Mycotoxicosis :

• The word mycotoxin stems from Greek word “mykes” which means mould and “toxicuum” means poison.
• Mycotoxicosis refers to all diseases caused by the effect of toxin produced by moulds.
• Disease is often subclinical and difficult to diagnose.
• Problems occur worldwide , but especially climates with high temperature and humidity and where grain is harvested with high water content .

Types of toxins :

a. Aflatoxins :  produced by Aspergillus flavus

b. T2 fusarium toxin : by Fusarium spp.

                 [mouth lesion and thin egg shells ]

c. Ochratoxins :    by Aspergillus ochraceus

    [ interfere with function of kidney , proventriculus and gizzard ]

d. Rubratoxin :  by Penicillium rubrum

    [ interfere with thiamine metabolism and causes symptoms of deficiency ]

Species affected :

        The species are with decreasing order of susceptibility :

        Ducks , turkeys , geese, pheasants , chicken

Route of infection :

• Ingestion of fungal spores which are readily carried in air

    (concentrate , silage or forage )

• Bedding

• Both fungal spores and formed toxins are highly resistant.

Mycotoxin exert their effects through four primary mechanism :

1. Reduction of feed intake/ feed refusal .
2. Alteration in nutrient content of feed in terms of nutrient absorption and metabolism
3. Effect on endocrine and exocrine system
4. Suppression of immune system

Fungi species :

a. Field fungi :

• Invade the seeds while the crop is still in the field .
• Include the species of :
• Fusarium
• Alternaria
• Cladosporium
• Diplodia
• Gibberella
• Helminthosporium

b. Storage fungi :

• They invade grains or seeds during storage.
• Species : Aspergillus , Penicillium

Signs :

• Signs vary with the species affected ; mycotoxin , the dose ingested and period of exposure
• Diarrhoea
• Paralysis / inco-ordination
• Reduced feed efficiency
• Reduced weight gain / egg production / hatchability
• Increased condemnation
• Pale shanks, combs, bone marrow

    Fig : Oral lesions in poultry, including the tip of the tongue and the palate

 and the floor of the oral cavity  can be an indicator of a mycotoxin problem.

   Fig : Oral lesions in poultry, such as the one circled here,

                   can be an indicator of mycotoxicosis.

Postmortem lesions :

• Lesions also vary in accordance with same factors as signs
• Mycotoxin can cause damage to mucosa with which they come in contact .
• They can also be absorbed and affect blood coagulation , resulting in petechiae and larger haemorrhages in various tissues.
• Liver and kidney lesions :

                Liver may be enlarged and fatty or show bile retention or tumor

• Enteritis of variable degree may be seen
• Hydropericardium
• Pale bone marrow
• Regression of bursa of fabricius
• Gizzard erosion

• Multiplication of moulds in cereals requires selenium and

             This element is important for production of hepatic       

                  lipases .

                                ⬇  

             Aflatoxin inhibit synthesis and transport of lipid in liver      

                                ⬇   

  Fig :  Fatty deposition in liver of a broiler                             Deficiencies of fat soluble vitamins ( A,D,E,K )

               chicken with aflatoxicosis.

• Aflatoxin has been shown to be carcinogenic in rodents.                                                                                                                                                 

Diagnosis :

• History
• Signs and lesions
• Histology
• Identification and quantification of toxins in samples of feed or feed residue .

Differential diagnosis :

• Poor nutrition
• Poor management
• Physical damage to tissues
• Infectious bursal disease