Quantitative evaluation of ruminal nutrient degradation using in situ and in vitro methods
Quantitative evaluation of ruminal nutrient degradation using in situ and in vitro methods
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DissertationPrüfungsdatum
06.08.2024Datum der Veröffentlichung
06.09.2024Erstgutachter
Südekum, Karl-HeinzZweitgutachter
Hummel, JürgenMetadaten
Zur Langanzeige
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Inhalt
Quantitative evaluation of ruminal nutrient degradation using in situ and in vitro methods Studies on ruminally cannulated animals are expensive and time consuming. Furthermore they are limited to a few facilities and animal welfare issues make reduced numbers of animal experiments desirable. One alternative is to simulate rumen fermentation using long-term continuous systems, allowing investigation of a large number of treatments in a relatively short period of time. Lack of standardisation of continuous culture systems impairs the comparison of research data. Therefore, the focus of a comprehensive review as one major part of the thesis was to compile and compare technical and other methodical aspects of the semi-continuous culture system ‘rumen simulation technique’ (RUSITEC). Crucial or non-standardised characteristics were highlighted, standardisation of procedures was suggested and limits of standardisation were considered. Procedural steps which were evaluated encompassed choice and feeding of donor animals, type of feeds or rations, sampling time of inoculum and, further, the technical structure and procedure of the RUSITEC systems with a motor, pump, vessels and buffer solution. Moreover, the choice of incubation bags with regard to pore size and material, the incubation time, the experimental run period and the selection of experimental feed have an impact on the results. To improve the comparability of studies, specified technical standards will reduce the variability within and between different models of the RUSITEC system. Finally, standardisations were proposed to reduce variability in the design of simulation systems, variability in the rumen inoculum and to improve the comparability of RUSITEC research data.
Another major objective of the thesis was to directly compare the ruminal fermentation characteristics and degradability of two common forages, i.e., grass silage (GS) and maize silage (MS), by parallel application of a coupled in vivo-in situ approach in rumen-cannulated sheep as well as the in vitro RUSITEC system. Both forages were incubated in the RUSITEC system as well as fed to rumen-cannulated sheep in six independent runs of 20 days in total with 14 days of adaptation and 6 days of sampling. The degradability coefficients of dry matter, organic matter and acid detergent fibre were affected by the method (each P < 0.05), while neutral detergent fibre (aNDFom) degradability was not different between RUSITEC and in situ measurements (P = 0.10). Likewise, Pearson correlation coefficients confirmed the comparability of in vitro and in situ values for aNDFom degradability, being 0.54 (P = 0.04) and 0.78 (P = 0.02) for GS and MS, respectively. Regarding the fermentation profile, total volatile fatty acid (VFA) concentrations were much higher in vitro than in vivo (P < 0.01), likely due to the missing absorptive capacity of the RUSITEC system.
A comparison of absolute fermentation values between methods appears not feasible. However, the order of individual VFA proportions was similar between in vivo and in vitro and the correlations for both total and individual VFA further supported this congruency, especially for MS. The in vitro data appeared well comparable to the data from the coupled in vivo-in situ approach, especially for MS, with a high reproducibility in both methods.
Therefore, the RUSITEC system may represent a sufficient replacement for laborious in vivo and in situ measurements when assessing nutrient degradability and general fermentation characteristics of feedstuffs. Adjustments in in situ incubation times as well as the standardisation of the operation of the RUSITEC system may further increase the significance of this in vitro method in the future. Likewise, further research on diurnal fermentation patterns is encouraged to substantiate the present findings. Quantitative Bewertung des Nährstoffabbaus im Pansen mittels in situ- und in vitro-Methoden
Studien an pansenfistulierten Tieren sind mit einem hohen Kosten- und Zeitaufwand verbunden. Darüber hinaus sind sie nur an wenigen Versuchseinrichtungen möglich und aus Tierschutzgründen ist eine Reduzierung der Anzahl an Tierversuchen grundsätzlich anzustreben. Eine Alternative besteht darin, die Pansenfermentation mithilfe künstlicher Systeme zu simulieren, was u. a. die Untersuchung einer großen Anzahl von Behandlungen in relativ kurzer Zeit ermöglicht. Die mangelnde Standardisierung kontinuierlicher Kultursysteme beeinträchtigt bisher den Vergleich von Forschungsdaten. Daher lag ein Schwerpunkte dieser Arbeit darin, eine umfassende Übersicht zu technischen und methodischen Aspekten des semikontinuierlichen Kultursystems „Pansensimulationstechnik“ (RUSITEC) zu erstellen. Möglichkeiten und Grenzen der technischen und methodischen Vorgehensweise wurden validiert und Vorschläge zu einer Standardisierung erarbeitet. Verfahrensschritte wie die Auswahl und Fütterung der Spendertiere, die Art der Futtermittel bzw. Rationen, der Probenahmezeitpunkt des Inokulums sowie der technische Aufbau und das Handling der RUSITEC-Systeme mit Motor, Pumpe, Gefäßen und Pufferlösung wurden behandelt. Weiterhin hatten die Auswahl der Inkubationsbeutel hinsichtlich Porengröße und -material, die Inkubationszeit, die Versuchslaufzeit und die Auswahl des Versuchsfutters Einfluss auf die Versuchsergebnisse. Um die Vergleichbarkeit von Studien zu verbessern, ermöglichen festgelegte technische Standards, die Variabilität innerhalb und zwischen verschiedenen RUSITEC-Systemen zu reduzieren. Abschließend wurde eine Standardisierung vorgeschlagen, um die Variabilität des RUSITEC-Systems zu vermindern und damit die Vergleichbarkeit der RUSITEC-Daten zu verbessern. Einen weiteren Schwerpunkt bildete der direkte Vergleich der Pansenfermentationseigenschaften und des Nährstoffabbaus durch parallele Anwendung eines gekoppelten in-vivo-in-situ-Ansatzes im Pansen fistulierter Schafe sowie des in-vitro-RUSITEC-Systems. Eingesetzt wurden zwei typische Grobfutter; Grassilage (GS) und Maissilage (MS). Beide Futtermittel wurden in sechs unabhängigen Läufen mit insgesamt 20 Tagen, davon 14 Tage Anpassung und 6 Tagen Probenahme untersucht. Die ruminale Abbaubarkeit der Trockenmasse, der organischen Masse und der Säure-Detergenzien-Faser (ADF) wurden durch die Methode beeinflusst (P < 0,05), während sich die Abbaubarkeit der Neutral-Detergenzien-Faser (aNDFom) zwischen RUSITEC- und in-situ-Messungen nicht unterschied (P = 0,10). Ebenso bestätigten die Pearson-Korrelationskoeffizienten die Vergleichbarkeit der in-vitro- und in-situ-Werte für die aNDFom-Abbaubarkeit; sie betrugen bei GS 0,54 (P = 0,04) und bei MS 0,78 (P = 0,02). Wahrscheinlich aufgrund der fehlenden Absorption im RUSITEC-System waren dia Gesamtkonzentrationen flüchtiger Fettsäuren (VFA) in vitro viel höher als in vivo (P < 0,01). Ein Vergleich absoluter Werte für VFA zwischen den Methoden scheint nicht möglich. Allerdings waren die VFA-Profile in vivo und in vitro ähnlich, und die Korrelationen sowohl für die Summe der VFA als auch für die einzelnen VFA untermauerten diese Kongruenz weiter, insbesondere bei MS. Die in-vitro-Daten waren insgesamt gut mit den Daten des gekoppelten in-vivo-in-situ-Ansatzes vergleichbar, insbesondere für die MS. Das RUSITEC-System kann als ein ausreichender Ersatz für aufwändige in-vivo- und in-situ-Messungen bei der Ermittlung des Nährstoffabbaus und genereller Fermentationseigenschaften von Futtermitteln angesehen werden. Anpassungen der in-situ-Inkubationszeiten sowie die Standardisierung der Verfahrensweisen des RUSITEC-Systems könnten der Anwendung dieser in-vitro-Methode in Zukunft zugutekommen. Ebenso sind weitere Untersuchungen zu diurnalen Fermentationsmustern zu empfehlen, um die vorliegenden Ergebnisse zu festigen.
Another major objective of the thesis was to directly compare the ruminal fermentation characteristics and degradability of two common forages, i.e., grass silage (GS) and maize silage (MS), by parallel application of a coupled in vivo-in situ approach in rumen-cannulated sheep as well as the in vitro RUSITEC system. Both forages were incubated in the RUSITEC system as well as fed to rumen-cannulated sheep in six independent runs of 20 days in total with 14 days of adaptation and 6 days of sampling. The degradability coefficients of dry matter, organic matter and acid detergent fibre were affected by the method (each P < 0.05), while neutral detergent fibre (aNDFom) degradability was not different between RUSITEC and in situ measurements (P = 0.10). Likewise, Pearson correlation coefficients confirmed the comparability of in vitro and in situ values for aNDFom degradability, being 0.54 (P = 0.04) and 0.78 (P = 0.02) for GS and MS, respectively. Regarding the fermentation profile, total volatile fatty acid (VFA) concentrations were much higher in vitro than in vivo (P < 0.01), likely due to the missing absorptive capacity of the RUSITEC system.
A comparison of absolute fermentation values between methods appears not feasible. However, the order of individual VFA proportions was similar between in vivo and in vitro and the correlations for both total and individual VFA further supported this congruency, especially for MS. The in vitro data appeared well comparable to the data from the coupled in vivo-in situ approach, especially for MS, with a high reproducibility in both methods.
Therefore, the RUSITEC system may represent a sufficient replacement for laborious in vivo and in situ measurements when assessing nutrient degradability and general fermentation characteristics of feedstuffs. Adjustments in in situ incubation times as well as the standardisation of the operation of the RUSITEC system may further increase the significance of this in vitro method in the future. Likewise, further research on diurnal fermentation patterns is encouraged to substantiate the present findings.
Studien an pansenfistulierten Tieren sind mit einem hohen Kosten- und Zeitaufwand verbunden. Darüber hinaus sind sie nur an wenigen Versuchseinrichtungen möglich und aus Tierschutzgründen ist eine Reduzierung der Anzahl an Tierversuchen grundsätzlich anzustreben. Eine Alternative besteht darin, die Pansenfermentation mithilfe künstlicher Systeme zu simulieren, was u. a. die Untersuchung einer großen Anzahl von Behandlungen in relativ kurzer Zeit ermöglicht. Die mangelnde Standardisierung kontinuierlicher Kultursysteme beeinträchtigt bisher den Vergleich von Forschungsdaten. Daher lag ein Schwerpunkte dieser Arbeit darin, eine umfassende Übersicht zu technischen und methodischen Aspekten des semikontinuierlichen Kultursystems „Pansensimulationstechnik“ (RUSITEC) zu erstellen. Möglichkeiten und Grenzen der technischen und methodischen Vorgehensweise wurden validiert und Vorschläge zu einer Standardisierung erarbeitet. Verfahrensschritte wie die Auswahl und Fütterung der Spendertiere, die Art der Futtermittel bzw. Rationen, der Probenahmezeitpunkt des Inokulums sowie der technische Aufbau und das Handling der RUSITEC-Systeme mit Motor, Pumpe, Gefäßen und Pufferlösung wurden behandelt. Weiterhin hatten die Auswahl der Inkubationsbeutel hinsichtlich Porengröße und -material, die Inkubationszeit, die Versuchslaufzeit und die Auswahl des Versuchsfutters Einfluss auf die Versuchsergebnisse. Um die Vergleichbarkeit von Studien zu verbessern, ermöglichen festgelegte technische Standards, die Variabilität innerhalb und zwischen verschiedenen RUSITEC-Systemen zu reduzieren. Abschließend wurde eine Standardisierung vorgeschlagen, um die Variabilität des RUSITEC-Systems zu vermindern und damit die Vergleichbarkeit der RUSITEC-Daten zu verbessern. Einen weiteren Schwerpunkt bildete der direkte Vergleich der Pansenfermentationseigenschaften und des Nährstoffabbaus durch parallele Anwendung eines gekoppelten in-vivo-in-situ-Ansatzes im Pansen fistulierter Schafe sowie des in-vitro-RUSITEC-Systems. Eingesetzt wurden zwei typische Grobfutter; Grassilage (GS) und Maissilage (MS). Beide Futtermittel wurden in sechs unabhängigen Läufen mit insgesamt 20 Tagen, davon 14 Tage Anpassung und 6 Tagen Probenahme untersucht. Die ruminale Abbaubarkeit der Trockenmasse, der organischen Masse und der Säure-Detergenzien-Faser (ADF) wurden durch die Methode beeinflusst (P < 0,05), während sich die Abbaubarkeit der Neutral-Detergenzien-Faser (aNDFom) zwischen RUSITEC- und in-situ-Messungen nicht unterschied (P = 0,10). Ebenso bestätigten die Pearson-Korrelationskoeffizienten die Vergleichbarkeit der in-vitro- und in-situ-Werte für die aNDFom-Abbaubarkeit; sie betrugen bei GS 0,54 (P = 0,04) und bei MS 0,78 (P = 0,02). Wahrscheinlich aufgrund der fehlenden Absorption im RUSITEC-System waren dia Gesamtkonzentrationen flüchtiger Fettsäuren (VFA) in vitro viel höher als in vivo (P < 0,01). Ein Vergleich absoluter Werte für VFA zwischen den Methoden scheint nicht möglich. Allerdings waren die VFA-Profile in vivo und in vitro ähnlich, und die Korrelationen sowohl für die Summe der VFA als auch für die einzelnen VFA untermauerten diese Kongruenz weiter, insbesondere bei MS. Die in-vitro-Daten waren insgesamt gut mit den Daten des gekoppelten in-vivo-in-situ-Ansatzes vergleichbar, insbesondere für die MS. Das RUSITEC-System kann als ein ausreichender Ersatz für aufwändige in-vivo- und in-situ-Messungen bei der Ermittlung des Nährstoffabbaus und genereller Fermentationseigenschaften von Futtermitteln angesehen werden. Anpassungen der in-situ-Inkubationszeiten sowie die Standardisierung der Verfahrensweisen des RUSITEC-Systems könnten der Anwendung dieser in-vitro-Methode in Zukunft zugutekommen. Ebenso sind weitere Untersuchungen zu diurnalen Fermentationsmustern zu empfehlen, um die vorliegenden Ergebnisse zu festigen.
Schlagwörter
Pansensimulation, RUSITEC, Parallelstudie, Pansenfermentation, Guidelines, In vitro, Methodical comparison, Rumen fermentation
Klassifikation (DDC)
630 Landwirtschaft, VeterinärmedizinZugehörige Publikation(en)
https://doi.org/10.1016/j.anifeedsci.2022.115325https://doi.org/10.1016/j.anifeedsci.2024.115900
Deitmers, Jan-Helge: Quantitative evaluation of ruminal nutrient degradation using in situ and in vitro methods. - Bonn, 2024. - Dissertation, Rheinische Friedrich-Wilhelms-Universität Bonn.
Online-Ausgabe in bonndoc: https://nbn-resolving.org/urn:nbn:de:hbz:5-78254
Online-Ausgabe in bonndoc: https://nbn-resolving.org/urn:nbn:de:hbz:5-78254
@phdthesis{handle:20.500.11811/12084,
urn: https://nbn-resolving.org/urn:nbn:de:hbz:5-78254,
doi: https://doi.org/10.48565/bonndoc-371 ,
author = {{Jan-Helge Deitmers}},
title = {Quantitative evaluation of ruminal nutrient degradation using in situ and in vitro methods},
school = {Rheinische Friedrich-Wilhelms-Universität Bonn},
year = 2024,
month = sep,
note = {Quantitative evaluation of ruminal nutrient degradation using in situ and in vitro methods Studies on ruminally cannulated animals are expensive and time consuming. Furthermore they are limited to a few facilities and animal welfare issues make reduced numbers of animal experiments desirable. One alternative is to simulate rumen fermentation using long-term continuous systems, allowing investigation of a large number of treatments in a relatively short period of time. Lack of standardisation of continuous culture systems impairs the comparison of research data. Therefore, the focus of a comprehensive review as one major part of the thesis was to compile and compare technical and other methodical aspects of the semi-continuous culture system ‘rumen simulation technique’ (RUSITEC). Crucial or non-standardised characteristics were highlighted, standardisation of procedures was suggested and limits of standardisation were considered. Procedural steps which were evaluated encompassed choice and feeding of donor animals, type of feeds or rations, sampling time of inoculum and, further, the technical structure and procedure of the RUSITEC systems with a motor, pump, vessels and buffer solution. Moreover, the choice of incubation bags with regard to pore size and material, the incubation time, the experimental run period and the selection of experimental feed have an impact on the results. To improve the comparability of studies, specified technical standards will reduce the variability within and between different models of the RUSITEC system. Finally, standardisations were proposed to reduce variability in the design of simulation systems, variability in the rumen inoculum and to improve the comparability of RUSITEC research data.
Another major objective of the thesis was to directly compare the ruminal fermentation characteristics and degradability of two common forages, i.e., grass silage (GS) and maize silage (MS), by parallel application of a coupled in vivo-in situ approach in rumen-cannulated sheep as well as the in vitro RUSITEC system. Both forages were incubated in the RUSITEC system as well as fed to rumen-cannulated sheep in six independent runs of 20 days in total with 14 days of adaptation and 6 days of sampling. The degradability coefficients of dry matter, organic matter and acid detergent fibre were affected by the method (each P < 0.05), while neutral detergent fibre (aNDFom) degradability was not different between RUSITEC and in situ measurements (P = 0.10). Likewise, Pearson correlation coefficients confirmed the comparability of in vitro and in situ values for aNDFom degradability, being 0.54 (P = 0.04) and 0.78 (P = 0.02) for GS and MS, respectively. Regarding the fermentation profile, total volatile fatty acid (VFA) concentrations were much higher in vitro than in vivo (P < 0.01), likely due to the missing absorptive capacity of the RUSITEC system.
A comparison of absolute fermentation values between methods appears not feasible. However, the order of individual VFA proportions was similar between in vivo and in vitro and the correlations for both total and individual VFA further supported this congruency, especially for MS. The in vitro data appeared well comparable to the data from the coupled in vivo-in situ approach, especially for MS, with a high reproducibility in both methods.
Therefore, the RUSITEC system may represent a sufficient replacement for laborious in vivo and in situ measurements when assessing nutrient degradability and general fermentation characteristics of feedstuffs. Adjustments in in situ incubation times as well as the standardisation of the operation of the RUSITEC system may further increase the significance of this in vitro method in the future. Likewise, further research on diurnal fermentation patterns is encouraged to substantiate the present findings.},
url = {https://hdl.handle.net/20.500.11811/12084}
}
urn: https://nbn-resolving.org/urn:nbn:de:hbz:5-78254,
doi: https://doi.org/
author = {{Jan-Helge Deitmers}},
title = {Quantitative evaluation of ruminal nutrient degradation using in situ and in vitro methods},
school = {Rheinische Friedrich-Wilhelms-Universität Bonn},
year = 2024,
month = sep,
note = {Quantitative evaluation of ruminal nutrient degradation using in situ and in vitro methods Studies on ruminally cannulated animals are expensive and time consuming. Furthermore they are limited to a few facilities and animal welfare issues make reduced numbers of animal experiments desirable. One alternative is to simulate rumen fermentation using long-term continuous systems, allowing investigation of a large number of treatments in a relatively short period of time. Lack of standardisation of continuous culture systems impairs the comparison of research data. Therefore, the focus of a comprehensive review as one major part of the thesis was to compile and compare technical and other methodical aspects of the semi-continuous culture system ‘rumen simulation technique’ (RUSITEC). Crucial or non-standardised characteristics were highlighted, standardisation of procedures was suggested and limits of standardisation were considered. Procedural steps which were evaluated encompassed choice and feeding of donor animals, type of feeds or rations, sampling time of inoculum and, further, the technical structure and procedure of the RUSITEC systems with a motor, pump, vessels and buffer solution. Moreover, the choice of incubation bags with regard to pore size and material, the incubation time, the experimental run period and the selection of experimental feed have an impact on the results. To improve the comparability of studies, specified technical standards will reduce the variability within and between different models of the RUSITEC system. Finally, standardisations were proposed to reduce variability in the design of simulation systems, variability in the rumen inoculum and to improve the comparability of RUSITEC research data.
Another major objective of the thesis was to directly compare the ruminal fermentation characteristics and degradability of two common forages, i.e., grass silage (GS) and maize silage (MS), by parallel application of a coupled in vivo-in situ approach in rumen-cannulated sheep as well as the in vitro RUSITEC system. Both forages were incubated in the RUSITEC system as well as fed to rumen-cannulated sheep in six independent runs of 20 days in total with 14 days of adaptation and 6 days of sampling. The degradability coefficients of dry matter, organic matter and acid detergent fibre were affected by the method (each P < 0.05), while neutral detergent fibre (aNDFom) degradability was not different between RUSITEC and in situ measurements (P = 0.10). Likewise, Pearson correlation coefficients confirmed the comparability of in vitro and in situ values for aNDFom degradability, being 0.54 (P = 0.04) and 0.78 (P = 0.02) for GS and MS, respectively. Regarding the fermentation profile, total volatile fatty acid (VFA) concentrations were much higher in vitro than in vivo (P < 0.01), likely due to the missing absorptive capacity of the RUSITEC system.
A comparison of absolute fermentation values between methods appears not feasible. However, the order of individual VFA proportions was similar between in vivo and in vitro and the correlations for both total and individual VFA further supported this congruency, especially for MS. The in vitro data appeared well comparable to the data from the coupled in vivo-in situ approach, especially for MS, with a high reproducibility in both methods.
Therefore, the RUSITEC system may represent a sufficient replacement for laborious in vivo and in situ measurements when assessing nutrient degradability and general fermentation characteristics of feedstuffs. Adjustments in in situ incubation times as well as the standardisation of the operation of the RUSITEC system may further increase the significance of this in vitro method in the future. Likewise, further research on diurnal fermentation patterns is encouraged to substantiate the present findings.},
url = {https://hdl.handle.net/20.500.11811/12084}
}
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