Seasonal variation in sesquiterpene lactone concentration and composition of forage chicory (Cichorium intybus L.) cultivars

Palatability and anthelmintic activity of chicory (Cichorium intybus L.) forage are influenced by the sesquiterpene lactones lactucin (LAC), 8-deoxylactucin (DOL) and lactucopicrin. Therefore, the objective of this study was to determine how sesquiterpene lactone concentration and composition vary during the growing season. Three forage chicory cultivars (Puna, Forage Feast and Lacerta) grown in West Virginia and Pennsylvania (USA) were managed during two consecutive years to maintain plants in the vegetative stage, and sesquiterpene lactones in leaves were quantified after each growth interval. Cultivars differed in the total concentration of sesquiterpene lactones and in the proportions of LAC and DOL. Total sesquiterpene lactone concentration generally decreased or remained constant during the season, but the specific response depended on the cultivar. Differences in seasonal patterns between years corresponded with unusual climatic conditions. The three cultivars had similar concentrations of DOL in the spring. Forage Feast provided a dramatically lower concentration of DOL during the summer. Uniformly high concentrations of DOL across the growing season in Puna and Lacerta make these cultivars attractive for use in bioactive pastures for control of Haemonchus contortus. Changes in both sesquiterpene lactone concentration and composition during the season result in large variations in forage bitterness.