VMC 311: Systematic Veterinary Bacteriology and Mycology (2+1)

AFLATOXICOSIS

• The name aflatoxin derives from Aspergillus flavus toxin. Afalatoxins are a group of approx.
• 20 related toxic compounds produced by some strains of A. flavus and A.parasiticus during growth on a variety of cereal grains and food stuffs such as maize, cotton seed and groundnuts.
• High humidity and high temperature during pre-harvesting, harvesting, transporatation and storage, as well as damage to feed crops by insects, drought and mechanical injury during harvesting, favours the growth and toxin production of Aspergillus flavus.
• Mould growth and toxin formation require a moisture content of the substrate greater than 15%, temp.25⁰C and adequate aeration.
• Aflatoxins are a group of related bisfuranocumasin compounds with toxic, carcinogenic, teratogenic and mutagenic activity.
• The four major aflatoxins are B1, B2, G1 and G2. These mycotoxins are named according to their position and fluorescent colour on thin layer chromatography (TLC).
• B1and B2 produce blue colour and G1, G2 gives green fluorescence.
• Aflatoxins M1, M2 are hydroxylated metabolites of B1 and B2 that are excreted in the milk of lactating animals such as dairy cows.