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dc.contributor.advisorSundset, Monica Alterskjær
dc.contributor.authorSalgado, Alejandro Flores
dc.date.accessioned2017-05-31T10:57:32Z
dc.date.available2017-05-31T10:57:32Z
dc.date.issued2017-06-01
dc.description.abstractEnteric methane (CH4) from gut microbial fermentation of complex organic polymers in ruminants comprises an important source of the anthropogenic CH4 emissions and may also represent a significant loss of metabolic energy to the host animal depending on diet. CH4 is produced by specialized microbes called methanogens. Extensive research exists on enteric CH4 production and methanogens in domestic ruminants, but little is known about arctic herbivores. Reindeer (Rangifer tarandus tarandus), muskox (Ovibos moschatus), and rock ptarmigan (Lagopus muta), typically consume plants rich in toxic plant secondary metabolites (PSMs). PSMs may depress enteric CH4 production in high concentrations. The objective of this PhD project was to characterize the gut microbiome from these animals, with special emphasis on CH4 metabolism and related to diets high in PSMs. Investigating the microbiology of methanogenesis would help better understand their digestive physiology. Molecular biology techniques were used for these studies: quantitative real-time PCR, amplicon sequencing, and shotgun metagenomics. Reindeer fed lichens (high in PSMs) and muskoxen feeding on an autumn pasture presented increased proportions of methanogens (Methanobrevibacter ruminantium and Methanobrevibacter olleyae) that may be related to the low CH4 output previously described for these ruminants. Housing methanogens with expected low CH4 potentials might result in reduced energy losses in reindeer. Other factors apart from high PSMs contents may account for the presence of these methanogens. Rock ptarmigans mostly contained methanol-utilizing methanogens, potentially related to methanol production from pectin degradation. This thesis presents the first molecular study of the gut microbiota in muskoxen and rock ptarmigans. Muskoxen possessed bacteria mediating fiber degradation, which would allow them live off fibrous plants like graminoids. Rock ptarmigans presented a diverse microbiota with bacteria involved in PSMs degradation and a variable range of polysaccharides (e.g. hemicellulose, starch). In both cases, their gut microbiota would allow them utilizing the available food.en_US
dc.description.doctoraltypeph.d.en_US
dc.description.popularabstractEnteric methane (CH4) from ruminants, a by-product from gut microbial digestion, constitutes a substantial source of man-related CH4 emissions. It also represents an energy loss to the animal that may be important during energetically restrictive conditions. The diet of reindeer, muskoxen, and rock ptarmigans include plants with toxic plant secondary metabolites (PSMs), which may depress methanogenesis. In this PhD thesis, we studied the microbial bases for CH4 metabolism in these arctic herbivores in relation to methanogenesis and diets high in PSMs, using molecular biology techniques. Reindeer fed lichens (high in PSMs) and muskoxen feeding on late autumn pastures housed methanogens associated with low CH4 emissions. Other factors apart from PSMs contents may account for the presence of these methanogens. Muskoxen and ptarmigans possessed a diverse gut microbiota specialized in the degradation of their respective diets.en_US
dc.description.sponsorshipFunding was provided by the Reindeer Husbandry Research Fund (linked to the framework of the International Polar Year (IPY) as part of the consortium IPY#399 EALAT: Climate change and reindeer husbandry), UiT The Arctic University of Norway, and Nansenfondet 2014.en_US
dc.descriptionPaper III of this thesis is not available in Munin. <p> Paper III: Salgado‐Flores, A., Tveit, A. T., Wright, A. D., Pope, P. B., Sundset, M. A.: “Characterization of the cecum microbiome from wild and captive rock ptarmigans from Svalbard and northern Norway in relation to diet composition”. (Manuscript).en_US
dc.identifier.isbn978-82-8266-140-9
dc.identifier.urihttps://hdl.handle.net/10037/11080
dc.language.isoengen_US
dc.publisherUiT The Arctic University of Norwayen_US
dc.publisherUiT Norges arktiske universiteten_US
dc.rights.accessRightsopenAccessen_US
dc.subject.courseIDDOKTOR-002
dc.subjectVDP::Mathematics and natural science: 400::Basic biosciences: 470::Molecular biology: 473en_US
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Basale biofag: 470::Molekylærbiologi: 473en_US
dc.subjectVDP::Mathematics and natural science: 400::Basic biosciences: 470::Genetics and genomics: 474en_US
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Basale biofag: 470::Genetikk og genomikk: 474en_US
dc.subjectVDP::Mathematics and natural science: 400::Basic biosciences: 470::Bioinformatics: 475en_US
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Basale biofag: 470::Bioinformatikk: 475en_US
dc.subjectVDP::Mathematics and natural science: 400::Basic biosciences: 470::General microbiology: 472en_US
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Basale biofag: 470::Generell mikrobiologi: 472en_US
dc.titleGut metagenomics in relation to diet and methanogenesis in arctic herbivoresen_US
dc.typeDoctoral thesisen_US
dc.typeDoktorgradsavhandlingen_US


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