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In vivo and In Vitro Measurements of Ruminal Redox Potential : a Comparative Study

Julien , Christine and Troegeler-Meynadier, Annabelle and Marden, Jean-Philippe and Enjalbert, Francis and Bayourthe, Corine In vivo and In Vitro Measurements of Ruminal Redox Potential : a Comparative Study. (2009) In: ADSA/ASAS Joint Annual Meeting, 12-16 July 2009, Montréal, Canada . (Unpublished)

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Official URL: http://adsa.asas.org/meetings/2009/

Abstract

This experiment compared ruminal in vivo and in vitro conditions in which redox potential (Eh) and fermentative parameters were measured during 3 consecutive days. A rumen fistulated dry dairy cow was adapted during 13 days to a hay-based diet supplemented with 43% of concentrates. Ruminal pH and Eh were measured in vivo from feeding (0h) to 6 hours (6h) at 15 min interval on d1 and d2. On d3, ruminal fluid was sucked out and divided in 10 flasks for in vitro use. In each flask, substrates (starch, hay and urea) and a buffer solution (pH 7) were added and flasks were kept from light and air at 39° C in a waterbath rotary shaker. The pH and Eh were recorded at the start of incubation (0h) to 6 hours (6h) every 15 min. For both methods, VFA and DL-lactate contents were determined at 0h and 6h. At 0h, in vivo Eh (– 217 mV) differed (P = 0.003) from in vitro value (– 123 mV) probably because of ruminal fluid contact with air outside the rumen. After 45 min, Eh measured in rumen (– 227 mV) were not different from Eh recorded in incubated milieu (– 183 mV). After 2 h, both methods yielded similar Eh values. At 0h, total VFA and DL-lactate contents were significantly different between in vivo (60.1 and 0.03 mM, respectively) and in vitro (36.9 and 0.62 mM, respectively) methodologies, owing to the transfer of rumen fluid and the dilution by buffer for incubation purposes. At 6h, no more significant difference was observed, suggesting therefore that in vitro reflected in vivo conditions. At 6h, contents of individual VFA did not differ (49.1 mM of acetate, 10.4 mM of propionate and 9.16 mM of butyrate, on average). In conclusion, during a 6-h incubation, our in vitro experimental method offered a fermentative and reducing environment close to the rumen. Moreover, this present study put forward the capacity of ruminal microbiota to restore reducing conditions in vitro after an exogenous perturbation.

Item Type:Conference or Workshop Item (Poster)
Audience (conference):International conference without published proceedings
Uncontrolled Keywords:
Institution: Université de Toulouse > Ecole Nationale Vétérinaire de Toulouse - ENVT
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT
French research institutions > Institut National de la Recherche Agronomique - INRA
Other partners > LESAFFRE (FRANCE)
Laboratory name:
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Deposited By: Annabelle Troegeler

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