Effects of pure plant secondary metabolites on methane production,rumen fermentation and rumen bacteria populations in vitro |
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| Authors: | M Joch J Mrázek E Sk?ivanová L ?ermák M Marounek |
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| Affiliation: | 1. Nutrition and Feeding of Farm Animals, Institute of Animal Science, Prague, Czech Republic;2. Department of Microbiology, Nutrition and Dietetics, Czech University of Life Sciences, Prague, Czech Republic;3. Institute of Animal Physiology and Genetics, Czech Academy of Sciences, Prague, Czech Republic |
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| Abstract: | In this study, the effects of seven pure plant secondary metabolites (PSM s) on rumen fermentation, methane (CH4) production and rumen bacterial community composition were determined. Two in vitro trials were conducted. In trial 1, nine concentrations of 8‐hydroxyquinoline, α‐ terpineol, camphor, bornyl acetate, α‐ pinene, thymoquinone and thymol were incubated on separate days using in vitro 24‐hr batch incubations. All compounds tested demonstrated the ability to alter rumen fermentation parameters and decrease CH4 production. However, effective concentrations differed among individual PSM s. The lowest concentrations that reduced (p < .05) CH4 production were as follows: 8 mg/L of 8‐hydroxyquinoline, 120 mg/L of thymoquinone, 240 mg/L of thymol and 480 mg/L of α‐ terpineol, camphor, bornyl acetate and α‐ pinene. These concentrations were selected for use in trial 2. In trial 2, PSM s were incubated in one run. Methane was decreased (p < .05) by all PSM s at selected concentrations. However, only 8‐hydroxyquinoline, bornyl acetate and thymoquinone decreased (p < .05) CH4 relative to volatile fatty acids (VFA s). Based on denaturing gradient gel electrophoresis analysis, different PSM s changed the composition of bacterial communities to different extents. As revealed by Ion Torrent sequencing, the effects of PSM s on relative abundance were most pronounced in the predominant families, especially in Lachnospiraceae , Succinivibrionaceae , Prevotellaceae , unclassified Clostridiales and Ruminococcaceae . The CH 4 production was correlated negatively (?.72; p < .05) with relative abundance of Succinivibrionaceae and positively with relative abundance of Ruminococcaceae (.86; p < .05). In summary, this study identified three pure PSM s (8hydroxyquinoline, bornyl acetate and thymoquinone) with potentially promising effects on rumen CH4 production. The PSM s tested in this study demonstrated considerable impact on rumen bacterial communities even at the lowest concentrations that decreased CH4 production. The findings from this study may help to elucidate how PSM s affect rumen bacterial fermentation. |
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| Keywords: | alkaloid essential oil Ion Torrent methane rumen bacteria rumen fermentation |
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