Mycotoxins

Mycotoxins are toxic metabolites of fungi such as Aspergillus spp. that causes a range of diseases in many species. :53 Mycotoxicoses is the disease that is caused by a mycotoxin.

What kind of mycotoxins can be found?
Aflatoxin is produced by Aspergillus flavus and Aspergillus parasiticus and may be found in moldy feeds, especially peanuts. :53 :190 Aflatoxin B1 (AFB1) is of primary concern because it is the most abundant and the most toxic. :190 The acute, oral median lethal dose of aflatoxin is about 0.3 mg/kg body weight. :190

Zearalenone is an oestrogenic substance that is frequently recovered from maize and other grains contaminated by Fusarium graminearum. :191

Trichothecenes, specifically T-2 toxin and vomitoxin, is another group of toxin produced by some strains of the fungus Fusarium tricinctum. :191 It is relatively common in fibrous raw materials that have been harvested or stored in poor conditions. :191 Administration per oz of 4 mg/kg body weight of T-2 toxin causes death within 24 hours. :192 Vomitoxin (4-deoxynivalenol) may be found in cereal grains. :192

Ochratoxin, a nephrotoxin, is produced by toxigenic strains of Aspergillus ochraceus. :192

Citrinin, another nephrotoxin, is found in moldy cereals contaminated by various fungal species of Aspergillus and Penicillium. Some rabbits die less than 24 hours after oral administration of a single 100–130 mg/kg body weight dose. :192

Symptoms
Mycotoxicoses appears in chronic and acute forms. :190 The acute form is caused by a rapid ingestion of large amounts of toxins over a short period of time.

Some symptoms of aflatoxic poisoning in rabbits include the following: :190-191
 * decreased feed intake (anorexia)
 * weight loss and emaciation
 * lesions in the liver
 * changes in blood constituents
 * jaundice (icterus) in the terminal stages

Some symptoms of zearalenone toxicity in rabbits include the following: :191
 * hypertrophic development of the genital tract of the female rabbit
 * changes in blood serum enzyme activities

Some symptoms of T-2 toxin poisoning in rabbits include the following: :192
 * feed refusal
 * lesions of the digestive tract
 * impairment of blood-clotting mechanisms
 * alteration of ovarian activity of sexually mature female rabbits

Some symptoms of vomitoxin toxicity in rabbits include the following: :192
 * feed refusal
 * vomiting
 * fetal resorption in female rabbits

Some symptoms of citrinin toxicity in rabbits include the following: :192
 * acute erosive gastritis
 * fluid diarrhea
 * renal damage with tubular dysfunction and necrosis

Causes
Mold growth can occur on stored grains or other raw materials because of non-hygenic storage conditions or in the field on standing crops or during the harvesting of feedstuffs due to certain fungi. :190