2. Mycotoxins are secondary metabolites (secondary metabolite:
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1. 1 Mycotoxins
Mycotoxins are secondary metabolites (secondary metabolite: A compound that is not necessary for growth or maintenance of cellular functions but is synthesized, generally, for the protection of a cell or micro-organism, during the stationary phase of the growth cycle. Many are used in foods, pharmaceuticals, and other industrial applications.) of fungi that are recognized as toxic to other life forms.
a. Field fungi : fungi that attack plants that grow in the field (occurring prior to harvest) grow under special conditions. (Fusarium)
b. Storage fungi : Storage fungi usually invade grain or seed during storage and are generally not present in large quantities before harvest in the field. The most common storage fungi are species of Aspergillus and Penicillium. Contamination occurs through spores contaminating the grain as it is going into storage from the harvest. The development of fungi is influenced by the:
Moisture content of the stored grain
Condition of the grain going into storage
Length of time the is grain stored and
Amount of insect and mite activity in the grain
3. 3 2. Characteristics of mycotoxin induced disease
a. not transmitted among animals
b. Pharmaceutical treatment does not alter the course of disease
c. Mycotoxicosis most often presents as a uncertain, sub-acute or chronic condition
4. 4 3.Treatment of mycotoxin-induced disease a. For most mycotoxins, there is no specific treatment or antidote
b. Supplement with vitamins & selenium may be helpful, and provision of adequate high-quality protein
5. 5 4.Prevention of mycotoxin-induced disease a. Avoiding
f. Adding (organic acids will prevent mold growth)
6. 6 A- Aflatoxin 1. Sources :
Aspergillus flavus & A.paraciticus :
2. Factor favoring production of aflatoxins
a. Temperature : 25-30 ?c
b. Grain moisture
7. 7 3. Chemical characteristics Exhibit intense blue or green fluorescence under UV.
: aflatoxins B1, B2, G1 and G2
: aflatoxin M1 is a metabolites of AFB1 found in animal urine, milk or tissues.
8. 8 5.Mechanism of toxicologic damage