USDA - Kentucky Report (Annual Report to SERA-IEG 8, Tall Fescue Toxicosis/Endophyte Workshop)

Authors: Klotz, James; Smith, Lori; BUSH, L - UNIVERSITY OF KENTUCKY; Strickland, James

Submitted to: SERA-IEG 8
Publication Type: Other
Publication Acceptance Date: 10/19/2008
Publication Date: 10/19/2008
Citation: Klotz, J.L., Smith, L.L., Bush, L.P., Strickland, J.R. 2008. USDA - Kentucky Report (Annual Report to SERA-IEG 8, Tall Fescue Toxicosis/Endophyte Workshop). SERA-IEG 8. pgs 54-58.

Interpretive Summary: Of the ergopeptine alkaloids produced by the endophyte (Neotyphodium coenophialum) of tall fescue, ergovaline has been reported as the most abundant in endophyte-infected tall fescue (Lolium arundinacea). As a result much focus has been placed on ergovaline and its impact on grazing animal health (i.e., induction of Fescue Toxicosis) and performance. Research using various vascular models have shown that there is a sustained contractile response to ergovaline, but not to chemically less complex ergot alkaloid (such as lysergic acid). Further, contractile data collected following repetitive additions of ergovaline have suggested that ergovaline, but not lysergic acid may bioaccumulate in vascular tissues. The objectives of the research in this report were to determine if repetitive additions of ergovaline or lysergic acid result in alkaloid bioaccumulation in vascular tissue treated exposed in vitro. To accomplish this objective, lateral saphenous veins collected from mixed breed and gender cattle were exposed to repetitive additions (up to 8 additions) of either ergovaline (10-7 M) or lysergic acid (10-5 M) over a 3 hour period. Vein samples were removed from the in vitro system after 2, 4, 6, or 8 additions of either alkaloid and analyzed for the treatment alkaloid content via HPLC/MS. These analyses indicated that both alkaloids were present in the tissue, but only ergovaline showed increasing concentrations within the vascular tissue as a result of the repetitive additions. Data would indicate (though confirmation is needed) that ergovaline (and potentially other ergopeptines) may bioaccumulate in animals grazing endophyte-infected tall fescue over time, thereby raising the risk of intoxication.

Technical Abstract: Of the ergopeptine alkaloids produced by the endophyte (Neotyphodium coenophialum) of tall fescue, ergovaline has been reported as the most abundant in endophyte-infected tall fescue (Lolium arundinacea). As a result much focus has been placed on ergovaline and its impact on grazing animal health (i.e., induction of Fescue Toxicosis) and performance. Research using various vascular models have shown that there is a sustained contractile response to ergovaline, but not to chemically less complex ergot alkaloid (such as lysergic acid). Further, contractile data collected following repetitive additions of ergovaline have suggested that ergovaline, but not lysergic acid may bioaccumulate in vascular tissues. The objectives of the research in this report were to determine if repetitive additions of ergovaline or lysergic acid result in alkaloid bioaccumulation in vascular tissue treated exposed in vitro. To accomplish this objective, lateral saphenous veins collected from mixed breed and gender cattle were exposed to repetitive additions (up to 8 additions) of either ergovaline (10-7 M) or lysergic acid (10-5 M) over a 3 hour period. Vein samples were removed from the in vitro system after 2, 4, 6, or 8 additions of either alkaloid and analyzed for the treatment alkaloid content via HPLC/MS. These analyses indicated that both alkaloids were present in the tissue, but only ergovaline showed increasing concentrations within the vascular tissue as a result of the repetitive additions. Data would indicate (though confirmation is needed) that ergovaline (and potentially other ergopeptines) may bioaccumulate in animals grazing endophyte-infected tall fescue over time, thereby raising the risk of intoxication.