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Other Names: Avian Mycotoxicosis

Mycotoxicoses are diseases resulting from consumption or exposure to mycotoxins. Mycotoxins are secondary metabolites of fungi that can cause serious health problems in animals, especially chickens. They are produced by various molds belonging primarily to the species of the Aspergillus, Penicillium, and Fusarium genera. Mycotoxins are produced both pre- and post-harvest in crops and other feed and food commodities. Mycotoxins have also been isolated and in some cases, abundant in straw, dust, materials used for animal bedding, certain pasture grasses, hay, medicinal herbs, fruits and nuts.
Ingestion of mycotoxins can cause acute, overt disease with high morbidity and death to chronic, depressed resistance to pathogens and reduced productivity. Chronic ingestion of low levels of mycotoxins can cause a wide range of metabolic, physiologic, and immunologic disturbances in chickens. The European Union (EU) and the Federal Department of Agriculture (FDA) in the United States, has established limits for several mycotoxins that are regulated.
MycotoxinExposure EffectsRegulatory limits for animal feed
Aflatoxins (AF)Causes liver damage, tumors, gastrointestinal dysfunction, reduced productivity, birth defects, and suppressed immune system.EU: <20 ppb
For starter and grower feeds, corn, and peanut products intended for poultry feed, excluding cottonseed meal: <20 ppb

Laying hen feed, corn and peanut products intended for mature poultry: <100 ppb

Cottonseed meal intended for all poultry: <300 ppb
CitrininCauses kidney damage, watery fecal droppings, reduced weight gain, anemia, hyperkalemia, metabolic acidosis, and reduced blood pHEU/FDA: No restrictions set
Cyclopiazonic acidPoor weight gain and feed conversion, reproductive tract impairmentEU/FDA: No restrictions set
ErgotamineTissue necrosis and neurological signsEU/FDA: No restrictions set
Deoxynivalenol (DON)Damages the epithelial intestinal barrier of the chicken's gastrointestinal tract, inhibits protein synthesis, and predisposes them to developing necrotic enteritisEU: < 5 ppm
FDA (only advisory level, does not enforce): < 10 ppm for grain and grain by-products and < 5 ppm for complete feeds.
FumonisinsDamages the intestinal barrier of the GI system, decreases nutrient absorption, predisposes chickens to developing necrotic enteritisEU: < 20 mg/kg
FDA: < 50 mg/kg
FusarochromanoneTibial dyschondroplasiaEU/FDA: No restrictions set
MoniliforminAcute deathEU/FDA: No restrictions set
Ochratoxin A (OTA)Weight loss, granular degeneration in the epithelium and mononuclear cell infiltration and activation of capillary endothelium in the kidney and liver; degenerative changes and depletion of lymphoid organs (bursa of Fabricius, thymus and spleen)EU: < 0.1 mg/kg
FDA: No restrictions set
OosporeinCauses kidney damage, extensive visceral gout, dehydration, reduced feed intake, and decreased egg productionEU/FDA: No restrictions set
SterigmatocystinDecreased egg production, reduced feed intake, pale egg shells, liver impairment, embryo malformations and mortalityEU/FDA: No restrictions set
T-2 Toxins (T-2)Oral lesions, irritation, hemorrhage, and necrosis of digestive tract, and immune system impairment.EU/FDA: No restrictions set
Zearalenone (ZEA)Reproductive impairment, egg shell quality, problems with vitamin D3 metabolismEU/FDA: No restrictions set
Certain types of fungi and mycotoxins are attracted to particular crop species, climates, and weather events, and their distribution differs across geographical regions.
The effects of mycotoxins vary widely in poultry and depend on many factors such as whether there is co-contamination with multiple types of mycotoxins, amount (dose) ingested, duration of exposure, species, age, stress level, diet, and immune system. Poultry can develop an acute condition or chronic due to mycotoxins. Diagnosis of mycotoxins in poultry can be difficult, due to a number of complicating factors which include:
  • Mold growth is not uniform in feed, which makes testing feed samples difficult, slow and expensive.
  • Usually there are multiple mycotoxins involved, making diagnosis difficult as there are additive and even synergistic interactions.
  • Mycotoxins affect more than one body system simultaneously.
  • Not all mycotoxins can be detected in routine mycotoxin testing by commercial laboratories.
  • Forage (hay, silage) and animal bedding (straw, shavings ) are not regulated for the presence of mycotoxins.
Often times, symptoms are general and similar to that caused by many other diseases. Also, since chronic cases involve the ingestion of low levels of mycotoxins over a period of times, feed, bedding and pasture contamination is often overlooked. Samples of at least 500g (1lb) of suspected contaminated feed or ingredient should be properly collected in separate containers and promptly submitted to a feed testing laboratory for analysis.

Clinical Signs

Feed refusal
Blackening of the comb, toes and beak
Decreased egg production
Impaired egg quality
Oral lesions
Altered feathering
Increased water intake
Weight loss or stunted growth
Poor skin


  • History
  • Clinical signs
  • Physical exam
  • Mycotoxin Multiresidue screen
  • RT iq-PCR assay

Reported Cases

  • Case 1: Mycotoxicosis in a Chickens A disease syndrome characterized by raised yellowish-white lesions in the oral cavity was observed in several commercial broiler flocks. Growth rates were depressed, and 10% died. Fowl pox was ruled out by infectivity tests in susceptible birds with lesion material. A similar outbreak occurred in fancy pigeons fed visibly moldy feed. The oral lesions in pigeons contained large numbers of avirulent Staphylococcus epidermidis and Escherichia coli. Identical oral lesions were produced in the laboratory by feeding chickens small concentrations of fusariotoxin T-2 produced by the fungus Fusarium tricinctum. Ref


Supportive careIsolate the bird from the flock and place in a safe, comfortable, warm location (your own chicken "intensive care unit") with easy access to water and food. Limit stress. Call your veterinarian.
ProbioticsHave showed benefit at reducing the harmful effects of mycotoxinsM Ferrer et al., 2015
Sea buckthorn (Hippophae rhamnoides)Berries, leaves, juice and oil have shown to be of benefit in reducing the harmful effects of mycotoxins in the dietT Ramasamy et al., 2010
Vitamins E and COral supplementation of additional vitamins might partially counteract the toxicity of infection with multiple mycotoxinsAhmadi A et al., 2015; Salimian J et al., 2014; Weber M et al., 2007; Rizzo AF et al., 1994
Banana peelDried banana peel added to feedShar ZH et al., 2016
Turmeric extract (Curcuma longa))5 mg/kg in feed has shown to provide protection against the toxic effects of aflatoxins on the chicken's liver and kidneyGholami-Ahangaran et al., 2015; Rangsaz et al., 2011
Bacillus subtilis1000g/t added to diet helps offset the negative effects of mycotoxinsJia R et al., 2016; Fan Y et al., 2013
Black cumin (Nigella sativa)2-5% added to feedKhan SH et al., 2013; Aydin R et al., 2008
Yeast extract (Saccharomyces cerevisiae)1 g/kg added to dietMatur E et al., 2011; Matur E et al., 2010
Neutral electrolyzed oxidizing water (NEW)Soaking contaminated foods in 60mg/L available chlorine, pH 7.01) for 15 minutes at room temperatureJardon-Xicotencatl S et al., 2015
Mycofix SelectProvides some protective effects against the toxinsLee JT et al., 2012
Beer fermentation residue (BFR)1% of feed, reduced severity of the effects of aflatoxinsBovo et al., 2015
SeleniumAdding sodium selenite (0.6 mg/kg)Chen et al., 2014
Rosemary (Rosmarinus officinalis) extract500 ppmManafi et al., 2014



  • Store feed in a sealed, rodent-proof container that contains no holes.
  • Do not let food ever get damp. Moisture is the number one instigator for mold growth. Keep under 14% moisture.
  • Feed should be inspected regularly for temperature, insects, and wet spots.
  • During wet weather chickens should not have access to compost areas and uneaten decaying fruits and vegetables should be removed from these areas at all times.
  • Ensure your birds do not eat potting mixes and plant fertilizers as these are common sources of toxic molds and bacteria

Scientific References

Good Overviews

Risk Factors

  • Purchasing poor or low quality feed products
  • Feeding birds feed or using bedding that is moldy or suspected of mold contamination.