Fungal toxins and ways to deal with mycotoxins

Animal feed farms include more than 80% of the costs of the breeding unit. The raw materials that are prepared from different places to supply livestock feed have the possibility of transferring contamination and various problems to the animal husbandry.

One of the problems of molds and fungi and the poison they produce is mycotoxins.

Today, fungal toxins are a global problem, so that about 25% of the grains produced in the world are contaminated with mycotoxins.

Fungi are aerobic multicellular organisms whose needs for growth (water, etc.) are much less than bacteria.

All species of fungi and molds are not harmful and useful species are used in some production processes.

When mold or fungus suffers from temperature, humidity and… stress. In self-defense, it secretes substances called fungal toxins (mycotoxins) that remain on food. These substances are actually the secondary metabolites of fungi, which are very resistant to heat and high temperatures on the building. They have no effect.

Mushrooms and molds in different stages of plant growth, from the time it is on the ground (before harvesting) to the time of harvesting – storage – transportation – feed factories, etc., have the possibility of forming and producing fungal toxins.

There is always the suspicion that where mold is not observed, there may not be fungal toxins contamination. While the presence of molds is not a proof of the presence or absence of fungal toxins. Because in a time and place, it is possible that the conditions for mold growth are available and due to stress, they also produce their poison, but then the conditions for mold growth are eliminated, and the fungus or mold is gone, but its toxins still remain in the food.

It is also possible to see mold in some places, but this mold has not yet been under stress conditions and has not produced itself.

How mycotoxins work

Mycotoxins act through three mechanisms:

1- Creating interference in the metabolism and absorption of dietary nutrients

2- Negative effects on endocrine and exocrine systems

3- Suppression of the immune system

Fungal toxins cause problems in animals, including:

1- Decrease in food consumption

2- Increasing vulnerability to diseases by disrupting the body’s immune system

3- Increasing the percentage of infertility and increasing miscarriages and increasing false pregnancies

4- Increase of somatic cells in milk

5- vaginal discharge and vaginal inflammation

6- Remaining of fungal toxins in livestock products that cause cancer in humans

7- Increase in mortality

The presence of these toxins causes the liver to enter the detoxification process and due to spending a lot of energy to remove these toxins and the fact that the liver devotes part of its activities to this. The productivity of the animal’s energy intake decreases. As a result, the liver, which is the main organ, gets damaged.

Mycotoxins have an inhibitory effect on the body’s immune system, but the way each of them affects this system is different. All three toxins (aflatoxin – acratoxin – T2Toxin ) prevent protein biosynthesis.

Aflatoxin by preventing prescription

T2Toxin by binding to specific points of the ribosome

Ochra toxin by preventing the activity of phenylalanine RNA

Important fungal toxins

The three main families of fungi producing mycotoxins are (Aspergillus-Fusarium and Penicillium).

The effects of mycotoxins are affected by various factors such as the type of mycotoxin, the amount of poison that the animal receives, the duration of receiving the poison, the species of the animal, the age of the animal (young people are more sensitive), the sex of the animal (males are more sensitive), environmental factors such as stress and pollution. Bacteria are placed.

Ruminants are less sensitive to mycotoxins than monogastrics, rumen microbes are responsible for metabolizing toxins.

Poultry and horse are more sensitive to aflatoxin.

In general, aflatoxins are more common under hot and dry conditions, while Fusarium toxins are more common under humid conditions.

Tricotene toxins are the most dangerous mycotoxins for ruminants.

(Trichothecen = Don-Das-T2toxin)

By inhibiting protein synthesis, trichothecenes cause a wide range of side effects, from reduced immune function to digestive problems. Due to their non-polar structure, these mycotoxins are not absorbed by toxin binders, and microbial methods must be used to destroy them.

    Zearalenon = ZEA

Mycotoxin zearalenone is produced from Fusarium fungus (F.Graminearum) ZEA. It is insoluble in water and stable against heat. The chemical structure of ziralenone is similar to the hormone estrogen. For this reason, it is called false estrogen hormone, and when it enters the body, it disturbs the body’s hormonal system and shows the symptoms of estrogen hormone.

Ziralenone is an estrogenic mycotoxin.

Effects of Ziralenone:

1- Increasing abortion

2- Increased vaginal secretions

3- Increased swelling and protrusion of the vagina

4- Decrease in fertility

5- Increasing breast volume in heifers

6- Increasing false estrus

7- Increasing the number of vaccinations per pregnancy

This poison causes early puberty and breast size increase in small amounts and leads to abortion in high amounts.

Deoxynivalenol (Don) = Vomi toxin

Don mycotoxin is produced from Fusarium graminarium and coaminatum fungi. The most common mycotoxin in Silo is Don. The amount of this poison in corn silage and wheat bran is higher than other food components.

Fusarium graminarium occurs in wheat and barley. It also causes rotting of corn stalks. Another name of this mycotoxin is Fosarium fodder.

And mitoxin is a nauseating poison and a factor that causes vomiting and lack of appetite.

Effects of DoN:

1- Increase in somatic cells in milk

2- Reduction of milk production

3- Decrease in fertility

4- Negative effect on the immune system


Mycotoxin is produced from Fusazium fungus Poa species and Sportrichiodes species (F. sportrichiodes and F. poa).

T2 poison is very toxic, the amount of this poison in corn silage is more than other food components.

Effects of T2:

1- Negative effects on the immune system

2- Stomach and inflammation of intestines and stomach

3 Bleeding and wounds of breast, stomach and intestines

4 Observing blood in the stool

5 lack of estrous cycle

This toxin stimulates fat peroxidation and prevents protein synthesis, resulting in cell death.


Fumonisin mycotoxin is produced from Fusarium species Proliferatum and Moniliform (F. monilform and F. proliferatum). The amount of this toxin is higher on sorghum and corn fodder than on other food components.

Effects of fumonisin:

1- Adding an immune system

2- Liver disease

3- Accumulation of fluids in the lungs


Ochratoxin is produced by Penicillium and Aspergillus fungi. The amount of this toxin in the atmosphere is more than other food components. The most toxic of them is Ochratoxin A, which is a potential nephrotoxin that causes kidney and urinary tract damage. Ocratoxin A is rapidly decomposed in the rumen of dairy cows by rumen protozoa, but it is a dangerous toxin for calves. The fungi that produce this toxin grow in cold and moist conditions in barn fodder.

Ekra toxin effects:

1- Daily weight loss

2- Weakening of food consumption

3- Weakening of the immune system

4- Kidney wounds


Aflatoxins are produced by Aspergillus fungi (Flavous and parasiticus). The word Aflatoxin includes the letters A and F, representing the genus Aspergilus and the Flavous species respectively, which is combined with the word toxin.

The amount of this toxin in corn, cottonseed meal, peanuts and soy is more than other food components, four different types of aflatoxins named G1, G2, B1, B2 (the strongest and most common of them is B1) are known in food and livestock products.

This toxin is metabolized in the body by the liver and turned into other mycotoxins and is transferred to its consumers through animal products. When a dairy cow feeds on food contaminated with aflatoxin B, the enzymes in the liver convert it into aflatoxin M. which is excreted in milk and urine. Aflatoxin M1 and M2 are derived from aflatoxins B1 and B2, respectively.

Aflatoxin B1 is one of the teratogenic, mutagenic and carcinogenic agents in humans. Every 65 units of aflatoxin B1 in food can be converted into 1 unit of aflatoxin M1 in animal milk. (On average, 1.7% of the amount of aflatoxin B1 in the animal diet is secreted in the form of metabolite M1 in milk) as the amount of aflatoxin in raw milk is less than 0.3 ppb (parts per billion) is ideal.

The maximum allowed amount of aflatoxin in animal feed or milk that is not dangerous is called Action Level. If AL of milk is more than 0.5 ppb, it cannot be consumed and must be destroyed.

One of the problems of aflatoxins is their resistance to heat (they can withstand temperatures of 100 degrees for a long time). The resistance of this fungal toxin is higher than Staphylococcus aureus and Clostridium botulinum toxins.

Aflatoxin survives in the heat of pasteurization and cannot be destroyed by heating. (Aflatoxin enters milk easily and is resistant to heat and boiling)

Fungal toxins are deactivated at a temperature of 250 degrees Celsius, but it is not a suitable method for cleaning animal feed.

UV irradiation reduces the toxicity of aflatoxin, and if it is used continuously and for a long time, it completely deactivates it, but due to the high cost, it is not economical.

In the production of aflatoxin, the issue of temperature and relative humidity of the environment is important, and at temperatures below 7 degrees Celsius and above 40 degrees Celsius, these fungi are unable to produce toxins. (The best temperature for toxin is between 24-28 degrees Celsius and 93-98% humidity Is).

Any negligence in drying the grain products, increasing the humidity of the warehouse and massing the product increases the severity of these molds.

The factors that can cause the growth of fungi and toxin production are:

1- Contamination of agricultural products before harvest

2- Postponing the drying time of the products and its high moisture content

3- Vegetable and storage pests

4- Food storage conditions in the warehouse in terms of temperature and humidity

Fungal toxins are produced in sufficient quantities within 2 to 6 weeks and have their effects on consuming animals after one week.

Effects of aflatoxin:

1- Adding an immune system

2- Disorder in the digestive system

3- Fatty coating in the liver

4- Transmission of aflatoxin metabolites in animal products

5- The effects of Tanzania head

6- Liver cirrhosis

Fungal toxins can have a synergistic cooperation, which is much more destructive, such as:

  The synergistic effect of DAS + T2toxin = ulcers of the digestive system / watery stools / acidosis

  The synergistic effect of DON + T2toxin = watery feces / reduction of milk fat

Due to the fact that a small percentage of mycotoxins are neutralized by the gut microbes and the majority of them are absorbed by the body, solutions for detoxification are suggested, including:

A) Physical methods

    Cleaning and sieving contaminated seeds can reduce the amount of aflatoxin by 50%, also mixing contaminated food with healthy food is suitable and useful for diluting the amount of mycotoxin.

  Separation of broken and damaged seeds

   Storing grains and fodder in a dry place with less than 7% humidity (preventing temperature, pH and humidity fluctuations in warehouses)

    Inactivation by heat and radiation

b) Chemical methods

Increasing nutrients such as protein, energy (fat-carbohydrate), vitamins, amino acids (lysine-methionine) can be effective. These additives are attached to poisons and prevent their effects.

 Ammonia treatment of grains contaminated with aflatoxin is successful, but this process is dangerous.

The use of mycotoxin absorbers (toxin binder)

That is, substances that can absorb toxins and remove them from the digestive system in a non-absorbable way.

    There are two types of mycotoxin attractants:

    Non-ionic absorbents = toxin, clay binders

    Organic absorbents that include living microorganisms and yeast cell wall extract (glucomannan)

Clay binders toxin

Toxin, clay binders from aluminum silicate, sodium bentonite, potassium bentonite, zeolite and… is. In general, it belongs to the (Hscas) group. (hydrated sodium calcium aluminum silicate)

Due to the charged structures they have (they are polar), in order to neutralize the charge of their structure, they create bonds with charged elements and remove them from the reach of the body.

By creating a high active contact surface and creating an electric charge, these materials cause the absorption of fungal toxins and are excreted from the digestive system without absorption. (The absorption of fungal toxins in these toxin binders depends on the molecular weight and weight of the particles).

In fact, the toxin of clay binders, based on the holes they have, destroys any substance that is similar to the structure of their holes upon contact with them, and the structure of these holes is very similar to the structure of aflatoxin. Therefore, it has absorbed aflatoxin well. Because these toxin binders only absorb polar toxins (aflatoxin) and are ineffective on other non-polar toxins (T2toxin, Din, Acratoxin, etc.).

Also, due to the presence of these toxin binders (sodium bentonite, potassium bentonite, zeolite), it also absorbs the nutrients and pregnant elements of the diet and vitamins A and E, and removes them from the reach of the body and excretes them.

Toxins of clay binders (sodium bentonite, potassium bentonite, zeolite) cause:

1- Reduce the absorption of minerals such as Mn-Zn-Mg-Ca-Na.

2- Using them in amounts above 0.5% reduces the performance of polar antibiotics.

3- Bentonite can be combined with tylosin and tilmycosin antibiotics.

4- Toxins Natural clay binders extracted from mines (not processed) can contain dioxins and heavy metals.

Among the advantages of using clay adsorbents, in addition to aflatoxin absorption, we can mention the increase in the food absorption coefficient due to the delay in the movement of food in the digestive tract. Also, due to the absorption of toxic gases, ammonia, etc., it eliminates unpleasant odors and more moisture in the bed .

Yeast cell wall extract (glucomannan)

In casein, the binders are based on beta-glucagan (inner wall of yeast) and they are extracted from the inner wall of yeast. As a result, they do not absorb the nutrients of the diet and micronutrients.

Due to their spiral and spring-like structure, they have a high absorption capacity, so that 1 gram of them covers an area equal to 20 square meters. And on the other hand, because they absorb mycotoxins based on hydrogen and van der Waals bonds, they have a high affinity for absorption, which is effective even in small amounts of toxins.

Yeast cell wall can increase the growth of lactate-consuming bacteria to stabilize rumen pH and microbial growth, and this way increases food consumption and improves nutrition and digestion.

Binder toxin made from dried yeast is much simpler and cheaper than the production of yeast cell wall, and also the absorption property of fungal toxin in dried yeast is much less than that of yeast cell wall.

Yeast cell wall absorbs ochratoxin and zearalenone. But for less absorbable or non-absorbable mycotoxins such as trichoxones, microbial detoxification should be used. (Trichothecen=don-das-T2txin)

In choosing the toxin binder, the following points should be considered:

Due to the abundance of fungal toxins, the toxin binder should be broad-spectrum.

 A suitable answer can be obtained with a low dose of Binder toxin. Because the high consumption dose of Binder toxin, in addition to economic loss, causes the ration space to be occupied by a non-nutritive component.

If the stability of the toxin binder and mycotoxin activity is not strong enough, it is possible that the toxins are separated from the absorbent in the end parts of the digestive system and start their activity again.

The high capacity of absorbing fungal toxins to absorb high levels of fungal toxins

The high combined tendency to absorb low levels of fungal toxins

In addition to in-vitro (laboratory) conditions, the presentation of toxin information should also include in-vivo conditions.

Mycotoxins are absorbed by the digestive system within 30 minutes, and since the largest amount of toxins are absorbed through the initial part of the digestive system, the quick action of a fungal toxin absorber is very important.

Considering the polarity of clay binders toxin and the absorption of polar poisons such as aflatoxin and toxin binders containing yeast cell wall and the absorption of ocratoxin and zearalenone by them and the toxin of microbial binders and the absorption of trichocenes by them, the best choice is the combination of silicate adsorbents and yeast wall and poison It is a biological remover.

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