AEM
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Mackie, R. I.
Right arrow Articles by Gilchrist, F. M. C.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Mackie, R. I.
Right arrow Articles by Gilchrist, F. M. C.
Agricola
Right arrow Articles by Mackie, R. I.
Right arrow Articles by Gilchrist, F. M. C.

 Previous Article  |  Next Article 

Appl Environ Microbiol. 1979 September; 38(3): 422-430

Changes in Lactate-Producing and Lactate-Utilizing Bacteria in Relation to pH in the Rumen of Sheep During Stepwise Adaptation to a High-Concentrate Diet

R. I. Mackie{dagger} and Frances M. C. Gilchrist

1 Rumen Biochemistry Section, Veterinary Research Institute, Onderstepoort, 0110, Republic of South Africa

ABSTRACT

Changes in the numbers and types of lactate-producing and lactate-utilizing bacteria in the rumen of sheep were followed during stepwise adaptation from a low- to a high-concentrate diet. The mean numbers of bacteria increased after each change in diet when increasing amounts of maize grain were substituted for maize stover. A surge in number of amylolytic bacteria always preceded an increase in lactate-utilizing bacteria, and with the final diet containing 71% grain and molasses the two groups tended to balance each other, which resulted in low lactic acid accumulation. The lactate utilizers thus played a key role in controlling the fermentation. Orderly shifts occurred among the predominating amylolytic and lactate-utilizing bacteria in response to the gradual decrease in ruminal pH as the amount of maize meal in the diet increased. Among the lactate utilizers, the succession began with acid-sensitive Veillonella and Selenomonas, which were superseded by more acid-tolerant Anaerovibrio and Propionibacterium. Among the amylolytic bacteria, Bacteroides was superseded by more acid-tolerant Lactobacillus and Eubacterium. The ecological succession of predominating genera was shown to be correlated significantly with ruminal pH and, more specifically, with the length of time as well as the extent to which the pH remained below a certain critical undefined value in the rumen, arbitrarily set at pH 6.00.


FOOTNOTES

{dagger} Present address: Department of Dairy Science, University of Illinois, Urbana, IL 61801.


Appl Environ Microbiol. 1979 September; 38(3): 422-430




This article has been cited by other articles:




Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
J. Bacteriol. Microbiol. Mol. Biol. Rev. Eukaryot. Cell All ASM Journals

Copyright © 1979 by the American Society for Microbiology. All rights reserved.