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dc.contributor.author G. en_US
dc.contributor.author A. en_US
dc.contributor.author J. A. en_US
dc.contributor.author L. en_US
dc.contributor.author G. en_US
dc.contributor.author J. en_US
dc.contributor.author C. en_US
dc.date.accessioned 2012-01-10T16:33:55Z
dc.date.available 2012-01-10T16:33:55Z
dc.date.issued 2012-01-10 en_US
dc.identifier http://dx.doi.org/10.2527/jas.2010-3703 en_US
dc.identifier.citation Holtrop , G , Belanche , A , Guada , J A , Abecia , L , de la Fuente , G , Balcells , J & Castrillo , C 2012 , ' Study of the effect of presence or absence of protozoa on rumen fermentation and microbial protein contribution to the chyme ' Journal of Animal Science , vol 89 , no. 12 , pp. 4163-4174 . , 10.2527/jas.2010-3703 en_US
dc.identifier.other PURE: 174762 en_US
dc.identifier.other dspace: 2160/7733 en_US
dc.identifier.uri http://hdl.handle.net/2160/7733
dc.description.abstract The aim of this study was to investigate the effect of presence or absence of protozoa on rumen fermentation and efficiency of microbial protein synthesis under different diets. Of 20 twin paired lambs, 1 lamb of each pair was isolated from the ewe within 24 h after birth and reared in a protozoa-free environment (n = 10), whereas their respective twin-siblings remained with the ewe (faunated, n = 10). When lambs reached 6 mo of age, 5 animals of each group were randomly allocated to 1 of 2 experimental diets consisting of either alfalfa hay as the sole diet, or 50:50 mixed with ground barley grain according to a 2 × 2 factorial arrangement of treatments. After 15 d of adaptation to the diet, the animals were euthanized and total rumen and abomasal contents were sampled to estimate rumen microbial synthesis using C31 alkane as flow marker. Different (15N and purine bases) and a novel (recombinant DNA sequences) microbial markers, combined with several microbial reference extracts (rumen protozoa, liquid and solid associated bacteria) were evaluated. Absence of rumen protozoa modified the rumen fermentation pattern and decreased total tract OM and NDF digestibility in 2.0 and 5.1 percentage points, respectively. The effect of defaunation on microbial N flow was weak, however, and was dependent on the microbial marker and microbial reference extract considered. Faunated lambs fed with mixed diet showed the greatest rumen protozoal concentration and the least efficient microbial protein synthesis (29% less than the other treatments), whereas protozoa-free lambs fed with mixed diet presented the smallest ammonia concentration and 34% greater efficiency of N utilization than the other treatments. Although 15N gave the most precise estimates of microbial synthesis, the use of recombinant DNA sequences represents an alternative that allows separate quantification of the bacteria and protozoa contributions. This marker showed that presence of protozoa decrease the bacterial-N flow through the abomasum by 33%, whereas the protozoa-N contribution to the microbial N flow increased from 1.9 to 14.1% when barley grain was added to the alfalfa hay. Absolute data related to intestinal flow must be treated with caution because the limitations of the sampling and maker system employed. en_US
dc.format.extent 12 en_US
dc.relation.ispartof Journal of Animal Science en_US
dc.title Study of the effect of presence or absence of protozoa on rumen fermentation and microbial protein contribution to the chyme en_US
dc.contributor.pbl Institute of Biological, Environmental and Rural Sciences en_US


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