Download A HIDDEN ENEMY IN A SEA OF SILAGE ALAN GOTLIEB

MYCOTOXINS
A HIDDEN ENEMY IN A SEA OF
SILAGE
ALAN GOTLIEB
UNIVERSITY OF VERMONT
MYCOTOXINS
1.
2.
3.
4.
5.
SERIOUS FOOD CONTAMINANTS
WHY / WHERE PRODUCED?
CONDITIONS OF PRODUCTION
MANAGEMENT FOR CONTROL
FUTURE PREVENTION METHODS
Not all fungi produce toxins
SMUT
ASPERGILLUS EAR ROT
produces aphlatoxin
FUNGUS MOLD
TYPICAL PROBLEMS
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Reduced milk production
Poor weight gain
Reproduction problems
Reduced feed intake
Typically chronic, low level
maladies in dairy cows
Animal Symptoms
Mimic many
infectious diseases
and other
noninfectious ailments
Related Symptoms
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Refusal of feed
Diarrhea
Nervousness
Staggers
Clear nasal discharge
Laminitis
General unthriftiness
FUSARIUM EAR ROT
• Common in the north
• Produces: t-2, vomitoxin (DON),
zearalenone, fusaric acid
FUSARIUM EAR ROT
FUSARIUM KERNAL INFECTION
CORN INFECTION
• Silks infected directly by Fusarium
• Fungus moves down silk and enters
kernel and cob
• Stalks infected directly or through
insect borer injury
• Roots infected directly or through
insect damage
Stress Increases Ear Rot
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Drought
Flood
Low fertility (potassium)
Root and stalk rot
Insect damage
Bird damage
Foliage disease blight
LODGING DUE TO
FUSARIUM
STALK ROT
Diagnosis here
was low K
FUSARIUM
MOLD
FUSARIUM
STALK ROT
FUSARIUM STALK ROT
Fertility balance
important for control
FOLIAGE DISEASES CAN
INCREASE EAR ROTS
NORTHERN
CORN
LEAF BLIGHT
SOUTHERN
LEAF BLIGHT
EAR INFECTION
EYE SPOT
WITH BACK LIGHT
Ear Rot and Foliage Disease
Disease
Severity
% ear rot
SCLB
SCLB
low
high
9
35
Eyespot
Eyespot
low
high
6
29
STORAGE:
FUNGUS GROWTH AND
MYCOTOXIN
CONTAMINATION
PLASTIC BAG
INSIDE BAG
UPRIGHT SILO MOLD
PENICILLIUM ROQUEFORTII
PR MOLD
Conditions for Fungus Growth
In Storage
• Moisture above 22%
• Temperature above 32 degrees F
• Oxygen present
ASPERGILLUS
KERNAL ROT
Aphlatoxin severe
in the south
Two years ago
Contaminated milk
dumped in several states
Best temperature for efficient
toxin production
• Fusarium toxins 45-75 F
• Penicillium toxins 40-90 F
Fungus Produced Spoilage in Corn
Fungus growth at
60% moisture
can take as little as
1 day
PILES ARE
AN INCUBATOR FOR DISASTER
BAD SITUATION
Best Preservation Method
• Bunker
• Upright silo
• Bag
• Wrapped bail
ELIMINATE:
OXYGEN, SOIL CONTAMINATION
RAIN WATER
THESE ARE KEY to prevent spoilage
Spoilage and Toxin levels
• silage from 85 Vermont farms
was tested
• samples were from spoiled and
unspoiled areas
• 38% of farms had >3ppm
vomitoxin in spoiled feed
• In all cases toxin level in spoiled
feed was greater than in
adjacent normal feed (<1ppm)
RAIN AND SNOW MELT MOVE TOXINS
Toxins can Move
• Mycotoxins are highly soluble
• Rain can wash toxins from a spoiled
layer down into normal silage
• Bunkers must be covered and kept
covered
• Toxin can migrate in silage liquid
CONTROL CHECK LIST
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Purchase disease resistant varieties
Rotate corn at regular intervals
Plow down crop debris
Harvest at recommended maturity
Harvest corn silage before frost
Sharpen chopper knives and adjust for
correct length to improve packing
• Pack bunker silos tightly
MORE CONTROL
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Use secure plastic cover on bunkers
Patch holes in plastic covers / bags
Discard obviously spoiled feed
Remove refused feed from feed
bunkers
• Match daily rate of feed removal to
silage face:
Bunker - 4 to 6 inches per day
Upright - 3 to 4 inches per day
• Stop feeding problem feed source or
dilute with clean feed when possible
Adsorbents
• Bentonite and other clay like
materials
• Mined from sediment deposits
(ancient marine animals and volcanic
ash)
• Used as flow or binding agents in
feed
• Can adsorb many chemicals
Adsorbents continued
• Only anecdotal evidence in dairy
• Increased feed intake and milk
production reported
• Often fed at 4 to 8 oz per day per cow
• Recommendation: Use local
success experiences in making
decisions
Additional Considerations
• Consider using a bacterial silage
inoculant
• Consider use of acid additive in high
moisture corn (not silage)
• Consider use of acid application to
feeding face of bunker silo
Mycotoxins and the Rumen
• Mycotoxins were designed to inhibit
neighboring organisms
• The rumen and intestinal flora are
probable active sites for toxin impact
• Toxins could change the population
profile of beneficial organisms in the
rumen
PENNICILLIUM
EAR
INFECTION
Current
Vermont
Research
PENNICILLIUM KERNAL INFECTION
Penicillium loves acid
Acid not useful treatment in silage
Acid Tolerant Penicillium
• Working with 200 corn silage isolates
• Produce 9 different toxin related
products
• Roquefortine, Penicillic acid, etc.
• Using TLC to screen
• Next step to challenge rumen flora
Mycotoxin Testing
• HPLC
• ELISA
• GC Mass Spectrophotometry
HPLC
A Matrix Mess
Corn Silage Sample #5
1.5 ppm DON
ELISA
VERATOX DON in Spiked Haylage
10
Trial #1
No Significant Difference
P< 0.29
r squared = 0.37
9
8
Trial #2
Significant Difference
P < 0.01
r squared = 0.52
7
Spike
VERATOX
Spiked Haylage
5
4
3
2
1
0
0H
1H
2H
3H
4H
5H
0H
0.5H
T rial #1
1H
1.5H
2H
2.5H
T rial #2
dek ipS ega lyaH no NOD NEERCSADIR
ecnereffid tnacifingis oN
1 9 . 0 <P
59.0 = derauqs r
HPLC in Haylage Spiked
6
No Significant Difference
P<0.77
r squared = 0.99
5
4
DON ppm
DON ppm
6
0H
0
3
0.4
2
1
0
Sample
SAMPLE
H5
H4
H3
H2
ELPMAS
H1
mpp
VERATOX DON In Corn Silage Spiked
6
Spiked Corn Silage
No Significant Difference
P<0.86
r squared = 0.86
5
DON ppm
4
Spike (ppm)
3
VERATOX DON ppm
HPLC in Spiked Corn Silage
2
6
No Significant Difference
P<0.76
r squared = 0.93
1
5
0
0C
1C
2C
3C
4C
5C
4
DON ppm
SAMPLE
RIDASCREEN DON IN CORN SILAGE SPIKED
Spike (ppm)
3
HPLC ppm
2
8
1
No Significant Difference
P<0.21
r squared = 0.77
7
0
6
0C
1C
2C
3C
SAMPLE
DON ppm
5
Spike (ppm)
4
RIDASCREEN DON ppm
3
2
1
0
0C
1C
2C
3C
SAMPLE
4C
5C
4C
5C
Test Conclusions
• HPLC is a useful method for quantitative
determination of DON in ensiled corn and
hay crops
• RIDASCREEN® DON is a useful method for
quantitative determination of DON in
ensiled crops
• VERATOX® DON may suffer from matrix
effects in some corn silage and suffers
from severe matrix effects in haylage
Question:
Are toxins in dairy cows
worse today than 25
years ago?
Answer:
YES, I think so
WHY?
• The dose makes the toxin
• Cows today produce twice as
much milk
• Cows eat twice as much food
today
• Cows are not twice as big as 25
years ago
• Cows are getting more toxin per
pound of body weight
• Cows are under more stress
We can make matters worse
• Continuous corn (can increase corn
pathogen inoculum in field)
• No till or minimum tillage leaves
infected debris on soil surface (more
pathogen inoculum)
• Harvest late
• Harvest frosted corn for silage
Future Prevention
• Corn silks resistant to fungus
infection
• Plants able to metabolize toxins
as they form
• Bacterial inoculants able to
metabolize toxins during
fermentation
• Specific adsorbents to remove
toxin from feeds
• As yet there are no magic bullets