Mycotoxins: A Hidden Cause of Immunosuppression

Mycotoxins are toxic compounds produced by certain fungi that contaminate crops and animal feed under specific conditions. These toxins, such as aflatoxins, deoxynivalenol (DON), and ochratoxin A, pose serious health risks to animals and humans. Among their many effects, some mycotoxins directly impair the immune system, causing immunosuppression that weakens the body’s ability to fight infections and recover from diseases. Immunosuppression caused by mycotoxins can lead to increased disease susceptibility, lower vaccine efficacy, and reduced productivity in livestock, emphasizing the urgent need for effective management and detoxification strategies.

Mycotoxins are toxic secondary metabolites produced by certain fungi, such as Aspergillus, Fusarium, and Penicillium, commonly found in crops like corn, wheat, and barley. These toxins develop under specific conditions, such as high humidity and temperature during crop growth, harvest, or storage. Humans and animals can be exposed to mycotoxins through various routes, including consuming contaminated food or feed, inhaling dust containing fungal spores, or direct skin contact with infected materials. Once ingested or absorbed, mycotoxins can cause acute poisoning or long-term effects such as carcinogenicity, immunosuppression, and organ damage, posing serious risks to health and productivity.

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The immune system includes many types of cells, each with a specific job to protect the body from pathogens:

However, mycotoxins can weaken the immune system. They suppress the immune system by altering the functions of various immune cells, making host harder to fight infections. Mycotoxins can also disrupt the balance of cytokine and immune cell populations, harming the overall immune defense mechanism.

Six major mycotoxins affect the immune system differently. Aflatoxins suppress macrophage function and T-cell activation, weakening immunity. Ochratoxins impair B-cell function, reducing antibody production. Deoxynivalenol (DON) induces oxidative stress and promotes inflammation. Fumonisins suppress lymphocyte proliferation, disrupt the production of cytokines and cause cell damage. Zearalenone skews cytokine balance, leading to immunosuppression. T-2 toxin interfere with the immune system by blocking protein synthesis followed by inhibition of RNA and DNA synthesis. Collectively, these mycotoxins increase disease susceptibility and reduce vaccine efficacy.

Aflatoxins are produced by Aspergillus flavus and Aspergillus parasiticus, commonly found in contaminated grains, such as corn and peanuts. Once ingested, aflatoxins exert their immunotoxic effects through multiple mechanisms. They primarily target immune cells like macrophages, dendritic cells, and T-cells, impairing their activation and reducing their ability to mount effective immune responses. Aflatoxins also induce oxidative stress by generating ROS, leading to cellular damage and inflammation. This increased oxidative stress further suppresses immune cell function and alters cytokine production, shifting the balance toward pro-inflammatory or immunosuppressive responses. Additionally, aflatoxins interfere with antigen presentation by macrophages and dendritic cells, reducing the ability to stimulate adaptive immune responses.

Ochratoxin A (OTA), the most toxic form of ochratoxins, is produced by Aspergillus and Penicillium fungi, commonly contaminating a wide range of feed products, including grains, oilseeds, legumes, and by-products. OTA’s chemical stability allows it to persist through feed processing, making it one of the most common contaminants. OTA impacts the immune system by causing atrophy of immune organs such as the thymus, spleen, and lymph nodes, suppressing antibody production, and altering immune cell functions like macrophages and T-cells. It also disrupts cytokine production, leading to immune imbalances that contribute to inflammation or suppression. Additionally, OTA induces cell death through necrosis and apoptosis, reducing the replacement of damaged immune cells due to inhibited protein synthesis.

Deoxynivalenol (DON), produced by Fusarium fungi, is a prevalent mycotoxin contaminating cereal grains and animal feed. DON exposure induces oxidative stress by generating ROS, leading to lipid peroxidation and damage to cell membranes and macromolecules. This triggers an inflammatory response through the activation of mitogen-activated protein kinases (MAPKs) and the NF-κB pathway, resulting in increased expression of pro-inflammatory cytokines such as TNF-α, IL-1β, and IL-6. Additionally, DON disrupts ribosomal function, inhibiting protein synthesis and promoting apoptosis in immune cells, thereby impairing the overall immune response and increasing susceptibility to infections.

Fumonisins, produced by Fusarium verticillioides and Fusarium proliferatum, adversely affect the immune system by impairing lymphatic organs and lymphocyte function. Among the fumonisin homologs, fumonisin B1 (FB1) is the most prevalent and abundant mycotoxin contamination in stale corn. Exposure to fumonisins decreases the proliferation of splenic lymphocytes and disrupts cytokine production, including IL-2, IL-4, IL-12, and IFN-γ, which are critical for immune responses. This immunotoxicity is partly due to oxidative stress, apoptosis, and cellular damage, particularly to mitochondrial structures. Fumonisins induce apoptosis via the intrinsic pathway, involving Bcl-2 family proteins, leading to increased Bax and decreased Bcl-2 expression. These effects weaken the immune response, making animals more susceptible to infections and diseases.

Zearalenone (ZEN), produced by Fusarium species, commonly contaminates cereal crops like wheat, corn, and barley. ZEN exposure disrupts immune responses by inducing oxidative stress and promoting the secretion of pro-inflammatory cytokines (e.g., IL-1β, IL-6, TNF-α) via NLR family pyrin domain containing 3 (NLRP3) inflammasome activation. This impairs macrophage functions, such as phagocytosis and cytokine production, leading to suppressed immune responses. ZEN also affects signaling pathways like MAPKs and NF-κB, reducing the production of crucial immune mediators. Consequently, ZEN's immunotoxic effects make hosts more susceptible to infections and inflammation-related diseases.

T-2 toxin, also produced by Fusarium species, impacts the immune system by exhibiting both immunostimulatory and immunosuppressive effects, depending on dosage and exposure duration. At high doses, T-2 toxin induces immunosuppression by damaging lymph nodes, spleen, bone marrow, and thymus, leading to leucopenia and increased susceptibility to infections like Salmonella and Listeria. It impairs protein synthesis, resulting in T lymphocyte suppression and cytokine production inhibition. At lower doses, T-2 toxin can stimulate the immune system, increasing serum IgE and IgA levels. The toxin also activates pathways involving oxidative stress, ER stress, and apoptotic responses, further compromising immune functions.

In humans, mycotoxins can suppress the immune system, increasing susceptibility to viral infections and related diseases such as respiratory illnesses and immune-mediated disorders. Prolonged exposure to certain mycotoxins, like aflatoxin B1, is strongly associated with carcinogenicity, leading to increased risks of liver cancer and other malignancies. Additionally, mycotoxins can induce chronic inflammation by promoting oxidative stress and altering cytokine production, exacerbating health issues such as metabolic disorders, cardiovascular diseases, and autoimmune conditions. These combined effects pose significant health risks, underscoring the importance of monitoring and controlling mycotoxin exposure in food to protect public health.

In animals, mycotoxins cause significant health issues, including growth retardation, reduced vaccine efficacy, and immunosuppression, which increase the risk of infections and diseases. For instance, T-2 toxin damages the lymphatic system, reduces antibody production, and suppresses cytokine synthesis, weakening the immune response. This impairment leads to higher susceptibility to diseases like Salmonella and Listeria, and compromises the overall health and productivity of livestock. Animals exposed to mycotoxins also exhibit stunted growth and poor feed conversion, impacting their development. Consequently, the livestock industry suffers economic losses due to decreased animal performance, increased veterinary costs, and reduced meat and milk production. Effective management of mycotoxin contamination in animal feed is crucial for maintaining animal health, ensuring food safety, and sustaining industry profitability. Implementing stringent quality controls and regular monitoring can help mitigate these adverse effects and safeguard both animal and human health.

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To control mycotoxins during storage and processing, it is crucial to adopt a multi-pronged approach. Low temperatures slow down fungal growth, while effective drying reduces moisture levels, hindering mold proliferation. Antifungal agents, such as preservatives or organic acids, can further inhibit fungal activity. Mycotoxin management, including biotransformation ways like enzymatic detoxifiers (e.g. Toxi-free PLUS®) and adsorbents like activated carbon or clay, are used to neutralize or decrease toxicity in contaminated feed. Regular monitoring of storage conditions and implementing quality control measures throughout processing are essential for minimizing contamination and ensuring the safety of feed for livestock.

Feed additives like adsorbents and mycotoxin-degrading enzymes play an important role in mitigating the harmful effects of mycotoxins in animal feed. Adsorbents, such as bentonite and clay, are effective in binding polar mycotoxins like aflatoxins, reducing their bioavailability. However, they are less effective against non-polar mycotoxins and may adsorb essential nutrients, potentially impacting animal nutrition. On the other hand, mycotoxin-degrading enzymes exhibit high specificity, effectively detoxifying non-polar mycotoxins such as OTA, DON, and ZEA. These enzymes break down the mycotoxins into non-toxic metabolites, enhancing feed safety and supporting animal health. Integrating these additives into feed formulations can improve growth performance, boost immune responses, and enhance overall livestock productivity.

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Nutritional supplementation is also an effective approach to mitigate the impact of mycotoxins in animal feed. Adding antioxidants helps alleviate oxidative stress, protecting animal cells from damage caused by free radicals. Immune support supplements, such as natural herbs like Ganoderma, Cordyceps, and probiotics like Bacillus species, can enhance the animal's immune system, improving their ability to resist diseases. The use of these supplements can improve overall animal health, promote growth and development, and increase feed conversion efficiency.

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Toxi-Free PLUS® is a comprehensive mycotoxin-degrading agent combining three mycotoxin-degrading enzymes (Epoxide reductase, Esterase, and Peptidase), adsorbents, and selected plant extracts to provide complete protection. It reduces the toxicity of polar and non-polar mycotoxins, preventing immunosuppression and decreasing the risk of secondary bacterial infections. In addition, it can also improve reproductive performance in sows, enhance growth performance in pigs and broilers, and increase egg production in laying hens. Toxi-Free PLUS® is patented in the United States and China and meets Halal certification requirements, ensuring product safety and reliability.

< Product Link: Toxi-Free PLUS®>

Mycotoxins can severely impact animals by compromising their immune systems, making them more susceptible to infections and diseases. This leads to significant health risks such as reduced growth performance, lower vaccine efficacy, and increased morbidity and mortality. Recognizing the importance of addressing mycotoxin contamination is essential for maintaining animal health and productivity. Life Rainbow offers effective solutions to mitigate these risks and improve livestock well-being. For comprehensive mycotoxin management and product inquiries, reach out to Life Rainbow Biotech today. Our expert guidance and products will ensure the safety and health of your animals.