Nitrogen metabolism by ruminal microorganisms: Current understanding and future perspectives

Morrison, M and Mackie, RI (1996) Nitrogen metabolism by ruminal microorganisms: Current understanding and future perspectives. Australian Journal of Agricultural Research, 47 2: 227-246. doi:10.1071/AR9960227

Author Morrison, M
Mackie, RI
Title Nitrogen metabolism by ruminal microorganisms: Current understanding and future perspectives
Journal name Australian Journal of Agricultural Research   Check publisher's open access policy
ISSN 0004-9409
Publication date 1996-01-01
Year available 1996
Sub-type Article (original research)
DOI 10.1071/AR9960227
Open Access Status Not yet assessed
Volume 47
Issue 2
Start page 227
End page 246
Total pages 20
Place of publication COLLINGWOOD
Language eng
Abstract This review presents an outline of our current understanding of ruminal nitrogen metabolism from three perspectives: proteolytic microorganisms and their enzymes, intraruminal recycling of microbial protein, and enzymes of ammonia assimilation. Some of the pending advances and future research opportunities in these areas are also discussed. The 'smugglin' concept appears to offer the potential to inhibit peptide-utilizing bacteria selectively in the rumen, as demonstrated by initial studies with Prevotella ruminicola. The relative contributions of protozoa-, bacteriophage-, and self-mediated lysis of bacteria to intraruminal recycling of microbial protein are not yet quantified, and further efforts to understand the biology and dynamics of ruminal bacteriophage and protozoa populations are warranted. In Ruminococcus flavefaciens and Prevotella ruminicola, glutamate dehydrogenase (GDH) appears to be the predominant route of ammonia assimilation irrespective of ammonia concentration, and peptides modulate GDH activity in P. ruminicola. The physiological basis behind the difference between optimal ammonia concentrations for ruminal fibre digestion and microbial protein synthesis remains unclear. Molecular biology techniques extend beyond their application in pursuit of the 'superbug' concept, by offering new and exciting opportunities to understand better microbial physiology, diversity, and ecology. Fundamental research in these areas must be continued if further advances in feed utilization and nutrient retention are to be realized.
Keyword Amino-Acids
Proteolytic Activity
Rumen Fluid
Ammonia Concentration
Peptide Metabolism
Bacterial Protein
Glucose Toxicity
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: ResearcherID Downloads - Archived
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