There’s bad news if you feed livestock: Nearly all of the world’s feed grain supply is contaminated with at least one mycotoxin. Almost 2/3 of corn harvested in 2018 that was tested by Kemin Customer Laboratory Services (CLS) was positive for mycotoxins. More importantly, however, nearly 50% of those samples contained multiple toxins.
Mycotoxins — the products of a mold’s natural defense to environmental stressors — can cause of a range of health problems in both ruminant and monogastric animals. And for producers, that means erosion of profit potential.
The good news is that you’re not fighting mycotoxins alone. A combination of vigilant management practices and incorporating appropriate additives into your feed ration may help minimize the chances that livestock will experience health or performance problems after consuming mycotoxin-contaminated feed.
Fusarium molds are one of the major sources of health issues across many species, including humans. The Fusarium genus includes many different species of molds which are responsible for the propagation of specific arrays of mycotoxins. For example, F. graminearum and F. sporotrichioides produce trichothecenes like deoxynivalenol (DON), zearalenone and T-2 toxin; whereas, F. proliferatrum and F. verticillioides produce fumonisins.
Both ruminants and monogastric animals are susceptible to internal damage from mycotoxins produced by Fusarium molds. Depending on toxin levels, that damage can range from minor immune maladies to acute — sometimes fatal — gastrointestinal diseases.
When an animal ingests mycotoxins in contaminated feed, the most common place for damage to internal systems is in the gastrointestinal (GI) tract. When functioning optimally, the junctions between epithelial tissues in the GI tract are tight, which prevents any harmful compounds from entering systemic circulation into the body. When an animal undergoes stress — heat stress, for example — those junctions loosen, allowing mycotoxins to penetrate epithelial tissue and enter other internal systems.
The loosening of tight junctions — commonly referred to as “leaky gut” — and subsequent mycotoxin ingestion and/or infiltration by an invasive bacteria or virus can cause acute symptoms like reduced feed intake. Chronic ingestion of mycotoxins can cripple an animal’s intestinal immunity and make it susceptible to scores of other illnesses, especially those caused by environmental conditions like heat stress. To protect livestock and poultry from increased susceptibility to challenges posed by mycotoxins, managing Fusarium mycotoxins like zearalenone and fumonisin is critical.
Zearalenone is an estrogenic mycotoxin, which binds to the same receptors as the natural hormone estrogen binds. It causes increased estrogenic activity that can adversely affect reproduction through symptoms such as lowered embryo survival, increased infertility and the attrition of testosterone in young male animals.
Cattle are typically less adversely affected by zearalenone (the same is true with fumonisin) because of the presence of other bacteria in the rumen that prevent the toxin from reaching lower portions of the gut where leaky gut is more likely to expose other internal systems to the toxin. However, zearalenone can still lead to increased abortion in pregnant sows and dairy cattle as well as reduced hatchability and declined egg production in layers.
Because fumonisin and zearalenone are both secreted by the same family of mold, Fusarium, it’s common for a feed source to be infected by both mycotoxins — and their symptoms are often similar. When a ruminant or monogastric animal ingests fumonisin, it causes decreased milk production and feed intake, ultimately eroding a herd’s reproductive and feeding efficiency. Gut health is also primarily compromised by fumonisin.
Fumonisin acts like certain lipids (sphingosins) and can inhibit lipid metabolism in the liver, cause immune depression and damage the nervous system and brain. Fumonisin contamination is especially bad for horses because it can cause leukoencephalomalacia (a central nervous disease).
Every mycotoxin has specific symptoms and affects different animals with varying severity. Deoxynivalenol (DON) is much more likely to cause GI system damage to hogs than other livestock species, for example. Despite this type of variability, one thing is certain: In the vast majority of cases, a single mycotoxin is not working alone. It’s common for different toxins to impact an animal concurrently, sometimes broadening the number of symptoms or increasing a single symptom’s severity. That’s especially true with fumonisin and zearalenone, given that they share the mold genus Fusarium.
“Concurrent contamination of different species of Fusarium molds is likely going to happen. If you find fumonisin, there is a high possibility that you are going to find zearalenone,” Kemin Technical Services Manager Venkatesh Mani explained. “Because both toxins are produced from the same genus of Fusarium, they will be produced in almost the same environmental conditions, and there’s a possibility that the toxins will overdose because both species of mold will be secreting the toxins.”
Though researchers have identified individual mycotoxins and how they inflict damage on animals when ingested, there’s little research on concurrent infections, including those caused by molds of the same genus. “The toxicity of mycotoxin combinations cannot always be predicted based upon their individual toxicities. Multi-exposure may lead to additive, synergistic or antagonistic toxic effects,” according to a research paper by a team of mycotoxin and cell biology researchers at the University of Western Brittany in Brest, France. “The data on combined toxic effects of mycotoxins are limited, thus the health risk from this multi-exposure is not well-known.”
Though much remains to be learned about what happens when two toxins affect an animal at the same time, researchers have determined that when zearalenone and fumonisin affect an animal in high doses alongside DON, there is a synergistic effect, meaning they have common symptoms that lead to more acute and severe damage than when infecting an animal alone. See more about concurrent infections here.
Given the need for additional research regarding synergistic and antagonistic relationships between mycotoxins and the variability in symptoms and their severity when multiple mycotoxins infiltrate an animal’s internal systems, the most effective treatment is one that offers broad-spectrum control. Specific toxins may require different treatments depending on the severity and speed of their absorption and damage. “Although the mechanism that sequesters the toxins during treatment is more or less the same, binding mycotoxins is a contact sport. The binding efficiency will vary not only by the toxins but also by treatment,” said Mani. Considering the high probability of multiple toxin contamination, a treatment with broad-spectrum binding efficiency will provide producers the greatest return on investment. KALLSIL™ – an enhanced zeolite mineral from Kemin – has been shown to impact multiple secondary fungal metabolites, including zearalenone and fumonisin.
KALLSIL is a natural anti-caking aid that improves feed ingredient flowability and reduces damage from secondary fungal metabolites. Zeolite is an aluminosilicate, a mineral compound in which some of its silicon ions have been replaced by aluminum. The linkages between ions in zeolite yield crystalline structures with openings, or cavities, that enable molecules to physically bind with harmful metabolites. As shown in vitro, the result is a strong total binding efficiency of enhanced zeolite for more than 55% for fumonisin and 34% for zearalenone.1
The enhanced zeolite in KALLSIL is unique in its broad-spectrum efficacy at low inclusion levels compared to similar products. Though it’s effective for fumonisin and zearalenone — and may help prevent the two from inflicting more serious synergistic damage in infected animals — enhanced zeolite has also been shown to reduce damage from other common metabolites, such as aflatoxin and T-2 toxin. KALLSIL is added to a feed ration at a rate of 2-4 ounces per head per day in cattle and 2-4 pounds per ton of swine or poultry feed.
“What many people don’t yet understand is the chronic element, the continuous exposure to mycotoxins,” Mani said. “Even if you continue to feed grain that has toxin levels below the damage threshold, the animals will develop chronic illnesses because of the interaction between multiple mycotoxins. This is very important to livestock producers because while these toxins aren’t necessarily killing animals, they are among the biggest factors in terms of losing money from animal performance.”
Learn more about how KALLSIL can help promote efficiency and performance by reducing the impact of fungal metabolites.
1KALLSIL™: An Enhanced Zeolite Flow Agent, MC-19-17358.
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