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. 1992 Sep;58(9):2730–2736. doi: 10.1128/aem.58.9.2730-2736.1992

Metabolism of toxic pyrrolizidine alkaloids from tansy ragwort (Senecio jacobaea) in ovine ruminal fluid under anaerobic conditions.

A M Craig 1, C J Latham 1, L L Blythe 1, W B Schmotzer 1, O A O'Connor 1
PMCID: PMC183000  PMID: 1444382

Abstract

The ability of ovine ruminal fluid to metabolize pyrrolizidine alkaloid (PA) from Senecio jacobaea under anaerobic conditions was evaluated. Four fistulated sheep fed PA served as individual sources of ruminal fluid, which was incubated in a defined minimal salts medium under two different anaerobic conditions, denitrifying and methanogenic. Anaerobic cultures amended with ovine ruminal fluids (20%), PA (100 micrograms/ml), and a defined minimal salts medium were monitored for a period of several days. These cultures revealed that while PA was not depleted in sterile, autoclaved controls or under denitrifying conditions, it was metabolized during periods of active methanogenesis under methanogenic conditions. In addition, samples of ruminal fluid were separated by differential centrifugation under anaerobic conditions, and the resultant supernatants were tested for their ability to metabolize PA as compared with those of the respective uncentrifuged control fluids. Uncentrifuged controls exhibited a PA depletion rate of -4.04 +/- 0.17 micrograms of PA per ml per h. Supernatants 1 (centrifuged at 41 x g for 2 min), 2 (centrifuged at 166 x g for 5 min), and 3 (centrifuged at 1,500 x g for 10 min) exhibited significantly slower depletion rates, with slopes of data representing -1.64 +/- 0.16, -1.44 +/- 0.16, and -1.48 +/- 0.16 micrograms of PA metabolized per ml per h, respectively, demonstrating no statistically significant difference among the supernatant cultures. Microscopic evaluations revealed that protozoa were present in the control whole ruminal fluid and to a lesser extent in supernatant 1, while supernatants 2 and 3 contained only bacteria.(ABSTRACT TRUNCATED AT 250 WORDS)

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Selected References

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  1. BLACKBURN T. H., HOBSON P. N. Proteolysis in the sheep rumen by whole and fractionated rumen contents. J Gen Microbiol. 1960 Feb;22:272–281. doi: 10.1099/00221287-22-1-272. [DOI] [PubMed] [Google Scholar]
  2. Craig A. M., Sheggeby G., Wicks C. e. Large scale extraction of pyrrolizidine alkaloids from tansy ragwort (Senecio jacobaea). Vet Hum Toxicol. 1984 Apr;26(2):108–111. [PubMed] [Google Scholar]
  3. EADIE J. M., HOBSON P. N. Effect of the presence or absence of rumen ciliate protozoa on the total rumen bacterial count in lambs. Nature. 1962 Feb 3;193:503–505. doi: 10.1038/193503a0. [DOI] [PubMed] [Google Scholar]
  4. Healy J. B., Young L. Y. Anaerobic biodegradation of eleven aromatic compounds to methane. Appl Environ Microbiol. 1979 Jul;38(1):84–89. doi: 10.1128/aem.38.1.84-89.1979. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Jones R. J. Does ruminal metabolism of mimosine explain the absence of Leucaena toxicity in Hawaii? Aust Vet J. 1981 Jan;57(1):55–56. doi: 10.1111/j.1751-0813.1981.tb07097.x. [DOI] [PubMed] [Google Scholar]
  6. Kurihara Y., Eadie J. M., Hobson P. N., Mann S. O. Relationship between bacteria and ciliate protozoa in the sheep rumen. J Gen Microbiol. 1968 Apr;51(2):267–288. doi: 10.1099/00221287-51-2-267. [DOI] [PubMed] [Google Scholar]
  7. Lanigan G. W. Peptococcus heliotrinreducans, sp. nov., a cytochrome-producing anaerobe which metabolizes pyrrolizidine alkaloids. J Gen Microbiol. 1976 May;94(1):1–10. doi: 10.1099/00221287-94-1-1. [DOI] [PubMed] [Google Scholar]
  8. McDougall E. I. Studies on ruminant saliva. 1. The composition and output of sheep's saliva. Biochem J. 1948;43(1):99–109. [PMC free article] [PubMed] [Google Scholar]
  9. Russell G. R., Smith R. M. Reduction of heliotrine by a rumen microorganism. Aust J Biol Sci. 1968 Dec;21(6):1277–1290. doi: 10.1071/bi9681277. [DOI] [PubMed] [Google Scholar]
  10. Segall H. J., Wilson D. W., Dallas J. L., Haddon W. F. trans-4-Hydroxy-2-hexenal: a reactive metabolite from the macrocyclic pyrrolizidine alkaloid senecionine. Science. 1985 Aug 2;229(4712):472–475. doi: 10.1126/science.4012327. [DOI] [PubMed] [Google Scholar]
  11. Shelton D. R., Tiedje J. M. Isolation and partial characterization of bacteria in an anaerobic consortium that mineralizes 3-chlorobenzoic Acid. Appl Environ Microbiol. 1984 Oct;48(4):840–848. doi: 10.1128/aem.48.4.840-848.1984. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Veira D. M. The role of ciliate protozoa in nutrition of the ruminant. J Anim Sci. 1986 Nov;63(5):1547–1560. doi: 10.2527/jas1986.6351547x. [DOI] [PubMed] [Google Scholar]

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