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Investigating the impact of dietary fibre on the gut microbiota

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thesis
posted on 29.03.2022, 01:18 by Hasinika Kalhari Ariyaratne Hewawasam Gamage
Diets low in complex polysaccharides have been shown to perturb the gut microbiota-host relationship, and thus impact host health. As evidence supporting this hypothesis continues to grow, therapeutic modulation of the gut microbiota through supplementation of complex polysaccharides for preventing or treating diseases has gained significant scientific and commercial interest. Several supplements in the form of dietary fibre or prebiotics are marketed commercially for this purpose. However, only limited work has been conducted to scientifically evaluate the ability of these products to alter the gut microbiota and improve host health. In this work, we investigated the impact of commercially available dietary fibre and cereal products on the gut microbiota and metabolite production. We used an in vitro adult digestive and gut microbiota model system and a high fat diet fed mouse model to examine the effect of dietary fibre supplementation on the gut microbiota, metabolites and host physiology. Using an in vitro infant digestive and gut microbiota model system we investigated the impact of cereal products on the infant gut microbiota and metabolites. Our results demonstrated significant shifts in the overall gut microbiota community structure upon addition of each product. The abundance of various bacterial taxa associated with fibre digestion and anti-inflammatory capabilities increased with fibre additions. However, the specific nature of the alterations was product-dependent. Fibre supplementation in mice ameliorated high fat diet-induced changes in the abundance of specific gut bacteria, whilst no significant changes in the glucose clearance or body weight were observed. Further, we demonstrated significant differences in the gut microbiota response to a high fat diet and fibre supplementation upon weekly overnight fasting in mice. The product-dependent impact on the gut microbiota and metabolites highlights the need for stringent scientific evaluation of commercial fibre products for their effect on the gut microbiota and host physiology.

History

Table of Contents

Chapter 1. Introduction -- Chapter 2. Fibre supplements derived from sugarcane stem, wheat dextrin and psyllium husk have different in vitro effects on the gut microbiota -- Chapter 3. Effect of fibre supplementation on high fat diet-induced changes in the mouse gut microbiota -- Chapter 4. Effect of weekly overnight fasting and fibre supplementation on the gut microbiota of mice fed a high fat diet -- Chapter 5. Cereal products derived from wheat, sorghum, rice and oats alter the infant gut microbiota in vitro -- Chapter 6. Conclusions and future directions -- Appendices.

Notes

Includes bibliographical references Empirical thesis.

Awarding Institution

Macquarie University

Degree Type

Thesis PhD

Degree

PhD, Macquarie University, Faculty of Science and Engineering, Department of Molecular Sciences

Department, Centre or School

Department of Molecular Sciences

Year of Award

2017

Principal Supervisor

Ian T. Paulsen

Rights

Copyright Hasinika Kalhari Ariyaratne Hewawasam Gamage 2017. Copyright disclaimer: http://mq.edu.au/library/copyright

Language

English

Extent

1 online resource (xxi, 250 pages) illustrations (some colour)

Former Identifiers

mq:71210 http://hdl.handle.net/1959.14/1271990