7. Zusammenfassung Untersuchungen zur Bedeutung der Magen-Darm-Flora auf das Immunsystem von Hühnern Nasser Ali Abou Hashem Elsayed Instiut für Bakteriologie und Mykologie, Veterinärmedizinische Fakultät, Universität Leipzig Leipzig, Juli, 2002 (128 Seiten, 60 Abbildungen, 21 Tabellen und 227 Referenzen) Viele komplexe bakterielle Kontrollmechanismen der Darmmikroflora sind am Ausschluss pathogener Keime beteiligt. Dysregulationen im gastrointestinalen Ökosystem können den schützenden Effekt der indigenen Mikroflora schwächen, was die Kolonisation von pathogenen Keimen im Darmkanal begünstigt. Dysregulationen im gastrointestinalen Ökosystem treten bei Jungtieren hauptsächlich unter Stress, bei der Futterumstellung oder Verdauungsstörungen in Erscheinung. Alle diese Situationen kommen bei Jungvögeln vor. Dem zu Folge ist es nicht überraschend, dass Jungvögel empfindlicher für die Kolonisation von pathogenen Darmerregern wie Salmonellen sind. Das Verstehen der gastrointestinalen Mikroflora ist nicht nur für die Entwicklung von Probiotika sondern auch für das Entwickeln neuer Präbiotika wichtig. 1. Effekt von 0.5% Inulin im Trinkwasser und 1% Leinsamen im Futter auf die natürliche Besiedlung junger Küken mit S. Enteriditis, die Zugaben von Inulin im Trinkwasser (I-Gruppe) oder Inulin und Leinsamen (IL-Gruppe) an die jungen Küken führte zur Reduzierung der Nachweisrate von S. Enteritidis bei natürlich besiedelten Küken. 2. Effekte von 0.5% Inulin im Trinkwasser und 1% Leinsamen im Futter auf die intestinale bakterielle Besiedlung und den Immunstatus von SPF Hühnern, die bakteriologischen Untersuchungen offenbarten einen signifikanten Abfall der aeroben Gesamtbakterienzahl im Dünndarm und in Zäkum, aber nicht in Kropf und Rektum, insbesondere von der dritten Versuchswoche in den IL- und I-Gruppen gegenüber den Kontrolltieren. Die Zahl der gramnegativen Bakterien war in der zweiten Woche im Kropf und Dünndarm in den IL- und I-Gruppen deutlich rückläufig sowie in der dritten Woche im Zäkum und Rektum aber nicht in der C-Gruppe. Die Bdellovibrionenzahl stieg signifikant nur im Zäkum und im Rektum der IL- und I-Gruppen an, dem gegenüber konnten in der C-Gruppe keine Bdellovibrionen isoliert werden. Bedeutsame Unterschiede der Körpergewichte zwischen all den Gruppen zeigten sich nicht, wobei das signifikante Ansteigen die Quotient aus Bursa Fabricii/Körpergewicht in den IL- und I-Gruppen gegenüber der C-Gruppe auffielen. 3. Effekte von Inulin auf die Darmflora, den Endotoxin- und PC-BP-Blutspiegel und den Immunstatus von Broilern, nach der ersten Woche der Inulin-Verabreichung zeigten sich kaum Unterschiede in den Gesamtzahlen der aeroben Bakterien im Zäkum in der I-Gruppe (mit Inulin) und C-Gruppe (ohne Inulin). Hingegen stieg die Gesamtkeimzahl in der I-Gruppe gegenüber der C-Gruppe deutlich an. Gramnegative Bakterien fielen zahlenmäßig nach 2 Wochen deutlich bei der I-Gruppe ab. Die Bdellovibrionen steigen nach einer Woche in dieser I-Gruppe etwas an. Ab der zweiten Woche bis zum Ende des Versuchs (also nach 5 Wochen) stieg die Bdellovibrionenzahl in der I-Gruppe signifikant gegenüber der C-Gruppe. Dem gegenüber fiel die C. perfringens-Zahl in dieser I-Gruppe ab, welches in der ersten Versuchswoche von geringer Signifikanz war. In der dritten Woche fielen die zäkalen C. perfringens-Zahlen deutlich in der I-Gruppe gegenüber der C-Gruppe ab, wobei die Clostridien negativ zu den Bdellovibrionen im Zäkum korrelierten. Die Entwicklungen der Körpergewichte im Vergleich der beiden Gruppen zeigten insbesondere ab der 5.Woche signifikante Vorteile in der I-Gruppe. Die Quotienten aus Bursa Fabricii/Körpergewicht und Pankreas/Körpergewicht nahmen deutlich 2 Wochen nach der Inulin-Verabreichung bis zum Versuchsende zu. Die Endotoxin-Blutspiegel reduzierten sich in der I-Gruppe im Vergleich zu den Kontrolltieren besonders deutlich zum Ende des Experiments in der 6. Woche. Ebenso war eine Reduktion des PC-BP-Blutspiegels in der I-Gruppe in der zweiten Woche feststellbar in der 5.Woche. Die PC-BP-und Endotoxin-Blutspiegel korrelierten negativ zu den Körpergewichtzunahmen. Ebenso wirkten sich Zunahmen der aeroben Gesamtkeimzahl, gramnegativen- und Clostridien-Zahlen ungünstig auf die Körpergewichtszunahmen aus. Andererseits zeigt sich hierbei eine positive Korrelation zwischen der Bdellovibrionenzahl und der Körpergewichtzunahme. 4. In den Untersuchungen zur Dynamik der normalen Darmflora im Zäkum der jungen Broiler und erwachsenen Zuchthühner, fanden wir eine umgekehrte Beziehung zwischen dem zahlenmäßigen Vorkommen von Bdellovibrionen und C. perfringens. Die Anzahl der Bdellovibrionen korrelierte negativ zu den aeroben Gesamtkeimzahlen, den gramnegativen und C. perfringens-Bakterienzahlen sowie Endotoxin- und PC-BP (phosphoryl choline-binding protein)-Blutspiegeln. Andererseits korrelierten sie positiv zu den Quotienten aus Bursa Fabricii/Körpergewicht und Pankreas/ Körpergewicht. Die Endotoxin- und PC-BP-Blutspiegel korrelierten positiv mit dem Anstieg der Gesamtkeimzahlen. Das Pankreas/Körpergewicht-Verhältnis korrelierte positiv zum Verhältnis Bursa Fabricii/Körpergewicht. Die Resultate der vorliegenden Untersuchungen weisen darauf hin, dass Inulin für Hühner schützende Effekte offeriert: 1) Deutlich abnehmende intestinale Keimzahlen von C. perfringens. 2 ) Anstieg der Bdellovibrionenzahl. 3 ) Abfall des Endotoxin-Blutspiegels. 4 ) Abfall des PC-BP-Blutspiegels. 5 ) Verbesserung des Immunstatus der Vögel. Aus unseren Resultaten und vorhergehenden Studien können wir feststellen, dass Inulin- und Leinsamen als Funktionelle Futtermittel bei Geflügel eingestuft werden können, weil sie das Risiko einiger Erkrankungen verringern (z.B. durch Salmonellen). Inulin und Leinsamenl besitzen förderliche Effekte auf die intestinale Mikroflora und verbessern den Immunstatus der Tiere. Sie spielen eine wichtige Rolle in der Erhaltung der Homöostase in den ökologischen Systems des Magen-Darm-Traktes. Weiterführende Untersuchungen wären wünschenswert in Bezug auf die diätetischen Effekte des Inulins auf die anderen wichtigen Vertreter der Darmflora bei Hühnern wie Laktobazillen und Bifidobakterien. Auch die Kombination von Inulin mit Probiotika (Synbiotika) und deren Rolle zur verbesserten lokalen Immunität des Gastrointestinaltrakts und der kompetiven Exclusion pathogener Bakterien wie Salmonella-Serovare wären zu untersuchen. / 6. Summary Investigations on the significance of the gastrointestinal flora for the immune system of chickens Nasser Ali Abou Hashem Elsayed Institute of Bacteriology and Mycology, Faculty of Veterinary Medicine, University of Leipzig. Leipzig, July, 2002 (128 pages, 60 figures, 21 tables and 227 references) Many complex bacterial control mechanisms are involved in regulating the composition of the gut microflora and in excluding intestinal pathogens. Imbalances in the gastrointestinal ecosystem can weaken the protective effect of the indigenous microflora which gives enteric pathogen a better chance to colonize in the gut. Imbalances in the ecosystem mainly occur in the young animal, during periods of stress, changes in the periods of nutritive application and/ or digestive disorders. The young bird combines all these situations. It therefore not surprise that the young bird is prone to the colonization with enteric pathogens such as salmonellae. Understanding the gastrointestinal microflora is essential not only for the development of probiotics but also for developing new prebiotics. 1- Effect of inulin 0.5% via drinking water and feed supplement with 10% linseed on the natural colonization of young chicks with S. Enteritidis was examined; the addition of inulin to the drinking water (I-group) or inulin and linseed to the young chicks (IL-group) reduced the incidence of a naturally intestinal colonization with S. Enteritidis. 2- Effect of inulin 0.5 % via drinking water and food supplemented with 1% linseed on the intestinal bacterial population and the immune status of SPF chicken was investigated, the bacteriological examinations revealed a significant decrease in total aerobic bacterial count in the small intestine and caecum only but not in the crop and rectum of the IL-group and I-group respectively at the third week of the trial in comparison with control birds. Gram-negative bacterial counts also were significantly decreased in crop and small intestine of IL-group and I-group at the second week and in the caecum and rectum at the third week but not in the C-group. Bdellovibrio bacteriovorus counts were significantly increase only in the caecum and rectum of the IL-group and I-group respectively at the second week but can not be isolated from the C-group. There was no important difference in BW between all groups but there was a significant increase in BF/BW ratio in the I- group and in the IL-group than in C-group indicated increase immune capacity of IL-group and I-group. 3- The effect of inulin on the intestinal flora, endotoxin and PC-BP blood levels and on the immune status of broiler chicken was investigated, There was no significant difference in the total aerobic bacterial counts in the caecum of I-group (with inulin) and C-group (without inulin) after one week of inulin administration but at the second week the total bacterial count by I-group was significantly decreased than in C-group. Gram-negative bacterial counts were also significantly decreased after 2 weeks of inulin administration by I-group, whereas the Bdellovibrio counts were slightly increased in I-group after one week of inulin administration. At the second week and until the end of the experiment (5 weeks) the Bdellovibrio counts were significantly increased in I-group than in C-group. On the other hand, there was a decrease in the C. perfringens caecal counts of I-group, which were slightly significant at the first week of the experiment. At the third week there was a strongly significant decrease in C. perfringens caecal counts of the I-group in comparison with C-group. There was also a negative correlation between C. perfringens and Bdellovibrio caecal counts. There were no significant changes in BW between I-group (with inulin) and C-group (without inulin) during the experiment but at the 5th week, there was a significant increase in the BW of I-group, whereas there was a significant increase in BF/BW ratio in the I-group after 2 weeks of inulin administration until the end of the experiment. The endotoxin level in the blood of I-group was significantly reduced in comparison with control birds especially at the end of the experiment at 6th week. There was also a significant reduction in phosphoryl choline binding protein (PC-BP) at the second week and at the 5th week in the blood of the I-group in comparison with control birds. The PC-BP, endotoxin levels in the blood of birds were negatively related to the growth rates of BW. Also at increasing total aerobic, gram-negative and clostridial bacterial counts there were an adverse effect on the BW, whereas there was a positive correlation between Bdellovibrio count and growth rate of BW of birds. 4- When studying the dynamic of normal caecal flora of young (broilers) and adult (breeders) chicken we have found a conversely relationship between Bdellovibrio and C. perfringens counts. The Bdellovibrio count was negatively related to total aerobic, gram-negative bacterial counts and endotoxin blood level. On the other hand Bdellovibrio caecal counts were positively related with the BF/BW and P/BW ratios and to body weight, whereas the increase in the endotoxin and PC-BP blood levels had negative effect on these immune ratios. The endotoxin blood levels were also found positively related to phosphoryl choline-binding protein (PC-BP) levels and to increasing in the total aerobic and gram-negative bacterial counts. P/BW ratio was positively related with BF/BW ratio. Results of the present studies indicate that inulin offer protection to chickens by: 1- Markedly decreased intestinal colonization by C. perfringens counts. 2- Increase in Bdellovibrio bacteriovorus counts. 3- Decrease in the endotoxin level of blood. 4- Decrease in the PC-BP level of blood. 5- Enhancing the immune status of the bird. From our results and previous studies, we can conclude that inulin and linseed can be classified as functional diat in poultry, because they reduce the risk of some diseases (like Salmonella). Inulin and linseed have enhanced effects on the intestinal microflora and on the immune status of birds and play important role in the maintenance of homeostasis in the ecological system. Additional research is required in order to determine the effect of dietary inulin on the other important intestinal flora of chicken like Lactobacillus and bifidobacteria. Also the combination of inulin with probiotic (synobiotic) and their role in enhancing the local immunity of gastrointestinal tract and the competitive exclusion against pathogenic bacteria like Salmonella.

Techn. University, Diss., 2005--München.

Thesis was divided into two parts. The first theoretical part describes the raw material for the production of coffee and coffee substitutes. It characterizes important substances contained in coffee such as chlorogenic acid and caffeine in coffee or inulin supplements and describes their effects on the human body. The second part deals with the determination of total polyphenols using the Folin-Ciocalteu reagent in 9 selected samples of roasted coffee, green coffee and coffee substitute mixtures with the addition of instant coffee. These samples were measured content of caffeine and chlorogenic acid by HPLC with UV-VIS detector. From the measured values showed that the highest content of chlorogenic acid was in the samples of green coffee of 200 mg / 100 ml cup of coffee (7 g). Caffeine reached the highest content of coffee roasted at 85 mg / 100 ml of coffee. The samples were also subjected to sensory analysis, where the best impression detected in samples of roasted coffee. Worst overall impression was recorded at a sample of substitutes with instant coffee.

The investigation on inulin, which forms the subject of the present thesis, is an extension of the earlier work of Irvine and Steele, who placed the study of this polysaccharide on an exact basis.

The purpose of the study was to compare the impact of 3 weeks of consumption of commercial yoghurt enriched with Bifidobacterium animalis subsp. lactis BB-12 and Lactobacillus acidophilus LA-5 (P), and the same yoghurt supplemented with prebiotic-inulin (S), on feacal bacterial counts of healthy adults. A randomized, parallel-group, crossover, open-label – DBPC intervention with 66 volunteers was carried out. The 3 week administration of both P and S yoghurt increased (P lower 0.01) counts of bifidobacteria and Lactobacillus acidophilus, and reduced (P lower 0.01) counts of Clostridium spp., Enterococcus spp. and E. coli in fecal samples, in comparison with the control croup. The consumption of probiotics and synbiotics yoghurt reduced (P lower 0.05) the counts of tyramine producing enterococci and E. coli among the faecal isolates. In the synbiotics group, counts of bifidobacteria and Lactobacillus acidophilus remained higher, and counts of Clostridium spp., Enterococcus spp. and E. coli lower (P lower 0.05) after 1 week wash out period, in comparison with the preadministration phase. It was concluded that the synbiotics yoghurt was superior to the probiotics product in maintaining the increased levels of beneficial bacteria and decreased counts of potentially patogens bacteria in the intestine.

Yacon (Smallanthus sonchifolius) root products are susceptible to oxidation, reduced quality and functional properties. The optimum water blanching process for yacon root slices was determined through a central composite design with variable temperature (80-100 degrees Celsius), blanching time (2-6 min), and citric acid concentration (0.04-0.20%). Phenolics and fructooligosaccharides of yacon slices were also evaluated after blanching. Yacon slices (3-4 mm) blanched at 90 degrees Celsius, 3.9 to 4.1min, and 0.05% to 0.07% citric acid showed the lowest polyphenol oxidase activity, highest whiteness value, and the highest sensory appearance scores. A second experiment showed that blanching at 100 degrees Celsius with 0.07% citric acid can maintain higher chlorogenic acid (3.52 mg/g more), inulin (5.41% more), and total sugar (34.9%) in yacon slices than blanching without citric acid. Thus, addition of less than 0.1% citric acid to boiling water can minimize loss of functional components of yacon slices during blanching.

Anxiety disorders, including generalized anxiety disorder (GAD), are prevalent mental health conditions with a complex etiology. The gut microbiota and diet have emerged as important factors in modulating anxiety symptoms. This thesis aimed to investigate the relationship between gut microbiota composition and anxiety symptoms in the context of GAD. This involved an in silico analysis of a cohort of GAD patients and healthy controls, coupled with experiments using a microbiota-humanized mouse model. A comprehensive in silico analysis was conducted using basic statistics and machine learning techniques on the human cohort. The analysis explored the associations between anxiety symptoms and various factors, including demographics, dietary intake, gastrointestinal symptoms, inflammatory markers, stool metabolites, microbiota composition, and PICRUSt2 microbiota predicted function. GAD patients exhibited higher gut microbiota abundance of Bacteroides, which was positively associated to carbohydrate degradation pathways. Machine learning analysis identified abdominal pain as a key indicator for distinguishing GAD donors. Moreover, anxiety symptoms were negatively correlated with inulin intake in GAD patients, altogether suggesting an association between a carbohydrate degradation imbalance in the GAD microbiota, abdominal pain, and anxiety symptoms. To investigate further, germ-free mice were colonized with stool samples from healthy controls and GAD patients, and they were fed either a low or high-fiber (inulin) diet. Assessments included behavioral tests, microbiota analysis, colonic gene expression, and mucus degradation. Bacteroides abundance positively correlated with anxiety-like behavior, mucus degradation, and expression of colonic genes related to immune activation, pain, and intestinal permeability, further supporting the results observed in the donor cohort. Improvements in metabolic parameters were also observed in mice fed high-fiber diet. Furthermore, we found that inulin dosage played a crucial role in mediating the observed immune activation and anxiety-like behavior, with excessive inulin supplementation showing a detrimental effect. This study provides insights into the complex relationship between dietary fiber, gut microbiota composition, and anxiety symptoms in mice and humans. Further studies are needed to determine optimal dosages of inulin supplementation as a potential therapeutic approach for managing anxiety symptoms. / Dissertation / Doctor of Philosophy (Medical Science) / Generalized anxiety disorder (GAD) is a common anxiety disorder that has complex causes. There's growing evidence that gut bacteria, known as microbiota, along with diet, can impact anxiety symptoms. In our study, we explored this connection by examining a group of GAD patients and healthy individuals, and by conducting experiments using a mouse model. We found that GAD patients have a microbiota with higher levels of Bacteroides and higher ability to feed from carbohydrates compared to healthy controls. We believe this is associated to abdominal pain and higher anxiety symptoms. To explore this in more depth, we introduced the gut microbiota from GAD patients and healthy controls into mice with no previous microbiota. Because we also found that GAD patients who ate foods with more specific fiber (inulin) content had less anxiety symptoms, we fed them a low or high-inulin diet and assessed anxiety-like behavior. We found that Bacteroides levels were associated with high anxiety-like behavior and gene expression in the colon associated to inflammation and pain in mice, further supporting the results found in the humans. Although more research is still needed, this study helps us better understand how the interaction between dietary fiber and gut bacteria can affect anxiety.

Submitted in complete fulfillment for the Degree of Master of Technology: Biotechnology, Durban University of Technology, 2010. / Xanthomonas campestris pv phaseoli produced an extracellular endoinulinase on various carbon sources. The highest inulinase production of 9.24 ± 0.03 IU ml¯¹by X. campestris pv. phaseoli was attained using an optimized medium comprising of 3% sucrose and 2.5% tryptone. Inulinase production in X. campestris pv. phaseoli was further enhanced through ethylmethanesulfonate mutagenesis. The resulting mutant, X. campestris pv. phaseoli KM 24 demonstrated enhanced inulinase production of 22.09 ± 0.03 IU ml¯¹after 24 h, which was 2.4 – fold higher than that of the wild type. Inulinase production by this mutant was scaled up in a 5 L fermenter yielding a final activity of 21.87 ± 0.03 IU ml¯¹with an inulinase/invertase (I/S) ratio of 2.6 after 18 h. Maximum volumetric (21 865 IU 1¯¹ h¯¹) and specific (119 025 IU g¯¹ h¯¹) productivities of inulinase were attained in a fermenter after 18h growth. Inulin hydrolysis by the crude inulinase and subsequent detection of mono- and oligosaccharides indicated the presence of an endoinulinase. The extracellular endoinulinase from the mutant KM 24 was purified to homogeneity by gel filtration chromatography and had a specific activity of 174.74U/mg. the optimum pH and temperature of the purified enzyme were found to be 6.0 and 50°C, respectively. The enzyme was stable up to 60°C, retaining over 60% activity for 30 min, but activity rapidly declined at temperatures above 60°C. The pure inulinase enzyme was also found to be stable between pH 6-9. The Lineweaver-Burk plots showed that the apparent Km and Vmax values of the inulinase for inulin were 1.15 mg/ml and 15µM/min, respectively. The Kcat value was found to be 0.145 min¯¹ with an enzyme catalytic efficiency of 0.126 mg¯¹.ml.min¯¹.This mutant demonstrated good potential for large scale production of inulinase and fructooligosaccharides. / National Research Foundation

Metabolic syndrome (MetS) is a group of obesity-related metabolic abnormalities that predisposes to type II diabetes mellitus (T2DM) and cardiovascular disease. The dramatic increase in incidence of obesity and MetS over the last 25 years amidst relatively constant host genetics supports the role for non-genetic factors such as gut microbiota composition as an important contributor to the development of these disorders. Microbiota can interact with the host, in a manner influenced by genetics and diet that result in low-grade chronic inflammation. A critical risk factor for the pathogenesis of obesity and its related MetS involves alteration of gut microbiota composition with increased innate immune system activation in the intestine increasing risk. Diet-induced obesity is often modeled by comparing mice fed high-fat diet (HFD), which is made from purified ingredients, vs. normal chow diet (NCD), which is a low-fat assemblage of relatively unrefined plant and animal products. The mechanism by which HFD promotes adiposity is complex but thought to involve low-grade inflammation and altered gutmicrobiota. Here, I investigated the extent to which physiological effects to which HFD-induced adiposity is driven by fat content per se vs. other factors that differentiate HFD vs. NCD or other compositionally-defined diets (CDD) and, moreover sought to define the mechanisms that drove such effects. Relative to NCD, HFD, and to a lesser but nonetheless significant extent, CDD induced increased adiposity in addition to a rapid and marked loss of cecal and colonic mass, indicating that both lipid content and other aspects of HFD are obesogenic.CDD-induced effects were not affected by adjusting dietary protein levels/types but could be largely eliminated by exchanging insoluble fiber (cellulose) for soluble fiber (inulin). Moreover, replacing cellulose with inulin in HFD protected mice against decreased intestinal mass, hyperphagia and increased adiposity. Such protective effects of inulin correlated with increased levels of short-chain fatty acids, which are the products of bacterial fermentation of inulin. Lack of a microbiota, achieved by use of germ-free mice prevented generation of SCFA and eliminated the beneficial effects of inulin. Together, these results indicate that HFD-induced obesity is promoted by its lack of soluble fiber, which, when present, supports microbiota-mediated intestinal epithelia homeostasis that prevents inflammation driving obesity and MetS.

Environmental contamination is a public health concern. In particular persistent organic pollutants like Polychlorinated Biphenyls (PCBs) have been associated with multiple chronic inflammatory diseases, including non-alcoholic fatty liver disease (NAFLD). NAFLD prevalence has steadily increased and is expected to continue to rise with an estimated 25% of the world’s population and 80-100 million people affected in the United States alone. Importantly, the liver is the primary site for endobiotic and xenobiotic metabolism, hence its proper function is critical for the body’s response to innate and extrinsic molecules. One way to combat the deleterious effects of PCB toxicity and fatty liver disease is by increasing consumption of beverages and foods that contain beneficial bioactive nutrients, like dietary polyphenols. However, the biological properties of these dietary compounds are subject to their bioavailability which is directly dependent on the activity of the liver. The first aim of this dissertation was to test the hypothesis that in the presence of a compromised liver, PCB-126 toxicity is altered. Indeed, hepatic and systemic PCB-126 toxicity was exacerbated in this severe liver injury mouse model with an observed increase in hepatic inflammation, systemic inflammation, and early markers of endothelial cell dysfunction. Interestingly, we also observed an increase in the novel gut-liver axis derived cardiovascular disease (CVD) marker trimethylamine-N-oxide (TMAO). Taken altogether, aim 1 proved that a compromised liver can alter PCB toxicity, with implications of the gut microbiota in disease pathology. In aim 2 we investigated whether GTE can protect against MCD-induced hepatic toxicity and development of NAFLD. Results indicated that MCD mice exhibited severe liver injury and gut dysbiosis and unexpectedly, GTE had no protective effects. Interestingly MCD mice displayed differential epigallocatechin-3-gallate (EGCG) metabolism at the hepatic and gut microbiota level, which may alter polyphenol bioavailability and therapeutic potential. Overall, the results provide insight into how a dysfunctional liver and gut dysbiosis can alter polyphenol metabolism, possibly reducing its therapeutic efficiency. In aim 3 we sought to determine potential protective effects of a prebiotic in this mouse model. MCD-fed mice were exposed to PCB-126 with or without inulin supplementation. Although findings from this study are preliminary, our evidence indicates that inulin restores body weight and body composition in this MCD+PCB mouse model and alters the expression of Cyp1a1 in PCB exposed mice, suggesting that inulin’s protective effects may be a result of its ability to interact with the AhR pathway. However further analysis will need to be done to examine the effects of inulin on hepatic, systemic, and gut microbiota endpoints. Overall the data contained in this dissertation suggests that in the presence of a compromised liver both pollutant toxicity and nutrient metabolism are altered, with implications of the gut-microbiota in disease risk. These findings suggest that individuals with end stage liver injury may be more susceptible to pollutant-induced toxicity and nutritional intervention may be unsuccessful at mitigating disease risk.