0.857
IF5
0.900
IF
Q3
JCR
0.92
CiteScore
0.405
SJR
Q2
SJR
20
MNiSW
165.24
ICV
ORIGINAL PAPER
 
CC-BY 4.0
 
 

Studies on N-metabolism in different gastrointestinal sections of sheep using the digesta exchange technique. 2. Passage of endogenous nitrogen

A. Sandek 1,  
J. Kowalczyk 3,  
M. Gabel 1,  
T. Żebrowska 3,  
 
1
Institute for Ecological-Compatible Animal Husbandry, University of Rostock, Justus-von-Liebig-Weg 8, 18059 Rostock, Germany
2
Institute for Applied Agroecology, Justus-von-Liebig-Weg 8, 18059 Rostock, Germany
3
The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, 05-110 Jabłonna, Poland
4
Research Institute for the Biology of Farm Animals, Research Unit Nutritional Physiology "Oskar Kellner", Wilhelm-Stahl-Allee 2,18196 Dummerstorf, Germany
J. Anim. Feed Sci. 2001;10(4):605–618
Publish date: 2001-11-06
KEYWORDS
ABSTRACT
Using a combination of fistulation and the 15N isotope technique, the flow rates of endogenous N secreted postruminal into different sections of the digestive tract were estimated in growing sheep by digesta exchange between 15N-labelled and unlabelled animals. To investigate the influence of fibre (CF) on these flow rates the estimations were made on two groups that received approximately isonitrogenous diets (16% CP in DM) differing in crude fibre content (Group 1: 14.7%, Group 2: 24.9% CF in DM). The passage rates of total N and 15N at the duodenum and ileum and the excretion in faeces were measured directly. These data were used to calculate the passage of postruminal N secreted in the different intestinal sections. The microbial N passage at the proximal duodenum and distal ileum was calculated as the product of RNA passage at the duodenum and ileum, and the N:RNA ratio of bacteria isolated from rumen fluid. The flow rates of endogenous N into the duodenum and through the ileum and the excretion rate in faeces were estimated by measuring the appearance and disappearance rates of 15N in appropriate intestinal sections of the unlabelled animals receiving 15N-labelled digesta or in the labelled animals getting unlabelled digesta by digesta exchange. The microbial flow rate through the duodenum was in average 5.8 g N/d in Group 1 and 5.1 g N/d in Group 2 (50 and 46% of NAN flux), and 0.9 g N/d (Group 1) to 1.3 g N/d (Group 2) through the ileum (19 and 22 % of NAN flux). The portion of rumen undegraded protein-N of NAN flow was in Group 1 47% both in the duodenum and in the ileum. In Group 2 it was 42% . The endogenous NAN entering the duodenum was low for Group 1 (0.40 g N/d = 3.4% of NAN) and approximately three-fold higher for Group 2 (1.3 g N/d = 12% of NAN). The corresponding values for endogenous N at the ileum were 1.6 g/d (34% of NAN) and 2.2 g/d (36% of NAN) , indicating that in relative terms, endogenous N secretion in this section of the digestive tract was independent of the feeding regime. The excretion rate of endogenous N in faeces varied between the individual experiments (1.84 to 2.39 g N/d for Group 1; 1.54 to 2.00 g N/d for Group 2). In relation to total faecal N excretion the endogenous fraction was higher for Group 1 (56%) than for Group 2 (40%). During all of the experiments, endogenous N as a proportion of total N increased from the duodenum to the rectum. Despite some reservations about the 15N dilution method, its use together with the technique of digesta exchange between labelled and unlabelled animals is a potentially useful way to quantify the passage of postruminal secreted N in dependence of nutritional factors. Further studies are needed to refine the methodology.
CORRESPONDING AUTHOR
J. Voigt
Research Institute for the Biology of Farm Animals, Research Unit Nutritional Physiology "Oskar Kellner", Wilhelm-Stahl-Allee 2,18196 Dummerstorf, Germany
 
CITATIONS (5):
1. Dietary starch source influences in growing goats: the intestinal losses of endogenous nitrogen and amino acids
Chuanshe Zhou, Zhiliang Tan, Yafei Pan, Shimin Liu, Shaoxun Tang, Zhihong Sun, Xuefeng Han, Min Wang
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2. A Model of Net Amino Acid Absorption and Utilization by the Portal-Drained Viscera of the Lactating Dairy Cow
M.D. Hanigan, C.K. Reynolds, D.J. Humphries, B. Lupoli, J.D. Sutton
Journal of Dairy Science
3. Effect of method of conservation of timothy on endogenous nitrogen flows in lactating dairy cows
D.R. Ouellet, R. Berthiaume, G. Holtrop, G.E. Lobley, R. Martineau, H. Lapierre
Journal of Dairy Science
4. Nitrogen transactions along the gastrointestinal tract of cattle: A meta-analytical approach1,2
J. C. Marini, D. G. Fox, M. R. Murphy
Journal of Animal Science
5. Distribution of 15N in Amino Acids During 15N-Leucine Infusion: Impact on the Estimation of Endogenous Flows in Dairy Cows
H. Lapierre, D.R. Ouellet, R. Berthiaume, R. Martineau, G. Holtrop, G.E. Lobley
Journal of Dairy Science
ISSN:1230-1388