Low-level DON and ZEA contamination in animal feed in Lombardy

Fungal contamination of animal feed is a challenge to the animal production system. Fungi growing on animal feed produce mycotoxins such as deoxynivalenol (DON) and zearalenone (ZEA). Mycotoxin contamination causes feed refusal and decreased productivity in farm animals. However, there are limited studies on mycotoxin contamination of animal feed, particularly in the context of Italy. Therefore, we aimed to study the presence and concentrations of DON and ZEA in animal feed over 10 years using enzyme-linked immunosorbent assay. A total of 19,523 feed matrices were sampled by the Regional Breeders Association of Lombardy, Italy, between January 2014 and December 2023. The feed matrices sampled were cotton seed, cereals (wheat, wheat bran, barley, maize), alfalfa hay, maize silage, compound feed, and total mixed rations. Here, we show that DON was detected in 84.3% of samples with the maximum concentration of 64.4 µg/kg, whereas ZEA was detected in 76.2% of samples with the maximum concentration of 55.0 µg/kg. However, these values are within the safe limits recommended by the European Union for farm animals, which is 900 µg/kg for DON and 100 µg/kg for ZEA. As expected, maize was one of the most contaminated feed matrices for both DON and ZEA. There was also variability in feed matrices over the years. For instance, DON and ZEA concentrations in maize peaked in 2014 and 2015, followed by consistently low values. The difference in DON and ZEA contamination across the years could be due to the influence of climatic factors such as precipitation, temperature, and humidity during the cultivation or storage phase. Hence, our next step is to study the association of climatic variables with the DON and ZEA levels in the feed matrices. In conclusion, DON and ZEA contamination is prevalent in animal feed matrices in Lombardy, but not above the threshold. Monitoring the mycotoxin concentrations at the individual feed ingredient is one of the mitigations strategies to combat mycotoxin contamination.