Beyond aflatoxin: Unseen dangers of other mycotoxins in livestock feeds

While much attention has been rightfully paid to aflatoxins, experts warn that they are not the only threat under the mycotoxins umbrella. Fusarium trichothecenes, ochratoxins, and DON have been identified in surveys across Kenya and other countries in sub-Saharan Africa as posing substantial risks to both animal and human health.

By Smart Farmer writer
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Livestock nutrition is a critical aspect of animal husbandry, with the basic diet often comprising cereals, cereal byproducts, and fodders. Unfortunately, these essential components are highly susceptible to mould growth, leading to the production of mycotoxins.

In this article, we get insights from top animal nutrition experts, including Mrs Susan Warui, Ms Melanie Frisch, and Mr Michael Mugo, articulated during a recent workshop for animal feed manufacturers, farmers, and other stakeholders. It was organised to provide a comprehensive understanding of mycotoxins and the practical strategies for their management.

Aflatoxin

Since their detection in the 1960s when an entire flock of turkeys in England was destroyed by contaminated peanuts, aflatoxins have become the subject of much research and attention. In East Africa, they have been classified as a human security threat.

In Kenya, maize contaminated with aflatoxins has been implicated in deadly epidemics three times since 1981. In 2004, there was an acute outbreak of the toxin in the eastern and central regions, said to have been one of the worst in human history. There were 317 cases reported, out of which 125 lives were lost.

Aflatoxins are carcinogenic metabolites produced by several Aspergillus species such as A. flavus and A. parasiticus, as a survival mechanism. They are mainly found in raw materials such as maize, wheat, sunflower, cotton, and groundnuts, and can enter our bodies through the consumption of contaminated animal products.

Exposure to high levels of this toxin through food can have severe consequences, including immune suppression, jaundice, acute liver failure, and cancer. In extreme cases, it can result in death.

“Understanding how aflatoxins enter the human body through animal products, especially milk, shows the need for the implementation of measures to prevent their transfer. By highlighting these challenges and discussing potential solutions, we aim to contribute to the industry's efforts in safeguarding both human and animal health,” says Mrs Warui, the managing director, Essential Drugs.

However, while aflatoxins have been referred to simultaneously as mycotoxins and garnered significant attention, the experts are warning that they are not the only toxins of concern under that umbrella.

“Recent surveys in Kenya and sub-Saharan Africa suggest the prevalence of other mycotoxins such as fusarium trichothecenes, ochratoxins, and Don in Kenya and the continent. So, though the focus has been on aflatoxin, these lesser-known mycotoxins also pose substantial risks to both animal and human health,” she adds.

“Mycotoxins are naturally occurring metabolites from moulds and pose harm to both humans and animals, often in relatively low doses,” says Michael Mugo, technical sales manager of Essential Drugs.

Moulds can grow in various substrates, including cereals, cereal byproducts, nuts, peanuts, macadamia nuts, fruits, spices, oil cake, and major protein sources such as oil cakes in feeds.

Moisture and high temperatures create favourable conditions for mould growth in the fields and in storage.

According to Mugo, the consequences of mycotoxin exposure range from economic losses and diseases to immune system suppression.

“Some mycotoxins act as allergens, irritants, or carcinogens,” he says. However, he advises, it's crucial to note that not all moulds produce harmful allergens. For instance, penicillin, a long-used antibiotic, is produced by fungi.

The experts point out that fusarium species of moulds are prevalent in fields, with additional mycotoxins such as ochratoxins, deoxynivalenol, fumonisins, zearalenone, and more.

"Let's not always focus only on aflatoxins; there are more, which cause even more damage. You could have high levels of aflatoxin as a single toxin, probably in your feed or raw materials, but if you have smaller doses of many of them, the effect might even be worse than having just high levels of aflatoxins,” cautions Mugo.

According to Melanie Frisch, the visual presence of mould does not necessitate toxin production, nor do ideal growth conditions. There are over 400 different toxins that can be produced by fungi, showcasing vast variance in chemical structure.

Mycotoxin effects on animals are challenging to analyse due to non-specific symptoms.

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