Research Project: Understanding and Mitigating the Adverse Effects of Poisonous Plants on Livestock Production Systems

Location: Poisonous Plant Research

2023 Annual Report

Objectives
Objective 1: Develop science-based guidelines for grazing livestock on rangelands infested with toxic plants and evaluate the potential for establishing improved forage species on infested sites to improve livestock productivity, reduce the risk of livestock loss, and improve other rangeland ecosystem services. See project plan for Sub-Objectives 1.1, 1.2, 1.3, 1.4. Objective 2: Evaluate the risks of livestock losses due to variations in quantitative and qualitative differences in toxin accumulation in various plant species. See project plan for Sub-Objectives 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7. Objective 3: Enhance feed and food safety by improving risk assessment and diagnosis of plant-induced poisoning to livestock by improving analytical methods for analyzing plant and animal tissues for toxins; measuring toxicokinetics, assessing carcinogenic and genotoxic potential, and identifying toxin metabolites and biomarkers of toxicoses. See project plan for Sub-Objectives 3.1, 3.2, 3.3, 3.4. Objective 4: Develop improved procedures with guidelines for diagnostic and prognostic evaluation to reduce negative impacts of poisonous plants on livestock reproduction and embryo/fetal growth by improving early identification of poisoned animals, predicting poisoning outcomes, and management and treatment options through improved understanding of clinical, morphological and molecular alterations of plant-induced toxicoses. See project plan for Sub-Objectives 4.1, 4.2, 4.3. Objective 5: Develop guidelines to aid producers and land managers in making genetic-based herd management decisions to improve livestock performance on rangelands infested with poisonous plants through the use of animal genetics, physiological pathways, and molecular mechanisms of action that underlie the effects of toxic plants. See project plan for Sub-Objectives 5.1, 5.2.

Approach
The livestock industry in the western United States loses over $500,000,000 annually from death losses and abortions due to poisonous plants (Holechek, 2002). Actual losses due to poisonous plants are much greater due to wasted forage and increased management costs. Plant poisonings occur worldwide and include 333 million poisonous plant-infested hectares in China (Xing et al. 2001; Lu et al. 2012) and 60 million hectares in Brazil (Low, 2015). There are hundreds of genera of toxic plants representing thousands of species. The Poisonous Plant Research Laboratory (PPRL) provides numerous solutions to toxic plant problems using an integrated, interdisciplinary approach representing several scientific disciplines and continues to provide worldwide leadership in poisonous plant research to the livestock industry and consumers. The PPRL research team investigates plant poisonings in a systematic manner by identifying the plant, determining the toxin(s), evaluating the mechanisms of action, and describing the effects in animals. The ultimate goal is to develop research-based solutions to reduce livestock losses from toxic plants. There are five coordinated objectives in this project plan providing guidelines for potential scientific-based management. The project focuses on several toxic plants including larkspur, locoweed, lupine, and dehydro-pyrrolizidine alkaloid (DHPA)-containing plants utilizing the research disciplines at the PPRL. This research will reduce livestock losses from plants and enhance the economic well-being of rural communities, improve rangeland health by combating invasive plant species, and help to provide safe animal products free from potential plant toxins for consumers.

Progress Report
This report documents progress for project 2080-3263-014-000D, titled, “Protection of Food and Water Supplies from Pathogens and Human Induced Chemicals of Emerging Concern”. In support of Objective 1, ARS researchers at Logan, Utah, evaluated the ability of various herbicides to control larkspur (Delphinium species) at two different locations. Plots were established and sprayed with herbicides at one location during the summer of 2021. Those plots were evaluated for control, 1 year after treatment, during the summer of 2022 and 2 years after treatment the summer of 2023. Plots were established and sprayed with herbicides at a second location during the summer of 2022. Plots were evaluated for control, 1 year after treatment, during the summer of 2023. The herbicides were applied at two different times of plant growth. First application was during the early vegetative growth stage and the second application was when plants were in the flowering stage. In support of Objective 2, ARS researchers at Logan, Utah, collected two Delphinium species over the growing season to determine how alkaloid concentrations change over the growing season and between years and how they might vary at different locations. Samples have been analyzed for alkaloid concentration and data presented at the 76th Annual Society of Range Management meeting in Boise, Idaho. A manuscript detailing this work is being prepared for submission to a peer reviewed journal. ARS scientists at Logan, Utah, also continue research to characterize the alkaloid profiles from several Delphinium species that had not been investigated previously. Methyllycaconitine, the larkspur toxin most commonly associated with poisoning of cattle was detected in most species. A manuscript detailing this work is being prepared for submission to a peer reviewed journal. Under Sub-objective 2.2, ARS scientists at Logan, Utah, surveyed several Astragalus species for swainsonine and selenium and are preparing a publication. Under Sub-objective 2.4, ARS scientists at Logan, Utah, have completed the macro and micro-nutrient analyses of the plants and are preparing a publication. Under Sub-objective 2.7, ARS scientists at Logan, Utah, have collected specimens from various herbarium collections representing several taxa of interest. Chemical analysis has been completed for most of the samples. A manuscript detailing this work is being prepared for submission to a peer reviewed journal. In support of Objective 3, ARS researchers at Logan, Utah, have completed animal work studying six pyrrolizidine alkaloids in a P53 knockout mouse model. Additional groups will be completed this summer. The microscopic studies and statistical analyses are mostly completed. This work has already resulted in several peer-reviewed publications and presentations. A recent presentation entitled “Comparison of Acute Dehydropyrrolizidine Alkaloid Toxicosis in C57BL6/J Mice Gavaged with Riddelliine, Riddelliine N-oxide, Senecionine, Senecionine N-oxide, Seneciphylline, Lasiocarpine and Heliotrine” was awarded best graduate student present at the 2022 ACVP meeting. Two more manuscripts describing this work have been submitted for publication. In support of Objective 4, ARS researchers at Logan, Utah, are actively evaluating various drugs as potential therapeutic treatments for animals poisoned by several plants. Some recent work has shown that a drug which is already on the market can be used as a drug treatment for the hemlock toxin coniine in a mouse model. Additional studies will be performed in a goat model this summer. Additionally, ARS researchers at Logan, Utah, studied the effect of cattle intoxication from larkspur (Delphinium spp.) on their consumption of a basal diet and subsequent weight gain. A manuscript describing these results has been submitted for publication in a peer-reviewed journal. Under Sub-objective 4.2, ARS researchers at Logan, Utah, identified four toxic diterpenoid hepatotoxins in the plant Salvia reflexa. The toxicities of these compounds were confirmed in goats, mice, and cattle. This research has been detailed in four book chapters and two peer-reviewed publications. Additionally, two large poisoning incidents of more than 300 animals were recently identified and determined to be caused by Salvia reflexa. A publication detailing the findings in those cases, in addition to another describing the comparative pathology of S. reflexa in mice, goats and cattle have been prepared, and are currently under review. In support of objective 5, ARS researchers at Logan, Utah, compared pen raised sheep versus sheep that were raised on death camas (Zigadenus paniculatus) infested rangelands to determine if there is a difference in how much death camas they will eat and if there is a difference in their susceptibility to the adverse effects of death camas. Sheep were grazed when the plant was in the early vegetative stage of plant growth and again when the plant was in the flower stage to determine if animals had a difference in preference depending upon the phenological growth stage. Samples are currently being processed and analyzed for nutrition content and data is being prepared for statistical analysis.

Accomplishments
1. Endophyte produced bioactive secondary metabolites in Ipomoea species. Understanding host symbiont relationships and the bioactive metabolites produced is critical to our basic understanding of these relationships and required to better predict risk and make recommendations to reduce livestock losses. ARS researchers in Logan, Utah, in collaboration with other researchers surveyed several Ipomoea taxa for endophyte produced bioactive metabolites in Ipomoea species that are responsible for various poisonings of animals. The research has impact as it provides basic information but also provides information to extension agents and range scientists at the various government agencies, as well as livestock producers, and other investigators studying toxic plants and natural products.

2. Slaframine and swainsonine transport and biosynthesis in Slafractonia legumnicola. Slaframine and swainsonine are two mycotoxins produced by the pathogen Slafractonia leguminicola. ARS Researchers in Logan, Utah, in collaboration with scientists at New Mexico State University, investigated the role of a transmembrane reporter in the transport of two mycotoxins, swainsonine and slaframine. The research has impact as it provides basic information to other scientific researchers about the transport of swainsonine and slaframine and the role of this transporter in pathogenesis. Understanding these mechanisms may provide information to disrupt the pathogen and subsequent poisoning of livestock.

3. Selenium application methodologies and rates determined for forages. Application of selenate to forages is effective at increasing forage selenium concentrations and thus alleviating selenium deficiencies in livestock. Little is known of methods and high application rates of selenium that can be applied to forages to obtain desired and safely elevated selenium concentrations for grazing livestock. ARS researchers at Logan, Utah, and scientists at Oregon State University have determined effective ways to apply selenate amendments to produce safe selenium-biofortified forages that producers can use with targeted grazing strategies to produce healthier livestock in selenium deficient areas.

Review Publications
Stegelmeier, B.L., Davis, Z.T. 2023. Poisonous plants. In: Haschek-Hock, W.M., Rousseaux, C.G., Wallig, M.A., Bolon, B., editors. Haschek and Rousseaux's Handbook of Toxicologic Pathology: Environmental toxicologic pathology and selected toxicant classes. 4th Edition, Volume 3. San Diego, CA: Academic Press. p. 489-546.
Green, B.T., Welch, K.D., Lee, S.T., Stonecipher, C.A., Gardner, D.R., Stegelmeier, B.L., Davis, T.Z., Cook, D. 2023. Biomarkers and their potential for detecting livestock plant poisonings in western North America. Frontiers in Veterinary Science. 10. Article 1104702. https://doi.org/10.3389/fvets.2023.1104702.
Ubiali, D.G., Lee, S.T., Gardner, D.R., Cook, D., Pereira, G.O., Riet-Correa, F. 2022. Cestrum axillare (Solanaceae) poisoning in ruminants. Toxicon. 218:76-82. https://doi.org/10.1016/j.toxicon.2022.09.005.
Hueza, I.M., Dipe, V.V., Gotardo, A.T., Gardner, D.R., Almeida, E., Gorniak, S.L. 2023. Potential immunomodulatory response associated with L-mimosine in male Wistar rats. Toxicon. 226. Article 107084. https://doi.org/10.1016/j.toxicon.2023.107084.
Das, S., Gardner, D.R., Neyaz, M., Charleston III, A.B., Cook, D., Creamer, R. 2023. Silencing of the transmembrane transporter (swnT) gene of the fungus Slafractonia leguminicola results in a reduction of mycotoxin transport. Fungi. 9(3). Article 370. https://doi.org/10.3390/jof9030370.
Hall, J.A., Bobe, G., Filley, S.J., Bohle, M.G., Pirelli, G., Wang, G., Davis, T.Z., Banuelos, G.S. 2023. Impact of selenium biofortification on production characteristics of forages grown following standard management practices in Oregon. Frontiers in Plant Science. 14. Article 1121605. https://doi.org/10.3389/fpls.2023.1121605.
Hall, J.A., Bobe, G., Filley, S.J., Pirelli, G.J., Bohle, M.G., Wang, G., Davis, T.Z., Banuelos, G.S. 2023. Effects of amount and chemical form of selenium amendments on forage selenium concentrations and species profiles. Biological Trace Element Research. 201:4951-4960. https://doi.org/10.1007/s12011-022-03541-8.
Zabaleta, G., Lee, S.T., Cook, D., Aguilar, M., Iannone, L.J., Robles, C., Martinez, A. 2022. Indole-diterpenes alkaloid profiles of native grasses involved in tremorgenic syndromes in the Argentine Patagonia. Toxicon. 217:107-111. https://doi.org/10.1016/j.toxicon.2022.08.001.
Paim, R.C., de Paula, L., Soares, D.S., Rocha, T.G., Ribeiro, A.L., Barros, N., dos Santos, F.C., Ferreira, H.D., Gomes-Klein, V.L., Soto-Blanco, B., de Oliveira-Filho, J.P., da Cunha, P., Riet-Correa, F., Pfister, J., Cook, D., Fioravanti, M., Botelho, A. 2023. Toxic plants from the perspective of a "Quilombola" community in the Cerrado region of Brazil. Toxicon. 224. Article 107028. https://doi.org/10.1016/j.toxicon.2023.107028.
Quach, Q.N., Clay, K., Lee, S.T., Gardner, D.R., Cook, D. 2023. Phylogenetic patterns of bioactive secondary metabolites produced by fungal endosymbionts in morning glories (Ipomoeaee, Convolvulaceae). New Phytologist. 238(4):1351-1361. https://doi.org/10.1111/nph.18785.
Pistan, M.E., Gutierrez, S.A., Schnittger, L., Gardner, D.R., Cholich, L.A., Gonzalez, A.M. 2022. Localization of the fungal symbiont (Chaetothyriales) in Ipomoea carnea. Botany. 100(9):729-736. https://doi.org/10.1139/cjb-2022-0033.
Kono, I.S., Faccin, T.C., de Lemos, G.A., Di Santis, G.W., Bacha, F.B., Guerreiro, Y.A., de Oliveira Gaspar, A., Lee, S.T., de Castro Guizelini, C., Leal, C.B., de Lemos, R.A.A. 2022. Outbreaks of Brachiaria ruziziensis and Brachiaria brizantha intoxications in Brazilian experienced cattle. Toxicon. 219. Article 106931. https://doi.org/10.1016/j.toxicon.2022.106931.
Schardl, C.L., Afkhami, M.E., Gundel, P.E., Iannone, L.J., Young, C.A., Creamer, R., Cook, D., Berry, D. 2022. Diversity of seed endophytes: Causes and implications. In: Scott, B., Mesarich, C., editors. The Mycota: Plant relationships. 3rd Edition, Volume 5. Cham, CH: Springer Cham. p. 83-132. https://doi.org/10.1007/978-3-031-16503-0_5.