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United States Department of Agriculture

Agricultural Research Service



2008 Annual Report

1a. Objectives (from AD-416)
Identify non-traditional plant resources and associated management methods with potential to enhance nutrition and health of small ruminants produced in central Appalachia. Specific objective 1: Identify plant resources and determine plant growth characteristics and management practices that can expand forage options. Specific objective 2: Identify plant resources and plant management strategies that can help control gastrointestinal helminths which infect small ruminants.

1b. Approach (from AD-416)
Controlled environment, field plot, and laboratory experiments will be conducted to determine growth habit, herbage yield, and chemical composition of non-traditional pasture legumes, forbs and grasses with potential for use as forage or forage supplements for small ruminants. Emphasis will be placed on plant species having physical properties or chemical constituents that disrupt the life cycle of the gastrointestinal nematode, Haemonchus contortus or provide immune system support for the ruminant. Non-traditional plant species used in these studies include condensed tannin-containing legumes, American potato bean, purslane, artemisia, and chicory. Condensed tannin-containing forage species will be evaluated for economic potential for hay production under central Appalachian growing conditions using criteria of yield, forage quality, and stand persistence. Native Appalachian plant species that have the potential to provide sufficient yield and bioactive constituents for small ruminants will be identified. The effect of plant species, management, and season on antioxidant capacity of traditional and non-traditional forage species will be measured using samples from multi-year field studies. The influence of edaphic and solar conditions on physical and chemical properties of plant resources will be determined using plants grown with and without mineral deficiencies, with varying levels of UV light, or with natural radiation attenuation. Potential adverse effects of non-traditional plant resources on rumen metabolism and potential alterations in bioactivity by rumen microbial activity will be assessed using in vitro rumen fermentation assays. Anthelmintic activity of plant materials and isolated constituents will be determined using in vitro and in vivo parasite assays. The effect of plant morphology, sward density, and canopy height on hatching and migration of parasite larvae will be evaluated to determine how physical characteristics of pastures can be manipulated to disrupt the parasite life cycle.

3. Progress Report
This project was initiated in 2008. Most experiments are in the implementation stage and preliminary results will not be available until 2009. Plots containing non-traditional legumes with potential as dual purpose forages in central Appalachia have been established at high and low altitude sites in WV and PA for adaptation studies. Tannin concentrations in herbage are being quantified. Experimental procedures needed to investigate effects of UV light on tanniferous forages are being refined. In collaboration with parasitologists at Virginia Tech, the effects of selected plant materials on mature Haemonchus contortus (barberpole worm), a major gastrointestinal parasite in sheep and goats, are being investigated using a gerbil model system. In vitro parasite assays are being used to determine whether sesquiterpene lactone constituents in Artemisia annua and forage chicory inhibit H. contortus egg embryonation and hatching and larval motility. Germplasm of A. annua has been screened to identify plants with high concentrations of artemisinin, and selected specimens have been cloned for further evaluation. Herbage from chicory cultivars is being analyzed to determine whether differences in condensed tannin concentrations exist and whether concentrations vary with season and environmental conditions. Degradation of sesquiterpene lactones in rumen fluid, and the presence of sesquiterpene lactones in feces from sheep grazing chicory, are being assessed. A collaborative 2-year SARE research proposal to study the use of chicory pastures for parasite control has been funded. Methods to quantify third stage larvae of H. contortus on pastures are being developed to support studies on physical disruption of the life cycle of the parasite. The potential use of a citrus oil formulation as a pasture treatment for control of H. contortus is being studied in controlled environments. Analytical tools to measure the antioxidant potential of forages have been acquired, and methods for oxygen radical absorbance capacity, ferric reducing antioxidant power, and total phenolics have been adapted to obtain preliminary data for representative forages. Sand culture procedures are being implemented to determine nutrient limitations on condensed tannin concentrations and antioxidant capacity of tannin-containing forages. This project is aligned with NP 215, Pasture, Forage, Turf and Range Land Systems; Component 2. Pasture Management Systems to Improve Economic Viability and Enhance the Environment; Problem Statement D. Need for appropriate plant materials to improve the economic viability and enhance the environment in pasture-based livestock systems, and will provide plant materials and associated management strategies to expand forage options and gastrointestinal parasite control strategies for small ruminants in humid, temperate climates.

4. Accomplishments
1. Quantification of artemisinin from Artemisia annua without chemical derivatization using gas chromatography with electron-capture detection. Artemisinin is an anti-parasitic sesquiterpene lactone that has been reported to lack UV and visible chromophores in its chemical structure; thus, artemisinin has traditionally been derivatized for analysis by high performance liquid chromatography. Alternatively, more complicated and expensive methods of detection have been used. Work done in collaboration with Chinese colleagues has resulted in development of a simplified method for analysis of underivatized artemisinin using gas chromatography with electron capture detection. Plant extracts can be analyzed directly, and the method is sensitive to less than 9 µg/mL, allowing dry samples as small as 100 mg to be accurately quantified. The method can be used to screen plant populations for high-artemisinin producing specimens and assess quality of A. annua plants and extracts destined for the pharmaceutical and medicinal botanicals markets. [NP 215, Pasture, Forage, Turf and Range Land Systems; Component 2. Pasture Management Systems to Improve Economic Viability and Enhance the Environment; Problem Statement D. Need for appropriate plant materials to improve the economic viability and enhance the environment in pasture-based livestock systems]

5. Significant Activities that Support Special Target Populations

Review Publications
Liu, S., Tian, N., Liu, Z., Huang, J., Li, J., Ferreira, J.F. 2008. An affordable and sensitive determination of artemisinin in Artemisia annua L. by gas chromatography with electron capture detector. Journal of Chromatography A. 1190:302-306.

Last Modified: 2/23/2016
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