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dc.contributor.authorBelanche, A.
dc.contributor.authorde la Fuente Oliver, Gabriel
dc.contributor.authorMoorby, J. M.
dc.contributor.authorNewbold, C. Jamie
dc.date.accessioned2015-12-22T16:11:58Z
dc.date.available2015-12-22T16:11:58Z
dc.date.issued2012-07-08
dc.identifier.issn0021-8812
dc.identifier.urihttp://hdl.handle.net/10459.1/49284
dc.description.abstractBacterial predation by protozoa has the most deleterious effect on the efficiency of N use within the rumen, but differences in activity among protozoal groups are not completely understood. Two in vitro experiments were conducted to identify the protozoal groups more closely related with rumen N metabolism. Rumen protozoa were harvested from cattle and 7 protozoal fractions were generated immediately after sampling by filtration through different nylon meshes at 39°C, under a CO2 atmosphere to maintain their activity. Protozoa were incubated with 14C-labeled bacteria to determine their bacterial breakdown capacity, according to the amount of acid-soluble radioactivity released. Epidinium tended to codistribute with Isotricha and Entodinium with Dasytricha; therefore, their activity was calculated together. This study demonstrated that big Diplodiniinae had the greatest activity per cell (100 ng bacterial CP per protozoa and hour), followed by Epidinium plus Isotricha (36.4), small Diplodiniinae (34.2), and Entodinium plus Dasytricha (14.8), respectively. However, the activity per unit of protozoal volume seemed to vary, depending on the protozoal taxonomy. Small Diplodiniinae had the greatest activity per volume (325 ng bacterial CP per protozoal mm3 and hour), followed by big Diplodiniinae (154), Entodinium plus Dasytricha (104), and Entodinium plus Dasytricha (25.6). A second experiment was conducted using rumen fluid from holotrich-monofaunated sheep. This showed that holotrich protozoa had a limited bacterial breakdown capacity per cell (Isotricha 9.44 and Dasytricha 5.81 ng bacterial CP per protozoa and hour) and per protozoal volume (5.97 and 76.9 ng bacterial CP per protozoal mm3 and hour, respectively). Therefore, our findings indicated that a typical protozoal population (106 total protozoa/mL composed by Entodinium sp. 88%, Epidinium sp. 7%, and other species 4%) is able to break down ∼17% of available rumen bacteria every hour. Entodinium sp. is responsible for most of this bacterial breakdown (70 to 75%), followed by Epidinium sp. (16 to 24%), big Diplodiniinae (4 to 6%), and small Diplodiniinae (2 to 6%), whereas holotrich protozoa have a negligible activity (Dasytricha sp. 0.6 to 1.2% and Isotricha sp. 0.2 to 0.5%). This in vitro information must be carefully interpreted, but it can be used to indicate which protozoal groups should be suppressed to improve microbial protein synthesis in vivo.
dc.description.sponsorshipThis study was supported by the Framework 7 program from the EU “Innovative and practical management approaches to reduce nitrogen excretion by ruminants (Rednex)” and the Welsh government. We thank the Institute of Biological, Environmental and Rural Sciences staff for their assistance and collaboration.
dc.format.mimetypeapplication/pdf
dc.language.isoeng
dc.publisherAmerican Society of Animal Science
dc.relation.isformatofReproducció del document publicat a: https://doi.org/10.2527/jas.2012-5118
dc.relation.ispartofJournal of Animal Science, 2012, vol. 90, núm. 12, p. 4495-4505
dc.rights(c) American Society of Animal Science, 2012
dc.subject.classificationRemugants
dc.subject.classificationProtozous
dc.subject.otherRuminants
dc.subject.otherProtozoa
dc.titleBacterial protein degradation by different rumen protozoal groups
dc.typeinfo:eu-repo/semantics/article
dc.date.updated2015-12-15T18:16:03Z
dc.identifier.idgrec023070
dc.type.versioninfo:eu-repo/semantics/publishedVersion
dc.rights.accessRightsinfo:eu-repo/semantics/openAccess
dc.identifier.doihttps://doi.org/10.2527/jas.2012-5118
dc.relation.projectIDinfo:eu-repo/grantAgreement/EC/FP7/211606


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