Fungal toxin and their application microbiology .pptx

Fungal toxin and their application microbiology
micro

1. Fungal toxin

2. Overview Mycotoxins ( Myco = of fungal origin) Toxic substances produced by fungi (molds) growing on crops/grains in the field or in storage. Secondary metabolites (chemicals) of a fungus that produce toxic results in another organism. Unlike bacterial toxins, fungal toxins (mycotoxins) are not proteins and therefore are not usually detectable by the immune systems of humans and animals Lack of visible appearance of fungus does not negate presence of mycotoxins. Toxins can remain in the organism after fungus has been removed. Cytotoxic: disrupt cell structures such as membranes, and processes such as protein, DNA, and RNA synthesis. Can be heat stable, not destroyed by canning or other processes.

3. Most fungi do not produce Mycotoxin Many fungi are edible Mushrooms are fungi Moldy feeds may be degraded without presence of mycotoxin, or may be unaffected in value.

4. How was the concept of Mycotoxins developed ? An outbreak of an unknown disease killed poultry birds in 1960s This was named Turkey X disease After investigations it was finally traced to mycotoxins in groundnut meal feed imported from Brazil The feed was shown to contain a compound that could cause cancer, Today we know this mycotoxin by the name of AFLATOXIN - A CLASS I CARCINOGEN

5. Information About Fungus Range from single cells to fruiting bodies that form Molds, mushrooms, smuts, and yeasts. Absorb nutrients from living or deceased organisms, contain no chlorophyll. If multicellular, they have tubular filaments called hyphae that branch out. Reproduce using spores.

6. Factors causing variation in effects Species, (breed) Age Sex Nutritional status Other diseases Other mycotoxins Extent of exposure

7. Storage conditions that favor production Temperature (40 - 90° F ; 4 - 32o C) Relative Humidity (> 70%) Moisture (22-23% in grain) Oxygen (1-2%)

8. Route of infection Ingestion/skin contact/ in halation Blood stream & lymphatic system Inhibit protein synthesis Damage macrophages system Inhibit particle clearance of the lungs Increase sensitivity to bacterial endotoxins

9. Common Mycotoxins Cool, wet weather Fusarium Toxins Deoxynivalenol (DON or Vomitoxin) - Considered a "marker" T-2 toxin (T-2) Zearalenone (F-2) Fumonisin Hot, humid weather • Aflatoxin

10. Toxicity of mycotoxins Acute Chronic Mutagenic Teratogenic

11. Acute toxicity Deterioration of liver and kidney functions, leading to death in extreme cases Interference with protein synthesis Skin sensitivity affected Necrosis of skin Immunodeficiency Neurotoxins cause trembling in small doses and brain damage or death in slightly higher doses

12. Chronic toxicity Induction of cancer (Liver, esophagus) Induction of tumors Induction is never detected at the time of ingestion and remains undetected till the disease is advanced Mutagenic & Teratogenic toxicity Replication of DNA is affected producing mutagenic and teratogenic effects

13. Potential uses of mycotoxins Medical application - Trichothecenes are known to possess antileukemic activity; zearalenone derivatives have been considered as potential treatment for menopausal syndrome in women; Agriculture application derivatives of zearalenone as growth promoter in sheep and cattle; other have been considered for use as herbicides and insecticides.

14. Effects of Molds/Mycotoxins Molds Decrease production (5-10%) Decrease digestibility (5%) Mycotoxins - Impact on milk production, weight gain greater than Molds Mimic other herd health problems Depressed immune system Off-feed Diarrhoea Haemorrhage Abortions Reproduction issues

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