Mycotoxins in pet food, The invisible killer for pets!
The threat of mycotoxins is nothing new to the companion animal industry. However, never before has it been so prevalent and public. Most recently, the reality of mycotoxins in pet food manifested in the death of more than 70 dogs and illness in 80 more in the U.S. due to aflatoxin poisoning. This led to a massive recall of pet food products after they were found to be the source of the issue (FDA, 2021).
Although pet food manufacturers have stringent quality and safety practices in place for choosing ingredients, even with strict testing procedures for mycotoxins in incoming materials and finished pet food, there can be challenges in knowing exactly what might be hiding in seemingly safe ingredients.
The effects of some food-borne mycotoxins are acute with symptoms of severe illness appearing quickly after consumption of food products contaminated with mycotoxins. Other mycotoxins occurring in food have been linked to long-term effects on health, including the induction of cancers and immune deficiency. Of the several hundred mycotoxins identified so far, about a dozen have gained the most attention due to their severe effects on animal health and their occurrences in food.?????
Aflatoxins are amongst the most poisonous mycotoxins and are produced by certain moulds (Aspergillus flavus?and?Aspergillus parasiticus) which grow in soil, decaying vegetation, hay, and grains. Crops that are frequently affected by?Aspergillus?spp. include cereals (corn, sorghum, wheat and rice), oilseeds (soybean, peanut, sunflower and cotton seeds), spices (chili peppers, black pepper, coriander, turmeric and ginger) and tree nuts (pistachio, almond, walnut, coconut and Brazil nut). The toxins can also be found in the milk of animals that are fed contaminated feed, in the form of aflatoxin M1. Large doses of aflatoxins can lead to acute poisoning (aflatoxicosis) and can be life threatening, usually through damage to the liver. Aflatoxins have also been shown to be genotoxic, meaning they can damage DNA and cause cancer in animal species. There is also evidence that they can cause liver cancer in humans.
Ochratoxin A is produced by several species of?Aspergillus?and?Penicillium?and is a common food-contaminating?mycotoxin. Contamination of food commodities, such as cereals and cereal products, coffee beans, dry vine fruits, wine and grape juice, spices and liquorice, occurs worldwide. Ochratoxin A is formed during the storage of crops and is known to cause a number of toxic effects in animal species. The most sensitive and notable effect is kidney damage, but the toxin may also have effects on fetal development and on the immune system. Contrary to the clear evidence of kidney toxicity and kidney cancer due to ochratoxin A exposure in animals, this association in humans is unclear, however effects on kidney have been demonstrated.
Patulin is a mycotoxin produced by a variety of moulds, particularly?Aspergillus,?Penicillium?and?Byssochlamys. Often found in rotting?apples?and apple products, patulin can also occur in various mouldy fruits, grains and other foods. Major human dietary sources of patulin are apples and apple juice made from affected fruit. The acute symptoms in animals include liver, spleen and kidney damage and toxicity to the immune system. For humans, nausea, gastrointestinal disturbances and vomiting have been reported. Patulin is considered to be genotoxic however a carcinogenic potential has not been demonstrated yet.????
Fusarium fungi are common to the soil and produce a range of different toxins, including trichothecenes such as deoxynivalenol (DON), nivalenol (NIV) and T-2 and HT-2 toxins, as well as zearalenone (ZEN) and fumonisins. The formation of the moulds and toxins occur on a variety of different cereal crops. Different fusarium toxins are associated with certain types of cereal. For example, both DON and ZEN are often associated with wheat, T-2 and HT-2 toxins with oats, and fumonisins with maize (corn). Trichothecenes can be acutely toxic to humans, causing rapid irritation to the skin or intestinal mucosa and lead to diarrhoea. Reported chronic effects in animals include suppression of the immune system. ZEN has been shown to have hormonal, estrogenic effects and can cause infertility at high intake levels, particularly in pigs. Fumonisins have been related to oesophageal cancer in humans, and to liver and kidney toxicity in animals.
What is aflatoxin?
Mycotoxins are toxic compounds that are naturally produced by certain types of moulds (fungi). Moulds that can produce mycotoxins grow on numerous foodstuffs such as cereals, dried fruits, nuts and spices. Mould growth can occur either before harvest or after harvest, during storage, on/in the food itself often under warm, damp and humid conditions. Most mycotoxins are chemically stable and survive food processing.
Several hundred different mycotoxins have been identified, but the most commonly observed mycotoxins that present a concern to animals health include aflatoxins, ochratoxin A, patulin, fumonisins, zearalenone and nivalenol/deoxynivalenol. Mycotoxins appear in the food chain as a result of?mould infection ouldou louo?of?crops both before and after harvest. Exposure to mycotoxins can happen either directly by eating infected food or indirectly from animals that are fed contaminated feed, in particular from milk.
Where does aflatoxin appear?
A. flavus?can grow in a temperature range of 54–118° F, with optimum growth at 98.6° F. Its moisture requirements are low, meaning just 13–13.2% is optimal for growth.
Aflatoxin is usually seen in corn, cottonseed, peanuts, almonds and their associated byproducts. For this reason, corn is one of the ingredients in dog food that poses the greatest risk to companion animals.
All of these crops are typically grown in the southern U.S., where the temperature and moisture are optimal year after year. However, in 2020, the August 25 Drought Monitor showed that these optimal conditions spread far to the north and east, into corn-growing regions.
A recent report in the results of the Alltech Summer Harvest Survey showed that this change in weather patterns has created an unusual situation in which aflatoxin is being detected at higher than normal levels in corn samples outside of the normal high-risk areas. This now presents a new set of challenges for pet food manufacturers to consider when purchasing ingredients.
A. flavus?can infest the corn plant through the silks at pollination, affecting the grain, and via stalks and leaves damaged by insects and weather events, such as high winds and hail. Infestation can be field-wide but is more often pocketed in areas of greater plant stress. This can make it challenging to identify aflatoxin in corn grain, as it may only be present in a few kernels in a truckload. Therefore, when testing incoming ingredients for mycotoxins, multiple pooled samples are required to accurately identify the potential risk.
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Stored corn needs to be dried to less than 14% moisture and closely monitored for mold growth and insect damage. Screening the grain going into and/or out of storage is a good practice to remove the damaged and cracked kernels that can be a primary source of not only aflatoxin but other mycotoxins as well.
In addition to the risk attached to raw whole grains, feed producers should be aware of the higher risk of concentrated levels of mycotoxins that can be present in processed cereal by products like bran which is often used in pet food.
Mycotoxin symptoms in pets
While no pet owner wants to think about the risk of mycotoxins, it is important to know what to watch for to ensure early action can be taken where necessary to alleviate the problem. One of the primary signs of pets ingesting food contaminated with mycotoxins is liver damage, this can occur from either acute or chronic exposure. Other typical symptoms of mycotoxin contamination in dogs include:
Aflatoxin is one of the most potent mycotoxins and a known carcinogenic, and long-term exposure can lead to death, causing devastation for pet owners and their families.
If your dog displays any of these clinical signs, it is important to visit the veterinarian as soon as possible. Take a picture of your dog food and the bag’s lot number for reference, as well.
Mitigating the threat of mycotoxins
To identify, manage and mitigate the mycotoxin challenge in feed production and to counteract the effects of mycotoxins before pets can encounter them, feed producers are advised to have a robust mycotoxin management plan in place, that can assess and manage risk at each step in the supply chain.?
Add bile acids in the pet food can help to accelerate the degradation of mycotoxins, and the non-polar groups of bile acids excreted into the intestine combine with mycotoxins to enhance the water solubility of the toxins; and improve the enzymatic hydrolysis of the toxins by intestinal enzymes, which is the transformation of mycotoxins into non-toxic substances. Excreted with feces.
For pet owners, where practical, it is encouraged to ask the manufacturer questions about their mycotoxin testing program and mitigation plan.
Daily use of bile acids can help promote liver function and improve digestion and absorption in pets, can effectively prevent the liver diseases which is caused by mycotoxins.
With a joined-up approach to mycotoxin management, the pet food industry can help to avoid a repeat of the recent feed recalls, and families can rest assured that they will not have to face up to the sad reality of losing a beloved pet.