Submitted to: Grass and Forage Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/23/2011
Publication Date: 4/1/2011
Citation: Foster, J.G., Cassida, K.A., Sanderson, M.A. 2011. Seasonal variation in sesquiterpene lactone concentration and composition of forage chicory (Cichorium intybus L.) cultivars. Grass and Forage Science. DOI: 10.1111/j.1365-2494.2011.00801.x. Interpretive Summary: Chicory (Cichorium intybus L.) has become a valuable forage species for pastures because it improves forage availability and nutritive value during summer and it contains sesquiterpene lactones that help control gastrointestinal nematode infections in small ruminants. Because the anthelmintic effect could be related to both total sesquiterpene lactone concentration and the proportions of the individual constituents, lactucin, 8-deoxylactucin and lactucopicrin, this study was undertaken to determine seasonal variations in cultivars of different origins. Cultivars Grasslands Puna, INIA le Lacerta and Forage Feast were established in 2004 in West Virginia and Pennsylvania. Stands were managed to maintain plants in the vegetative stage, and herbage was collected after each growth interval during 2005 and 2006. In 2005, an increase in sesquiterpene lactone concentration occurred in WV-grown cultivars during a period of low rainfall. Otherwise, sesquiterpene lactone concentrations decreased during the two seasons in Puna and Forage Feast and remained stable in Lacerta. Variations in the fraction of total sesquiterpene lactones represented by lactucin, 8-deoxylactucin and lactucopicrin during the two growing seasons were small relative to the differences in sesquiterpene lactone composition among the three cultivars. If the individual sesquiterpene lactones are not equally effective against gastrointestinal parasites, the results of this study suggest that chicory cultivars will differ in anthelmintic potential and that seasonal variations in sesquiterpene lactone concentration and composition will have minimal impact. Accumulation of sesquiterpene lactones in herbage associated with unpredictable environmental stresses such as water deficit may have important parasitological implications because infective parasite larvae proliferate in pastures when conditions are warm and moist. The data obtained in this study supplement results from other comparative studies with these cultivars and support development of recommendations concerning chicory cultivar selection and use for small ruminant production.
Technical Abstract: Chicory (Cichorium intybus L.) herbage contains sesquiterpene lactones that are believed to help control gastrointestinal nematodes in small ruminants. Because the anthelmintic effect could be related to both total sesquiterpene lactone concentration and the proportions of the principal constituents, lactucin (LAC), 8-deoxylactucin (DOL), and lactucopicrin (LPIC), this study was undertaken to determine seasonal variations in forage chicory cultivars that have different sesquiterpene lactone compositions. Cultivars grown in West Virginia and Pennsylvania were managed during 2005 and 2006 to maintain plants in the vegetative stage, and sesquiterpene lactones in leaves were quantified after each growth interval. Lacerta provided a moderate, but consistent concentration of sesquiterpene lactones with a high proportion DOL. Puna provided a constant, high proportion of DOL, offsetting the decreasing total sesquiterpene lactone concentration that occurred as the season progressed. These two cultivars have value for use in integrated programs for gastrointestinal parasite control in small ruminants because their chemical uniformity across the grazing season give them broad applicability to climatic regions corresponding to the moist, temperate northeastern USA. Forage Feast is less desirable for use in bioactive pastures because it provides low DOL concentrations during most of the grazing season. Unanticipated environmental events may alter normal seasonal patterns in sesquiterpene lactone concentration and composition, and these alterations may be either beneficial or detrimental. Results provide a chemical basis for investigating unexplained grazing behaviors in chicory pastures.