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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 • • • • • 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 • • • • • • • 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 • • • • • • • 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 • • • • • • 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 • • • • 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