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Competition between reductive acetogenesis and methanogenesis in the pig large-intestinal flora
K G De Graeve1, J P Grivet, M Durand
1Laboratoire de Nutrition et Sécurité Alimentaire, Institut National de la Recherche Agronomique, Jouy-en-Josas, France.
The Journal of Applied Bacteriology
|January 1, 1994
Summary
In pig hindgut bacteria, inhibiting methane production with BES significantly boosted acetate formation, especially under high H2 levels. This suggests reductive acetogenesis is a key pathway when methanogenesis is suppressed.
Area of Science:
- Microbiology
- Biochemistry
- Animal Science
Background:
- Acetogenesis and methanogenesis are key microbial processes in the pig hindgut.
- Understanding the interplay between these pathways is crucial for gut health and nutrient cycling.
Purpose of the Study:
- To investigate the impact of hydrogen (H2) levels and methanogenesis inhibition on reductive acetogenesis in pig hindgut bacteria.
- To determine the role of methanogenesis in regulating acetate production pathways.
Main Methods:
- Incubation of pig hindgut bacterial suspensions with 13CO2 and NaH13CO3.
- Assay of 13C incorporation into short-chain fatty acids using quantitative nuclear magnetic resonance.
- Application of varying H2 concentrations and the methanogenesis inhibitor 2-bromoethane-sulphonic acid (BES).
Main Results:
- Increasing H2 levels enhanced methane production and 13CO2 incorporation into butyrate and acetate.
- BES effectively inhibited methanogenesis, significantly increasing mono- and double-labelled acetate formation, particularly at high H2.
- A significant interaction between BES and H2 showed BES increasing labelled acetate proportion from 17.1% to 50.9% at high H2.
Conclusions:
- Methanogenesis can inhibit both homoacetate fermentation and H2/CO2-dependent acetate synthesis in the pig hindgut.
- Reductive acetogenesis becomes a more significant acetate formation pathway when methanogenesis is inhibited.
- Acetogenesis and methanogenesis coexist, but controlling methanogenesis can shift the balance towards acetate production.