RESUMEN
Perennial ryegrass (Lolium perenne) infected by Epichloë festucae var. lolii contains alkaloids that are responsible for toxicosis in several countries, but few cases are reported in Europe. Lolitrem B is generally the most abundant alkaloid and is recognized to be responsible for livestock staggers, whereas ergovaline is less frequently documented in perennial ryegrass. Lolitrem B and ergovaline were monitored over a three-year period in endophyte-infected perennial ryegrass 'Samson' sown in southern France. Alkaloid concentrations were strongly influenced by the stage of maturity of the plant; maximum concentrations were always measured at the fully ripe stage. Over the three years of analysis, variations in lolitrem B in the whole plant at the fully ripe stage were low (from 1296 to maximum 1871 µg/kg dry matter), whereas ergovaline varied considerably (from 526 to 2322 µg/kg dry matter), suggesting that abiotic factors play a key role in determining ergovaline levels in endophyte-infected perennial ryegrass.
Asunto(s)
Ergotaminas/análisis , Alcaloides Indólicos/análisis , Lolium/química , Micotoxinas/análisis , Alimentación Animal/análisis , Clima , Ecosistema , Endófitos/fisiología , Epichloe/fisiología , Ergotaminas/metabolismo , Francia , Alcaloides Indólicos/metabolismo , Lolium/crecimiento & desarrollo , Lolium/microbiología , Micotoxinas/metabolismo , Enfermedades de las Plantas/microbiología , Toxinas Biológicas/análisis , Toxinas Biológicas/metabolismoRESUMEN
Tall fescue (Lolium arundinaceum) infected by Epichloe coenophiala contains ergot alkaloids responsible for fescue toxicosis in Australia, New Zealand, and the United States, with only a few cases occurring in Europe. The detection of Epichloe in 166 L. arundinaceum collected in southern France revealed that 60% were infected, 51% being high ergovaline producers. The ergovaline level in endophyte-infected tall fescue Kentucky 31 was monitored during 3 years in various parts of the plant. Maturation of plants, recorded according to the BBCH scale, appeared to be the main factor for estimating the risk of toxicity. Ergovaline levels of ≥300 µg/kg dry matter were obtained at the end of spring, the beginning of autumn, and mid-winter. Positive correlation between ergovaline level and cumulative degree-d was observed, whereas rainfall had no effect. These results suggest that the lack of fescue toxicosis observed in France cannot be explained by the lack of ergovaline in tall fescue.