Location:2009 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
Plots containing nontraditional legumes with potential bioactivity 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. Research on breeding and management strategies to maximize herbage yield, nutritional value, and medicinal properties of purslane, American potato bean, and cup plant has been conducted by project affiliates under SCA 58-1932-7-767. Lespedeza and birdsfoot trefoil have been grown in sand culture with nutrient deficiencies, and the oxygen radical absorbance capacity of lipophilic extracts of the herbage have been determined. A preliminary rumen in vitro fermentation experiment was completed to evaluate the impact of commercial dewormers and isolated plant constituents on rumen bacterial populations using metagenomic procedures to identify shifts in bacterial, protozoal, archeal, and fungal populations. Rumen fermentation studies with chicory to evaluate the impact on dry matter digestion, volatile fatty acid patterns, and changes to secondary compounds have been initiated. In vitro parasite assays are being used to determine effects of chicory cultivars, chicory sesquiterpene lactones, orange oils, and extracts and constituents of Artemisia annua on H. contortus egg hatching and larval motility. A. annua plants that have high concentrations of artemisinic acid and dihydroartemisinic acid, are being selected. In collaboration with Virginia Tech parasitologists (SCA 58-1932-5-534), effects of A. annua extracts and components thereof, chicory sesquiterpene lactones, and orange oils on mature H. contortus have been evaluated using a gerbil model system. Sheep artificially infected with H. contortus have been treated with orange oils, and treatment effects on worm egg numbers in feces and worm burdens in sheep are being determined. Methods to quantify third- stage larvae of H. contortus on pastures are in the validation phase and studies on physical disruption of the life cycle of the parasite are being initiated. The potential use of orange oils as a pasture treatment for control of H. contortus is being studied in controlled environments. Herbage from chicory cultivars has been analyzed to determine whether differences in condensed tannin concentrations exist and how sesquiterpene lactone concentration and composition change during the growing season. Sesquiterpene lactone extracts have been prepared from the cultivars Puna and Forage Feast and used to demonstrate differential anthelmintic effects of individual constituents. The sesquiterpene lactone concentration in feces from goats and sheep grazing chicory are being determined. Procedures for extraction and quantification of cichoriin in chicory are being developed. This project will provide plant materials and associated management strategies to expand forage options and gastrointestinal parasite control strategies for small ruminants in humid, temperate climates.
1. Chicory sesquiterpene lactones differ in their ability to inhibit hatching of Haemonchus contortus eggs. Forage chicory is a valuable forage species because it is nutritious and it contains sesquiterpene lactones that can reduce gastrointestinal parasite burdens in sheep and goats. Our previous research showed that forage chicory contains three prevalent sesquiterpene lactones and that cultivars can be divided into two groups based on sesquiterpene lactone composition. We selected a cultivar with high sesquiterpene lactone concentration from each group and used extracts containing the same sesquiterpene lactone concentration to investigate the ability of each extract to inhibit hatching of H. contortus eggs. The extract from one cultivar was twice as effective as the other. Results indicated that the individual sesquiterpene lactones differ in anthelmintic activity and that cultivars in which 8-deoxylactucin is a high proportion of the total sesquiterpene lactones might be preferable for use in bioactive pastures for H. contortus control.
2. Chicory sesquiterpene lactone concentration, but not composition, varies over the growing season. Sesquiterpene lactones are bitter secondary metabolites that can impact palatability and contribute to anthelmintic effects of chicory herbage. Our research has previously shown that chicory cultivars differ in sesquiterpene lactone concentration and composition. Because growing conditions can influence secondary metabolism in plants, we analyzed sesquiterpene lactones in herbage from three chicory cultivars collected throughout two successive growing seasons in West Virginia and Pennsylvania. The total concentration of sesquiterpene lactones in all cultivars was highest in late spring and summer and lowest in the fall, but sesquiterpene lactone composition was constant for each cultivar. This information will help producers select the best cultivar(s) for their forage applications.
3. In vivo studies demonstrate anthelmintic effects of orange oils on Haemonchus contortus. Haemonchus contortus (barber pole worm) is a blood-sucking abomasal parasite responsible for major losses to small ruminant producers worldwide. Resistance of this nematode to commercial dewormers has produced a demand for alternative control methods. Collaborators at Virginia Tech (SCA 58-1932-4-0437) artificially infected gerbils and sheep with infective third-stage H. contortus larvae and then treated animals with emulsions containing orange terpene oil and orange Valencia oil to determine the deworming potential of the orange oils. Gerbils were sacrificed and the number of worms in the stomach was counted. Treated animals had significantly fewer worms than untreated control animals. In the sheep trial, the orange oil emulsion caused high fecal egg count reduction in treated animals compared to control sheep. Results show that orange oil emulsions have promise as an alternative to commercial dewormers for sheep and goats.
4. Prairie bromegrass provides high-quality fall pasture for lambs. Productivity of most pasture species used in Appalachia decreases in autumn at the time when nutrient needs of grazing lambs are greatest. Prairie bromegrass is a nutritious forage species that grows well during the cooler periods of the year. This characteristic makes it a good candidate for Appalachian pastures for finishing lambs in fall; however, it has not been evaluated for this application. We used multiple stocking rates on prairie bromegrass pastures to determine lamb performance and plant persistence under Appalachian conditions. Weight gains of fall-grazed lambs and gain per acre were excellent and yield of the pastures the following year was not adversely affected by the fall grazing. These results show that prairie bromegrass is an excellent alternative resource for forage-based lamb finishing systems in Appalachia.
5. Identified nutritional characteristics and antioxidant capacity of sweet wormwood. Artemisinin is prevalent in sweet wormwood (Artemisia annua L.). Although this compound is mostly known for its antimalarial effects, several publications have documented its effects against other parasites such as Babesia, Eimeria, Schistosoma, Neospora, Fasciola, Chlonorchis, Leishmania, and Trypanosoma, some of which affect small ruminants. We have previously shown that goats fed a diet containing 33% sweet wormwood for one week did not exhibit any anti-feeding or toxic response. Sweet wormwood sesquiterpenes also did not inhibit rumen microbes. Information on the nutritional and anti-nutritional characteristics of sweet wormwood and its potential value as an animal feed has been lacking. In an international, multidisciplinary effort, we have established that tissues of the plant are a rich source of antioxidants, crude protein, vitamins, calcium, and potassium while the amounts of anti-nutritional compounds (e.g., phytates, oxalic acid, and tannins) are negligible. Results suggest that sweet wormwood might be incorporated in diets of small ruminants to support nutritional and health needs of the animals.
5. Significant Activities that Support Special Target Populations
A research update was presented at the Appalachian Grazing Conference, March 6-7, 2009, in Morgantown, WV. A workshop and research update on improving small ruminant grazing practices for small farms in central Appalachia was conducted with the Mountain State University Medicinal Botanicals Program (SCA 58-1932-7-767) on July 11, 2009, in Beaver, WV.
Brisibe, E.A., Umoren, U.E., Brisibe, F., Magalhaes, P.M., Ferreira, J.F., Luthria, D.L., Wu, X., Prior, R. 2009. Nutritional characterization and antioxidant capacity of different tissues of Artemisia Annua L. Food Chemistry. 115:1240-1246.