Evidence in support of a role for plant-mediated proteolysis in the rumens of grazing animals

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dc.contributor.author Merry, Roger J.
dc.contributor.author Leemans, David K.
dc.contributor.author Kingston-Smith, Alison H.
dc.contributor.author Theodorou, Michael K.
dc.contributor.author Thomas, Howard
dc.date.accessioned 2008-12-11T12:20:50Z
dc.date.available 2008-12-11T12:20:50Z
dc.date.issued 2005-02-12
dc.identifier.citation Merry , R J , Leemans , D K , Kingston-Smith , A H , Theodorou , M K & Thomas , H 2005 , ' Evidence in support of a role for plant-mediated proteolysis in the rumens of grazing animals ' British Journal of Nutrition , pp. 73-79 . , 10.1079/BJN20041303 en
dc.identifier.issn 1475-2662
dc.identifier.other PURE: 91943
dc.identifier.other dspace: 2160/1537
dc.identifier.uri http://hdl.handle.net/2160/1537
dc.identifier.uri http://www.journals.cambridge.org/action/displayIssue?jid=BJN&volumeId=93&issueId=01 en
dc.description Kingston-Smith, A. H., Merry, R. J., Leemans, D. K., Thomas, Howard, Theodorou, M. K. (2005). Evidence in support of a role for plant-mediated proteolysis in the rumens of grazing animals. British Journal of Nutrition, 93(1), 73-79. Sponsorship: DEFRA / BBSRC RAE2008 en
dc.description.abstract The present work aimed to differentiate between proteolytic activities of plants and micro-organisms during the incubation of grass in cattle rumens. Freshly cut ryegrass was placed in bags of varying permeability and incubated for 16 h in the rumens of dairy cows that had previously grazed a ryegrass sward, supplemented with 4 kg dairy concentrate daily. Woven polyester bags (50 μm pore size) permitted direct access of the micro-organisms and rumen fluid enzymes to the plant material. The polythene was impermeable even to small molecules such as NH3. Dialysis tubing excluded micro-organisms and rumen enzymes/metabolites larger than 10 kDa. DM loss was 46·3 % in polyester, 36·2 % in polythene and 38·1 % in dialysis treatments. It is possible that the DM loss within polythene bags occurred due to a solubilisation of plant constituents (e.g. water-soluble carbohydrates) rather than microbial attachment/degradation processes. The final protein content of the herbage residues was not significantly different between treatments. Regardless of bag permeability, over 97 % of the initial protein content was lost during incubations in situ. Electrophoretic separation showed that Rubisco was extensively degraded in herbage residues whereas the membrane-associated, light-harvesting protein remained relatively undegraded. Protease activity was detected in herbage residues and bathing liquids after all incubation in situ treatments. Although rumen fluid contains proteases (possibly of plant and microbial origin), our results suggest that, owing to cell compartmentation, their activity against the proteins of intact plant cells is limited, supporting the view that plant proteases are involved in the degradation of proteins in freshly ingested herbage. en
dc.format.extent 7 en
dc.language.iso eng
dc.relation.ispartof British Journal of Nutrition en
dc.title Evidence in support of a role for plant-mediated proteolysis in the rumens of grazing animals en
dc.type Text en
dc.type.publicationtype Article (Journal) en
dc.identifier.doi http://dx.doi.org/10.1079/BJN20041303
dc.contributor.institution Institute of Biological, Environmental and Rural Sciences en
dc.description.status Peer reviewed en


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