MYCOTOXINS

Index

• General Characteristics of Mycotoxins
• Definition
• Common Members of the Mycotoxin Family
• Analysis of Mycotoxins
• Troubleshooting of Mycotoxin Problems in Livestock
• Sampling skills
• Sources of the Testing Kits
• Suggestions to Prevent the Mycotoxins contamination
• References
• More on Mycotoxins....

General Characteristics of Mycotoxins

Definition

"myco" ----> "fungus"

"toxin" ----> "poison" (Cheeke and Shull, 1985)

Mycotoxins are toxic, secondary metabolites of low molecular weight produced by naturally occurring fungi. (Chu, 1992)

Mycotoxins are neither infectious nor contagious, but can occur on a herd-wide basis. (Wren, 1994)

[Index] Definition [Mycotoxin Family] [Analysis of Mycotoxins] [Sampling] [Testing Kits] [Preventing Mycotoxin Contamination] [References]

Common Members of the Mycotoxin Family

• Aflatoxins
• Trichothecenes
• Zearalenone
• Fumonisin
• Ochratoxins
• Slaframine

Analytical Techniques for Mycotoxins

The "General Referee on Mycotoxins " gives a good overview of analytical techniques . It is published in the "Annual Report on Mycotoxins", which appears annually in the February/March issue of the Journal of the Association of Official Analytical Chemists. (Chu, 1992)

Because of the diversity of chemical structures and physicochemical properties of mycotoxins, approaches for their analysis vary considerably. The analysis is further complicated by the typically uneven distribution of mycotoxuns in samples and by sample matrix interference. (Chu, 1992)

Troubleshooting Mycotoxin Problems in Livestock

Sampling Skills

Mycotoxin contamination of foods and feeds is usually heterogeneous. Therefore, precautions must be taken in sampling to obtain a reliable quantitative estimate of the concentration of a mycotoxin in a given lot. (Wood, 1992)

• Samples must be representative of entire lot
• Obtain samples from multiple locations
• Use of a grain or forage sampling probe is recommended
• Obtain samples from a moving grain stream
• Take samples at various unloading sites
• 10 pounds minimum
• mix thoroughly
• subsampling
• send 2 to 5 pounds for analysis
• freezing or air-tighted packing if necessary (especially for high moisture samples)

(Ideas listed were adapted from Dr. Larry Thompson's lecture and from Wren, 1994)

[Index] Definition [Mycotoxin Family] [Analysis of Mycotoxins] [Sampling] [Testing Kits] [Preventing Mycotoxin Contamination] [References]

Sources of Mycotoxins test kits (Spainhour and Posey, 1992)

• CSID
• Minicolumn

Suggestions to Prevent Mycotoxin Contamination of Feed Stuffs

• Control the environmental factors that influence fungal growth: (Diekman and Green, 1992)
• Moisture content of grain (<14%)
• Relative humidity (<70%)
• Temperature (-2.2 Centigrade)
• Oxygen availability (<0.5%)
• Control the physical condition of the grain: (Adapted from Dr. Thompson's lecture)
• Minimize grain damage during harvest
• Screen grain to reduce broken kernels
• Clean storage system regularly (Wren, 1994)
• Use mold inhibitors and anti-caking additives (Diekman and Green, 1992)
• Ammoniation - to reduce aflatoxin concentrations (Diekman and Green, 1992)
• Floating separation - Fusarium-infected kernels are lighter than sound kernels (Diekman and Green, 1992)
• Wash, wet or dry milling and heating process (roasting, boiling, baking and frying) (Wood, 1992)
• Addition of 0.5% hydrated sodium calcium aluminosilicate in formulated feed (Diekman and Green, 1992)

• Reduce the stress to animals
• Increase plane of nutrition

(Comment)

Not all molds (or fungi) are toxic. Part of the deleterious impact of mycotoxins on ruminants may be caused by the indirect effect of reduced nutrition from the infected grains or forages. (Adapted from Dr. Thompson's lecture)

[Index] Definition [Mycotoxin Family] [Analysis of Mycotoxins] [Sampling] [Testing Kits] [Preventing Mycotoxin Contamination][References]

References

Cheeke, P.R. (1995) Endogenous Toxins and Mycotoxinz in Forage Grasses and Their Effects on Livestock. J. Anim. Sci. 73:909-918.

Cheeke, P.R. and Shull, L.R. (1985) Mycotoxins (Chap. 12). In: Natural toxicants in feeds and poisonous plants. AVI. pp393-477.

Chu, S.F.(1992) Recent Progress on Analytical Techniques for Mycotoxins in Feedstuffs. J. Anim. Sci. 70:3950-3963.

Diekman, M.A. and Green, M.L. (1992) Mycotoxins and Reproduction in Domestic Livestock. J. Anim. Sci. 70:1615-1627.

Price, W.D., Lovell, R.A. and McChesney, D.G. (1993) Naturally Occurring Toxins in Feedstuffs: Center for veterinary Medicine Perspective. J. Anim. Sci. 71:2556-2562.

Richard, J.L., Bennett, G.A., Ross, P.F. and Nelson, P.E. (1993) Analysis of Naturally Occurring Mycotoxins in Feedstuffs an Food. J. Anim. Sci. 71:2563-2574.

Spainhour, C.B. and Posey, D. (1992) Mycotoxins: A Slient Enemy. Large Animal Veterinarian. Nov./Dec. Page 20-25.

Thompson, Larry. (1996) Lecture for PLPA 652 ('Mycotoxins')

Wren, G.. (1994) Blaming Mycotoxins Can Be A Risky Venture. Bovine Veterinarian. Nov. Page 4 -10.

Wood, G.E.. (1992) Mycotoxins in Foods and Feeds in the United States. J. Anim. Sci. 70:3941-3949.

More References on FDA recommendations The poisonous plant database

[Index] Definition [Mycotoxin Family] [Analysis of Mycotoxins] [Sampling] [Testing Kits] [Preventing Mycotoxin Contamination] [Research][References]