| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
West Virginia University,4, Morgantown 26506
Abstract
The purpose of this study was to examine the effects of various liquid dilution (D) rates and pH levels, at a constant solids retention time, on metabolism and fermentation patterns of rumen microbes in continuous culture. The D rates were 4, 8, 12 and 16%/h. At each D rate, fermentations were conducted at pH 4.5, 5.5, 6.5 and 7.5. Under these conditions, pH 6.5 was found to be optimum for fiber and organic matter digestion, with only small D effects. Total nonstructural carbohydrate digestion was high (89 to 95%) at all pH and D rate combinations. As pH increased from 5.5 to 7.5, the molar percentage of acetic acid increased while that of propionate and butyrate decreased. These ratio changes were due to a large increase in acetate production (mol/24 h) accompanied by a small increase in propionate and a decrease in butyrate production. The D rate increases caused propionate molar percentage and production rate to increase, but had little effect on butyrate and acetate. Protein digestion and microbial growth and efficiency were affected by specific sets of pH and D conditions. At pH 4.5 and 7.5, at the 4%/h D rate, values for these characteristics were high, but were decreased by increases in D. The data also suggest that energetic uncoupling resulted from high D rates at these pH levels. At pH 6.5 protein digestion, microbial growth and efficiency were high at all D rates, with increases as D rate increased. Ar pH 5.5, protein digestion and microbial growth were low at all D rates. Osmotic pressure changes were found to have little effect on fermentation or metabolism.
1 Published with the approval of the Director of the West Virginia Agr. and Forestry Exp. Sta. as Scientific Article No. 1808. This research was supported with funds provided by the Hatch Act and by Agway, Inc., Syracuse, NY.
2 Associate Statistician, West Virginia Agr. and Forestry Exp. Sta.
3 Present address: H. K. Webster Co., Lawrence. MA.
4 Division of Anim. and Vet. Sci.
This article has been cited by other articles:
|
|
 |
|
  S. Calsamiglia, P. W. Cardozo, A. Ferret, and A. Bach Changes in rumen microbial fermentation are due to a combined effect of type of diet and pH J Anim Sci, March 1, 2008; 86(3): 702 - 711. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Cerrato-Sanchez, S. Calsamiglia, and A. Ferret Effect of the magnitude of the decrease of rumen pH on rumen fermentation in a dual-flow continuous culture system J Anim Sci, February 1, 2008; 86(2): 378 - 383. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Cerrato-Sanchez, S. Calsamiglia, and A. Ferret Effects of Patterns of Suboptimal pH on Rumen Fermentation in a Dual-Flow Continuous Culture System J Dairy Sci, September 1, 2007; 90(9): 4368 - 4377. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Cerrato-Sanchez, S. Calsamiglia, and A. Ferret Effects of Time at Suboptimal pH on Rumen Fermentation in a Dual-Flow Continuous Culture System J Dairy Sci, March 1, 2007; 90(3): 1486 - 1492. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. A. AbuGhazaleh and W. R. Buckles The Effect of Solids Dilution Rate and Oil Source on Trans C18:1 and Conjugated Linoleic Acid Production by Ruminal Microbes in Continuous Culture J Dairy Sci, February 1, 2007; 90(2): 963 - 969. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. A. AbuGhazaleh, M. B. Riley, E. E. Thies, and T. C. Jenkins Dilution Rate and pH Effects on the Conversion of Oleic Acid to Trans C18:1 Positional Isomers in Continuous Culture J Dairy Sci, December 1, 2005; 88(12): 4334 - 4341. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
W. J. Wales, E. S. Kolver, P. L. Thorne, and A. R. Egan Diurnal Variation in Ruminal pH on the Digestibility of Highly Digestible Perennial Ryegrass During Continuous Culture Fermentation J Dairy Sci, June 1, 2004; 87(6): 1864 - 1871. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J-S. Eun, V. Fellner, and M. L. Gumpertz Methane Production by Mixed Ruminal Cultures Incubated in Dual-Flow Fermentors J Dairy Sci, January 1, 2004; 87(1): 112 - 121. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. M. Krause, D. K. Combs, and K. A. Beauchemin Effects of Forage Particle Size and Grain Fermentability in Midlactation Cows. I. Milk Production and Diet Digestibility J Dairy Sci, August 1, 2002; 85(8): 1936 - 1946. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
