ANALYSIS OF ENDOPHYTE TOXINS - FESCUE AND OTHER GRASSES TOXIC TO LIVESTOCK

Research on livestock toxicoses caused by Acremonium (endophyte)-infec ted grasses strongly implicate the ergopeptine alkaloids with A. coeno phialum-infected fescue and paxilline and the lolitrem alkaloids with A. lolii-infected perennial ryegrass as the causative agents. Isolatio n, identification, and detection of these toxins involves extraction w ith appropriate solvents, clean-up procedures, and chromatographic met hods with known standards. Thin-layer, high-performance liquid and gas chromatography along with ultraviolet and mass spectrometric (i.e., e lectron impact, chemical ionization, tandem mass) characterizations ha ve been reported. These methods have varying degrees of success depend ing on the matrix from which the alkaloids have been extracted. Ergova line is the primary ergopeptine alkaloid isolated from cultures of A. coenophialum and also from infected fescue grass and seeds toxic to li vestock. Other compounds isolated from the endophyte-infected fescue i nclude: lysergic acid amide (ergine), the clavine class of ergot alkal oids (chanoclavine I, agroclavine, elymoclavine, penniclavine), the py rrolizidine alkaloids (N-formylloline, N-acetylloline, M-methlyloline, N-acetylnorloline), and the unique pyrrolopyrazine alkaloid peramine. The loline alkaloids and peramine have been more associated with the insect-deterrent properties of the endophyte-infected fescue than with livestock toxicoses. Also, both peramine and the ergopeptine alkaloid s (ergovaline, ergotamine) have been isolated from A. lolii-infected p erennial ryegrass. More recently, paxilline and lolitrem B have been d etected in laboratory cultures of A. coenophialum isolated from tall f escue. The ergot alkaloids in endophyte-infected perennial ryegrass ma y be more related to decreased animal productivity (weight gains, repr oduction problems), whereas the lolitrems cause the staggers syndrome. The detection, isolation, identification, and analyses of these compo unds from Acremonium-infected grasses is presented.