ABSTRACT
Larkspurs (Delphinium spp.) are poisonous plants on rangelands throughout the Western United States and Canada. Larkspur-induced poisoning in cattle is due to norditerpene alkaloids that are represented by two main structural groups of norditerpene alkaloids, the N-(methylsuccinimido) anthranoyllycoctonine type (MSAL-type) and the non-MSAL type. Information on the alkaloid composition and resulting toxicity in mice and cattle is lacking for a number of Delphinium species, including Delphinium stachydeum. The objective of this study was to determine the alkaloid composition of D. stachydeum and to characterize its relative toxicity in mice and cattle compared to two reference species Delphinium barbeyi and Delphinium occidentale. D. stachydeum contains the non-MSAL-type alkaloids but not the MSAL-type alkaloids. D. stachydeum was less toxic than D. barbeyi and D. occidentale in the mouse model. D. stachydeum was less toxic than the MSAL-containing D. barbeyi but much more toxic than the non-MSAL-containing D. occidentale in cattle as measured by heart rate and time of exercise. These results indicate that predictions of Delphinium toxicity can't be accurately made based solely on results from the mouse model or the absence of the MSAL-type alkaloids in the plant.
Subject(s)
Alkaloids/toxicity , Cattle Diseases/physiopathology , Delphinium/toxicity , Plant Components, Aerial/toxicity , Plant Extracts/toxicity , Plant Poisoning/veterinary , Toxins, Biological/toxicity , Alkaloids/analysis , Alkaloids/chemistry , Alkaloids/isolation & purification , Animals , Cattle , Cattle Diseases/etiology , Delphinium/chemistry , Delphinium/growth & development , Diterpenes/analysis , Diterpenes/chemistry , Diterpenes/isolation & purification , Diterpenes/toxicity , Humans , Lameness, Animal/etiology , Lethal Dose 50 , Male , Mice , Muscle Weakness/etiology , Nevada , Oregon , Plant Components, Aerial/chemistry , Plant Components, Aerial/growth & development , Plant Extracts/chemistry , Plant Extracts/isolation & purification , Plant Poisoning/etiology , Plant Poisoning/physiopathology , Species Specificity , Tachycardia/etiology , Toxins, Biological/analysis , Toxins, Biological/chemistry , Toxins, Biological/isolation & purification , Tremor/etiology , UtahABSTRACT
Toxic plants such as Delphinium spp. (i.e., larkspur) are a significant cause of livestock losses worldwide. Correctly determining the causative agent responsible for the death of an animal, whether by disease, poisonous plant, or other means, is critical in developing strategies to prevent future losses. The objective of this study was to develop an alternative diagnostic tool to microscopy and analytical chemistry to determine whether a particular poisonous plant was ingested. Polymerase chain reaction (PCR) is a tool that may allow detection of the genetic material from a specific plant within a complex matrix such as rumen contents. A pair of oligonucleotide primers specific to Delphinium spp. (i.e., larkspur) was developed; using these primers, a PCR product was detected in samples from an in vivo, in vitro, and in vivo/in vitro coupled digestion of Delphinium occidentale. Lastly, larkspur was detected in a matrix of ruminal material where the amount of larkspur was far less than what one would expect to find in the rumen contents of a poisoned animal. The PCR-based technique holds promise to diagnose larkspur and perhaps other toxic plant caused losses.
