Mycotoxins in animal feed

Last updated September 14, 2024

Mycotoxins are secondary metabolites produced by filamentous fungi, commonly detected as contaminants in agricultural commodities globally. Exposure to these toxins can be very detrimental to both humans and animal, and can lead to mycotoxicosis, which can be a variety of medical conditions. In animals, exposure through feed can disrupt nutrient digestion, absorption, metabolism, and even affect animal physiology.^[1] The most common fungi that produce mycotoxins include Fusarium , Aspergillus , and Penicillium .^[2]

Effects on animals

There are six known types of mycotoxins that affect animals.^[2]

Mycotoxin	Fungi	Effect on animals
Aflatoxin	Aspergillus flavus, Aspergillus parasiticus	liver disease, carcinogenic and teratogenic effects
Trichothecenes	Fusarium graminearum, Fusarium sporotrichioides	immunologic effects, hematological changes, digestive disorders, edema
Zearalenone	Fusarium graminearum	estrogenic effects, atrophy of ovaries and testicles, abortion
Ochratoxin	Aspergillus ochraceus, Penicillium verrucosum	nephrotoxicity, mild liver damage, immune suppression
Ergot alkaloid	Claviceps purpurea, Claviceps paspaspali	nervous or gangrenous syndromes
Fumonisin	Fusarium verticillioides, Fusarium proliferatum	pulmonary edema, leukoencephalomalacia, nephrotoxicity, hepatotoxicity

Effects on feed production

The most common mycotoxin is aflatoxin. It can be very carcinogenic to both humans and animals. Aflatoxin is produced by two species of Aspergillus, A. flavus and A. parasiticus, which are known to affect plants including cereal grains, figs, nuts, and tobacco.^[2] Cereal grains are one of the main ingredient in animal feed. The animals most at risk of having serious problems with aflatoxins are trout, ducklings, and pigs, while cattle are less at risk.

Ergot alkaloids are associated with grasses that are produced in a structure of Claviceps called the sclerotia. Some of the conditions that result from ergot ingestion in animals include gangrene, abortion, convulsions, hypersensitivity, and ataxia.^[2]

Fumonisins were the most recent mycotoxin found to affect humans and animals negatively. The most produced toxin for this group of fungi is fumonisin B1.^[2] Studies have shown that it can cause diseases such as equine leukoencephalomalacia in horses, hydrothorax and porcine pulmonary edema in swine, and it can negatively affect the immune system.

Mycotoxin prevention

Studies on mycotoxins show that there are three ways to preventing them from contaminating feed. The first occurs before there is a possibility of fungal infection. The second is when the fungi are starting to produce the toxins. And the final way to prevent contamination is when the material is known to be heavily infected.^[4]

Other methods of prevention include planting species that are able to defend naturally against mycotoxins, proper fertilization, weed control, and proper crop rotation. The way the crops are stored after harvesting also plays an important role in staying mycotoxin free. If there is too much moisture then fungi have a better chance of growing and producing mycotoxins. Along with moisture levels, factors such as temperature, grain condition, and the presence of chemical or biologicalcan determine whether or not mycotoxin producing fungi will grow.^[2]

Decontamination of animal feed

There are several different methods being used to remove mycotoxins from feed products. One way is the use of adsorbents that bind with the mycotoxins and pull them away from the feed. Another method for decontaminating feed is with the use of activated charcoal in the form of a porous non-soluble powder that can bind with a variety of harmful substances. Activated charcoal is often used to remove other types of toxins or poisoning that have been ingested.^[3]

Turkey X disease

This disease was the turning point for the use of the term mycotoxin. In the 1960s, about 100,000 turkey poults died near London, England due to peanut meal that was contaminated by Mycotoxins produced by Aspergillus flavus. Studies showed that the age group that was most affected was turkeys from two to twenty weeks old. Some of the first signs of Turkey X were neurological symptoms and coma, which would result in death.^[5]

Related Research Articles

Fusarium ear blight (FEB), is a fungal disease of cereals, including wheat, barley, oats, rye and triticale. FEB is caused by a range of Fusarium fungi, which infects the heads of the crop, reducing grain yield. The disease is often associated with contamination by mycotoxins produced by the fungi already when the crop is growing in the field. The disease can cause severe economic losses as mycotoxin-contaminated grain cannot be sold for food or feed.

Aflatoxins are various poisonous carcinogens and mutagens that are produced by certain molds, particularly Aspergillus species mainly by Aspergillus flavus and Aspergillus parasiticus. According to the USDA, "They are probably the best known and most intensively researched mycotoxins in the world." The fungi grow in soil, decaying vegetation and various staple foodstuffs and commodities such as hay, maize, peanuts, coffee, wheat, millet, sorghum, cassava, rice, chili peppers, cottonseed, tree nuts, sesame seeds, sunflower seeds, and various cereal grains and oil seeds. In short, the relevant fungi grow on almost any crop or food. When such contaminated food is processed or consumed, the aflatoxins enter the general food supply. They have been found in both pet and human foods, as well as in feedstocks for agricultural animals. Animals fed contaminated food can pass aflatoxin transformation products into milk, milk products, and meat. For example, contaminated poultry feed is the suspected source of aflatoxin-contaminated chicken meat and eggs in Pakistan.

Ergot or ergot fungi refers to a group of fungi of the genus Claviceps.

Foodborne illness is any illness resulting from the contamination of food by pathogenic bacteria, viruses, or parasites, as well as prions, and toxins such as aflatoxins in peanuts, poisonous mushrooms, and various species of beans that have not been boiled for at least 10 minutes.

A mycotoxin is a toxic secondary metabolite produced by fungi and is capable of causing disease and death in both humans and other animals. The term 'mycotoxin' is usually reserved for the toxic chemical products produced by fungi that readily colonize crops.

Aspergillus flavus is a saprotrophic and pathogenic fungus with a cosmopolitan distribution. It is best known for its colonization of cereal grains, legumes, and tree nuts. Postharvest rot typically develops during harvest, storage, and/or transit. Its specific name flavus derives from the Latin meaning yellow, a reference to the frequently observed colour of the spores. A. flavus infections can occur while hosts are still in the field (preharvest), but often show no symptoms (dormancy) until postharvest storage or transport.

T-2 mycotoxin is a trichothecene mycotoxin. It is a naturally occurring mold byproduct of Fusarium spp. fungus which is toxic to humans and other animals. The clinical condition it causes is alimentary toxic aleukia and a host of symptoms related to organs as diverse as the skin, airway, and stomach. Ingestion may come from consumption of moldy whole grains. T-2 can be absorbed through human skin. Although no significant systemic effects are expected after dermal contact in normal agricultural or residential environments, local skin effects can not be excluded. Hence, skin contact with T-2 should be limited.

Aspergillus is a genus consisting of several hundred mold species found in various climates worldwide.

<span class="mw-page-title-main">Trichothecene</span> Large family of chemically related mycotoxins

The trichothecenes are a large family of chemically related mycotoxins. They are produced by various species of Fusarium, Myrothecium, Trichoderma/Podostroma, Trichothecium, Cephalosporium, Verticimonosporium, and Stachybotrys. Chemically, trichothecenes are a class of sesquiterpenes.

Fermentek Ltd. is a biotechnological company in the Atarot industrial zone of Jerusalem, Israel. It specializes in the research, development and manufacture of biologically active, natural products isolated from microorganisms as well as from other natural sources such as plants and algae.

Cyclopiazonic acid (α-CPA), a mycotoxin and a fungal neurotoxin, is made by the molds Aspergillus and Penicillium. It is an indole-tetramic acid that serves as a toxin due to its ability to inhibit calcium-dependent ATPases found in the endoplasmic and sarcoplasmic reticulum. This inhibition disrupts the muscle contraction-relaxation cycle and the calcium gradient that is maintained for proper cellular activity in cells.

The fumonisins are a group of mycotoxins derived from Fusarium and their Liseola section. They have strong structural similarity to sphinganine, the backbone precursor of sphingolipids.

Mycotoxicology is the branch of mycology that focuses on analyzing and studying the toxins produced by fungi, known as mycotoxins. In the food industry it is important to adopt measures that keep mycotoxin levels as low as practicable, especially those that are heat-stable. These chemical compounds are the result of secondary metabolism initiated in response to specific developmental or environmental signals. This includes biological stress from the environment, such as lower nutrients or competition for those available. Under this secondary path the fungus produces a wide array of compounds in order to gain some level of advantage, such as incrementing the efficiency of metabolic processes to gain more energy from less food, or attacking other microorganisms and being able to use their remains as a food source.

<span class="mw-page-title-main">Sterigmatocystin</span> Chemical compound

Sterigmatocystin is a polyketide mycotoxin produced by certain species of Aspergillus. The toxin is naturally found in some cheeses.

Pathogenic fungi are fungi that cause disease in humans or other organisms. Although fungi are eukaryotic, many pathogenic fungi are microorganisms. Approximately 300 fungi are known to be pathogenic to humans; their study is called "medical mycology". Fungal infections are estimated to kill more people than either tuberculosis or malaria—about two million people per year.

Microbial toxins are toxins produced by micro-organisms, including bacteria, fungi, protozoa, dinoflagellates, and viruses. Many microbial toxins promote infection and disease by directly damaging host tissues and by disabling the immune system. Endotoxins most commonly refer to the lipopolysaccharide (LPS) or lipooligosaccharide (LOS) that are in the outer plasma membrane of Gram-negative bacteria. The botulinum toxin, which is primarily produced by Clostridium botulinum and less frequently by other Clostridium species, is the most toxic substance known in the world. However, microbial toxins also have important uses in medical science and research. Currently, new methods of detecting bacterial toxins are being developed to better isolate and understand these toxins. Potential applications of toxin research include combating microbial virulence, the development of novel anticancer drugs and other medicines, and the use of toxins as tools in neurobiology and cellular biology.

Aflatoxin B₁ is an aflatoxin produced by Aspergillus flavus and A. parasiticus. It is a very potent carcinogen with a TD₅₀ 3.2 μg/kg/day in rats. This carcinogenic potency varies across species with some, such as rats and monkeys, seemingly much more susceptible than others. Aflatoxin B₁ is a common contaminant in a variety of foods including peanuts, cottonseed meal, corn, and other grains; as well as animal feeds. Aflatoxin B₁ is considered the most toxic aflatoxin and it is highly implicated in hepatocellular carcinoma (HCC) in humans. In animals, aflatoxin B₁ has also been shown to be mutagenic, teratogenic, and to cause immunosuppression. Several sampling and analytical methods including thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC), mass spectrometry, and enzyme-linked immunosorbent assay (ELISA), among others, have been used to test for aflatoxin B₁ contamination in foods. According to the Food and Agriculture Organization (FAO), a division of the United Nations, the worldwide maximum tolerated levels of aflatoxin B₁ was reported to be in the range of 1–20 μg/kg (or .001 ppm - 1 part-per-billion) in food, and 5–50 μg/kg (.005 ppm) in dietary cattle feed in 2003.

Forensic mycology is the use of mycology in criminal investigations. Mycology is used in estimating times of death or events by using known growth rates of fungi, in providing trace evidence, and in locating corpses. It also includes tracking mold growth in buildings, the use of fungi in biological warfare, and the use of psychotropic and toxic fungus varieties as illicit drugs or causes of death.

Aspergillus parasiticus is a fungus belonging to the genus Aspergillus. This species is an unspecialized saprophytic mold, mostly found outdoors in areas of rich soil with decaying plant material as well as in dry grain storage facilities. Often confused with the closely related species, A. flavus, A. parasiticus has defined morphological and molecular differences. Aspergillus parasiticus is one of three fungi able to produce the mycotoxin, aflatoxin, one of the most carcinogenic naturally occurring substances. Environmental stress can upregulate aflatoxin production by the fungus, which can occur when the fungus is growing on plants that become damaged due to exposure to poor weather conditions, during drought, by insects, or by birds. In humans, exposure to A. parasiticus toxins can cause delayed development in children and produce serious liver diseases and/or hepatic carcinoma in adults. The fungus can also cause the infection known as aspergillosis in humans and other animals. A. parasiticus is of agricultural importance due to its ability to cause disease in corn, peanut, and cottonseed.

Aflatoxin M₁ is a chemical compound of the aflatoxin class, a group of mycotoxins produced by three species of Aspergillus – Aspergillus flavus, Aspergillus parasiticus, and the rare Aspergillus nomius – which contaminate plant and plant products.

References

↑ Xu, Ran; Kiarie, Elijah G.; Yiannikouris, Alexandros; Sun, Lvhui; Karrow, Niel A. (2022-06-08). "Nutritional impact of mycotoxins in food animal production and strategies for mitigation". Journal of Animal Science and Biotechnology. 13 (1): 69. doi: 10.1186/s40104-022-00714-2 . ISSN 2049-1891. PMC 9175326 . PMID 35672806.
1 2 3 4 5 6 Binder, Eva M (February 2007). "Managing the risk of Mycotoxins in modern feed production". Animal Feed Science and Technology. 133 (1–2): 149–166. doi:10.1016/j.anifeedsci.2006.08.008.
1 2 Huwig, Alexander; Freimund, Stefan; Käppeli, Othmar; Dutler, Hans (June 2001). "Mycotoxin detoxication of animal feed by different adsorbents". Toxicology Letters. 122 (2): 179–188. doi:10.1016/s0378-4274(01)00360-5. PMID 11439224.
↑ Jouany, Jean Pierre (October 2007). "Methods for preventing, decontaminating, and minimizing the toxicity of mycotoxins in feed". Animal Feed Science and Technology. 137 (3–4): 342–362. doi:10.1016/j.anifeedsci.2007.06.009.
↑ Wannop, C. C. (1961). "The Histopathology of Turkey 'X' Disease in Great Britain". Avian Diseases. 5 (4): 371–381. doi:10.2307/1587768. JSTOR 1587768.

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[1] Xu, Ran; Kiarie, Elijah G.; Yiannikouris, Alexandros; Sun, Lvhui; Karrow, Niel A. (2022-06-08). "Nutritional impact of mycotoxins in food animal production and strategies for mitigation". Journal of Animal Science and Biotechnology. 13 (1): 69. doi: 10.1186/s40104-022-00714-2 . ISSN 2049-1891. PMC 9175326 . PMID 35672806.

[Binder-2] 1 2 3 4 5 6 Binder, Eva M (February 2007). "Managing the risk of Mycotoxins in modern feed production". Animal Feed Science and Technology. 133 (1–2): 149–166. doi:10.1016/j.anifeedsci.2006.08.008.

[Huwig-3] 1 2 Huwig, Alexander; Freimund, Stefan; Käppeli, Othmar; Dutler, Hans (June 2001). "Mycotoxin detoxication of animal feed by different adsorbents". Toxicology Letters. 122 (2): 179–188. doi:10.1016/s0378-4274(01)00360-5. PMID 11439224.

[Jouany-4] Jouany, Jean Pierre (October 2007). "Methods for preventing, decontaminating, and minimizing the toxicity of mycotoxins in feed". Animal Feed Science and Technology. 137 (3–4): 342–362. doi:10.1016/j.anifeedsci.2007.06.009.

[5] Wannop, C. C. (1961). "The Histopathology of Turkey 'X' Disease in Great Britain". Avian Diseases. 5 (4): 371–381. doi:10.2307/1587768. JSTOR 1587768.

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