Production of bioactive metabolites by intestinal bacteria

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dc.check.embargoformatNot applicableen
dc.check.infoNo embargo requireden
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dc.contributor.advisorFitzgerald, Gerald F.en
dc.contributor.advisorStanton, Catherineen
dc.contributor.advisorRoss, R. Paulen
dc.contributor.authorMarques, Tatiana Milena
dc.contributor.funderScience Foundation Irelanden
dc.contributor.funderAlimentary Healthen
dc.date.accessioned2017-01-09T12:55:00Z
dc.date.available2017-01-09T12:55:00Z
dc.date.issued2013
dc.date.submitted2013
dc.description.abstractThe adult intestinal microbiota comprises a microbial ecosystem of approximately 100 trillion microorganisms, with specific bacterial communities holding distinct metabolic capabilities. Bacteria produce a range of bioactive compounds to survive unfavourable stimuli and to interact with other organisms, and generate several bioactive products during degradation of dietary constituents the host is not capable of digesting. This thesis addressed the impact of feeding potential probiotic bacteria and other dietary strategies such as pure fatty acids and prebiotics, on gut microbiota composition, short chain fatty acid (SCFA) production and modulation of metabolism in animal models. In the first experimental chapter (Chapter 2) a gas chromatography method for the quantification of SCFA was optimized and applied in the analysis of caecal samples obtained in animal studies described in other chapters of this thesis. In Chapter 3, t10, c12 CLA supplementation was shown to significantly alter murine gut microbiota composition and SCFA production rather than no supplementation. These changes were suggested to be extra factors affecting host lipid metabolism. Chapter 4 described the contrasting effects of CLA-producing strains, Bifidobacterium breve DPC 6330 and B. breve NCIMB 702258, on murine fat distribution/composition and gut microbiota composition, suggesting that these changes were most likely strain-dependent. In Chapter 5, dietary GABA-producing strain Lactobacillus brevis DPC 6108 was shown to significantly increase (p<0.05) serum insulin in healthy rats, leading to a second experiment using a type 1 diabetes rat model. Lb. brevis DPC 6108 administration did not change insulin levels in diabetic rats, but attenuated high levels of glucose when compared to diabetic control. However, an auto-immune-induced diabetes model was suggested as a better model to study GABA-related effects on diabetes. In Chapter 6 bovine milk oligosaccharides, 6’sialyllactose and Beneo Orafti P95 oligofructose supplementations were associated with depletion or reduction of less favourable bacteria, demonstrating that ingestion of these oligosaccharides might be a safe and effective approach to modulate populations of the intestinal microbiota. In Chapter 7 (General discussion) the major findings of all studies were reviewed and discussed.en
dc.description.sponsorshipScience Foundation Ireland (SFI Grant 07/CE/B1368)en
dc.description.statusNot peer revieweden
dc.description.versionAccepted Version
dc.format.mimetypeapplication/pdfen
dc.identifier.citationMarques, T. M. 2013. Production of bioactive metabolites by intestinal bacteria. PhD Thesis, University College Cork.en
dc.identifier.endpage287en
dc.identifier.urihttps://hdl.handle.net/10468/3450
dc.languageEnglishen
dc.language.isoenen
dc.publisherUniversity College Corken
dc.rights© 2013, Tatiana Milena Marques.en
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/3.0/en
dc.subjectMicrobiotaen
dc.subjectProbioticen
dc.subjectPrebioticen
dc.subjectShort chain fatty acidsen
dc.subjectFatty acidsen
dc.subjectMetabolitesen
dc.thesis.opt-outfalse
dc.titleProduction of bioactive metabolites by intestinal bacteriaen
dc.typeDoctoral thesisen
dc.type.qualificationlevelDoctoral Degree (Structured)en
dc.type.qualificationnamePhD (Food Science and Technology)en
ucc.workflow.supervisorg.fitzgerald@ucc.ie
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