2011 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.
Collection of data continues in WV on potential effects of UVB radiation related to altitude on bioactive nontraditional legumes with potential anthelmintic activity. Plant growth data is being collected under field & controlled environment conditions, and condensed tannin concentrations of herbage are being determined. Collection of greenhouse data related to effects of poor soil fertility on the antioxidant capacity & condensed tannin content of selected legumes is ongoing. The antioxidant capacity of alfalfa, orchardgrass, and chicory samples from multi-year field plot studies has been quantified; analysis of two brassica species from different sampling dates is underway. A lab assay procedure using a free-living roundworm was developed & used to assess the anthelmintic potential of trees and shrubs containing condensed or hydrolyzable tannins, Artemisia annua plants containing high concentrations of the compounds artemisinin and dihydroartemisinic acid, & several medicinal herbs. The effect of purslane and brassica seed extracts and brassica leaf extracts on hatching of Haemonchus contortus (barberpole worm) eggs and motility of the infective larvae was determined using laboratory bioassay procedures. Bulk sesquiterpene lactone extracts have been prepared from chicory leaves, and preparations are underway for evaluating differential effects of the chicory sesquiterpene lactone on H.contortus worms in vivo (gerbils, sheep) in collaboration with SCA partners at VA Tech. Investigation of the anthelmintic activity of artemisinin and Artemisia annua extracts in sheep is being conducted in collaboration with EMBRAPA, Brazil. Chemical analysis of chicory leaves representing herbage that was either consumed or rejected by sheep parasitized by H. contortus has revealed differences in nitrate and sesquiterpene lactone concentrations in the two forage types produced during a SARE project with Ohio St U researchers and farmer collaborators. A laboratory rumen fermentation experiment was completed to evaluate the impact of plants and plant extracts on rumen bacterial populations in goats using metagenomic procedures to identify shifts in bacterial, protozoal, archeal and fungal populations. Rumen fermentation studies with chicory leaves and sesquiterpene lactone extracts have been conducted to evaluate rates of tissue digestion and sesquiterpene lactone metabolism. A rapid method for quantifying third stage larvae of H. contortus on pasture plants is being used to determine parasite loads on pastures and examine potential for physical & chemical disruption of the life cycle of the parasite. A rapid, non-destructive procedure using near infrared reflectance spectroscopy is being developed for est. concentrations of the individual sesquiterpene lactones in chicory leaves. Substantial progress has been made in developing a chromatographic procedure for quantification of cichoriin in chicory. This project will provide plant materials & associated management approaches to expand forage options and H. contortus control strategies for small ruminants in humid, temperate climates.
New bioassay will improve screening of potential livestock de-wormers. Traditional bioassay methods to identify plant materials with potential to control worms in the digestive track of sheep and goats require culturing of gastrointestinal worms. Such culturing is time-consuming and expensive, involving maintenance of parasitized donor animals, isolation of worm eggs from feces, and culturing of fecal material to obtain infective larvae. ARS researchers at Beaver, WV established a modified bioassay method using Caenorhabditis elegans, a free-living roundworm, instead of gastrointestinal roundworms. C. elegans was easier to culture and maintain than gastrointestinal worm species and gave reliable results when screening for potential de-worming activity of medicinal and tannin-containing plants. This method has potential to reduce the expense and time required to identify plants that contain compounds with potential for gastrointestinal worm control in sheep and goats.
Forage turnips are safe for meat goats and may reduce harmful effect of barberpole worm infection. Drug-resistant, blood-feeding barberpole worms are a major animal health problem facing sheep and goat production throughout the world. Plants that may help combat these worms naturally are being sought. Some components of brassica plants such as turnips are toxic to worms that infest plants and might have potential to kill barberpole worms, but other components of brassicas sometimes cause anemia in animals and might make worm-induced anemia worse. ARS researchers at Beaver, WV investigated this paradox with a feeding trial indicating that feeding forage turnip did not lead to clinical anemia in healthy or parasitized goats and improved feed intake of the goats infected with barberpole worms. Results justify further work to investigate the feasibility of using forage brassicas to combat worm infections in goats.
Ferreira, J.F., Peaden, P., Keiser, J. 2011. In vitro trematocidal effects of crude alcoholic extracts of Artemisia annua, A. absinthium, Asimina triloba, and Fumaria officinalis. Parasitology Research. DOI: 10.1007/s00436-011-2418-0.
Singh, N.P., Ferreira, J.F., Park, J., Lai, H. 2011. Cytotoxicity of ethanolic extracts of Artemisia annua to Molt-4 human leukemia cells. Planta Medica. 77:1788-1793.
Katiki, L., Ferreira, J.F., Zajac, A., Masler, C.A., Lindsay, D., Chagas, A., Amarante, A. 2011. Caenorhabditis elegans as a model to screen plant extracts and compounds as natural anthelmintics for veterinary use. Veterinary Parasitology. 182:264-268.
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.
Foster, J.G., Cassida, K.A., Turner, K.E. 2011. In vitro analysis of the anthelmintic activity of forage chicory (Cichorium intybus L.) sesquiterpene lactones against a predominatly Haemonchus contortus egg population. Veterinary Parasitology. 180(3-4):298-306.