Mycotoxins in Food Chain, Animal Health and Contamination Control.ppt

Mainly mycotoxins in food chain

1. MYCOTOXINS
Dale M. Forsyth
Dept of Animal Sciences
Purdue University

2. MYCOTOXINS
Toxins produced by fungi
Metabolic products or by-products of
fungi (molds)

3. Why Great Concern?
Some mycotoxins are DEADLY at very
small dosages.
Some mycotoxins are carcinogenic.
Some mycotoxins cause huge losses in
productivity in animals.

4. Most fungi do not produce
Mycotoxins
Many fungi are edible
Mushrooms are fungi
Moldy feeds may be
degraded without
presence of mycotoxin,
or may be unaffected
in value.
some material
courtesy of Mark
Diekman

5. DIPLODIA Infested Corn
SpecieDiet Wkly
gain, g
Feed, %
of BW
F/G
Rat Autoclaved
Diplodia
31.8
30.3
12.0
a
11.0
b
3.70
4.88
Mouse Autoclaved
Diplodia
2.27
a
1.87
b
28.2
a
25.7
b
26.3
27.3
HamsterAutoclaved
Diplodia
7.19
a
4.43
b
12.0
11.6
Guinea
pig
Autoclaved
Diplodia
203.4
b
286.5
a
5.16
4.76
6.82
b
4.60
a

6. Effect of fungus Damage on
Digestibility of Corn by Rats
Item SoundDiplodia
zeae
SoundFusarium
Moniliforme
Energy studies
Dig. Energy,%90.7 89.4 91.0 89.5
Body Wt gain100 95 100 81
Protein studies
Dig. Nitrogen,%83.6 81.2 81.9 75.0
(Corn essentially 100% Fungus damaged)
Mitchel & Beadles, 1940

7. Feeds Most Susceptible to
Fungi-producing Mycotoxins
Corn
Wheat
Oats
Barley
Recently
Sorghum
Cottonseed
Peanut meal
Rye

8. Moldy grain is usually nontoxic
Competition between toxic and
nontoxic molds.
Entire mold population is not producing
mycotoxin
Conditions for growth are different for
mold growth vs mycotoxin production

9. Molds that attack grain can:
Decrease grade
Kernel damage
odor
Decrease milling quality
Decrease seed germination
Decrease dry matter
Decrease feeding value (sometimes)

10. Mycotoxins can cause:
Death
Poor performance from low FI, ADG
Respiratory problems
Reproductive problems
Liver, kidney or other organ damage
Cancer

11. Mycotoxins
Factors causing variation in effects
Species, breed
Age
Sex
Nutritional status
Other diseases
Other mycotoxins
Extent of exposure

12. Some mycotoxins are formed in
the field, some in storage
Storage conditions that favor
production of mycotoxins:
Temperature (40 - 90
o
F ; 4 - 32
o
C)
Relative Humidity (> 70%)
Moisture (22-23% in grain)
Oxygen (1-2%)

13. MOST COMMON
MYCOTOXINS in the USA
DEOXYNIVALENOL (vomitoxin) Fusarium
ZEARALENONE (Gibberella)
AFLATOXIN - Aspergillus flavus
FUMONISON - Fusarium moniliforme
ERGOT (ergotamine, dihydroergosine)
Claviceps

14. Trichothecene Mycotoxins
Nivalenol
Deoxynivalenol
T-2 toxin
HT-2 toxin
Diacetoxyscirpenol
Triacetoxyscirpendio
l
Fusarenone X
Verrucarin A, B, J
Roridin A, D, E, H
Many Others (29+)
These are “field”
toxins, not “storage”
toxins

15. Other Mycotoxins of
Growing Interest
Ochratoxins
Produced by Penicillium verrucosum and
several spp. Of Asperfillus.
Potently nephrotoxic and carcinogenic,
teratogenic and immunotoxic.
Public health problem, but little evidence of
problematic instances in swine.

16. Other Common Molds
Penicillium
Common blue mold
Capable of producing mycotoxin, usually
does not.
Diplodia
Affected cattle and sheep in Africa

17. Organisms - 1
Fusarium
Taxonomy is quite confusing
Has had classification changed various times
Fusarium roseum, Fusarium graminearum and
Gibberella zeae are all terms applied to the
same thing.
Gibberella zeae is the “perfect” (reproductive)
stage
Nickname “GIB” corn.

18. Fusarium toxins
Deoxynivalenol
Feed refusal
Emesis (so nicknamed “vomitoxin”)
Zearalenone
Estrogenic effects

19. Deoxynivalenol
Feed refusal factor
for pigs.
Emetic (vomiting)
but seldom see pigs
vomiting, refuse feed

20. Deoxynivalenol - Feed
Refusal
Nearly complete refusal at low dosages
(~5 ppm) by swine.
Reduced intake and poor performance
at very low dosages (~1 ppm or less)
Other animals much much less affected!
DON doesn’t account for all the refusal,
other metabolites are involved (though
seldom tested for).

21. DON Does Not affect
Reproduction
Purified Deoxynivalenol
DON, ppm CL'sFetuses
0 13.2 10.0
2 14.2 11.7
4 13.0 9.2
8 13.7 11.0

22. Field conditions that favor
Gib fungus
Cool, wet weather at silking time
Slow drying weather at harvest
Varieties with tight husks

23. Recovery of DON-infected CORN
DON is very stable!
Heat, chemicals, etc.
have no effect.
DON is water soluble!
So, can be leached
out and washed away.
Not too practical, so
Advice: feed to other
animals instead.

24. Guidelines on Levels
FDA guidelines on DON in feeds
10 ppm in grains, by-products for chickens
& cattle (5 ppm total ration)
5 ppm in ingredients for swine max
inclusion rate 20% (1 ppm total ration)
5 ppm ingredients max inclusion 40% (2
ppm) all other animals
Canada: 1 ppm pigs, calves, lambs, lactation.
5 ppm adult cattle, sheep, poultry

25. Zearalenone
Prepuberal gilts show enlarged, swollen
vulva as if in estrus
Interrupted reproductive cycles in
female swine
Prolapse of the vulva possible
Lengthened or absent estrous cycle
Little or no effect on growth

26. Little effect of Z on growth
ZENGAINFEED
INTAKE
F/G
0 10.3 .75 .49
10 10.7 .75 .51
20 11.0 .81 .49
40 12.2 .82 .53
Initial wt 10 kg, fed 4 wk. James & Smith (1982)

27. Organisims - 2
Aspergillus spp. - Especially A. flavus
Also A. parasiticus and Penicillium
puberulum.
Soil organism (A. flavus), so quite common,
especially in peanuts.
CAN produce AFLATOXIN
AFLATOXIN is probably the worst
common mycotoxin we deal with.

28. AFLATOXIN
Most references to “mycotoxin”,
unspecified, refer to Aflatoxin.
There is NO reason to assume similarities
with other mycotoxins, in any regard.
Can be deadly at low dosages
In 1st outbreaks (~1960) 100,000 turkeys
died + many ducks.
Associated with “groundnut” (peanut) meal

29. Aflatoxin (cont)
Occurs in corn and other grains also.
Temperature > 12 C (54 F) and high
humidity (83% at 30 C).
Therefore usually a bigger problem in USA in
South and Southeast.
Hepatic toxin - zonation, biliary
proliferation, degeneration.
Carcinogenic in chronic situations.

30. AFLATOXIN EFFECTS
Inhibits protein synthesis
Poor gain
Liver damage
Susceptibility to Infection
Residues / carcinogenicity
Reproduction in swine not primarily
affected

31. Aflatoxin on Performance
Growing Swine (53 Kg initial)
PPBFinal Wt,
Kg
ADG
(Kg)
F/G
20 104 .77a3.74a
385 97 .67b3.78a
750 91 .57b3.71a
1480 80 .41c3.97

32. Aflatoxin (cont)

33. A few of many Aflatoxins

34. Aflatoxin Detection
Black Light test - BYG fluorescence
Abused. Use very carefully by trained people
Presumptive test for organism, not aflatoxin
Many other things fluoresce, including
broken soybean seeds
Chromatography
Including rapid minicolumn in-field tests

35. Dealing with AFLATOXIN
FDA ACTION level is 20 ppb
Small amount may contaminate huge
quantities
Strategies to decontaminate must have
FDA approval in USA.
Some methods, however, can lower
aflatoxin levels.

36. DECONTAMINATION
Cleaning, separation, sorting
AMMONIATION
Binding Agents
Sodium aluminosilicate and hydrated
sodium calcium aluminosislicate
NOT GRAS for binding mycotoxins.
MUCH BETTER TO PREVENT FORMATION

37. Preventing Mycotoxins
Use “clean” procedures.
Prevent contamination
Inhibit mold growth
Drying
Refrigeration
Mold inhibitors

38. Additional Mycotoxins

39. FUMONISON
Deadly to horses
equine leukoencephalomalacia
Swine - pulmonary oedema
Renal toxicity and hepatotoxic

40. FUMONISON
Actually 8 analogs known, only B1, B2 &
B3 often found.
ORGANISM is Fusarium moniliforme [=F.
verticillioides (Sacc.) Nirenberg] or F.
proliferatum
Fusarium moniliforme is VERY COMMON
but seldom produces mycotoxin.

41. Fumonison - Levels
< 5 ppm for Horses
10 ppm for swine
50 ppm for cattle

42. ERGOT
Traditionally, this is a disease of RYE
and other small grains.
New threat in Grain Sorghum (milo) to
Western Hemisphere.
Has been prevalent in Africa for decades
(claviceps africana)
Has very rapidly spread in last 2 years, now
in USA.

43. Sorghum Ergot
Pathogen causes
ovary to exude a
sticky liquid.
Dihydroergosine at .6
ppm decreases FI &
ADG.
Effect appears to be
from poor feed intake
Dean et al, 1999

44. Traditional Ergot
Claviceps purpurea produces
ergotamine and other alkaloids.
Psychoactive - convulsions, hallucinations,
abortions
Paralysis, GI disturbance, gangrene of
extremities, death.

45. ADVICE
Avoidance of Mycotoxin formation is
best in every case
Some procedures for decontamination
exist (ammonia, HSCAS), but are
different for different mycotoxins, may
be ineffective and may not be legal.

46. Advice- continued
I would:
Feed NO moldy feeds to reproducing
animals.
Feed a small test amount to growers but
DO NOT encourage consumption.
If no ill effect is observed in test, then
dilute the suspect feed and incorporate
small amount into normal diet.

47. WWW References to
References
Australian Mycotoxin Newsletter
http://www.aciar.gov.au/aciarptp/
myconews.htm
Third Joint FAO/WHO UNEP International
Conference on Mycotoxins, Mar 1999
http://www.fao.org/WAICENT/FAOINFO/
ECONOMICS/ESN/mycoto/papers/