USE OF TOXIN BINDERS IN LIVESTOCK FEED FOR FOOD SAFETY, BETTER HEALTH & FCR
Dr.Surinder Khanna,Poultry Advisor,Ambala
The word mycotoxin literally means “fungus-poison.” Mycotoxins are produced naturally by molds and fungi in fields and during the storage of grains, feeds and forages.
As far back as the 1960s, a group of mycotoxins called aflatoxins was identified as being a significant health risk to humans. However, many other mycotoxins have the potential to harm humans and animals. Of all the known mycotoxins, aflatoxins are currently the only ones regulated by the FDA, with maximum amounts allowable in food for humans and animals.
Mycotoxins can be considered soilborne pathogens, since they originate in crops such as grains and forages. Dairy and beef cow diets generally include both grains and forages, which increases the risk of exposure to mycotoxins. Forages, fermented feeds and byproducts can represent a significant risk depending on soil contamination, forage harvesting date, silage management and storage conditions.
The concern over mycotoxin contamination in animal feeds is growing due to a combination of factors:
Changes in the climate and agronomic practices have created environments more suitable for mold growth.
The volume of grains traded globally has increased, thus increasing the potential for contamination.
Higher-producing dairy cows are more susceptible to the effects of mycotoxins.
The fungi and molds associated with mycotoxins fall into three broad groups:
Penicillium
Aspergillus
Fusarium
Hundreds of mycotoxins have been identified, and they’re usually associated with diseased and moldy crops, as well as growing conditions that encourage the growth of molds. The most commonly analyzed mycotoxins include deoxynivalenol (DON/vomitoxin), zearalenone, T-2 toxin, fumonisin B1, aflatoxins and ochratoxin A.
Mycotoxins seldom occur in isolation. Given the fact that one mold is capable of producing several mycotoxins, several molds can contaminate one feed ingredient. With several ingredients included in a ration, it’s not uncommon to find multiple mycotoxins in finished feeds. This allows for interactions among mycotoxins, resulting in synergistic or additive effects on the animal. Mycotoxin interactions result in unexpected animal toxicity and make diagnosis difficult.
Ruminants are exposed to mycotoxins in a variety of ways, including grazing pasture (fungal contamination of grasses); feed or total mixed ration (TMR) made with contaminated ingredients; and moldy silages.
Mycotoxins found in animal feeds have the potential to severely impact the economic well-being of a dairy farm through forage loss or reduced crop value, reduced milk production, milk or meat discards due to risk of contamination in the food chain, increased mortality rates, increased vaccination costs and reproductive losses.
Mycotoxins are found in nearly all forages and processed grains. Eliminating them from the environment is nearly impossible. Crop and dairy farmers will find that the level of mycotoxin contamination in feeds varies from year to year and from different growing conditions. Since the majority of feed grown and stored on dairy farms is forages – corn silage and hay crops – dairy farmers must be aware of the conditions that are conducive to the occurrence of mycotoxins in forages.
Fungicides have been found to have little effect on reducing or eliminating mycotoxins in forages. The best agronomic practice for controlling mycotoxins in forages is crop rotation. Monocultures, or the planting of closely related crops one after the other on the same field year after year, will enhance the risk of mycotoxin formation. Spores will transfer to the subsequent crop and thus allow fungal growth. Plowing under harvest residues will reduce spore contamination of the subsequent crop and thus reduce fungal infestation and mycotoxin formation. No-till systems seem to enhance the risk of mycotoxin formation in a field. Crop varieties that are more resistant to foliar fungal diseases reduce infection and thus mycotoxin formation in the crop.
Mycotoxin binders and absorbents added to cows’ diets have been around for many years. These products react with mycotoxins in the cow’s digestive system to render them ineffective or less effective. Binders come in two forms, inorganic or organic.
Inorganic binders are essentially clay (from soil) products consisting of a variety of chemical elements that react or bind with the mycotoxin molecules. Not all inorganic products work on all mycotoxins. Such materials are often inexpensive and easy to handle. These products are traditionally mixed with finished feeds at a mill or mixed on-farm in mixers. Costs are low, but they require a high inclusion rate.
Organic binders are essentially carbon-based polymers – carbohydrates. Examples would include products such as oat hulls, wheat bran, cellulose, pectins and yeast cell walls. Again, each of these binders can react with toxin molecules, making them ineffective in the digestive system.
In recent years, there has been much research conducted on yeast cell walls. Different strains of yeast have varying levels of cellulose and sugars, known as mannan-oligosaccharide (MOS). These molecules can and do bind with different mycotoxins. Advanced research is being conducted on MOS products to identify binding sites that will interact specifically with a selected mycotoxin.
Dairy farmers who feed fermented forages and/or pasture their cattle would benefit by adding mycotoxin binder products that contain both an inorganic and an organic mycotoxin binder. We know that some level of mycotoxins can be found in most feeds, no matter how careful a farmer is in growing and storing them. Mycotoxin binders are sensible insurance that will help control the problems associated with mycotoxins when the need arises.
Mold inhibitors are used to control mold contamination and prevent mold growth in order to minimize the risk of having proliferation of mycotoxin-producing molds in grain or feed . Acidifiers are commonly used as mold inhibitors, particularly organic acids such as propionic acid. Acidifiers display fungicidal properties by reducing the pH in grain and feed . However, the use of acidifiers as mold inhibitors have no effect on mycotoxins already present in contaminated grain and feed .
Mycotoxin binders or adsorbents are substances that bind to mycotoxins and prevent absorption through the gut .The most commonly used mycotoxin binders in Livestock feeds are aluminosilicate binders, which include clays, bentonites, zeolites, and hydrated sodium calcium aluminosilicate (HSCAS). The aluminosilicate binders are natural, inorganic mycotoxin binders containing a porous structure made of silica that is able to adsorb and trap mycotoxins . The aluminosilicate binders are very effective aflatoxin binders, but have limited activity against other types of mycotoxins .Furthermore, aluminosilicate binders are nonspecific and bind vitamins and trace minerals as well .
Other mycotoxin binders used in Livestock feeds are yeast components. The yeast components are natural, organic mycotoxin binders extracted from the cell walls of Saccharomyces cerevisiae, primarily α-mannans and β-glucans .The yeast components have a diverse mechanism of adsorption and act against a wide range of mycotoxins .Furthermore, organic yeast components are biodegradable and do not accumulate in the environment after being excreted in the manure, in contrast to inorganic silicate binders.
However, mycotoxin binders are vastly ineffective against vomotoxin . Vomitoxin is the colloquial term for deoxynivalenol (DON), the most common contaminant of grains and feed . Recently, sodium metabisulfite has been found to be a promising agent against vomitoxin .Although not approved by Food and Drug Administration as a DON-detoxifying agent, sodium metabisulfite reacts with DON to form a non-toxic component in a process that requires heat and humidity for optimal efficiency . The addition of sodium metabisulfite to diets naturally contaminated with vomitoxin seems to restore feed intake and improve growth performance of nursery pigs .However, sodium metabisulfite is known to degrade the vitamin thiamin, which needs to be supplemented in diets with sodium metabisulfite.
Role of gut microbiota on health status of the animals
The gastrointestinal (GI) tract of chickens harbor diverse and complex microbiota that plays a vital role in digestion and absorption of nutrients, immune system development and pathogen exclusion. In addition to this, the integrity, functionality, and health of the chicken gut depends on many factors including the environment, feed, and the GI microbiota. It has been reported that gut microbial diversity can be improved by probiotics. Probiotics are single or mixed cultures of live non-pathogenic microorganisms, when provided in adequate amount confers benefit to the host. Probiotics currently being used are Bacillus subtilis, lactic acid bacteria (LAB, eg.: L.plantarum), Streptococcus thermophilus, Enterococcus faecium, E. faecalis, Bifidobacterium spp., fungal strains such as Aspergillus oryzae and yeast (Saccharomyces cerevisiae). Teo et al., have reported that broiler birds fed with B. subtilis (PB6) had heavier bursas and heterophils with higher in vitro phagocytosis for E.coli. This indicates the role on chicken innate immune system possibly by supporting gut microflora. Such findings indicate that the interactions between animal and gut microbiota is fundamental to poultry health and production.
Occurrence of mycotoxins
United Nations Food and Agriculture Organization and the World Health Organization has estimated that 25% of the world’s crops such as nuts, cereals, and rice are contaminated by mold and fungal growth.
Need of broad-spectrum toxin binder
Considering that most feed samples are contaminated with multiple mycotoxins, a broad-spectrum mycotoxin binder is required for eliminating the risk. An ideal mycotoxin binder for animal feed application should have several qualities. First and foremost, it should have high binding efficacy against all common mycotoxins. It needs to be noted that poultry GI system has different pH at different locations and the binding should be intact when the feed passes through the GI system. Secondly, it should not bind to essential nutrients present in the feed such as vitamins and minerals. This is very important as materials such as charcoal show high binding efficacy against nutrients. It is also important to note that the mycotoxin binder should not get digested/degraded while passing through the GI tract as it can lead to release of the bound mycotoxins.
It is well established now that mycotoxin contamination in animal feed is very common. The levels of contamination and number of mycotoxins present may vary from time to time. Mycotoxins have growth inhibiting effect on beneficial bacteria and thereby they can alter the gut microbiota, which plays a major role in maintaining the intestinal health and overall health of the bird. So, it is essential to use a broad spectrum, efficacious mycotoxin binder in the animal feed, even when low levels of mycotoxin contamination are detected.
HOW TO ELIMINATE LIVESTOCK HEALTH RISKS WITH MYCOTOXIN BINDERS
More than 300 types of mycotoxins are produced by molds, which means that there’s a good possibility your operation has encountered problems because of mold damage and mycotoxin production.
Finding ways to protect livestock health, maintain profitable levels of production, and eliminate expensive veterinary costs is critical to running a successful operation.
Mycotoxin Binders:
Whether you want to lengthen the shelf life of feed or are focused on providing a nutritionally complete diet to your animals, mycotoxin binders work to enhance the quality of feed and raw materials while protecting livestock from dangerous health risks.
Benefits of Using Mycotoxin Binders:
Reduces the chance of mycotoxicosis
Improves animal health
Boosts livestock productivity
Avoids expensive veterinary costs
Toxin Binder Composition:
The key to eliminating the production of mycotoxins that lead to dangerous health issues is selecting a mycotoxin binder with a proven composition. Many of the best mycotoxin binders include a variety of the following elements:
Organic acids
Activated charcoal
Selected silicates
Yeast cell wall components
Surfactants and photogenic derivatives
Using mycotoxin binders is a great way to combat the loss of nutritive value in feeds that have been contaminated by toxins and have decreased in palatability. If you suspect that molds have contaminated your feed or raw materials, it’s essential that you immediately begin using binders. This will limit the possibility of disease due to absorption of toxins into the bloodstream.
There are 6 things you need to consider when addressing mycotoxin problems:
Mycotoxins lower the nutritional value and palatability of feeds and raw materials
Mycotoxins hamper your livestock’s ability to use vitamins, proteins, fats, carbohydrates, and minerals
Vital organ tissues can be damaged by mycotoxins, especially the rumen lining, liver, kidney, and intestinal tissue which lowers resistance to metabolic conditions like ketosis
Mycotoxins can disrupt normal ovary function
Mycotoxins suppress immune function, which lowers resistance to sickness and disease
Mycotoxins can negatively impact the health and production of livestock
Mycotoxins can infect and harm a variety of livestock species, so it’s important to know what to look for.
The addition of adsorbent (binder) materials to animal feeds is very common for the prevention of mycotoxicosis, especially aflatoxicosis.
Adsorption
Mycotoxin binders are nutritionally inert substances added to animal feed in order to tightly bind and immobilize mycotoxins in the gastrointestinal tract of animals, thus reducing their bioavailability.
This process is known as adsorption, and it constitutes the most well-known approach to detoxification of mycotoxins.
Adsorption is a suitable strategy for aflatoxins, ergot alkaloids and ochratoxins, but it is not an efficient method to counteract trichothecenes, fumonisins and zearalenone.
Efficacious adsorption of mycotoxins depends on the polarity and shape of the mycotoxin, and the type of bonds that are formed between the toxin and the adsorbent.
Examples of binder materials include:
Silicates
Clays
Yeast
Charcoal
Bentonites are highly promising materials for adsorption of aflatoxin B1 (AfB1). Bentonites are clay minerals which result from the decomposition of volcanic ash consisting mainly of the phyllosilicate mineral montmorillonite (smectite). Bentonites have been reported to effectively decrease the inhibitory effects of dietary AfB1.
Clay mineral binders alone are not an effective answer to all major mycotoxins. This holds especially true when it comes to counteracting Fusarium mycotoxins since their structures are not suitable for adsorption.
Activated charcoal represents a very unspecific binder, meaning that it also adsorbs nutrients.
How to choose the right product
An effective mycotoxin binder meets five key criteria, namely:
High adsorptive capacity
Irreversible – not easily undone
Specific – only binds mycotoxins
Safe
Scientifically proven through in vivo biomarker studies.
Mycotoxins are chemical compounds produced by actively growing molds (fungi) as secondary metabolites that can negatively affect Livestock performance. While not all molds produce toxins, over 300 types of mycotoxins are known to be produced by molds, with aflatoxin, vomitoxin, zearalenone, fumonisin, and ochratoxin generally regarded to be the most significant mycotoxins affecting livestock production .Young and breeding animals are generally more susceptible to mycotoxins.
The molds that produce the common mycotoxins found in livestock diets belong to the genera Aspergillus, Claviceps, Fusarium, and Penicillium.Feedstuffs may be contaminated before harvest of the main plant source, during post-harvest handling and storage, and during processing into animal-feed products. Grains such as corn, wheat, and barley may be easily contaminated with molds. Molds are categorized into field and storage fungi. Field fungi are those that grow in grains before they are harvested. These commonly include Fusarium species, which produce vomitoxin, zearalenone, and fumonisin. Storage fungi, which include molds of the genera Aspergillus and Penicillium, are significant producers of mycotoxins that commonly affect livestock such as aflatoxin and ochratoxin. These fungi can grow even at very low moisture levels, unlike the field fungi. Aspergillus flavus produces high concentrations of aflatoxin in grains even before harvest. It is important to distinguish between field and storage fungi, since this affects the distribution of mycotoxins. When conditions are favorable for field fungi to produce mycotoxins, grain from a geographic location is expected to be widely affected. Thus, large quantities of grain may be contaminated. In contrast, storage fungi should have a more localized distribution due to specific conditions during storage. In fact, not all grain may be affected evenly within a storage bin. Thus, storage mycotoxins may be difficult to detect without extensive sampling.
With the increase in the availability of distillers grains due to increasing ethanol production, the use of distillers grains in swine diets has also increased. Corn is the major grain product used to produce ethanol. Because most of the starch in the corn is consumed during fermentation, the resulting distillers grains co-product is more concentrated in other proximate components, such as fiber, protein, and fat, than is the source corn. However, if the corn grain used for fermentation has been contaminated with mycotoxins, the resulting distillers grains product may contain as much as three times the concentration of mycotoxins as the source corn.
Mycotoxicosis refers to poisoning due to the ingestion of mycotoxins. This condition can cause lower resistance to diseases, increased sensitivity to stress, and damage to vital organs, such as the liver and kidney. Ultimately, this may lead to mortalities and poor production performance.
Mold inhibitors are feed additives used to minimize mold contamination and prevent mold growth, thereby minimizing the risk of having mycotoxin-producing molds proliferate in grain or feed. Feed additives commonly used for this purpose include propionic acids and other organic acids. However, even if mold growth has been prevented, mycotoxins may still be present, because mold inhibitors have no effect on mycotoxins already present in contaminated feed.
Mycotoxin binders:
Mycotoxin binders or adsorbents are substances that bind to mycotoxins and prevent them from being absorbed through the gut and into the blood circulation. When other preventive measures against molds and mycotoxins have failed, the use of mycotoxin binders can be valuable. There also may be instances when feeds and feedstuffs cannot be checked for mycotoxins on a regular basis. Mycotoxin binders are routinely added in such cases as safety measures and as some form of assurance to customers. A variety of substances have the ability to bind mycotoxins. The most commonly used and most researched mycotoxin-binding agents are the aluminosilicates – clays and zeolites. These are natural adsorbents that include hydrated sodium calcium aluminosilicates (HSCAS), bentonite, and zeolite .Most of these products are efficient binders of aflatoxins. However, they have limited or no activity against other types of mycotoxins. Other substances with toxin-binding capability include cell-wall components of yeasts. Some studies have shown that the cell-wall fraction β-glucan of yeasts such as Saccharomyces cereviceae can be effective in binding a wide range of mycotoxins.Unlike clays, they can be added at low levels and are biodegradable.
Choosing the appropriate product:
In general, the following must be considered when choosing either mold-inhibitor or adsorbent products: efficacy in adsorbing the mycotoxin or inhibiting the mold of interest, and safety to the animal, the handler, and to pork consumers; high stability and ablility to withstand varying conditions during feed mixing; and cost effectiveness. Caution also must be exercised when using clay, because its high adsorptive capacity can limit the bioavailability of minerals. This is most important when diets contain marginal levels of trace minerals. The risk of dioxin contamination associated with the use of natural clays needs to be considered.6 It is important to know the source of clay products that will be used in swine diets. Dioxins are mainly by-products of industrial processes. Contamination of clay sources can be due to improper disposal or accidental leakage of these by-products into the environment.
Antioxidant:
An antioxidant is a product added to animal feeds to prevent oxidation of fat or vitamins. Antioxidants found in commercial products include ethoxyquin, butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), and propyl gallate. Combinations of these antioxidants are normally found in commercially available products to take advantage of the different properties of each antioxidant. For instance, an antioxidant-product combination may contain propyl gallate to provide a high level of initial protection and BHA for longer effect.
When is it advisable to use mold inhibitors, mycotoxin binders, and antioxidants?:
The use of mold inhibitors and mycotoxin binders in swine diets may be advisable in geographic areas that are highly conducive to mold growth in grains and where mycotoxin contamination is more likely. Mycotoxin binders should be used when it is suspected that feed ingredients are contaminated with mycotoxins at levels deemed unsafe for livestock. The use of these products becomes more important in situations when the moisture content of grains to be used for pig diets is greater than 14% and when storage conditions have a relative humidity that is higher than 85% and a temperature greater than 55°F.Thus, the use of mold inhibitors or mycotoxin binders may also be needed when diets have to be stored for a relatively longer period of time.
Antioxidants are highly applicable in areas where the climate is warm and when high levels of fat are added to the diet. Antioxidants are widely used in areas where by-products high in unsaturated fat (eg, fish meal) are commonly used. Oxidation of unsaturated fatty acids can produce substances that can cause off-flavors and toxic substances that can cause rancidity. These substances can also destroy nutrients like the fat-soluble vitamins.Adding an antioxidant minimizes fat oxidation, keeps the diet highly palatable, and helps prolong the shelf life of the feeds. It should be noted that antioxidants delay, but cannot prevent, fatty-acid oxidation.
Mycotoxin Binders in Poultry Feed:
The effects of mycotoxins on the health and productivity of poultry depends on the type of mycotoxins produced as well as the level of contamination. Mycotoxin poisoning can cause weight loss, decreased feed efficiency, and lower egg production. Mycotoxin binders used in poultry feed provide an exceptional level of health security and a more efficient way for birds to utilize maximum levels of nutrients that can improve production rates.
Mycotoxin Binders for Dairy Cattle:
Mycotoxin poisoning among dairy cows impacts the livestock by “reducing feed consumption, reducing nutrient utilization, altering rumen fermentation, suppressing immunity, altering reproduction, irritating tissues, and causing cellular death.”
There are 3 common symptoms of mycotoxin poisoning in dairy cattle:
A decrease in milk production
Infertility, abortion and decreased conception rates majorly due to zearalenone toxins
Reduced intake of dry matter
The increase in mineral or salt consumption usually occurs when mycotoxins impact the ability of cattle to properly absorb nutrients. Using toxin binders for dairy cattle limits mycotoxin occurrence and reduces toxicity.
Mycotoxin Binder for Horses:
Horses usually exhibit a variety of symptoms that indicate mycotoxin poisoning, including:
Reduced feed intake
Weight loss
Respiratory issues
Lower resistance to disease and sickness
Poor growth rates
Supplement your horses’ diet with mycotoxin binders and bolster your efforts with healthy feed storage practices, such as maintaining low levels of humidity and proper ventilation. Following these steps can prevent serious equine health problems from occurring.
Using Mycotoxin Binders to Reduce Economic Loss and Improve Livestock Health:
Routine use of mycotoxin binders will reduce toxin levels to a degree that will not impact livestock health or production rates. Common, expensive problems—like lameness, inflammation, and infertility—can all be a result of mycotoxin poisoning.
Here are 4 criteria for identifying successful mycotoxin binders:
Successful trials prove efficacy
Binds to a wide range of mycotoxins
High absorption capacity
Safe for animal consumption
Mycotoxins represent a massive economic loss for farmers and livestock operators each year. They force costs to skyrocket and require extensive labor to eliminate and control. Adding mycotoxin binders to feed not only improves livestock health and production levels, it also boosts profitability by eliminating costly veterinary services and other expenses associated with restoring livestock health.
Reference-On Request
