Aflatoxicosis in Laying Hens

Aflatoxicosis in Laying Hens

Aflatoxicosis in Laying Hens

Aflatoxicosis impairs all important parameters including weight gain, feed intake, feed conversion efficiency, pigmentation, processing yield, egg production, and male and female reproductive performance. Some influences are direct effects of intoxication, and others are indirect, such as from reduced feed intake. (1, 2)

Poultry feed ingredients are vulnerable to fungal growth and aflatoxin production. Aflatoxins are relatively stable compounds in normal food and feed products. (1, 2)

The aflatoxin B1 is the most toxic, and its hepatotoxicity is the primary effect in nearly all the animals. Chronic aflatoxicosis results in neoplasia in many species, usually in the liver. Even though several aflatoxin metabolites are carcinogenic, aflatoxin B1 is the most potent. (1, 2)

The severity of aflatoxicosis is enhanced by a diet low in fat, protein, and riboflavin or vitamin D3, and by a high tannic acid diet. (1, 2)

In hens, aflatoxins result in impaired egg production by reducing the synthesis and transport of yolk precursors in the liver with egg size and decreased yolk colour (with normal carotenoid levels in feed). (1, 2)

Aflatoxicosis is strongly associated with increased susceptibility to infectious diseases such as cecal coccidiosis, Marek's disease, salmonellosis, inclusion body hepatitis (IBH) and infectious bursal disease virus (IBDV). (1, 2)

The half-life of aflatoxin B1 in laying hens is about 67 hours, though feed: egg transmission is about 5000:1. (1, 2)

Aflatoxin B1 accumulated in reproductive organs is transferred to eggs (both yolk and albumen). Aflatoxin B1 and aflatoxicol were detected in ova and eggs for 7 days or longer. (1, 2, 3)

Mycotoxin cyclopiazonic acid has the additive toxicity of aflatoxin. (1, 2)

Observed Clinical Signs Happenings

Egg Drop

  • Drops in egg production
  • Egg production declines gradually

Feed Consumption Changes

  • Feed intake reduced or refusal
  • An indirect effect of intoxication (reduced feed intake)

Diet or Feed Changes

  • Recent Feed delivery
  • Recent formulation /diet
  • Other silo or improper storage
  • Another brand

Shell defects

  • Egg size decreased or reduced

Internal Egg contents defects

  • Blood and meat spots in egg contents
  • Pale yolks or yolk colour decreased or yolk discolouration
  • Yolk colour Abnormal

Aflatoxicosis in Laying Hens DOES NOT show, exhibit or manifest any of the following clinical signs happenings:

  1. Egg production declines rapidly
  2. Mortality above the standard
  3. Visibly sick birds
  4. Flock behaviour activity change
  5. Droppings abnormalities
  6. Respiratory abnormalities
  7. Neurological Nervous
  8. Lameness or unusual movements, incoordination, ataxia
  9. Eyes abnormalities
  10. Head, Comb, Wattles, Face, Nostrils, Sinuses, Mount, Beak, Earlobes, abnormalities (except eyes)
  11. Body Parts (Neck, wings, breast, abdomen, shanks, legs, hocks, feet, joints, vent, and skin) abnormalities
  12. Feathers abnormalities
Causing Agents
Toxins produced by molds Aspergillus flavus, A. parasiticus, and Penicillium puberulum, that are present in litter, grains or feed (especially grain or feed that has been damaged by insects, pests or weather).
Affected Systems/Organs
Immune system (increases susceptibility to infection). Liver and reproductive system. Hematological parameters. Reproductive system.
Consumption of affected grain, exposure to contaminated litter
Mainly Affects
Egg production, Egg Shell quality and Inner Egg quality
Careful choice and testing of feed raw materials, good grain and feed manufacturing and storage practices. Toxic feed should be removed and replace with unadulterated feed. Detoxification using mycotoxin-binders holds promise for using contaminated of feedstuff by fungi capable of producing mycotoxin is quite common. Detoxification using mycotoxin-binder holds promise for using contaminated feeds while preventing intoxication. Inorganic mineral absorbents or binders including various clays (bentonite clay), soils, and zeolites. Zeolites reduce the effects of aflatoxin and cyclopiazonic acid. Addition of organic aluminosilicate adsorbent to the feed. Yeast cell wall-based adsorbents.
Suggested Actions
  • Can be confirmed with clinical signs and gross lesions
  • Technical assistance recommended
  • Can be managed with feed additives, off-the-shelf medications
  • Diagnosis should be confirmed with rapid assays and/or a certified laboratory
  • Veterinary intervention is recommended

Impact on Egg quality


Impact on Liveability


Impact on Production


Overall Economic Impact


  1. Y.M. Saif. 2008. Disease of Poultry. 12th Edition. page 1207
  2. David E. Swayne. 2013.  Diseases of Poultry 13th Edition. page 1277
  3. Mark Pattison, Paul F. McMullin, Janet M. Bradbury. Dennis J. Alexander. 2008. Poultry Diseases. 6th Edition. pag 30
  4. Paul McMullin. 2004. A pocket Guide to Poultry Health and Disease. First Edition.
  5. Steven Leeson, John D. Summers. 2008. Commercial Poultry Nutrition. Third Edition.
  6. Donald D. Bell, Williams D. Weaver. 2009.  Commercial Chicken Meat and Egg Production. Fifth Edition.


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