The role of ciliate protozoa in the rumen
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First described in 1843, Rumen protozoa with their striking appearance were assumed to be important for the welfare of their host. However, despite contributing up to 50% of the bio-mass in the rumen, the role of protozoa in rumen microbial ecosystem remains unclear. Phylogenetic analysis of 18S rDNA libraries generated from the rumen of cattle, sheep, and goats has revealed an unexpected diversity of ciliated protozoa although variation in gene copy number between species makes it difficult to obtain absolute quantification. Despite repeated attempts it has proven impossible to maintain rumen protozoa in axenic culture. Thus it has been difficult to establish conclusively a role of ciliate protozoa in rumen fibre degradation. The development of techniques to clone and express ciliate genes in phage, together with bioinformatic indices to confirm the ciliate origin of the genes has allowed the isolation and characterisation of fibrolytic genes from rumen protozoa. Elimination of the ciliate protozoa increases microbial protein supply by up to 30% and reduces methane production by up to 11%. Our recent findings suggest that holotrich protozoa play a disproportionate role in supporting methanogenesis whilst the small entodiniium are responsible for much of the bacterial protein turnover. As yet no method to control protozoa in the rumen that is safe and practically applicable has been developed, however a range of plant extract capable of controlling if not completely eliminating rumen protozoa have been described.
Is part ofFrontiers In Microbiology, 2015, Vol.6, a1313
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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 ...
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 ...
Study of the effect of presence or absence of protozoa on rumen fermentation and microbial protein contribution to the chyme Belanche, A.; Abecia, Leticia; Holtrop, G.; Guada, J. A.; Castrillo, C.; de la Fuente Oliver, Gabriel; Balcells Terés, Joaquim (American Society of Animal Science, 2011-06-29)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 ...