Estimating passage kinetics using fibre-bound 15N as an internal marker

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Abstract

Acid detergent insoluble N (ADF-N) is resistant to microbial and mammalian enzymes and natural labeling of ADF-N with 15N could provide an internal marker for digesta passage kinetics studies. Two late-lactation ruminally and duodenally cannulated Holstein cows were used to evaluate fibre-bound 15N as passage kinetics markers. The cows were fed ad libitum on 70% forage:30% concentrate diets based either on lucerne hay (LH) or lucerne silage (LS). A pulse dose of lucerne intrinsically labeled with 15N, applied as (15NH4)2SO4 fertilizer, was given in addition to lucerne in the diet. Duodenal (n = 17) and faecal (n = 14) grab samples were collected for 72 h. The samples were analyzed for 15N-enrichment of neutral detergent fibre-bound N (NDF-15N) and acid detergent fibre-bound N (ADF-15N). Kinetic parameters were estimated using two-compartmental models comprised of either two age-independent compartments (G1 → G1) or one gamma age-dependent and one age-independent compartment (Gn → G1, n = 2-4). The models with an age-dependency in the first compartment improved curve-fitting and explained on average 0.99 of the variation in NDF-15N and ADF-15N-enrichment. Total mean residence time (TMRT) of NDF-15N was shorter (P < 0.05) than that of ADF-15N (40.2 versus 47.0 h). This suggests that part of the available fibre-bound N (NDF-15N minus ADF-15N) was digested and therefore NDF-15N does not satisfy the requirements of an ideal passage kinetics marker. Pre-duodenal sites accounted for 0.91 of compartmental mean residence time (CMRT) estimated from faecal sampling, suggesting that pre-duodenal compartments accounted for the majority of the ascending phase of marker excretion curve. The values of time delay, CMRT and TMRT for ADF-15N of 7.7, 39.3 and 47.0 h were within the range reported for external markers for cows fed at similar level of DM intake. The results from this study suggest that ADF-15N has significant potential as an internal passage kinetics marker. As compared to the commonly used external markers ADF-15N has the advantage that it does not modify the digestibility or flow characteristics of labeled particles.

Original languageEnglish (US)
Pages (from-to)29-41
Number of pages13
JournalAnimal Feed Science and Technology
Volume94
Issue number1-2
DOIs
StatePublished - Nov 27 2001

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dietary fiber
kinetics
cows
alfalfa
alfalfa silage
late lactation
alfalfa hay
digesta
acid detergent fiber
sampling
diet
detergents
neutral detergent fiber
Holstein
legumes
excretion
concentrates
digestibility
fertilizers
forage

All Science Journal Classification (ASJC) codes

  • Animal Science and Zoology

Cite this

@article{973fcf12e22c4b7fb2cbcb238aaa25c9,
title = "Estimating passage kinetics using fibre-bound 15N as an internal marker",
abstract = "Acid detergent insoluble N (ADF-N) is resistant to microbial and mammalian enzymes and natural labeling of ADF-N with 15N could provide an internal marker for digesta passage kinetics studies. Two late-lactation ruminally and duodenally cannulated Holstein cows were used to evaluate fibre-bound 15N as passage kinetics markers. The cows were fed ad libitum on 70{\%} forage:30{\%} concentrate diets based either on lucerne hay (LH) or lucerne silage (LS). A pulse dose of lucerne intrinsically labeled with 15N, applied as (15NH4)2SO4 fertilizer, was given in addition to lucerne in the diet. Duodenal (n = 17) and faecal (n = 14) grab samples were collected for 72 h. The samples were analyzed for 15N-enrichment of neutral detergent fibre-bound N (NDF-15N) and acid detergent fibre-bound N (ADF-15N). Kinetic parameters were estimated using two-compartmental models comprised of either two age-independent compartments (G1 → G1) or one gamma age-dependent and one age-independent compartment (Gn → G1, n = 2-4). The models with an age-dependency in the first compartment improved curve-fitting and explained on average 0.99 of the variation in NDF-15N and ADF-15N-enrichment. Total mean residence time (TMRT) of NDF-15N was shorter (P < 0.05) than that of ADF-15N (40.2 versus 47.0 h). This suggests that part of the available fibre-bound N (NDF-15N minus ADF-15N) was digested and therefore NDF-15N does not satisfy the requirements of an ideal passage kinetics marker. Pre-duodenal sites accounted for 0.91 of compartmental mean residence time (CMRT) estimated from faecal sampling, suggesting that pre-duodenal compartments accounted for the majority of the ascending phase of marker excretion curve. The values of time delay, CMRT and TMRT for ADF-15N of 7.7, 39.3 and 47.0 h were within the range reported for external markers for cows fed at similar level of DM intake. The results from this study suggest that ADF-15N has significant potential as an internal passage kinetics marker. As compared to the commonly used external markers ADF-15N has the advantage that it does not modify the digestibility or flow characteristics of labeled particles.",
author = "P. Huhtanen and Hristov, {Alexander Nikolov}",
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Estimating passage kinetics using fibre-bound 15N as an internal marker. / Huhtanen, P.; Hristov, Alexander Nikolov.

In: Animal Feed Science and Technology, Vol. 94, No. 1-2, 27.11.2001, p. 29-41.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Estimating passage kinetics using fibre-bound 15N as an internal marker

AU - Huhtanen, P.

AU - Hristov, Alexander Nikolov

PY - 2001/11/27

Y1 - 2001/11/27

N2 - Acid detergent insoluble N (ADF-N) is resistant to microbial and mammalian enzymes and natural labeling of ADF-N with 15N could provide an internal marker for digesta passage kinetics studies. Two late-lactation ruminally and duodenally cannulated Holstein cows were used to evaluate fibre-bound 15N as passage kinetics markers. The cows were fed ad libitum on 70% forage:30% concentrate diets based either on lucerne hay (LH) or lucerne silage (LS). A pulse dose of lucerne intrinsically labeled with 15N, applied as (15NH4)2SO4 fertilizer, was given in addition to lucerne in the diet. Duodenal (n = 17) and faecal (n = 14) grab samples were collected for 72 h. The samples were analyzed for 15N-enrichment of neutral detergent fibre-bound N (NDF-15N) and acid detergent fibre-bound N (ADF-15N). Kinetic parameters were estimated using two-compartmental models comprised of either two age-independent compartments (G1 → G1) or one gamma age-dependent and one age-independent compartment (Gn → G1, n = 2-4). The models with an age-dependency in the first compartment improved curve-fitting and explained on average 0.99 of the variation in NDF-15N and ADF-15N-enrichment. Total mean residence time (TMRT) of NDF-15N was shorter (P < 0.05) than that of ADF-15N (40.2 versus 47.0 h). This suggests that part of the available fibre-bound N (NDF-15N minus ADF-15N) was digested and therefore NDF-15N does not satisfy the requirements of an ideal passage kinetics marker. Pre-duodenal sites accounted for 0.91 of compartmental mean residence time (CMRT) estimated from faecal sampling, suggesting that pre-duodenal compartments accounted for the majority of the ascending phase of marker excretion curve. The values of time delay, CMRT and TMRT for ADF-15N of 7.7, 39.3 and 47.0 h were within the range reported for external markers for cows fed at similar level of DM intake. The results from this study suggest that ADF-15N has significant potential as an internal passage kinetics marker. As compared to the commonly used external markers ADF-15N has the advantage that it does not modify the digestibility or flow characteristics of labeled particles.

AB - Acid detergent insoluble N (ADF-N) is resistant to microbial and mammalian enzymes and natural labeling of ADF-N with 15N could provide an internal marker for digesta passage kinetics studies. Two late-lactation ruminally and duodenally cannulated Holstein cows were used to evaluate fibre-bound 15N as passage kinetics markers. The cows were fed ad libitum on 70% forage:30% concentrate diets based either on lucerne hay (LH) or lucerne silage (LS). A pulse dose of lucerne intrinsically labeled with 15N, applied as (15NH4)2SO4 fertilizer, was given in addition to lucerne in the diet. Duodenal (n = 17) and faecal (n = 14) grab samples were collected for 72 h. The samples were analyzed for 15N-enrichment of neutral detergent fibre-bound N (NDF-15N) and acid detergent fibre-bound N (ADF-15N). Kinetic parameters were estimated using two-compartmental models comprised of either two age-independent compartments (G1 → G1) or one gamma age-dependent and one age-independent compartment (Gn → G1, n = 2-4). The models with an age-dependency in the first compartment improved curve-fitting and explained on average 0.99 of the variation in NDF-15N and ADF-15N-enrichment. Total mean residence time (TMRT) of NDF-15N was shorter (P < 0.05) than that of ADF-15N (40.2 versus 47.0 h). This suggests that part of the available fibre-bound N (NDF-15N minus ADF-15N) was digested and therefore NDF-15N does not satisfy the requirements of an ideal passage kinetics marker. Pre-duodenal sites accounted for 0.91 of compartmental mean residence time (CMRT) estimated from faecal sampling, suggesting that pre-duodenal compartments accounted for the majority of the ascending phase of marker excretion curve. The values of time delay, CMRT and TMRT for ADF-15N of 7.7, 39.3 and 47.0 h were within the range reported for external markers for cows fed at similar level of DM intake. The results from this study suggest that ADF-15N has significant potential as an internal passage kinetics marker. As compared to the commonly used external markers ADF-15N has the advantage that it does not modify the digestibility or flow characteristics of labeled particles.

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