Are mycotoxins compromising nutritional quality of US corn?

Corn field with blue clouds in the background
'Corn is more susceptible to mycotoxin contamination than other feed commodities.' (Getty Images)

Retesting of feed ingredients before manufacture advised

A study from toxicology and mycotoxin experts at US poultry research organizations has revealed high levels of mycotoxin contamination in corn.

They argue the findings raise concerns for broiler producers relying on feed from the southeastern US.

Researchers analyzed 328 corn samples and found that every single sample contained at least one mycotoxin, with most samples contaminated by two or more.

This level of co-contamination not only poses health risks for poultry but also affects the nutritional quality of the feed, they argue.

Although production of crops has increased over the years, about 25% of the world’s cereal grain harvest is wasted due to mycotoxin contamination, note the authors.

“Corn is more susceptible to mycotoxin contamination by a variety of colonizing fungi than other animal feed commodities such as wheat, barley, oats, and soybeans (Magnoli et al., 2019). An estimated 60 to 80% of agricultural products are contaminated with mycotoxins (Eskola et al., 2020) with an estimated 61% containing multiple mycotoxins (DSM, 2023).”


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Although several surveillance papers have examined the occurrence and co-occurrence of mycotoxins, most use small sample sizes, report the authors.

They analyzed 328 corn samples obtained from grain elevators, feed mills, and farms in the 10 states in the southeastern part of the US, a major producer of broiler meat, for four major mycotoxins of poultry production concern and they examined their co-occurrence.

What did the study reveal?

Their analysis detected four key mycotoxins in the samples: fumonisin (FUM), deoxynivalenol (DON), aflatoxin (AFB1), and zearalenone (ZEA).

Fumonisin was the most common, appearing in 100% of the samples at levels ranging from 19 to 24,680 µg/kg. DON was found in nearly 70% of samples, while AFB1 and ZEA were detected in 17% and 44% of samples, respectively. Notably, 37% of the samples contained three mycotoxins, and nearly 5% were contaminated with all four.

The study also linked mycotoxin presence to shifts in nutrient content.

For instance, corn with aflatoxin contamination showed lower fat content and appeared darker, while DON-contaminated samples had higher starch levels but lower protein. Fumonisin was associated with higher protein and moisture levels but lower starch. ZEA contamination also correlated with reduced starch content.

Testing is critical

The study’s authors stress the importance of testing for multiple mycotoxins and considering their combined effects when setting safety standards.

“Although most samples were below regulatory levels, co-contamination could lead to decreased poultry production.”

For poultry producers, addressing mycotoxin contamination is critical to maintaining flock health and performance, as well as optimizing the nutritional value of feed.

“A more thorough understanding of the effects of mycotoxin levels on the nutrient content of corn will allow feed formulators to account for the changes in nutrient content caused by mycotoxin contaminated corn when formulating feed.

“Re-testing of feed ingredients immediately before feed manufacture should provide a valuable avenue for decreasing mycotoxin related losses as mycotoxin levels, particularly AFB1, can increase during storage.”

Source: Poultry Science