Omega-3 fatty acids, gut microbiota and associated inflammatory outcomes

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dc.contributor.advisor Stanton, Catherine en
dc.contributor.advisor Ross, R. Paul en
dc.contributor.advisor Fitzgerald, Gerald F. en Robertson, Ruairi C. 2017-04-18T12:24:39Z 2016 2016
dc.identifier.citation Robertson, R. C. 2016. Omega-3 fatty acids, gut microbiota and associated inflammatory outcomes. PhD Thesis, University College Cork. en
dc.identifier.endpage 342 en
dc.description.abstract The overall aim of this thesis was to investigate the potential of omega-3 polyunsaturated fatty acids (n-3 PUFA), particularly from algal sources, as regulators of gut microbiota development, behaviour and associated inflammatory and metabolic outcomes. In chapter 2, omega-3 supplemented (O3+), omega-3 deficient (O3-) and control diets were compared for their effect on behaviour and gut microbiota development in both adolescence and adulthood. O3- impaired communication, social and depressionrelated behaviours, whereas O3+ enhanced cognition. These behavioural changes were associated with alterations to gut microbiota composition and inflammatory outcomes such that O3- mice displayed an elevated Firmicutes:Bacteroidetes ratio and blunted systemic LPS responsiveness. Contrastingly, O3+ mice displayed greater fecal Bifidobacterium and Lactobacillus abundance and dampened hypothalamic-pituitaryadrenal axis activity. These results suggest that the beneficial effects of n-3 PUFA on neurobehavioural development are closely associated with comprehensive alterations in gut microbiota composition, HPA-axis activity and inflammation. Chapter 3 further assessed the role of n-3 PUFA on the cecal microbiota and metabolome. n-3 PUFA status induced subtle changes to the cecal microbiota in mothers and their offspring and, in addition, O3+ induced increased production of energy metabolites. O3- reduced production of short chain fatty acids. These results indicate that n-3 PUFA modulate cecal microbiota composition and function, which may have implications for chronic disease risk. In chapter 4, the transgenic fat-1 mouse model was utilised to examine the effects of maternal n-3 PUFA on offspring obesity risk. Offspring of mothers with a lower n-6/n-3 tissue ratio gained significantly less weight on a high fat diet. This reduced weight gain was associated with reduced gut permeability and changes to the gut microbiota and inflammatory outcomes. These results indicate that maternal n-3 PUFA status can significantly influence offspring adiposity through changes associated with gut microbiota. Algae are potent sources of n-3 PUFA and pose potential as alternative sustainable sources of such fatty acids than fish. However, little research has examined the effect of algae-derived n-3 PUFA on health. The aim of Chapter 5 was to screen the anti-inflammatory bioactivity of n-3 PUFA-rich algae lipid extracts. Exposure of the algae lipid extracts to lipopolysaccharide-stimulated THP-1 macrophages significantly reduced production of the pro-inflammatory cytokines IL-6 and IL-8 and the expression of a number of pro-inflammatory genes associated with toll-like receptor and chemokine activity. These data reveal that such n-3 PUFA-rich algae lipid extracts pose potential as anti-inflammatory functional ingredients. The aim of chapter 6 was to investigate the suitability of yoghurt as a food matrix in which to supplement an n-3 PUFA-rich lipid extract of Pavlova lutheri. Addition of the extract had little negative effect on the techno-functional properties of yoghurt. Furthermore, addition of the extract dose-dependently increased concentrations of n−3 PUFA. However, sensory analysis revealed that supplemented yoghurts were not well accepted. These results suggest that addition of this extract to yoghurt is a suitable method to increase n-3 PUFA concentration. Finally, Chapter 7 discusses the major findings and general conclusions arising from the work presented in this thesis. en
dc.description.sponsorship Teagasc (NutraMara programme (Grant-Aid Agreement No. MFFRI/07/01)); Enterprise Ireland (SMART FOOD project: ‘Science Based ‘Intelligent’/Functional and Medical Foods for Optimum Brain Health, Targeting Depression and Cognition’ project (Ref No. 13/F/411) with the support of the Marine Institute and the Department of Agriculture, Food and the Marine (DAFM) in Ireland) en
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher University College Cork en
dc.rights © 2016, Ruairi C. Robertson. en
dc.rights.uri en
dc.subject Microbiota en
dc.subject Omega-3 fatty acids en
dc.subject Inflammation en
dc.subject Algae en
dc.title Omega-3 fatty acids, gut microbiota and associated inflammatory outcomes en
dc.type Doctoral thesis en
dc.type.qualificationlevel Doctoral en
dc.type.qualificationname PhD (Science) en
dc.internal.availability Full text not available en Restricted to everyone for three years en 2020-04-17T12:24:39Z
dc.description.version Accepted Version
dc.contributor.funder Teagasc en
dc.contributor.funder Department of Agriculture, Food and the Marine en
dc.contributor.funder Marine Institute en
dc.contributor.funder Enterprise Ireland en
dc.description.status Not peer reviewed en Microbiology en Teagasc en
dc.check.reason This thesis is due for publication or the author is actively seeking to publish this material en
dc.check.opt-out Not applicable en
dc.thesis.opt-out false
dc.check.entireThesis Entire Thesis Restricted
dc.check.embargoformat E-thesis on CORA only en
dc.internal.conferring Summer 2017 en

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© 2016, Ruairi C. Robertson. Except where otherwise noted, this item's license is described as © 2016, Ruairi C. Robertson.
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