ORIGINAL PAPER
Effect of variation in the proportion of solid- and liquid-associated rumen bacteria in duodenal contents on the estimation of duodenal bacterial nitrogen flow
B. Vlaeminck 1,   V. Fievez 1  
,   D. Demeyer 1,   R. J. Dewhurst 2, 3
 
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1
Laboratory for Animal Nutrition and Animal Product Quality, Ghent University, Proefhoevestraat 10, 9090 Melle, Belgium
2
Institute of Grassland and Environmental Research, Plas Gogerddan, Aberystwyth, Ceredigion SY23 3EB, UK
3
Current address: Agriculture and Life Sciences Division, Lincoln University, Canterbury, New Zealand
CORRESPONDING AUTHOR
V. Fievez   

Laboratory for Animal Nutrition and Animal Product Quality, Ghent University, Proefhoevestraat 10, 9090 Melle, Belgium
Publication date: 2007-02-02
 
J. Anim. Feed Sci. 2007;16(1):37–42
 
KEYWORDS
ABSTRACT
The aim of this research was to examine to what extent variation in the relative proportions of solid- (SAB) and liquid-associated rumen bacteria (LAB) in duodenal bacteria have an impact on the estimation of duodenal flow of bacterial N. For this, four dairy cows were fed diets varying in forage: concentrate ratio (80:20, 65:35, 50:50 and 35:65). SAB and LAB were separated from rumen contents four h after the morning feeding. Adenine, cytosine and odd and branched-chain fatty acids were determined both in SAB and LAB and used to estimate bacterial N flow. Bacterial N flows were also calculated using a SAB:LAB ratio in duodenal bacteria, as estimated from the odd and branched-chain fatty acid pattern. Compared with calculations based on the estimated SAB:LAB ratio, estimations based on SAB or LAB only as a bacterial reference on average over- and underestimated bacterial N flow by 37 and 55 g N/d, respectively (P<0.05) when cytosine or adenine were used as bacterial marker. In contrast, due to the small differences in the OBCFA:N ratio between SAB and LAB, these differences were less than 15 g/d when OBCFA were used as bacterial marker. The results suggest that, depending on the marker used, changes in the proportions of SAB and LAB can have a substantial impact on estimated duodenal flow of bacterial N.
 
CITATIONS (4):
1.
Relationship between milk odd and branched-chain fatty acids and urinary purine derivatives in dairy cows supplemented with quebracho tannins—A study to test milk fatty acids as predictors of rumen microbial protein synthesis
J. Castro-Montoya, A. Henke, J. Molkentin, K. Knappstein, A. Susenbeth, U. Dickhoefer
Animal Feed Science and Technology
 
2.
Milk odd- and branched-chain fatty acids as biomarkers of rumen function—An update
V. Fievez, E. Colman, J.M. Castro-Montoya, I. Stefanov, B. Vlaeminck
Animal Feed Science and Technology
 
3.
The relationship between odd- and branched-chain fatty acids and microbial nucleic acid bases in rumen
Keyuan Liu, Xiaoyan Hao, Yang Li, Guobin Luo, Yonggen Zhang, Hangshu Xin
Asian-Australasian Journal of Animal Sciences
 
4.
The relationships of dairy ruminal odd- and branched- chain fatty acids to the duodenal bacterial nitrogen flow and volatile fatty acids
Keyuan Liu, Yang Li, Guobin Luo, Hangshu Xin, Yonggen Zhang, Guangyu Li
Livestock Science
 
ISSN:1230-1388