You may have heard quite a lot about mycotoxins as they are associated with a range of feedstuffs and can affect both us and our horses. But did you know that more than five hundreddifferent mycotoxins have been identified to date? and that most animal feedstuffs are likely to be contaminated with multiple mycotoxins?

In our latest Blog, we discuss what mycotoxins are, how they affect your horse and how you can help reduce their impact for optimum health and well-being:

What are Mycotoxins?

Mycotoxins are toxic chemical compounds produced by moulds belonging to the fungi group and pose a significant threat to crops and the animals who consume them.

Like bacteria, mould spores are ubiquitous in the environment, being inhaled and ingested by herbivores, like horses, daily. Flourishing in oxygen-rich environments with adequate temperature and humidity, mould spores multiply, forming colonies that produce toxic metabolic byproducts.

Whilst these toxins are not essential for mould growth, they can suppress the immune system of host plants, like forage or cereals, facilitating colony expansion. Mycotoxin production varies with internal and external environmental conditions, often resulting in multiple toxins produced by a single colony, with similar toxins also produced by other mould species. Despite efforts to eliminate mould organisms through heat and digestion, mycotoxins remain resilient to digestion, heat, and cold and can therefore, often become more common throughout the warmer seasons of spring and summer.

Types of Mycotoxins and their Effects on Horses

There are three main fungi genera which produce mycotoxins that affect horses and other animals, and these are Aspergillus, Pencillium and Fusarium:

Fusarium is typically found in the field, meaning mycotoxins are often present at the time of crop or forage harvesting. On the other hand, Aspergillus and Penicillium tend to develop during storage. For instance, Penicillium mycotoxins may manifest in low-quality haylage, particularly if air has penetrated the plastic wrapping.

The effects on horses vary depending on the mycotoxin groups, but most tend to be immunosuppressive, making horses more vulnerable to illness and disease. Trichothecenes derived from Fusarium, such as deoxynivalenol, tend to disrupt normal cell function and impact cells found in the small intestine, liver, and immune system. Clinical manifestations may include reduced feed intake, inhibited growth, and decreased body weight.

Another subset of Fusarium mycotoxins is fumonisins, to which horses seem to be particularly sensitive. Exposure to fumonisins can lead to equine leukoencephalomalacia (ELEM), linked to consumption of mouldy maize. Most damage from fumonisins occurs in horse’s hearts, central nervous systems, and livers characterised by symptoms like depression, ataxia, abnormal behaviour, head pressing, and often fatality. Liver complications may also arise, with horses often succumbing within hours of exhibiting clinical signs.

Exposure to and ingestion of mycotoxins can result in a broad spectrum of health effects, like bacterial infections, making it challenging to diagnose due to a vast array of potential culprits and clinical signs. In general, non-specific signs can include

• ill thrift or unexplained poor performance
• reduced appetite
• compromised immune function, resulting in increased susceptibility to disease
• central nervous system abnormalities
• behavioural changes
• changes in consistency of manure
• altered seasons and swollen mammary glands in mares
• joint swelling/stiffness
• sunburn

Diagnosing ingestion of mycotoxins typically involves eliminating other causal factors alongside feed testing by reputable laboratories as a possible avenue for confirmation.

Sources of Mycotoxins

Grass and Preserved Forage

Horses and ponies face mycotoxin risks from fungi dwelling on plants in their field and in conserved forage, like hay and haylage.

Hay poses a lower risk compared to silage, but the use of small bales of high dry matter silage (haylage) has increased more recently. Haylage, being easier to produce and often more appetising and nutritious than hay, also carries a heightened risk of mould and associated mycotoxins.

Compound Feed

Toxins present in feed or those generated during storage contribute to the risk, so it is important to ensure all your horse’s feed is of a high quality and free of moulds or dust. Additionally, feed might be subjected to inadequate storage conditions for prolonged periods, elevating the likelihood of mould contamination.

Bedding

In the UK, horses are frequently stabled for part of the year, particularly in winter and potentially in summer, if they need to be taken off grass for longer periods. Stabling can increase exposure to mycotoxins from mould-infested bedding, like straw, which some horses will consume, either inadvertently or through choice.

Furthermore, overweight horses or ponies may be fed straw as a means of reducing calorie intake whilst not compromising on fibre, and this can also increase the risk of mycotoxin ingestion. It is, therefore, vital if using straw as bedding or feed, to ensure it is clean and free of moulds and is stored correctly in a clean dry environment.

How can we Prevent and Minimise Mycotoxins?

While it’s impossible to eradicate mycotoxins entirely, preventive measures can mitigate their impact. Farmers can adopt practices such as crop rotation, soil cultivation, insect and weed control, and early harvesting to reduce mould levels. Post-harvest, cereals should be stored at moisture levels below 13%, with the addition of mould inhibitors if necessary. Horse owners should ensure feed quality by avoiding mouldy hay or grain and wetting down dusty feed and aways purchasing their feed from a reputable company whose feeds adhere to feed quality and safety schemes like The Feed Materials Assurance Scheme (FEMAS).

Ideally, hay should be stored for at least three months after cutting to allow mould organisms to die.

What about Toxin Binders?

Toxin binders are chemical compounds designed to safeguard horses from the effects of mycotoxins by actively ‘absorbing’ and removing them from the gut and are generally available as inorganic (e.g. bentonite clays) or organic (yeast cell membrane) compounds. In organic toxin binders, carbohydrate components of yeast and algae cell walls within the toxin binder, bind to mycotoxins, effectively removing them from the digestive tract before they have a chance to cause serious harm and negatively impact health and performance.

To help combat the risk of mycotoxins, ReMove is a fast-acting, non-medicated supplement designed to counteract mycotoxin contamination in your horse’s digestive tract. By targeting both polar and non-polar mycotoxins, ReMove’s Toxin Binder offers comprehensive protection to combat mycotoxins and safeguard against mycotoxin poisoning or ‘mycotoxicosis,’ through key active ingredients:

Firstly, the inclusion of Mycosorb A+, which contains a unique strain of yeast plus algae meal, provides a uniquely targeted approach to removing mycotoxins. While the yeast binds mycotoxins, aiding in their removal from the digestive system, the algae further enhances toxin absorption, expanding the range of toxins captured.

Additionally, the yeast strains actigen and ecocell contain Mannan Oligosaccharides (MOS), which act as prebiotics for the hindgut microbiome. MOS can bind to harmful pathogenic bacteria, removing them from the hindgut and, therefore, contributing to the growth of beneficial hindgut bacteria, promoting a healthy digestive system, and potentially boosting immunity.

Lastly, the proprietary powdered coconut oil – PowerStance, contains lauric acid known for its potential antimicrobial properties to help remove toxin producing microbes. By supporting gut health, maintaining appetite, and aiding digestion, PowerStance complements the overall effectiveness of ReMove – helping to safeguard your horse against the effects of mycotoxin ingestion, whilst facilitating optimal digestive and overall health.

If you have any questions about creating the best diet and nutrition for your horse or pony, please contact 01488 73322 or info@boomerangnutrition.co.uk