Mycotoxin Contamination in Pig Feed: Welfare and Health Impacts

Mycotoxins are toxic fungal metabolites that contaminate cereals and pig feed worldwide. Chronic exposure causes wide-ranging welfare harms including reproductive failure, immunosuppression, and neurological disease in pigs.

Key Facts

Major mycotoxins affecting pigs include deoxynivalenol (DON/vomitoxin), zearalenone (ZEN), fumonisin B1, aflatoxins, and ochratoxin A, produced by Fusarium, Aspergillus, and Penicillium species.
DON causes feed refusal, vomiting, reduced growth, and intestinal damage; pigs are among the most sensitive species, responding at concentrations tolerated by other livestock.
Zearalenone mimics oestrogen and disrupts reproductive function: it causes vulvovaginitis, pseudopregnancy, and infertility in gilts and sows.
Fumonisins cause pulmonary oedema (fluid in the lungs) in pigs, leading to respiratory distress and potentially fatal outbreaks.
Aflatoxins are potent liver toxins and immunosuppressants; chronic low-level exposure impairs vaccine efficacy and disease resistance.
Mycotoxin contamination is worsened by climate change: warmer, wetter harvest conditions favour fungal growth and toxin production.
EU regulations set maximum permitted levels for key mycotoxins in pig feed, but monitoring compliance in practice is challenging.
Feed additives including mycotoxin binders (clays, yeasts) can reduce absorption but do not eliminate the underlying contamination problem.

Welfare Considerations

Pigs experiencing mycotoxin toxicity suffer a range of welfare-relevant harms that are often invisible to farm staff because they develop gradually and mimic other conditions. Chronic DON exposure causes persistent gut discomfort and feed aversion — pigs that refuse feed lose condition, develop behavioural changes, and are more vulnerable to concurrent infections. Zearalenone-induced pseudopregnancy causes physiological and behavioural disruption in sows. Pulmonary oedema from fumonisins is acutely distressing — affected pigs struggle to breathe and may die rapidly. Immunosuppression from aflatoxins means that pigs suffer more severely from diseases they would otherwise resist. Comprehensive feed testing and supply chain management are essential welfare tools, not merely commercial considerations.

What You Can Do

If you are a pig farmer, implement routine mycotoxin testing of cereal raw materials especially after wet harvests.
Work with a nutritionist to select mycotoxin binders and antioxidants appropriate for your feed composition and risk level.
Store feed correctly — cool, dry, sealed conditions reduce mould growth and mycotoxin accumulation post-manufacture.
Monitor pig behaviour and performance for early signs of mycotoxin exposure: reduced feed intake, reduced growth, reproductive irregularities.
Support EU and international policy strengthening maximum permitted levels and enforcement for mycotoxins in animal feed.