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. 2014 Dec;90(3):663-77.
doi: 10.1111/1574-6941.12423. Epub 2014 Sep 29.

Study of methanogen communities associated with different rumen protozoal populations

Alejandro Belanche  1 , Gabriel de la Fuente, Charles J Newbold
Affiliations
Free PMC article

Study of methanogen communities associated with different rumen protozoal populations

Alejandro Belanche et al. FEMS Microbiol Ecol. 2014 Dec.
Free PMC article

Abstract

Protozoa-associated methanogens (PAM) are considered one of the most active communities in the rumen methanogenesis. This experiment investigated whether methanogens are sequestrated within rumen protozoa, and structural differences between rumen free-living methanogens and PAM. Rumen protozoa were harvested from totally faunated sheep, and six protozoal fractions (plus free-living microorganisms) were generated by sequential filtration. Holotrich-monofaunated sheep were also used to investigate the holotrich-associated methanogens. Protozoal size determined the number of PAM as big protozoa had 1.7-3.3 times more methanogen DNA than smaller protozoa, but also more endosymbiotic bacteria (2.2- to 3.5-fold times). Thus, similar abundance of methanogens with respect to total bacteria were observed across all protozoal fractions and free-living microorganisms, suggesting that methanogens are not accumulated within rumen protozoa in a greater proportion to that observed in the rumen as a whole. All rumen methanogen communities had similar diversity (22.2 ± 3.4 TRFs). Free-living methanogens composed a conserved community (67% similarity within treatment) in the rumen with similar diversity but different structures than PAM (P < 0.05). On the contrary, PAM constituted a more variable community (48% similarity), which differed between holotrich and total protozoa (P < 0.001). Thus, PAM constitutes a community, which requires further investigation as part of methane mitigation strategies.

Keywords: archaea; endosymbiotic; holotrich; methanogens; rumen protozoa.

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Figures

Figure 1
Figure 1
Diagram depicting sheep inoculation and rumen sampling.
Figure 2
Figure 2
Fluorescence microscopy images of the different protozoal fractions using propidium iodide dye and rhodamine filters. Protozoa fractions were obtained from holotrich-monofaunated (H60 and H20) and totally faunated sheep (F80, F60, F45, F35, F20, F5 and F < 5) using different nylon meshes (80, 60, 45, 35, 20 and 5 μm pore size).
Figure 3
Figure 3
(a) Ratio bacteria/protozoa, (b) methanogens/protozoa and (c) methanogens/bacteria in different rumen protozoal fractions obtained from holotrich-monofaunated (H60 and H20) and totally faunated sheep (F80, F60, F45, F35, F20, F5 and F < 5) using different nylon meshes (80, 60, 45, 35, 20 and 5 μm pore size). Data were log10-transformed to attain normality. Bars with different letters (a, b, c, d, e) of the same colour differ (P < 0.05).
Figure 4
Figure 4
(a) PCoA illustrating the differences in the endosymbiotic methanogens associated with different rumen protozoal fractions obtained from holotrich-monofaunated (H) and totally faunated sheep (F). Big circles indicate the 90% confidential interval. (b) Dendrogram depicting the effect of total protozoa fractionation on their endosymbiotic methanogen populations. Protozoa fractions (F80, F60, F45, F35, F20, F5 and F < 5) were generated by a sequential filtration of rumen fluids from different sheep (A, B, C and D) through nylon meshes with a pore size of 80, 60, 45, 35, 20 and 5 μm, respectively.
See this image and copyright information in PMC

References

    1. Abecia A, Waddams KE, Martínez-Fernandez G, Martín-García AI, Ramos-Morales E, Newbold CJ. Yáñez-Ruiz DR. An antimethanogenic nutritional intervention in early life of ruminants modifies ruminal colonization by Archaea. Archaea. 2014 In press. DOI: 10.1155/2014/841463. - DOI - PMC - PubMed
    1. Anderson MJ. A new method for non-parametric multivariate analysis of variance. Austral Ecol. 2001;26:32–46.
    1. Belanche A, De la Fuente G, Yáñez Ruiz DR, Newbold CJ, Calleja L. Balcells J. Technical note: the persistence of microbial-specific DNA sequences through gastric digestion in lambs and its potential use as microbial markers. J Anim Sci. 2011a;89:2812–2816. - PubMed
    1. Belanche A, Abecia L, Holtrop G, Guada JA, Castrillo C, de la Fuente G. Balcells J. Study of the effect of presence or absence of protozoa on rumen fermentation and microbial protein contribution to the chyme. J Anim Sci. 2011b;89:4163–4174. - PubMed
    1. Belanche A, de la Fuente G, Moorby JM. Newbold CJ. Bacterial protein degradation by different rumen protozoal groups. J Anim Sc. 2012a;90:4495–4504. - PubMed

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