Fescue Ergot Alkaloids?
(Rated as: good read)
Does anybody have more information about which types of ergot alkaloids, etc. are in Tall Fescue?
Harvest and Storage Method Affects Ergot Alkaloid Concentration in Tall Fescue
Craig Roberts and Robert Kallenbach
Crop Management DOI:10.1094/CM-2002-0917-01-BR
Tall fescue (Festuca arundinacea) is naturally infected with Neotyphodium coenophialum (Fig. 1), a fungal endophyte that causes “fescue toxicosis” in ruminants and horses (5). Fescue toxicosis includes many symptoms, such as reduced dry matter intake, poor weight gain, low blood prolactin, high body temperatures, high rectal temperatures, low conception rate, and vasoconstriction. Toxins responsible for fescue toxicosis are now known to be ergot alkaloids, a class of compounds produced by the fungal endophyte (2).
Fig. 1. Mycelia of Neotyphodium coenophialum, the tall fescue endophyte, growing between cell walls in the tall fescue leaf sheath.
When endophyte-infected (E+) tall fescue hay is ammoniated (treated with 3% anhydrous ammonia), livestock show little or no symptoms of fescue toxicosis. In one study, lambs consuming ammoniated E+ tall fescue hay had improved dry matter intake, higher daily gain, and increased concentrations of the hormone prolactin compared to lambs fed untreated E+ tall fescue hay (1). Although ammoniation increased fiber digestibility, the improved lamb performance was probably due to lower toxicity rather than increased nutrition; evidence of such was seen in prolactin levels, and because ammoniation did not improve lamb performance when hay was endophyte-free, even though it increased digestibility and rate of passage (1).
In contrast to ammoniation, ensiling does not appear to eliminate symptoms of fescue toxicosis. In one study, infected tall fescue was clipped in the autumn, ensiled, then fed to dairy calves; the calves exhibited low blood prolactin and high rectal temperatures (3).
There has been no experiment to compare the effects of harvesting and storing methods on ergot alkaloid concentration in E+ tall fescue. Yet such a study may prove that certain harvesting and storing methods can detoxify E+ tall fescue by directly decreasing ergot alkaloid concentration, while other methods may preserve toxins until feeding time. This experiment was conducted to determine if ergot alkaloid concentration in toxic tall fescue would be affected when forage was green chopped, ensiled, and cured as hay with and without ammoniation.
Trials with Four Harvest and Storage Treatments
Tall fescue infected with the endophyte (> 80%) was harvested in the autumn at the University of Missouri Southwest Experiment Station near Mt. Vernon, MO. Tall fescue was fertilized with N at 75 lb/acre in August, 2001, then clipped in mid-October. Four treatments were imposed: (1) green chop (control treatment); (2) ensiled forage; (3) hay; and (4) ammoniated hay. Green chop forage was frozen immediately after clipping. Ensiled forage was allowed to wilt to 55% moisture, then wrapped in air-tight plastic bags for 6 weeks. Hay was allowed to sun-cure to 16% moisture, then baled. Ammoniated hay was made by sun-curing hay to 16% moisture, wrapping dried hay in air-tight plastic bags, treating with 3% anhydrous ammonia, and storing for 6 weeks. Approximately 100 lb of dry matter was collected for each experimental unit. A 0.5 lb sub-sample was collected from each treatment, frozen, freeze-dried, ground to 1 mm, and analyzed with a commercial ELISA kit for ergot alkaloids (Agrinostics, Ltd., Watkinsville, GA).
The experimental design was a completely randomized design with six replications. Significance of main effects was assessed using routine analysis of variance techniques, and means were separated using the Fisher’s LSD means separation test with = 0.01.
Reducing Ergot Alkaloid Concentrations
The green chop tall fescue contained 1240 ppb ergot alkaloids (Fig. 2), and the ensiled tall fescue contained 972 ppb. These were statistically similar to one another. The hay and ammoniated hay contained much lower ergot alkaloid concentrations than the green chop and ensiled samples. Ergot alkaloid concentration in non-ammoniated hay averaged 373 ppb, a level lower than typical spring hay, probably due to its lack of endophyte-containing stems and seed heads (4). Ergot alkaloid concentration in ammoniated hay was 247 ppb and statistically similar to the non-ammoniated hay.
Fig. 2. Total ergot alkaloid concentration in tall fescue preserved as freeze-died, ensiled, ammoniated, and sun-cured hay. Tall fescue in this study was infected with the endophyte, Neotyphodium coenophialum at 90% infected tillers. Means with same letter are not statistically different with = 0.01.
Though this study did not include a feeding trial, other research indicates that E+ tall fescue is toxic when ergot alkaloid concentrations reach these high levels (4). Tall fescue produces symptoms of toxicosis when ergovaline, the most highly concentrated ergopeptine alkaloid, reaches 200 to 300 ppb (4).
The high concentration of ergot alkaloids in silage offers an explanation for poor performance when calves are fed ensiled E+ tall fescue (3). In addition, it indicates that an entire class of alkaloids is preserved in the ensiling process, because concentrations in the silage were similar to those in the green chop. The low ergot alkaloid concentration in the ammoniated hay partly explains why livestock consuming ammoniated E+ tall fescue hay show few symptoms of fescue toxicosis. Producers feeding E+ tall fescue to livestock should expect high concentrations of toxins in pasture, green chop, and silage. However, they can reduce toxin concentrations by making hay or ammoniating hay. Follow-up studies are underway to determine if spring-harvested hay and ammoniated hay contain significantly different concentrations of ergot alkaloids.
1. Chestnut, A. B., Fribourg, H. A., Gwinn, K. D., Anderson, P. D., and Cochran, M. A. 1991. Ammoniation of Acremonium coenophialum infested tall fescue hay fed to sheep. Anim. Feed Sci. Technol. 35:227-236.
2. Hill, N. S., Thompson, F. N., Dawe, D. L., and Stuedemann, J. A. 1994. Antibody binding of circulating ergopeptine alkaloids in cattle grazing tall fescue. Am. J. Vet. Res. 55:419-424.
3. Jackson, J. A., Sorgho, Z., and Hatton, R. H. 1988. Effect of nitrogen fertilization or urea addition and ensiling as large round bales of endophyte-infected tall fescue on fescue toxicosis when fed to dairy calves. Nutr. Repotrs Int. 37:335-345.
4. Rottinghaus, G. E., Garner, G. B., Cornell, C. N., and Ellis, J. L. 1991. HPLC method for quantitating ergovaline in endophyte-infested tall fescue: seasonal variation of ergovaline levels in stems with leaf sheaths, leaf blades, and seed heads. J. Agric. Food Chem. 39:112-115.
5. Strickland, J. R., Oliver, J. W., and Cross, D. L. 1993. Fescue toxicosis and its impact on animal agriculture. Vet. and Human Toxicol. 35:454-464
Link to the PDF file of the above.
|Re: Does anybody have more information about...|
heres an article claiming that there is great genetic diversity with this fungus, perhaps implying that alkaloid production vary greatly: http://www.ncbi.nlm.nih.gov/entrez/query
and slightly off topic, heres a listing of fungus classifications and corresponding alkaloids, from the huge listing (in the middle top half of page): http://digilander.libero.it/danielefocos
Neotyphodium coenophialum (a.k.a. Acremonium coenophialum)
Sclerotia are commonly known as ergots. It grows on Cannabis indica and other plants. The mean ergot alkaloids are :
=> ergotoxine group
=> ergotamine tartrate (Ergomar®, + caffeine / teine in Cafergot®)
=> dihydroergotamine (DHE) mesylate (Migranal®, D.H.E. 45®)
=> dihydroergocryptine (DHEC) (Almirid®, Hydergine®) (includes ergoloid mesylates)
=> ergonovine / ergometrine maleate (Ergotrate©)
=> lisuride (Cuvalit©, Dopergin©, Revanil©)
=> d-lysergic acid
=> d-isolysergic acid
It causes Saint Anthony's fire or ergotism from inadvertent ingestion of the sclerotia in flour prepared from infected cereal crops : it can produce gangrene of the extremities. Precursor for semisynthetic ergolins :
methysergide (Sansert®) (antagonist !)
methylergonovine maleate (Methergine©)
Claviceps paspali (a.k.a. paspalum staggers ergot)
=> D-lysergic acid amide (LSA)
i found it interesting that they listed marijuana as a host for ergot.
Claviceps-Infected Tall Fescue/Wheat/Barley
(Rated as: good read)
Ergot Peptide Alkaloid Spectra of Claviceps-Infected Tall Fescue, Wheat, and Barley
James K. Porter, Charles W. Bacon, Ronald D. Plattner, and Richard F. Arrendale.
J. Agric. Food Chem. 35, 359-361 (1987) (../rhodium/pdf /ergot.peptid
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