What is Mycotoxicosis in Pigs?
Pigs mainly eat a diet of grain, such as corn, barley, and wheat, supplemented with canola meal and soybeans for protein. With a diet that simple, there shouldn’t be any serious complications, right?
Unfortunately, there are still some potential problems you need to watch out for.
Mycotoxins affect pigs in many negative ways, from causing stillbirths to sudden death. Mycotoxicosis results from your pigs eating food contaminated with mycotoxins. When a pig gets this condition, there is no treatment, and therefore, your efforts should be placed on prevention.
You should continue reading if you want to learn more about mycotoxins and how they affect pigs. I will also discuss causes, symptoms, treatments, and preventatives for mycotoxins and mycotoxicosis.
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How Do Mycotoxins Affect Pigs?
Mycotoxins can have a severe effect on pigs, depending on the amount of exposure and the length of time the exposure occurred. The pigs can experience a wide range of effects that vary based on which mycotoxin they were exposed to, including:
Prolapses of the rectum and vagina
Red swollen vulva
Stillbirths
Poor libido
Hair loss
Variable lengths of the oestrus cycle
Decreased growth rate
Lowered food intake
Immunosuppression
No milk production
Reduced performance
Liver damage
Reduced blood supply because of contracting blood vessels
Depression
Blue skin
Gangrenous extremities
Increased respiration
Necrosis of the tail and ears
Kidney damage
Jaundice
Poor feed efficiency
Labored, open-mouthed breathing
Pulmonary edema
Cyanosis
Heart failure
Death
For more information on mycotoxins and their effects on pigs, you can watch this video:
What Are Mycotoxins?
Certain molds and fungi in foods produce toxins known as mycotoxins. This growth can occur both before and after harvest. Because of their chemical stability, most mycotoxins will also survive food processing.
Mycotoxins can be toxic to humans and animals when consumed at very low concentrations, absorbed through the skin, or inhaled. In other words, just a few milligrams in a pig’s feed and the animal could be facing serious health problems.
They affect many plants and grains, including corn, wheat, rye, oat, and barley. Due to their heat tolerance, they will survive the feed processing operations most of the time.
While there are more than 400 mycotoxins known, the most prevalent and toxic ones identified include:
Aflatoxins
Fumonisins
Ochratoxin A
Deoxynivalenol (Vomitoxin)
Patulin
Nivalenol
T-2
HT-2
Zearalenone
Ergotoxin
Despite knowing that mycotoxins come from food sources and understanding their symptoms, it may be hard to know what’s causing mycotoxin-related disease.
While they are not transmissible from one animal to another, they can be passed through milk and meat. In other words, the nursing young can get the mycotoxins from their mothers, and humans can contract the mycotoxins from pork.
Large numbers of fungal spores do not indicate there are mycotoxins present. At the same time, the absence of fungal spores does not mean there are no mycotoxins.
There are several common causes of the creation of mycotoxins in pigs’ feed:
Storage in ideal conditions for mold growth
Inconsistent environmental temperatures
Fungal growth in liquid feeding systems
Mixing clean grains with contaminated grains
Damaged grains
Damaged feed bins
Allowing grains to heat
Storing moist grain
Prolonged use of auto feeders
Retention of moldy food
What is the Cause of Mycotoxicosis?
Mycotoxicosis results from your pig ingesting feed containing toxic metabolites produced by specific fungi. These fungi will only be able to produce mycotoxins if they are given the perfect environment to do so.
They require the right amount of moisture, carbohydrates, and oxygen to reproduce, and the temperature must be within the correct range of 50℉ to 77℉ (10℃ to 25℃). However, fungal reproduction can occur outside of these specifications, with damaged crops more susceptible.
As I mentioned, the feed processing operation will not typically destroy mycotoxins, leaving them behind to contaminate your pigs’ feed. If your pigs consume enough of the affected feed, they will develop mycotoxicosis.
What Are the Symptoms of Mycotoxins?
The symptoms of mycotoxicosis vary based on the type of mycotoxin exposure. Additionally, the more mycotoxins your pigs consume, their symptoms will be greater. It is also possible for your pig to be exposed to more than one mycotoxin at a time.
Zearalenone or F2 Toxin
Fusarium graminearum, which is found in maize, produces the F2 toxin. It is an oestrogenic toxin, meaning it affects the reproductive cycle of the pigs. The common symptoms of this toxin include:
Prolapses of the rectum and vagina
Red swollen vulva
Stillbirths
Poor libido
Hair loss
Variable lengths of the oestrus cycle
Abortion
False heat
False pregnancy
Embryonic death
Zearalenone and its metabolites interact with estrogen receptors, causing adverse effects.
Aflatoxins
Aflatoxins are produced by Aspergillus flavus and are found in maize, soybeans, and peanuts. There are two forms of aflatoxicosis: acute and chronic.
Pigs are less likely to experience acute aflatoxicosis, but it causes severe liver lesions. Symptoms include jaundice, hemorrhages, and sudden death.
When pigs consume aflatoxin at lower levels, the effect is cumulative, which means they are likely to experience chronic aflatoxicosis following prolonged exposure. Symptoms include:
Decreased growth rate
Lowered food intake
Immunosuppression
Abortion
Reduced performance
Liver damage
Vomitoxin
Deoxynivalenol or vomitoxin is produced by Fusarium graminearum and is the most common contaminant of corn and wheat in North America.
Despite the name, there is rarely vomiting involved with this mycotoxin. Typically, any vomiting will occur within minutes of the first consumption of the mycotoxin as it boosts the levels in the pig’s body over the threshold, causing it to vomit.
Instead, the common symptoms you’ll need to look for include a sharp decrease in food intake that leads to a drastic reduction in growth. Vomitoxin causes an interference with neurotransmitters in the brain, protein synthesis, and modulation of immunity.
Ergotoxins
Claviceps purpurea is a fungus that affects grasses and cereal grains, such as oats, rye, and wheat. This fungus produces ergotoxins which interfere with blood flow. The signs of ergotoxins include:
Reduced blood supply because of contracting blood vessels
Depression
Blue skin
Poor growth
Gangrenous extremities
Increased respiration
Necrosis of the tail and ears
Ochratoxin
Ochratoxin is produced by Penicillium viridicatum, Penicillium verrucosum, and Aspergillus ochraceus. Its production occurs during storage and is toxic to the liver and kidneys. With this type of mycotoxin, there may not be a decrease in feed intake.
Symptoms of ochratoxin include:
Liver damage
Kidney damage
Reduced performance
Reduced growth
Jaundice
Poor feed efficiency
It’s important to note this mycotoxin’s effects go unnoticed until the pig is slaughtered. At this time, the exposure is identified by the pig’s enlarged liver or kidneys.
Fumonisin
Fusarium species produce fumonisins before harvest. These mycotoxins interfere with cell function and signaling and can also cause immunosuppression. The organs primarily affected include the heart, lungs, and liver.
Acute fumonisin toxicity symptoms include:
Labored, open-mouthed breathing
Pulmonary edema
Cyanosis
Heart failure
Death
In cases of chronic fumonisin toxicity, the pigs are more susceptible to secondary problems as their immune systems are suppressed. The toxicity to the liver is dependent on time and the level of the dose of fumonisin.
Despite the common thought that fumonisin requires high levels to seriously impact animal health, chronic exposure can have drastically affect the immune system, GI health, and lung and liver function.
How Do You Treat Mycotoxicosis?
The treatment for mycotoxicosis will depend on which mycotoxin your pigs were exposed to. What they all have in common is the removal of the affected grains from the pigs’ diet.
For aflatoxicosis, once the feed is removed, it needs to be replaced with a high-quality diet with the correct levels of protein, trace minerals, and vitamins. If the animals are experiencing immunosuppression, you will need to add antimicrobial therapy to boost their immunity.
No anti-toxin that can be prescribed to treat this condition. You will need to support your pigs as they work through the toxicity.
For ergotism, you’ll need to provide moderate environmental conditions and supportive treatment, including good bedding and decent housing.
The terminal appendages may be lost if the distal part of the limbs has progressed to gangrene and undergone severe tissue damage. The animal will need to be euthanized in cases of severe limb necrosis.
For trichothecene toxicosis, which can include Fusarim-produced mycotoxins, you will need to give your pigs anti-inflammatory medications. These medications include prednisolone, methylprednisolone, and dexamethasone.
Despite the advancements in science and modern medicine, treatment with drugs and antimicrobials has little to no effect on curbing the disease, regardless of which type of mycotoxin exposure was experienced.
Essentially, there is no treatment for mycotoxicosis. Your efforts are best placed on the prevention of this disease.
Can You Prevent Mycotoxicosis?
The appearance of mycotoxins in feed is typically due to one of the ingredients being contaminated. Grain contamination can occur before or after harvest in the field and storage.
For example, drought-stressed corn is considered high risk because it is less resistant to fungi. Because of these types of situations, you need to take steps to minimize stress through planting density, irrigation, fertilization, and other methods.
Damaged feed ingredients are highly susceptible to mold growth. During harvest, you must adjust your equipment to minimize kernel damage as much as possible while removing foreign parts.
When you are in heat and humidity, do not store your ground feed for more than 10 - 14 days. An example is corn screenings, which are excellent sources of growth for mold. Keeping it for more than two weeks can result in excessive mold growth.
Do not delay drying by more than six hours following harvest. The period between harvest and drying is critical as it is a peak time for mold growth. You will need to ensure you dry your grain to the appropriate levels.
Grain should be completely cooled before it is stored to prevent mold-causing condensation. You’ll also need to ensure that your storage bins are clean and in good condition. Any leaks or holes will need to be repaired as soon as possible to protect the integrity of your grain.
If you suspect you have a mycotoxin in your feed, you should follow these instructions:
Immediately find a replacement feed
Examine all equipment looking for moldy feed
Empty all feed bins and if you find contamination, clean them with a non-toxic fungicide
Closely examine the feed for signs of mold
If wet grain is stored, use a mold inhibitor to prevent growth
Check for other sources of poisoning, including bedding and straw
Send a feed sample to a lab for testing
Regrind the feed and mix with an alternative feed in a 1:10 ratio to feed to your growing stock on a test basis
Mycotoxins in low concentrations are often allowed in the swine diet so long as they are below the levels that will impact performance and health.
More people are using mold inhibitors and mycotoxin binders in feeds as a detoxification method; however, this is not yet scientifically proven. The mold inhibitors, as their name implies, prevent mold growth.
Mycotoxin binders will bind to the mycotoxins and prevent them from being absorbed into the gut. While this is a novel idea, further studies must be conducted to prove its efficacy and safety for the pigs consuming them, their nursing piglets, and the humans who eat the pigs.
Final Thoughts
Mycotoxins are dangerous even in low concentrations. Some of them have cumulative effects that build up over time in the pigs’ systems, having the same effect as if the pigs had eaten a large amount of them.
When a pig gets mycotoxicosis, there is no real treatment available. Depending on which toxin caused the illness, you may be looking at severe results such as loss of limbs or even death. For the best results, focus your efforts on preventing mycotoxicosis from occurring.
You can take many steps to prevent the condition from happening, such as not storing wet or hot food, checking for signs of mold, and replacing the feed if you suspect contamination. Acting quickly will keep your pigs healthy.
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