U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 Northern Great Plains Research Laboratory: Mandan, ND
 close



    Research

                    Research Projects
                                    Publications
                                    Collaborations
                                    News
                                    Software
                People

                    Staff Listing
                                    Careers


        


                    Employment
                        Work With Us
                                    ARS Vacancies at USDAJOBS
                    Local News
                        INTEGRATOR
                                    Bottom Line Ag SummitSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Plains Area Mandan, North Dakota Northern Great Plains Research Laboratory Research Publications at this Location





- ARS National Programs
- Search for a scientific manuscript
- Search for a research project
- ARS Software
- Programs and Projects
- Collaborations
- Subjects of Investigation
- Publications
- IACUC Executive Minutes

Title:   Author  item
                                            Kronberg, Scottitem
                                            HALAWEISH, FATHI - SDSU, BROOKINGS, SDitem
                                            HUBERT, MINDY - BROOKINGS, SDitem
                                            Weimer, Paul
  Submitted to: Journal of Chemical Ecology
                                    Publication Type: Peer Reviewed Journal
                                    Publication Acceptance Date: 11/8/2005
                                    Publication  Date: 2/26/2006
                                    Citation: Kronberg, S.L., Halaweish, F.T., Hubert, M.B., Weimer, P.J. 2006. Interactions between euphorbia esula toxins and bovine ruminal microbes. Journal of Chemical Ecology. 32(1):15-28.Interpretive Summary: It is well known that cattle graze little if any of the noxious weed leafy spurge while sheep and goats will usually ingest considerable amounts of it once they adapt to consuming it.  Previous research has indicated that a critical difference between cattle and these small ruminants in respect to their avoidance or ingestion of leafy spurge may involve differences in how the microbes in their rumens interact with toxic compounds in the weed.   This study evaluated how the toxicity of leafy spurge changed over time when it was fermented with ruminal microbes from cattle and sheep.  It also evaluated how the toxicity of leafy spurge changed over time when it was fermented with ruminal microbes from cattle that were exposed to a gram-negative antibiotic, and how the growth of several species of ruminal bacteria responded to toxins from leafy spurge.  Lastly, the study determined the levels of a leafy spurge toxin (ingenol) in fermented and non-fermented mixtures of leafy spurge and cattle ruminal microbes.  In general, toxicity of leafy spurge that was fermented with cattle or goat ruminal microbes increased with some fermentation time and there were few differences in toxicity as a function of the source of ruminal microbes (cattle versus goats).  Leafy spurge toxins had little negative impact on growth of several species of ruminal bacteria.  Levels of the leafy spurge toxin ingenol appeared to decrease with fermentation even though the toxicity of the fermented mixtures tended to increase.  This indicated that ruminal microbes probably converted ingenol into one or more other toxic compounds.
                                Technical Abstract: Toxicity of leafy spurge (LS; Euphorbia esula L.) compounds to brine shrimp after in vitro fermentation with cattle versus goat rumen digesta or with normal versus modified cattle rumen digesta was evaluated at different lengths of fermentation.  Levels of the toxin ingenol were determined for fermented and non-fermented mixtures of LS and cattle rumen digesta, and the toxicity of an extract of LS to common rumen microbes was evaluated.  Length of fermentation of LS with cattle versus goat rumen digesta affected the toxicity of these mixtures to brine shrimp differently.   In general, toxicity of the mixtures of LS and either cattle or goat digesta was greater after some fermentation time compared to no fermentation.   The only combination that resulted in significant shrimp toxicity without fermentation was with the highest extract concentration of LS and cattle digesta.  This result offered a potential explanation for why cattle learn to avoid LS while goats learn to ingest it.  Fermentation of LS with cattle digesta in the second trial also increased the toxicity of extracted compounds to brine shrimp.  Introduction of an antibiotic that preferentially inhibits gram-negative bacteria into the LS and cattle rumen digesta mixtures did not appear to affect their toxicities regardless of fermentation length.  Levels of toxic ingenol were observed in LS and cattle digesta mixtures (both fermented and non-fermented) that were consistent with the levels of ingenols reported for LS.  Finally, a toxic extract of LS had little or no negative effect on the growth of several common species of rumen bacteria.  
Key Words'Euphorbia esula, leafy spurge, ingenol, ruminal microbes, fermentation, cattle, goats.


Return to top


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov