Role of toxin binder in livestock and poultry feed

type of toxin binders

1. Silicate Products
2. Clay mineral
3. organic / Inorganic polymers
4. Carbon Products

Different types of materials have the ability to bind to mycotoxin. The most common bonding agents are aluminosilicates , clay and zeolite. These are natural adsorbents that include hydrated sodium calcium aluminosilicates, bentonite, and zeolite. Most toxin binders are effective adsorbents for aflatoxins. Other items with the ability to bind to mycotoxins are the cell wall components of yeasts. Some studies have shown that cell wall β-glucan of yeasts such as Saccharomyces Cerevisiae can be effective in binding a wide range of toxins. Unlike clay, they can be added at low levels

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What is the mechanism of action of toxin binders?

Silicate Products

Silicates are divided into subclasses, not by their chemistries, but by their structures. The silicate subclasses include neo-silicates (single tetrahedrons), sorosilicates (double tetrahedrons), inosilicates (single and double chains), cyclosilicates (rings), phyllosilicates (sheets), tectosilicate (frameworks). Silicates investigated as adsorbent materials are classified primarily as phyllosilicates and tectosilicates. Perhaps the most extensively studied of these materials is one designated a hydrated sodium calcium aluminosilicate (HSCAS). It is suggested that this specific silicate mineral can bind with aflatoxin by chelating the β-dicarbonyl moiety in aflatoxin with uncoordinated metal ions in the clay materials. Other silicates that have been studied include bentonites, zeolites, and clinoptilolites. The clay group is a subcategory of the phyllosilicates. Bentonite is a general clay material originating from volcanic ash and containing primarily montmorillonite as the main constituent. Montmorillonite clay is a hydrated sodium calcium aluminum magnesium silicate hydroxide. Clays are silica sheets that are similar to other phyllosilicates but contain a high concentration of water. Zeolites are classified as tectosilicates consisting of interlocking tetrahedrons. The zeolite structure provides vacant spaces that form channels of various sizes allowing the movement of molecules into and out of the structure. Zeolites can lose and absorb water without damage to their crystal structures. Much of the pioneering work with mycotoxin binders was done with silicates and specifically with the HSCAS material. Specific HSCAS included at 0.5% to 2.0% of the diet is well documented to adsorb aflatoxin and to prevent aflatoxicosis across species. Responses to HSCAS appear to be dose-dependent. This HSCAS is characterized as an “aflatoxin-selective clay,” is not a good adsorbent of other mycotoxins, and therefore, is not expected to be protective against feeds containing multiple mycotoxins. Cyclopiazonic acid, which has co-occurred with aflatoxin, is not adsorbed by HSCAS. Similarly, little effect was seen, using a silicate material, ochratoxin toxicity but did demonstrate reduced T-2 toxicity. Montmorillonite binds well with sterigmatocystin, a mycotoxin chemically similar to aflatoxin. Various clay products including calcium bentonite reduce aflatoxin residues in the milk of dairy cows. Several products were effective; however, sodium bentonite reduced milk aflatoxin more than a similar amount of calcium bentonite. Diatomaceous earth has shown the potential in vitro to bind aflatoxin, sterigmatocystin, T-2 toxin, zearalenone, and ochratoxin. Zeolites have not been proven to reduce the toxicity of T-2 toxin. Several studies have shown that chemical modifications have increased the binding of HSCAS with zearalenone, aflatoxin, ochratoxin, and zearalenone by octadecyl dimethyl benzyl ammonium-treated zeolite.

Clay mineral

The clay group is a subcategory of the phyllosilicates. Bentonite is a general clay material originating from volcanic ash and containing primarily montmorillonite as the main constituent.

Much of the pioneering work with mycotoxin binders was done with silicates and specifically with the HSCAS material. Specific HSCAS included at 0.5% to 2.0% of the diet is well documented to adsorb aflatoxin and to prevent aflatoxicosis across species. Responses to HSCAS appear to be dose-dependent.
Montmorillonite clay is a hydrated sodium calcium aluminum magnesium silicate hydroxide. Clays are silica sheets that are similar to other phyllosilicates but contain a high concentration of water. Zeolites are classified as tectosilicates consisting of interlocking tetrahedrons. The zeolite structure provides vacant spaces that form channels of various sizes allowing the movement of molecules into and out of the structure. Zeolites can lose and absorb water without damage to their crystal structures.

organic / Inorganic polymers

Some complex indigestible carbohydrates (cellulose, polysaccharides in the cell walls of yeast and bacteria such as glucomannans, peptidoglycans, and others), and synthetic polymers such as cholestyramine and polyvinylpyrrolidone can adsorb mycotoxins. Indigestible dietary fiber has absorbance potential for mycotoxins. Alfalfa fiber has reduced the effects of zearalenone.

Saccharomyces cerevisiae live yeast was shown to reduce the detrimental effects of aflatoxin. Fibrous material from the yeast cell wall was shown to have the potential to bind several mycotoxins. Esterified glucomannan polymer extracted from the yeast cell wall was shown to bind with aflatoxin, ochratoxin, and T-2 toxin, individually and combined. Additions of esterified glucomannan at 0.5 or 1.0 g/kg to diets supplying 2 mg of total aflatoxin resulted in dose-dependent responses in broiler chicks. The addition of esterified glucan polymer to aflatoxin-contaminated diets of dairy cows has significantly reduced milk aflatoxin residues as per one study. The esterified glucan polymer may have the capability to bind several mycotoxins. There is a mechanism of binding with zearalenone. A glucan polymer bound both T-2 toxin and zearalenone in vitro. Certain bacteria, particularly strains of lactic acid bacteria, propionibacteria, and bifidobacteria, appear to have the capacity to bind mycotoxins, including aflatoxin and some Fusarium-produced mycotoxins. The binding appears to be physical with deoxynivalenol, diacetoxyscerpenol, nivalenol, and other mycotoxins associated with hydrophobic pockets on the bacterial surface.

Carbon Products

Activated carbon is a general adsorptive material with a large surface area and excellent adsorptive capacity. It has been recommended as a general toxin adsorbing agent and is routinely recommended for various digestive toxicities. The effects of activated charcoal have been variable. Studies showed reduced aflatoxin residues in the milk of cows consuming different sources of charcoal, but responses to charcoal did not exceed that seen with a clay-based binder (a hydrated sodium calcium aluminosilicate or HSCAS). Low levels (45 g/cow daily) of activated carbon did not significantly reduce milk aflatoxin residues, whereas clay-type binders (225 g/cow daily) or an organic polymer of esterified glucan (10 g/cow daily) significantly reduced milk aflatoxin. Responses to charcoal suggest that charcoal may not be as effective in binding aflatoxin as clay-based binders. Activated charcoal may be important in binding zearalenone and/or deoxynivalenol. In an in vitro gastrointestinal model, activated carbon reduced the availability of deoxynivalenol and nivalenol.

The use of toxin binder in cattle feeds

The addition of Toxin binders to contaminated diets has been considered the most promising dietary approach to reduce the effects of Toxins. The theory is that the binder decontaminates mycotoxins in the feed by binding them strongly enough to prevent toxic interactions with the consuming animal and to prevent mycotoxin absorption across the digestive tract. Therefore, this approach is seen as prevention rather than therapy. Potential absorbent materials include activated carbon, aluminosilicates (clay, bentonite, montmorillonite, zeolite, phyllosilicates, etc.), complex indigestible carbohydrates (cellulose, polysaccharides in the cell walls of yeast and bacteria such as glucomannans, peptidoglycans, and others), and synthetic polymers such as cholestyramine and polyvinylpyrrolidone and derivatives.

Livestock enterprises face the maximum loss owed to the contamination of animal feed ingredients and compounded feeds by molds and their toxic metabolites known as mycotoxin. Some of the primary toxigenic molds and mycotoxins are indicated as follows:

What are the effects of not using toxin binders on the health of livestock?

The symptoms of mycotoxicosis in a dairy herd are not always obvious. Whilst mycotoxins can result in acute and obvious symptoms more often than not effects of mycotoxins are sub-clinical and non-specific. They can be wide-ranging depending on the levels and combinations of different mycotoxins involved, disease challenges, animal welfare, stress, and a whole range of other factors.

Recognizing when and to what degree mycotoxins are responsible for poor health and performance can be extremely difficult. The effects can be long-lasting with cows taking many months to fully recover. It is highly likely that mycotoxins predispose animals to disease and are likely to exaggerate the symptoms of disease and also prolong the effects of a disease:

• Reduction of feed intake
• Reduced milk output and reduced butterfat %
• Immunosuppression
• Decrease in rumen efficiency
• Increased disease susceptibility
• Mycotoxins are anti-microbial resulting in changes to rumen and gut microbial populations
• Inflammation and damage to the digestive tract, intestinal hemorrhages, scour
• Reduced nutrient absorption and impaired metabolism
• Effects on endocrine and exocrine systems, hormone, and enzyme levels
• Metabolic problems, retained placentas, ketosis, displaced abomasums, acidosis
• Infertility, metritis, cystic ovaries, poor conception rates, embryo loss, abortion
• Lameness, laminitis, leg swelling, swollen hocks, liver abscesses, udder edema
• Increased somatic cell count and mastitis
• Vaccine and drug failures and reduced effectiveness of antibiotics
• Reduced longevity