than 14.5% moisture can lead to Penicillium problems – although not all penicillins will cause a mycotoxin risk.

Back to the practicalities of this year, overall it looks good as far as mycotoxin contamination is concerned. But my advice would be not to let your guard down. If there’s any doubt, then an in-feed mycotoxin binder is needed – though getting the best one is something of a minefield.

If the doubt needs confirmation, then there are analytical tests that will assess the safety of the crop. But make sure appropriate sampling is carried out; this in itself can be a complex process when there’s a large heap of material involved.

> Born in Essex, schooled in Suffolk and a graduate of Reading University, Dr Phil Baynes has spent his career in pig welfare and nutrition. Now based in Cheshire, he runs Baynes Nutrition and is a consultant nutritionist to Provimi.

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