Comparison of the toxic effects of two duncecap larkspur (Delphinium occidentale) chemotypes in mice and cattle.
ABSTRACT To compare the toxic effects of a Delphinium occidentale chemotype containing N-(methylsuccinimido) anthranoyllycoctonine (MSAL)-type alkaloids and a D occidentale chemotype lacking MSAL-type alkaloids in mice and cattle.
225 male Swiss Webster mice and 11 Black Angus steers.
4 collections of larkspur containing MSAL-type alkaloids and 4 collections of larkspur lacking MSAL-type alkaloids were used. From each collection, total alkaloid extracts (0.05 to 0.20 mL) were administered via tail-vein injection in 27 to 29 mice. Dried, finely ground plant material from 1 collection with and 1 collection without MSAL-type alkaloids (doses equivalent to 37.6 mg of total alkaloids/kg) were each administered to 8 cattle via oral gavage in a crossover experiment; 3 cattle received a single dose equivalent to 150.4 mg of total alkaloids/kg (no MSAL-type alkaloids). In mice, clinical effects were monitored; in cattle, heart rate was monitored before (baseline) and 24 hours after treatment. At the 24-hour time point, cattle were exercised as a measure of muscle weakness.
In mice, mean LD(50) associated with alkaloid extracts prepared from plants that did or did not contain MSAL-type alkaloids was 2.3 and 54.2 mg/kg, respectively. In cattle at 24 hours after treatment, plant material containing MSAL-type alkaloids significantly increased heart rate from baseline and was associated with exercise-induced collapse; plant material lacking MSAL-type alkaloids had no similar effects.
Taxonomic classification of D occidentale alone was not a good indicator of the toxic risk to grazing cattle.
SourceAvailable from: M. Catherine Duryea[Show abstract] [Hide abstract]
ABSTRACT: Microorganisms frequently colonize the nectar of angiosperm species. Though capable of altering a suite of traits important for pollinator attraction, few studies exist that test the degree to which they mediate pollinator foraging behavior. The objective of our study was to fill this gap by assessing the abundance and diversity of yeasts associated with the perennial larkspur Delphinium barbeyi (Ranunculaceae) and testing whether their presence affected components of pollinator foraging behavior. Yeasts frequently colonized D. barbeyi nectar, populating 54-77% of flowers examined depending on site. Though common, the yeast community was species-poor, represented by a single species, Metschnikowia reukaufii. Female-phase flowers of D. barbeyi were more likely to have higher densities of yeasts in comparison to male-phase flowers. Pollinators were likely vectors of yeasts, as virgin (unvisited) flowers rarely contained yeasts compared to flowers open to pollinator visitation, which were frequently colonized. Finally, pollinators responded positively to the presence of yeasts. Bombus foragers both visited and probed more flowers inoculated with yeasts in comparison to uninoculated controls. Taken together, our results suggest that variation in the occurrence and density of nectar-inhabiting yeasts have the potential to alter components of pollinator foraging behavior linked to pollen transfer and plant fitness.PLoS ONE 10/2014; 9(10):e108214. DOI:10.1371/journal.pone.0108214 · 3.53 Impact Factor
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ABSTRACT: Toxic larkspur (Delphinium species) cause large economic losses from cattle deaths, increased management costs, and reduced utilization of pastures and rangelands. • We recommend that you obtain a risk assessment for larkspur on your range before turning out the cattle. Submit samples to USDA–ARS Poisonous Plant Research Laboratory for chemical evaluation at no charge. Information is available at: http://www.ars.usda.gov/main/site_main. htm?modecode=54-28-20-00. • Selection of cattle resistant to larkspur poisoning could reduce cattle losses and improve rangeland utilization. • The use of genetic-based herd management decisions can provide a tool for livestock producers to improve their profit margin and enhance the economic sustainability of rural American communities.Rangelands 02/2014; 36(1):10-15. DOI:10.2111/RANGELANDS-D-13-00031.1
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ABSTRACT: When livestock are poisoned by plants in a range setting, there is normally more than one poisonous plant in that area. Additionally, many plants contain more than one compound that is toxic to livestock. Frequently, much is known regarding the toxicity of the individual plants and their individual toxins; however, little is known regarding the effect of co-exposure to multiple toxic plants or even the effect of multiple toxins from an individual plant. In this review, we discuss some basic principles of mixture toxicology with a focus on our recent research wherein we examined the effect of co-administering multiple plant toxins from the same plant and the effect of co-administration of two different poisonous plants, each with different types of toxins. As combined intoxications are likely common, this information will be useful in further developing management recommendations for ranchers, and in designing additional experiments to study the toxicity of multiple poisonous plants to livestock.Journal of Agricultural and Food Chemistry 03/2014; 62(30). DOI:10.1021/jf500086u · 3.11 Impact Factor