This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Forsberg, C. W. Articles by Lam, K. Search for Related Content PubMed PubMed Citation Articles by Forsberg, C. W. Articles by Lam, K. Agricola Articles by Forsberg, C. W. Articles by Lam, K.

 Previous Article  |  Next Article 

Appl Environ Microbiol. 1977 March; 33(3): 528-537
Copyright © 1977 American Society for Microbiology. All Rights Reserved.

Use of Adenosine 5'-Triphosphate as an Indicator of the Microbiota Biomass in Rumen Contents

¹ Department of Microbiology, College of Biological Science, University of Guelph, Guelph, Ontario, N1G 2W1, Canada

ABSTRACT

A number of techniques were tested for their efficiency in extracting adenosine 5'-triphosphate (ATP) from strained rumen fluid (SRF). Extraction with 0.6 N H₂SO₄, using a modification of the procedure described by Lee et al. (1971), was the most efficient and was better suited for extracting particulate samples. Neutralized extracts could not be stored frozen before assaying for ATP because large losses were incurred. The inclusion of internal standards was necessary to correct for incomplete recovery of ATP. The ATP concentration in rumen contents from a cow receiving a ration of dried roughage (mainly alfalfa hay) ranged from 31 to 56 µg of ATP per g of contents. Approximately 75% of the ATP was associated with the particulate material. The ATP was primarily of microbial origin, since only traces of ATP were present in the feed and none was found in "cell-free" rumen fluid. Fractionation of the bacterial and protozoal populations in SRF resulted in the isolation of an enriched protozoal fraction with a 10-fold higher ATP concentration than that of the separated rumen bacteria. The ATP pool sizes of nine functionally important rumen bacteria during the exponential phase of growth ranged from 1.1 to 17.6 µg of ATP per mg of dry weight. This information indicates that using ATP as a measure of microbial biomass in rumen contents must be done with caution because of possible variations in the efficiency of extraction of ATP from rumen contents and differences in the concentration of ATP in rumen microbes.