Mycotoxin Binder is a Misnomer!

Mycotoxin Binder is a misnomer. This term only covers mycotoxin sequestering mode of action (MOA) without any reference to other technologies in use today. Global scientific and animal industry communities should look for a unified new name…

Livestock and poultry feeds and raw materials are susceptible to fungal/mould colonisation and subsequent mycotoxin production. Raw materials include maize, wheat, broken rice, millets, soybean meal, sunflower meal, rapeseed meal, byproducts such as DDGS, and various silages, hays, and grasses. Mycotoxins are a world-wide challenge due to the increasing global trading of raw materials as well as climate change and changing agricultural practices. Although animals can be exposed to more than 600 different mycotoxins, most research till date has focused on six groups of mycotoxins: aflatoxins (AF), ochratoxins (OTA), T-2/HT-2 toxin (T-2/HT-2), deoxynivalenol (DON), fumonisins (FB) and zearalenone (ZEN). The emerging mycotoxins such as enniatin, moniliformin, fusaric acid, and mycophenolic acid are also known to cause toxicity in animals. Masked mycotoxins have garnered greater attention in recent times due to their interference with the diagnosis of mycotoxicosis.

Mycotoxicosis is a condition observed in animals upon the ingestion of different concentrations of mycotoxins from the complete feed. Although mycotoxins can affect most organs and systems in animals, there are three systems that can be affected by many mycotoxins even at low concentrations. These are the animal’s immune system, GIT, and antioxidant system. To prevent negative effects, many strategies have been tried over the years, but very few have been practical.

MYCOTOXIN BINDER
Dietary supplementation with non-nutritive mycotoxin binders (mycotoxin-sequestrating agents), a global, practical, well-researched and effective mycotoxin management practice, has been in use for the last few decades. An effective mycotoxin binder prevents or limits mycotoxin absorption from the GIT of the animal. Ideally a mycotoxin binder should be effective against several mycotoxins as feeds are contaminated with more than one mycotoxin. To remain practical, mycotoxin binders should also be reasonably priced and should not occupy a large portion of the complete diet. Additionally, mycotoxin binders should be free of impurities, off flavours and odours.

Natural and synthetic clays are the most studied mycotoxin binders followed by yeast cell wall fractions. As there are hundreds of such binders in the market, it can be confusing for feed- and animal producers to know which one to choose. in vitro mycotoxin binding tests are commonly conducted on such products to understand the ability of the product to bind mycotoxins in the animal’s GIT. Aflatoxin B1 (AFB1) was the first mycotoxin to undergo such tests. A known amount of AFB1 was mixed with a known quantity of mycotoxin binder in a test tube and allowed to interact in a liquid media of pH 3 to 3.5 or 6 to 6.5. Most of the mycotoxins in the feed get released into GIT at the intestinal level and hence, the binding % at the alkaline pH was considered as the strong binding. Many times, a product would achieve a superior binding at acidic pH but show a significant desorption at alkaline pH.

MYCOTOXIN BINDER IS A MISNOMER
The binding mode of action (MOA) worked quite well for aflatoxins, ergot toxins and endo(bacterial) toxins. However, only a moderate binding (35 to 50%) was achieved for T-2 toxin, OTA, and ZEN. Only a maximum of 10% binding was achieved for DON. The effect of pH on FB binding was more severe. At an acidic pH, bentonite was able to bind more than 90% of FB but this was reduced to almost “zero” at alkaline pH. Such findings may be related to varying structure and polarity of mycotoxins. Since all mycotoxins can’t be bound by the so-called mycotoxin binder and the mycotoxin binder contains agents other than sequestering agents, the word “mycotoxin binder” is a misnomer. A suitable name covering all MOA of mycotoxin toxicity reduction should be employed.

BEYOND MYCOTOXIN BINDING
Selko^® has always looked beyond binding to manage multiple mycotoxins within the animal and incorporated specific ingredients in its TOXO^® product line (Figure 1). The combined MOA of these ingredients has delivered significant benefits in animals exposed to multiple mycotoxins (Figure 2). These MOAs include;
1. Use of yeast cell wall derivatives in the feed strengthens the tight junction proteins between intestinal epithelial cells to limit mycotoxin transfer into the blood circulation. This MOA has been proven both at animal and molecular levels.
2. Use of yeast beta-glucans in the feed enhances the macrophage activity. Such activity is very crucial for innate immunity, antibody-mediated immunity, and cell-mediated immunity. All beta-glucans are not the same and hence, attention should be given to the functional benefits rather than the quantity of beta-glucans in the product.
3. Use of anti-oxidants (Se, Vitamin E, Phytogenic compounds) in the feed can help to reduce the mycotoxin toxicity by reducing lipid peroxidation. Such compounds have been shown to reduce laminitis, mastitis and ruminitis in cows.
4. Various microbes and enzymes are also added to the feed to break down some of the mycotoxins into less toxic metabolites in the gastrointestinal tract (GIT). Despite some stability issues, such technologies support the concept of “beyond binding”.
5. As our understanding of molecular effects of mycotoxins is clearer with the use of new analytical techniques, there must be a continued effort to develop cutting edge technologies that can reduce the negative effects of mycotoxins on other organs and organ systems.

By looking at the above technologies beyond binding, a search for a suitable replacement name for mycotoxin binder should be on. There are instances of scientists using the name “Mycotoxin Detoxification Agent” (MDA). The definition of detoxification is “the physiological or medicinal removal of toxic substances from a living organism, which is mainly carried out by the liver”. This action mainly refers to the liver and does not include other organs. On top of this, MDA does not include binders such as bentonites and silicates. Another name used is “Mycotoxin Degradation Product” (MDP) which again mainly refers to degrading the mycotoxin into metabolites using enzymes and microbes. This name does not include binders such as bentonites and silicates and other gut health and immunity concepts. Last but not the least, the name Selko uses is “Mycotoxin Mitigation Product” (MDP). Mitigation means “making something less serious, painful, unpleasant etc”. This might include all MOA as they all try to make mycotoxin toxicity less serious. Of course, this is open for discussion.

CONCLUDING REMARKS
Mycotoxin Binder is a misnomer. This term only covers mycotoxin sequestering MOA without any reference to other technologies in use today. Global scientific and animal industry communities should look for a unified new name. Mycotoxin Mitigation Product may fit the bill and can be discussed further.

About Dr. Swamy Haladi
Dr. Haladi is the commercial and technical manager for the Mycotoxin Risk Management Programme of Selko Feed Additives. He obtained his Bachelor and Master degrees in veterinary science in India, and then moved to Canada to obtain his PhD in animal and poultry science. During his studies and career, he continued to gain more interest and knowledge in the area of mycotoxins, especially the global challenges around this topic. He published various articles in both peer-reviewed journals as well as industry magazines and he truly understands the global challenge of mycotoxins. He also developed practical limits for mycotoxins in various species.