Study of the effect of presence or absence of protozoa on rumen fermentation and microbial protein contribution to the chyme
Guada, J. A.
MetadataShow full item record
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.
Is part ofJournal of Animal Science, 2011, vol. 89, núm. 12, p. 4163-4174
European research projects
Showing items related by title, author, creator and subject.
Effect of diet and absence of protozoa on the rumen microbial community and on the representativeness of bacterial fractions used in the determination of microbial protein synthesis Belanche, A.; de la Fuente Oliver, Gabriel; Pinloche, Eric; Newbold, C. Jamie; Balcells Terés, Joaquim (American Society of Animal Science, 2012-04-21)Accurate estimates of microbial synthesis in the rumen are vital to optimize ruminant nutrition. Liquid- (LAB) and solid-associated bacterial fractions (SAB) harvested from the rumen are generally considered as microbial ...
Effect of type roughage and level of barley supplementation on digestibility, rumen fermentation and microbial-N yield Belanche, A.; de la Fuente Oliver, Gabriel; Guada, J. A.; Balcells Terés, Joaquim (Centre international de hautes études agronomiques méditerranéennes, 2011)Four cannulated ewes were used in a factorial (2 x 3) design to study the effect of two sources of roughage (alfalfa hay vs ammonium-treated straw, UTS) and three levels of ground barley grain supplementation (F:C ratio: ...
Effect of progressive inoculation of fauna-free sheep with holotrich protozoa and total-fauna on rumen fermentation, microbial diversity and methane emissions Belanche, A.; de la Fuente Oliver, Gabriel; Newbold, C. Jamie (Oxford University Press, 2014-12-15)Rumen methanogenesis represents an energy waste for the ruminant and an important source of greenhouse gas; thus, integrated studies are needed to fully understand this process. Eight fauna-free sheep were used to investigate ...