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אסיף מאגר המחקר החקלאי
פותח על ידי קלירמאש פתרונות בע"מ -
A new approach to the quantitative estimation of nitrogen metabolic pathways in the rumen
Year:
1991
Source of publication :
British Journal of Nutrition
Authors :
אהרוני, יואב
;
.
Volume :
66
Co-Authors:
Aharoni, Y., Department of Animal Science, Faculty of Agriculture, Rehovot 76-100, Israel
Tagari, H., Department of Animal Science, Faculty of Agriculture, Rehovot 76-100, Israel
Boston, R.C., School of Mathematics and Physical Sciences, Murdoch University, Murdoch, WA6150, Australia
Facilitators :
From page:
407
To page:
422
(
Total pages:
16
)
Abstract:
Rumen nitrogen metabolism values were estimated by the use of a single injection of 15(NH4)2S04 into the rumen of sheep and consecutive l5N enrichment measurements in the rumen ammonia pool, rumen non-NH3-N (NAN) pool, rumen purine pool and blood urea-N (BUN) pool for a period of 24 h. Synthesis and degradation of N compounds in the rumen and passage of N to and from the rumen were evaluated on a chemical rather than a microbial basis; microbial fractions were not separated. This model was examined in two experiments. In Expt 1 a ram (55 kg) was given a semi-synthetic diet (1067 g dry matter (DM), 22–8 g N) in which soya-bean meal provided over 90% of the N. In Expt 2, two rams (45 kg) were given in three consecutive periods a semi-synthetic basal diet containing: (1) roasted soya-bean meal (SBM, 725 g DM, 14–8 g N/d); or (2) fishmeal (FM, 728 g DM, 15–5 g N/d); or (3) raw soya-bean meal (RSBM, 724 g DM, 13–8 g N/d). In all these rations, the main protein source provided over 90% of the N. In Expt 1, 68–3% of N intake was degraded directly to NH3 in the rumen, 21–2% escaped rumen degradation and 10–5% was incorporated into stable N compounds in the rumen. Net NH3 transfer to the blood was 30–4%, NH3flow from the rumen was 66% and rumen NAN output was63% of N intake. In Expt 2, rumen NAN output was larger (7 67, 14 36 and 8 89 g N/d for diets containing SBM, FM and RSBM respectively; P < 0 05) and net NH3 loss to the blood was smaller (61, 0 39 and 417 g N/d for diets SBM, FM and RSBM respectively; P < 0 05) for diet FM as compared with the soya-bean diets. The percentage of rumen NAN that was synthesized from NH3 was larger for diet RSBM (36–4, 40 3 and 49 1 for diets SBM, FM and RSBM respectively; P < 0 05) than for the other two rations. NH3 pool sizes (g N) were 0 463, 0 385 and 0 301 for diets SBM, FM and RSBM respectively (P < 0.05), while their hourly turnover rates were 15–8, 26–1 and 512 for diets SBM, FM and RSBM respectively (P < 001), indicating no correlation between pool size and its turnover rate. The existence of a small and rapidly turning over NAN pool to which NH3 is first bound (SNAN1) was indicated by the difference in the shape of the NAN and purines l5N-enrichment curves in the first 3 h after label injection. The fact that the rate of NH3 initial binding to SNAN1 pool was related neither to ammonia pool size nor to SNAN1 pool size suggests the existence of an unknown control mechanism at this site. © 1991, The Nutrition Society. All rights reserved.
Note:
Related Files :
Animal
animal experiment
Blood
Duodenum
Male
metabolism
Models, Biological
Rumen
sheep
עוד תגיות
תוכן קשור
More details
DOI :
10.1079/BJN19910044
Article number:
Affiliations:
Database:
סקופוס
Publication Type:
מאמר
;
.
Language:
אנגלית
Editors' remarks:
ID:
32585
Last updated date:
02/03/2022 17:27
Creation date:
17/04/2018 01:11
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Scientific Publication
A new approach to the quantitative estimation of nitrogen metabolic pathways in the rumen
66
Aharoni, Y., Department of Animal Science, Faculty of Agriculture, Rehovot 76-100, Israel
Tagari, H., Department of Animal Science, Faculty of Agriculture, Rehovot 76-100, Israel
Boston, R.C., School of Mathematics and Physical Sciences, Murdoch University, Murdoch, WA6150, Australia
A new approach to the quantitative estimation of nitrogen metabolic pathways in the rumen
Rumen nitrogen metabolism values were estimated by the use of a single injection of 15(NH4)2S04 into the rumen of sheep and consecutive l5N enrichment measurements in the rumen ammonia pool, rumen non-NH3-N (NAN) pool, rumen purine pool and blood urea-N (BUN) pool for a period of 24 h. Synthesis and degradation of N compounds in the rumen and passage of N to and from the rumen were evaluated on a chemical rather than a microbial basis; microbial fractions were not separated. This model was examined in two experiments. In Expt 1 a ram (55 kg) was given a semi-synthetic diet (1067 g dry matter (DM), 22–8 g N) in which soya-bean meal provided over 90% of the N. In Expt 2, two rams (45 kg) were given in three consecutive periods a semi-synthetic basal diet containing: (1) roasted soya-bean meal (SBM, 725 g DM, 14–8 g N/d); or (2) fishmeal (FM, 728 g DM, 15–5 g N/d); or (3) raw soya-bean meal (RSBM, 724 g DM, 13–8 g N/d). In all these rations, the main protein source provided over 90% of the N. In Expt 1, 68–3% of N intake was degraded directly to NH3 in the rumen, 21–2% escaped rumen degradation and 10–5% was incorporated into stable N compounds in the rumen. Net NH3 transfer to the blood was 30–4%, NH3flow from the rumen was 66% and rumen NAN output was63% of N intake. In Expt 2, rumen NAN output was larger (7 67, 14 36 and 8 89 g N/d for diets containing SBM, FM and RSBM respectively; P < 0 05) and net NH3 loss to the blood was smaller (61, 0 39 and 417 g N/d for diets SBM, FM and RSBM respectively; P < 0 05) for diet FM as compared with the soya-bean diets. The percentage of rumen NAN that was synthesized from NH3 was larger for diet RSBM (36–4, 40 3 and 49 1 for diets SBM, FM and RSBM respectively; P < 0 05) than for the other two rations. NH3 pool sizes (g N) were 0 463, 0 385 and 0 301 for diets SBM, FM and RSBM respectively (P < 0.05), while their hourly turnover rates were 15–8, 26–1 and 512 for diets SBM, FM and RSBM respectively (P < 001), indicating no correlation between pool size and its turnover rate. The existence of a small and rapidly turning over NAN pool to which NH3 is first bound (SNAN1) was indicated by the difference in the shape of the NAN and purines l5N-enrichment curves in the first 3 h after label injection. The fact that the rate of NH3 initial binding to SNAN1 pool was related neither to ammonia pool size nor to SNAN1 pool size suggests the existence of an unknown control mechanism at this site. © 1991, The Nutrition Society. All rights reserved.
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