Document Detail


Effects of amino acids and peptides on rumen microbial growth yields.
MedLine Citation:
PMID:  2477424     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Experiments were conducted using mixed rumen bacterial cultures to determine which amino acids limited growth. Complete amino acid mixtures stimulated microbial growth alone and when added to casein. Amino acid subgroups did not stimulate growth alone or when added to casein or casein hydrolysates. Results were similar whether growth was limited by periodic addition of low amounts of carbohydrate or when higher amounts were added to batch cultures. Little growth occurred with ammonia as sole N source. Addition of 100 mg/L of amino acids and peptides quadrupled growth, peptides at 10 mg/L resulted in higher growth than the corresponding amount of free amino acids. Apparent saturation of growth occurred when 10 mg/L of a complete amino acid mixture or trypticase was added to cultures. The Michaelis constant values for amino acids and trypticase were determined to be .5 and 1.0 mg/L, respectively. Growth was a linear function of amount of carbohydrate fermented with the coefficient of slope increasing with increasing amino acid concentrations. These experiments demonstrate that growth stimulation from amino acids and proteins is due to the number of amino acids provided in a given mixture rather than specific growth limiting amino acids. Rumen bacterial growth is greatly stimulated by amino acids and peptides, with low affinity constant values, allowing good growth in the concentrations of amino acids and peptides found in vivo
Authors:
J L Argyle; R L Baldwin
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Journal of dairy science     Volume:  72     ISSN:  0022-0302     ISO Abbreviation:  J. Dairy Sci.     Publication Date:  1989 Aug 
Date Detail:
Created Date:  1989-11-16     Completed Date:  1989-11-16     Revised Date:  2003-11-14    
Medline Journal Info:
Nlm Unique ID:  2985126R     Medline TA:  J Dairy Sci     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  2017-27     Citation Subset:  IM    
Affiliation:
Department of Animal Science, University of California, Davis 95616.
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MeSH Terms
Descriptor/Qualifier:
Amino Acids / physiology*
Animals
Bacteria / growth & development*
Carbohydrates / physiology
Cattle / microbiology*
Culture Media
Female
Fermentation
Peptides / physiology*
RNA, Bacterial / analysis
Rumen / microbiology*
Chemical
Reg. No./Substance:
0/Amino Acids; 0/Carbohydrates; 0/Culture Media; 0/Peptides; 0/RNA, Bacterial

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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