Aflatoxicosis in Laying Hens
Poultry feed ingredients are vulnerable to fungal growth and aflatoxin production. Aflatoxins are relatively stable compounds in normal food and feed products.
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.
The severity of aflatoxicosis is enhanced by a diet low in fat, protein, and riboflavin or vitamin D3, and by a high tamic acid diet.
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 color (with normal carotenoid levels in feed).
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).
The half-life of aflatoxin B1 in laying hens is about 67 hours, though feed: egg transmission is about 5000:1
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.
Mycotoxin cyclopiazonic acid has additive toxicity of aflatoxin.
Observed Clinical Signs Happenings
- Drops in egg production
- Egg production declines gradually
Feed Consumption Changes
- Feed intake reduced or refusal
- Indirect effect of intoxication (reduced feed intake)
Diet or Feed Changes
- Recent Feed delivery
- Recent formulation /diet
- Other silo or improper storage
- Other brand
- Egg size decreased or reduced
Internal Egg contents defects
- Blood and meat spots in egg contents
- Yolk colour decreased or yolk discoloration or paler yolks
Aflatoxicosis in Laying Hens DOES NOT show, exhibit or manifest any of the following clinical signs happenings:
- Egg production declines rapidly
- Mortality above the standard
- Visibly sick birds
- Flock behaviour activity change
- Droppings abnormalities
- Respiratory abnormalities
- Neurological Nervous
- Lameness or unusual movements, incoordination, ataxia
- Eyes abnormalities
- Head, Comb, Wattles, Face, Nostrils, Sinuses, Mount, Beak, Ear lobes, abnormalities (except eyes)
- Body Parts (Neck, wings, breast, abdomen, shanks, legs, hocks, feet, joints, vent, and skin) abnormalities
- 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
Y.M. Saif. 2008. Disease of Poultry. 12th Edition. page 1207
David E. Swayne. 2013. Diseases of Poultry 13th Edition. page 1277
Mark Pattison, Paul F. McMullin, Janet M. Bradbury. Dennis J. Alexander. 2008. Poultry Diseases. 6th Edition.
Paul McMullin. 2004. A pocket Guide to Poultry Health and Disease. First Edition.
Steven Leeson, John D. Summers. 2008. Commercial Poultry Nutrition. Third Edition.
Donald D. Bell, Williams D. Weaver. 2009. Commercial Chicken Meat and Egg Production. Fifth Edition.