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
info@smartfarmerkenya.com

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.

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

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.

Mrs Susan Warui, managing director Essential Drugs, making a presentation

“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.

Dairy cows are particularly susceptible due to their higher feed consumption, with potential impacts on milk quality and human health through milk metabolites

“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.

“Cytotoxic effects are common, causing metabolic stress and damage on a cellular level. Aflatoxins and ochratoxins impact liver toxicity, altered gene expression and immune modulation, while other mycotoxins like T-2 toxin and deoxynivalenol have specific effects,” she adds.

Susceptibility to mycotoxins varies, based on species, with aflatoxins posing a high risk. “However, the impact of mycotoxins is complex and influenced by factors such as climate change, feed raw material susceptibility, and animal genetics.”

Melanie Friesch making a presentation about mycotoxins to animal feeds stakeholders and farmers in a Nairobi hotel.

Dairy cows are particularly susceptible due to their higher feed consumption, with potential impacts on milk quality and human health through milk metabolites.
So, what can be done about it?

From sourcing raw materials to implementing effective mycotoxin management strategies, the experts highlight the need for a comprehensive approach to safeguard both animal and human health in the food chain. Increased awareness, testing capabilities, and collaborative efforts are essential to mitigate the risks associated with mycotoxins and ensure the safety of livestock and consumers.

Mugo likens managing mycotoxins to keeping the doors of the guts closed to prevent the entry of harmful elements. “Managing mycotoxins well is like keeping the door to the guts closed. But if you don’t you leave the doors wide open for even bigger problems.”

He stresses the need for meticulous sourcing of raw materials for feed production. Despite the visual appeal of maize, mycotoxins may still be present, necessitating deliberate assessment and testing. The goal is to minimise mycotoxin risk by selecting ingredients with lower contamination levels.

While physical examination is common, relying solely on visual cues like discolouration may not be foolproof. “Both discoloured and seemingly healthy maize can carry toxins, necessitating a comprehensive approach, including assessment and testing, to minimize risks,” he explains.

“We (feed millers) should check our ingredients before we use them, “because, as they say, garbage in garbage out.”

Since mycotoxins are inevitable in feed raw materials due to storage conditions or field presence, the best approach is to find ways to reduce their bioavailability in the feed, Melanie advises.

Managing mycotoxins well is like keeping the door to the guts closed. But if you don’t you leave the doors wide open for even bigger problems

A high-quality mycotoxin binder, often mineral clay-based products, capable of targeting aflatoxin and a broader spectrum of toxins from different moulds should be added to the feed. They absorb mycotoxins, rendering them unavailable to the animal, allowing for safe excretion.

For fodder such as hay and silage, it is crucial to manage their conservation to prevent them from becoming sources of mycotoxins.

Farmers should also ensure proper postharvest handling practices, such as properly drying maize and ensuring adequate storage.

Mrs Warui emphasises the need for a comprehensive regulatory approach to handle the presence of various mycotoxins in different raw materials.

The workshop was organised by Essential Drugs Ltd in conjunction with Biochem Ltd, an animals nutrition company.

Established in 2006, Essential Drugs specialises in manufacturing premixes and stocking various products in the feed line. The company’s vision is to be the leading premix manufacturer in the region, and we currently holds a prominent position as the leading manufacturer of premixes in Eastern & Central Africa.

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