Mycotoxins, the hidden robbers

Mycotoxins remain one of the most persistent and underestimated challenges facing modern livestock production. Produced by fungi that contaminate cereals and feed, these toxins are found in virtually every agricultural region of the world and can affect animal health long before visible clinical signs appear. Mycotoxins are capable of causing oxidative stress, immune suppression and organ damage, ultimately compromising productivity, reproduction and profitability.

Mycotoxins may be produced by fungi during the pre-harvest of feed materials, one of these mycotoxins is for example zearalenone, which is associated with very significant problems in pigs, particularly reproductive problems. Other mycotoxins are produced by fungi during the storage period, when cereals are stored or shipped for some periods of time and the environmental conditions of storage allow for the production of these toxins.

The impact mycotoxins can have on pigs health and performance is closely related with the duration of exposure or ingestion, the level of contamination of the feed and the type of mycotoxin, also co-contamination, the presence of multiple mycotoxins in the same feed material concurrently also increases the toxicity of the feed. The Mycotoxin analysis of feed materials carried out at Kemin Customer Laboratory Services form the 1st of July 2025 until December 31^st found 28% of the samples contaminated with more than 3 mycotoxins and 14% of the samples tested contaminated with 3 mycotoxins. It is however important to note that pigs are very sensitive to mycotoxins and younger piglets or breeding animals are particularly sensitive.

The lesions and clinical signs can vary with the different mycotoxins. Aflatoxins for example are toxic to the liver result in reduced productivity and cause immunosupression. Toxins such as trichotecens, vomitoxin, are associated with dermal lesions, mucosal damage, immunosuppression, feed refusal, in some cases vomiting (hence the name) and more often, reduced productivity.

Fumonisins are also associated with immunosuppression, and if pigs are presented with feed contaminated with high levels of this mycotoxin, pulmonary oedema may occur, also liver damage

Ochratoxin is nephrotoxic (toxic to the kidneys), leading to increased water intake and urination, kidney lesions, which can also be observed at slaughter. As with previous mycotoxins, a common observation is the decreased performance and also immunosuppression.

Among the major mycotoxins encountered in livestock feed, zearalenone (ZEA) deserves special attention. Produced primarily by Fusarium species, zearalenone possesses potent oestrogenic activity and is particularly problematic in swine, with swollen vulvas being observed in females. This can also be observed in newborn gilts, reproductive failure, and also impairs the male reproductive performance due to its mimicking of estrogen.

Assessment of the presence of mycotoxins in feed is key to ensure its effect in the animals is mitigated and for this, sampling protocols that are representative of the feed or raw materials is key, preventing erroneous interpretations of results.

In summary, mycotoxins are very important to pigs due to their susceptivity. Also due to the nonspecific nature of the clinical signs associated with them, poor control may lead to difficulty in diagnosing the root cause of poor performance or poor results from a vaccination program because of immunosuppression caused by mycotoxins.

For the control of mycotoxins several interventions can be implemented both pre harvest and during storage. And not all interventions will lead to the same results as some mycotoxins are harder to control and preventing them from being available to our pigs.