Evaluating old and novel proxies for in vitro digestion assays in wild ruminants

ABSTRACT In vitro digestion assays provide useful data for wild ruminant ecologists. It remains highly constraining, however, to conduct these assays in the field. We evaluated various proxies for in vitro digestion assays that use ruminal liquor from wild ruminants. The ruminal liquor of freshly ki...

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Main Authors: Pierre‐Olivier Jean, Robert L. Bradley, Robert Berthiaume, Jean‐Pierre Tremblay
Format: Article
Language:English
Published: Wiley 2016-06-01
Series:Wildlife Society Bulletin
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Online Access:https://doi.org/10.1002/wsb.663
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author Pierre‐Olivier Jean
Robert L. Bradley
Robert Berthiaume
Jean‐Pierre Tremblay
author_facet Pierre‐Olivier Jean
Robert L. Bradley
Robert Berthiaume
Jean‐Pierre Tremblay
author_sort Pierre‐Olivier Jean
collection DOAJ
description ABSTRACT In vitro digestion assays provide useful data for wild ruminant ecologists. It remains highly constraining, however, to conduct these assays in the field. We evaluated various proxies for in vitro digestion assays that use ruminal liquor from wild ruminants. The ruminal liquor of freshly killed white‐tailed deer (Odocoileus virginianus) was used to measure in vitro true digestibility (IVTD), total gas, and volatile fatty acids (VFA) production of dominant summer and winter forage. We evaluated the ability of 4 proxies to predict these digestibility variables: 1) IVTD, total gas, and VFA produced with cow ruminal liquor; 2) acid detergent fiber (ADF) concentration; 3) CO2 production from soil–forage mixtures; and 4) predictive models based on near infrared spectra (NIRS) of forages. Predictions using NIRS were best correlated with all deer digestibility variables (each r2 > 0.93) with limited bias across forage species. Forage ADF and CO2 production from soil–forage mixtures were related with all digestibility variables (r2 = 0.62–0.95). Digestion assays using cow ruminal liquor was relatively good for predicting IVTD (r2 = 0.94) from deer ruminal liquor, but the weakest for predicting total gas (r2 = 0.63) and VFA production (r2 = 0.44). Calibrated NIRS models could substantially improve the prediction of in vitro digestibility variables. If access to NIRS technology or the ability to collect reference data with deer inocula for NIRS calibrations is impractical, forage ADF or CO2 production from soil–forage mixtures remain acceptable alternatives. Comparing the digestion kinetics and VFA production of wild and domestic ruminants is an innovative avenue for better understanding the adaptive ecophysiology of digestion by different herbivores. © 2016 The Wildlife Society.
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spelling doaj-art-979bf120b8ec43538143b9f78b062a152024-12-16T12:40:53ZengWileyWildlife Society Bulletin2328-55402016-06-0140235936710.1002/wsb.663Evaluating old and novel proxies for in vitro digestion assays in wild ruminantsPierre‐Olivier Jean0Robert L. Bradley1Robert Berthiaume2Jean‐Pierre Tremblay3Département de biologieUniversité de SherbrookeSherbrookeQCJ1K 2R1CanadaDépartement de biologieUniversité de SherbrookeSherbrookeQCJ1K 2R1CanadaDairy and Swine Research and Development CentreAgriculture and Agri‐Food CanadaLennoxvilleQCJ1M 1Z3CanadaDépartement de biologieCentre d'études nordiques and Natural Sciences and Engineering Research Council of Canada Industrial Research Chair in Integrated Management of Resources of Anticosti IslandUniversité LavalQuébecQCG1V 0A6CanadaABSTRACT In vitro digestion assays provide useful data for wild ruminant ecologists. It remains highly constraining, however, to conduct these assays in the field. We evaluated various proxies for in vitro digestion assays that use ruminal liquor from wild ruminants. The ruminal liquor of freshly killed white‐tailed deer (Odocoileus virginianus) was used to measure in vitro true digestibility (IVTD), total gas, and volatile fatty acids (VFA) production of dominant summer and winter forage. We evaluated the ability of 4 proxies to predict these digestibility variables: 1) IVTD, total gas, and VFA produced with cow ruminal liquor; 2) acid detergent fiber (ADF) concentration; 3) CO2 production from soil–forage mixtures; and 4) predictive models based on near infrared spectra (NIRS) of forages. Predictions using NIRS were best correlated with all deer digestibility variables (each r2 > 0.93) with limited bias across forage species. Forage ADF and CO2 production from soil–forage mixtures were related with all digestibility variables (r2 = 0.62–0.95). Digestion assays using cow ruminal liquor was relatively good for predicting IVTD (r2 = 0.94) from deer ruminal liquor, but the weakest for predicting total gas (r2 = 0.63) and VFA production (r2 = 0.44). Calibrated NIRS models could substantially improve the prediction of in vitro digestibility variables. If access to NIRS technology or the ability to collect reference data with deer inocula for NIRS calibrations is impractical, forage ADF or CO2 production from soil–forage mixtures remain acceptable alternatives. Comparing the digestion kinetics and VFA production of wild and domestic ruminants is an innovative avenue for better understanding the adaptive ecophysiology of digestion by different herbivores. © 2016 The Wildlife Society.https://doi.org/10.1002/wsb.663dairy cowforage qualityin vitro digestibilitymonitoring toolnear infrared spectroscopyrumen gas production
spellingShingle Pierre‐Olivier Jean
Robert L. Bradley
Robert Berthiaume
Jean‐Pierre Tremblay
Evaluating old and novel proxies for in vitro digestion assays in wild ruminants
Wildlife Society Bulletin
dairy cow
forage quality
in vitro digestibility
monitoring tool
near infrared spectroscopy
rumen gas production
title Evaluating old and novel proxies for in vitro digestion assays in wild ruminants
title_full Evaluating old and novel proxies for in vitro digestion assays in wild ruminants
title_fullStr Evaluating old and novel proxies for in vitro digestion assays in wild ruminants
title_full_unstemmed Evaluating old and novel proxies for in vitro digestion assays in wild ruminants
title_short Evaluating old and novel proxies for in vitro digestion assays in wild ruminants
title_sort evaluating old and novel proxies for in vitro digestion assays in wild ruminants
topic dairy cow
forage quality
in vitro digestibility
monitoring tool
near infrared spectroscopy
rumen gas production
url https://doi.org/10.1002/wsb.663
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AT robertlbradley evaluatingoldandnovelproxiesforinvitrodigestionassaysinwildruminants
AT robertberthiaume evaluatingoldandnovelproxiesforinvitrodigestionassaysinwildruminants
AT jeanpierretremblay evaluatingoldandnovelproxiesforinvitrodigestionassaysinwildruminants