Related Experiment Videos
More monensin-sensitive, ammonia-producing bacteria from the rumen
1Department of Animal Science, Cornell University, Ithaca, New York 14853.
Applied and Environmental Microbiology
|May 1, 1989
Summary
Two novel bacteria isolated from the bovine rumen efficiently ferment amino acids, not carbohydrates. These monensin-sensitive bacteria play a significant role in ruminal amino acid fermentation and ammonia production.
Area of Science:
- Microbiology
- Rumen microbiology
- Bacterial fermentation
Background:
- The bovine rumen hosts a complex microbial ecosystem crucial for nutrient digestion.
- Understanding bacterial roles in amino acid fermentation is key to optimizing ruminant nutrition.
- Monensin, an ionophore antibiotic, alters rumen fermentation patterns.
Purpose of the Study:
- To isolate and characterize novel bacteria from the bovine rumen.
- To investigate their ability to utilize carbohydrates versus amino acids.
- To determine their role in ruminal amino acid fermentation and ammonia production.
Main Methods:
- Isolation of monensin-sensitive bacteria from bovine rumen.
- Growth studies on various carbohydrate and amino acid sources.
- Fermentation assays measuring amino acid utilization and ammonia production.
- Coculture experiments with peptidase-producing bacteria.
- Continuous culture experiments to assess growth at different pH levels.
Main Results:
- Two distinct bacterial strains (short rods - SR, irregularly shaped - F) were isolated, poorly utilizing carbohydrates but growing rapidly on amino acids.
- Strain SR fermented arginine, serine, lysine, glutamine, and threonine; Strain F deaminated glutamine, histidine, glutamate, and serine.
- Strain SR required peptidase-producing bacteria for growth on long peptides (gelatin hydrolysate).
- Strain F showed enhanced ammonia production when cocultured with peptidase-producing bacteria on casein or gelatin hydrolysate.
- Strain SR washed out at pH 5.9, while Strain F grew at pH 5.3.
- Both strains exhibited high specific ammonia production activities in vivo.
Conclusions:
- The isolated bacteria are specialized in amino acid fermentation rather than carbohydrate utilization.
- Their ability to ferment specific amino acids and produce ammonia is significant for rumen function.
- Strain SR relies on extracellular peptidases, while Strain F demonstrates broader amino acid deamination capabilities.
- These bacteria, despite low in vivo cell numbers, likely play a crucial role in ruminal amino acid metabolism.