No description available.

No description available.

<p>Knowledge on fuel use and muscle metabolism in high altitude mammals is very limited. Yet, as the oxidation of carbohydrates offers an oxygen-saving advantage over the oxidation of fatty acids (15-30% more energy produced per oxygen used), one possible adaptation to maintain performance at high altitude is to elevate the use of carbohydrates as a fuel source for energy metabolism. To test this hypothesis, I performed intraspecific and interspecific comparisons of whole-body fuel use and muscle metabolism in closely related high (4000-4500 m) and low altitude (100-300 m) native mice (genus <em>Phyllotis</em>), which I collected at different locations in Andean and coastal regions of Peru. My results show a higher proportional use of carbohydrates when oxygen becomes limited in high altitude <em>Phyllotis</em> in comparison to their low altitude counterparts. This phenotype does not seem to result from similar phylogenetic history or from a chronic exposure to hypobaric hypoxia during development or adulthood. Accordingly, this thesis provides the first compelling evidence of enhanced carbohydrate utilization as an adaptation to high altitude, a hypothesis proposed nearly 30 years ago. The mechanisms responsible for this shift in fuel use are unknown. There were no strong indications of a greater capacity for carbohydrate oxidation in skeletal and cardiac muscles of high altitude <em>Phyllotis</em> mice. Finally, as this thesis provides the first report of whole-body fuel use in mice, a comparison with other mammalian species (rats, dogs and goats) revealed that the current model of mammalian fuel selection, which is thought to be conserved among mammals, does not apply to small mammals. I thus revisited the current model and proposed a new one general to all mammals. This thesis thus provides significant advancements not only in the field of high altitude physiology but also in the field of mammalian energetics.</p> / Doctor of Philosophy (PhD)

The absorption of free carbohydrates produced by digestion of dietary fiber in monogastric animals was investigated. Previous studies have shown that dietary fiber is partially digested by monogastric animals in its passage through the alimentary canal. However, the ability of monogastric animals to absorb the products of digestion of dietary fiber is uncertain. Male rats of the Sprague-Dawley strain were fed a refined carbohydrate diet in which sucrose comprised 66.6 percent. The urine of rats fed this diet contained only sucrose and its component monosaccharides, glucose and fructose, indicating that the carbohydrate composition of urine reflects the carbohydrate composition of the diet. The rats were then fed diets containing 5 percent guar gum (a galactomannan), 10 percent xylan (a polymer of xylose), or 10 percent wheat bran. The appearance in the urine of the component carbohydrates of the ingested dietary fiber was used as an indication of the absorption of the carbohydrates derived from fiber digestion. The urine of rats fed guar gum contained galactose. Rats fed xylan excreted xylose in the urine. Xylose and arabinose were identified in the urine of rats fed wheat bran. It is postulated that the polysaccharides of dietary fiber are degraded to simple sugars by bacteria in the colon. The results of this study indicate that free carbohydrates produced by digestion of dietary fiber are absorbed in monogastric animals. The potential nutritional and toxicological effects of the absorption of the carbohydrate components of dietary fiber are discussed. / Master of Science

An understanding of ecosystem-level carbon (C) sequestration, or net ecosystem production (NEP), requires the separation of heterotrophic, microbial respiration (RH) from autotrophic, root-derived respiration (RA) as the components of RS (i.e., NEP = NPP - RH). However, separating these two sources in situ has been problematic since they are closely coupled. This study utilizes two similarly aged Pinus taeda L. stands, 8 and 9 years-old, aimed at quantifying these two respiration components through in-situ root severing. In order to use root-severing treatments to separate RS into RH and RA components, confirmation of carbohydrate depletion coupled to RA decline is crucial. This study evaluated the changes in CO2 flux rates and carbohydrate supply upon root severing in Pinus taeda L. using a controlled laboratory validating a two-part field study. The first field study used root-severing cores to test in-situ if respiration components can be attained based on the depletion of carbohydrate supply. The second field study was aimed at how future changes in climate might affect the ability of forests to store C and how modern forestry practices might affect changes and was conducted over the course of two installations, spring and summer 2012. In this study we examined the effects of fertilization (0 and 100.9 kg N ha-1 ) and throughfall reduction (0 and -30%) on total soil respiration (RS) as well as the heterotrophic contribution to RS, in a fully replicated (n=4), 2x2 factorial design. In the controlled lab experiment RS and RA declined by 86% and 95% respectively by the end of an 86 day trial and NSC carbohydrates declined by 60% for soluble, 29% for insoluble, and 43% for total (soluble + insoluble). The decline of RA was highly correlated to with the decline of NSC’s at 0.90, 0.69 and 0.93 for soluble, insoluble and total, respectively. The companion field study revealed a mean decrease 21±0.5% of over the final three dates when severed root respiration stabilized. In the second study, testing throughfall reduction and fertilization levels there were no fertilization by throughfall reduction interactions on the contribution of RH to RS in either the spring or summer; however, the main effect of throughfall reduction was significant in the spring. During the spring, the mean contribution of RH to RS for ambient throughfall plots was 96±6.4%, while the mean contribution under throughfall reduction was 68±1.9%. During the summer, there were no differences among treatments and the overall contribution of RH to RS was 78±1.6%. Collectively, both of these studies revealed that the severing of roots from their primary energy source and the subsequent depletion of stored NSC that the use of in-situ methods allows for the quantification of soil respiration components RA and RH. Using these estimates to model NEP in the short-term can be variable by season, however, long-term monitoring may simplify future NEP modeling scenarios / Master of Science

Vem crescendo a cada dia o interesse pelo aproveitamento biológico dos carboidratos não-disponíveis no que se refere ao amido resistente (AR) e à fibra alimentar (FA) e seus efeitos sobre a fisiologia do intestino grosso. O objetivo do presente trabalho foi avaliar o efeito trófico, decorrente da fermentação de carboidratos não-disponíveis da banana verde, no intestino grosso de ratos adultos. As amostras estudadas foram: ABV (amido isolado de plátano verde - Musa paradisíaca L.) e MBV (banana nanicão - Musa acuminata, variedade Nanicão - verde cozida com casca, descascada e seca). Foi realizado estudo de média duração (28 dias) com ratos Wistar adultos, divididos em três grupos: grupo Controle (G-C), que recebeu ração padrão (R-C), e dois grupos experimentais, que receberam rações com concentrações crescentes de AR, ou seja, G-MBV recebeu ração R-MBV, com 5% de AR, e G-ABV recebeu ração R-ABV, com 10% de AR. Foram avaliados consumo e fermentabilidade in vitro das rações; peso corpóreo; peso e umidade das fezes; pH e histologia cecais. Não foi observada diferença no consumo médio diário de ração entre os grupos. O consumo de R-ABV proporcionou menor crescimento dos animais. No G-ABV, além da queda do pH cecal, houve aumento do peso seco das fezes e do conteúdo cecal, possivelmente devido ao aumento da microbiota intestinal. Ainda nesse grupo, houve aumento do peso total do ceco, evidenciando não somente ganho de umidade (aumento do peso do conteúdo cecal) como também possível proliferação celular (aumento do peso da parede do ceco). No G-MBV, houve queda do pH cecal, devido à produção de ácidos graxos de cadeia curta pela fermentação, e ganho de umidade no conteúdo cecal, resultado coerente com a maior presença de FA solúvel nesta ração. Porém, não houve aumento do peso seco das fezes nesse grupo. Pela análise histológica do tecido cecal, foi possível evidenciar que tanto a fermentação da R-ABV como a da R-MBV exerceram efeito trófico no intestino grosso desses animais (p<0,01). Os resultados obtidos indicam que os carboidratos não-disponíveis presentes na banana verde exercem efeitos positivos sobre a fisiologia dos animais, apontando a possibilidade de utilização dessa matéria-prima na elaboração de alimentos voltados para a prevenção de determinadas doenças crônicas não-transmissíveis. / The interest in unavailable carbohydrates, mainly in the possible effects of resistant starch (RS) and dietary fiber (DF) on the physiology of the large bowel, has recently increased. The present work aimed to evaluate the trophic effect, caused by the fermentation of unavailable carbohydrates from banana, on the large bowel of adult rats. Two samples were studied: ABV (starch isolated from unripe plantain - Musa paradisíaca L.) and MBV (unripe banana -Musa acuminata, variety Nanicão - cooked with peel, peeled and dried). An assay was carried during 28 days, with adult Wistar rats, divided into three groups: Control group (G-C), fed standard diet (R-C), and two experimental groups fed crescent RS concentrations (G-MBV, fed R-MBV with 5% RS, and G-ABV, fed R-ABV with 10% RS). Consumption and in vitro fermentation of the diets; body weight; feces weight and moisture; cecum pH and histology were evaluated. No difference was observed in the average daily consumption among the groups. Rats fed R-ABV presented decreased growth. On G-ABV, besides cecum pH decrease, there was an increase in feces and cecum content dry weight, possibly due to the increase in intestinal microbiota. There was an increase in cecum total weight, evidencing not only moisture gain (increase in cecum content weight) but also possible cellular proliferation (increase in the cecum wall weight). On G-MBV, there was a decrease in the cecum pH, due to the production of short-chain fatty acids by the fermentation, and moisture gain in the cecum content, which is coherent with the greater concentration of soluble DF in this diet. However, an increase in feces dry weight was not observed in this group. Considering the histology of the cecum tissue, it was possible to evidence that the fermentation of both R-ABV and R-MBV exerted trophic effect in the large bowel of the animais (p<0,01). The results obtained indicate that unavailable carbohydrates from unripe banana exert positive effects on the physiology of the animais, pointing to the possibility of using this product on the elaboration of foods aimed to preventing certain non-transmissible chronic diseases.

Vem crescendo a cada dia o interesse pelo aproveitamento biológico dos carboidratos não-disponíveis no que se refere ao amido resistente (AR) e à fibra alimentar (FA) e seus efeitos sobre a fisiologia do intestino grosso. O objetivo do presente trabalho foi avaliar o efeito trófico, decorrente da fermentação de carboidratos não-disponíveis da banana verde, no intestino grosso de ratos adultos. As amostras estudadas foram: ABV (amido isolado de plátano verde - Musa paradisíaca L.) e MBV (banana nanicão - Musa acuminata, variedade Nanicão - verde cozida com casca, descascada e seca). Foi realizado estudo de média duração (28 dias) com ratos Wistar adultos, divididos em três grupos: grupo Controle (G-C), que recebeu ração padrão (R-C), e dois grupos experimentais, que receberam rações com concentrações crescentes de AR, ou seja, G-MBV recebeu ração R-MBV, com 5% de AR, e G-ABV recebeu ração R-ABV, com 10% de AR. Foram avaliados consumo e fermentabilidade in vitro das rações; peso corpóreo; peso e umidade das fezes; pH e histologia cecais. Não foi observada diferença no consumo médio diário de ração entre os grupos. O consumo de R-ABV proporcionou menor crescimento dos animais. No G-ABV, além da queda do pH cecal, houve aumento do peso seco das fezes e do conteúdo cecal, possivelmente devido ao aumento da microbiota intestinal. Ainda nesse grupo, houve aumento do peso total do ceco, evidenciando não somente ganho de umidade (aumento do peso do conteúdo cecal) como também possível proliferação celular (aumento do peso da parede do ceco). No G-MBV, houve queda do pH cecal, devido à produção de ácidos graxos de cadeia curta pela fermentação, e ganho de umidade no conteúdo cecal, resultado coerente com a maior presença de FA solúvel nesta ração. Porém, não houve aumento do peso seco das fezes nesse grupo. Pela análise histológica do tecido cecal, foi possível evidenciar que tanto a fermentação da R-ABV como a da R-MBV exerceram efeito trófico no intestino grosso desses animais (p<0,01). Os resultados obtidos indicam que os carboidratos não-disponíveis presentes na banana verde exercem efeitos positivos sobre a fisiologia dos animais, apontando a possibilidade de utilização dessa matéria-prima na elaboração de alimentos voltados para a prevenção de determinadas doenças crônicas não-transmissíveis. / The interest in unavailable carbohydrates, mainly in the possible effects of resistant starch (RS) and dietary fiber (DF) on the physiology of the large bowel, has recently increased. The present work aimed to evaluate the trophic effect, caused by the fermentation of unavailable carbohydrates from banana, on the large bowel of adult rats. Two samples were studied: ABV (starch isolated from unripe plantain - Musa paradisíaca L.) and MBV (unripe banana -Musa acuminata, variety Nanicão - cooked with peel, peeled and dried). An assay was carried during 28 days, with adult Wistar rats, divided into three groups: Control group (G-C), fed standard diet (R-C), and two experimental groups fed crescent RS concentrations (G-MBV, fed R-MBV with 5% RS, and G-ABV, fed R-ABV with 10% RS). Consumption and in vitro fermentation of the diets; body weight; feces weight and moisture; cecum pH and histology were evaluated. No difference was observed in the average daily consumption among the groups. Rats fed R-ABV presented decreased growth. On G-ABV, besides cecum pH decrease, there was an increase in feces and cecum content dry weight, possibly due to the increase in intestinal microbiota. There was an increase in cecum total weight, evidencing not only moisture gain (increase in cecum content weight) but also possible cellular proliferation (increase in the cecum wall weight). On G-MBV, there was a decrease in the cecum pH, due to the production of short-chain fatty acids by the fermentation, and moisture gain in the cecum content, which is coherent with the greater concentration of soluble DF in this diet. However, an increase in feces dry weight was not observed in this group. Considering the histology of the cecum tissue, it was possible to evidence that the fermentation of both R-ABV and R-MBV exerted trophic effect in the large bowel of the animais (p<0,01). The results obtained indicate that unavailable carbohydrates from unripe banana exert positive effects on the physiology of the animais, pointing to the possibility of using this product on the elaboration of foods aimed to preventing certain non-transmissible chronic diseases.

The thesis deals with one group of small fruits, the genus Ribes, ie currants, and gooseberries. It assesses their physical and chemical parameters with respect to the possibility of use in these properties for the design of a new type of product – beverages. Titration, spectrometric and other methods were used for the evaluation of these properties. A total of fifteen of these methods were available (total juice yield, juice pH, total dry matter, soluble fruit dry matter, titratable acidity, formolic number, reducing carbohydrate content, D-glucose, D-fructose and sucrose content, total polyphenolic substance content, anthocyanins, vitamin C and total antioxidant capacity) and a total of nine analytes (copper, iron, magnesium, phosphorus, zinc, manganese, potassium, calcium and sodium) were selected for the determination of mineral elements. For two years (harvest 2014 and 2015), these parameters were monitored for color variants of currants (white, red and black) and gooseberries (green-fruited, yellow-fruited and red-fruited). A total of six white varieties were tested in the group of currants - Olin, Jantar, Primus, Blanka, Viktoria and Orion, eleven varieties of red currants - Junnifer, Jesan, Detvan, Rovada, Rubigo, J.V.Tets, Tatran, Losan, Kozolupský raný, Stanca, NŠLS 11/6 and eleven varieties of black currant varieties - Ometa, Démon, Triton, Ben Hope, Ruben, Ben Gairm, Ben Lomond, Moravia, Ben Conan, Fokus and Ceres. A total of five varieties of green-fruited gooseberries were tested - Zebín, Mucurines, Rixanta, Rodnik and Prima. Yellow-fruited gooseberries were available in four varieties - Lemon Giant, Invicta, Golden Fig and Darek. The red-fruited gooseberries included varieties - Rolonda, Alan, Karat, Karmen, Krasnoslawjanskij, Himnomacki Rot, Remarka, Tamara and Black Neguš. Using Tukey's test, an analysis was performed and by scoring individual varieties based on the results of individual analyzes, a list of recommended varieties was compiled for further work on the development of a new beverage. Unfortunately, in 2015 there were very few fruits of green-fruited and yellow-fruited gooseberries, so it was decided that the volume of fruit will fall on the testing of bioactive substances. Therefore, at the end of the work, it is not possible to objectively evaluate these varieties of gooseberries in the whole range of analyzes. Therefore, the point evaluation of varieties was based on the averages of individual varieties. The red-fruited varieties were available in full, and therefore a full evaluation could take place. The most significant differences between red gooseberry varieties were in the content of bioactive substances (the content of polyphenolic substances, anthocyanin dyes, and vitamin C) and antioxidant capacity. These results were provided to the food subject, which continued to work with these values. Based on this project, utility model No. PUV 2016-33171 and the resulting combined drink based on wine and fruit juice were developed.

Iminosugars are carbohydrate mimics, where the endocyclic ring oxygen has been replaced by nitrogen. This substitution affords these compounds their inhibitory activity towards sugar-processing enzymes (glycosidases) and, as a consequence, their chemotherapeutic potential in the treatment of a broad range of diseases. Several iminosugars are currently in clinical trials or have entered the market as approved drugs. This has consequently led to increasing levels of research into their synthesis and application, both in terms of the development of efficient methodology to access naturally occurring examples, and also to elaborate novel scaffolds. The presence of multiple chiral centres within iminosugars provides a considerable challenge in accessing these targets by asymmetric means, whereas carbohydrates pose a more attractive chiral pool. As such the majority of literature methods have employed this latter method. The focus of the thesis is on the elaboration of robust methodologies to access both naturally occurring and novel iminosugars, and their precursors, from readily available carbohydrate starting materials. Chapter 1 presents an introduction to iminosugars, including an overview of glycosidase inhibition by this class of sugar-mimic, their historical medical usage and the basis for their potential employment in treating diabetes, lysosomal storage disorders (LSDs) and cancer. This chapter also gives a general review of the methods employed in the literature for the assembly of iminosugar scaffolds. Chapter 2 is concerned with the synthesis of iminosugars from the carbohydrate glucuronolactone. This versatile chiron has previously allowed for access to many homochiral targets, and in this thesis is used to access DGJNAc on a gram-scale. This iminosugar has been shown to be a potent α-N-acetylgalactosaminidase inhibitor and is potentially extremely valuable in the treatment of late-stage cancer. Both enantiomers of glucuronolactone are also utilised in the divergent synthesis of every stereoisomer of two classes of five-membered iminosugars; the pyrrolidines (including DMDP), and the proline amides. These compounds demonstrate remarkable biological activity against a panel of glycosidases and hexosaminidases, allowing for the analysis of the structure-activity relationship between these compounds and the target enzymes. Chapter 3 describes the development of a novel, one-pot methodology - a tandem Strecker reaction and iminocyclisation - for the assembly of trihydroxy piperidine α-iminonitriles from a range of unbranched and branched pentose monosaccharides. These piperidine α-iminonitriles are precursors to pipecolic acids which may also be potentially valuable targets in the treatment of cancer.

Thesis (MScAgric (Animal Sciences))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: In recent years, the aim of the production of broilers became more focused on the increase of the performance of the birds in order to increase profit. To obtain an increased performance with broiler chicks, it is necessary to look at the development of their gastrointestinal tract, the feed requirements and the ability to digest certain nutrients in the period post hatch. Research have shown clear evidence of increased performance of chicks by the inclusion of certain carbohydrate and protein sources in the prestarter diets, but in contrast to this there are also some research that found no significant effects on the performance of broilers when certain carbohydrate and protein sources were included in the pre-starter diet. Therefore, the purpose of this study was to investigate the effect that a product containing specific carbohydrate and protein sources, included in the pre-starter diets of broiler chicks, would have on their performance. It was believed that the products to be tested would result in increased performance of the chicks in the following growth phases. Special emphasis was placed on the average daily gain (ADG), feed intake, cumulative feed intake, feed conversion ratio (FCR), European production efficiency factor (EPEF) and the protein efficiency ratio. Different inclusion levels of the different raw materials were investigated in the first trial. Three raw materials and a control were compared using a summit dilution process at 100:0, 66:34, 50:50, 34:66 and 0:100. Specific production parameters such as ADG total live weight gain, feed intake per week, cumulative feed intake, FCR, EPEF and PER were measured and calculated in order to determine if there were any significant differences between the treatments with the different raw material inclusions on the performance of the chicks. No significant differences (P>0.05) were found between the 13 treatments for the ADG, total live weight gain, feed intake per week, cumulative feed intake, FCR, EPEF and PER. The results therefore indicated that there were no significant differences between the different inclusion levels of the different raw materials and no significant differences for the production parameters for animals receiving diets with various levels of the three raw materials. It is thus concluded that these raw materials can be successfully utilised in pre-starter diets of broiler chicks. The effect of the contribution of sugar to the metabolisable energy (ME) of the raw materials was tested in a commercial grower trial. The three raw materials had inclusion levels leading to supply of either 12% or 18% of the ME in the form of sugar. No significant differences were found between the seven treatments for ADG, total live weight gain, feed intake per week, cumulative feed intake, FCR, EPEF or the PER. It was concluded that the percentage in contribution of sugars between 12 and 18% to the ME of the prestarter diets had no significant effects on the production parameters tested. / AFRIKAANSE OPSOMMING: Met die produksie van braaikuikens word daar deesdae al hoe meer klem gelê op die verhoging van die produksie van die kuikens om dan dus ‘n verhoging in die wins te bewerkstellig. Om hierdie verhoogde produksie by braaikuikens te kan bereik, is dit nodig om na eienskappe van die kuiken soos die ontwikkeling van die spysvertering stelsel, die nutrient- behoeftes van die kuiken en die vermoë om sekere nutriënte te kan verteer in die periode na uitbroei. Sommige navorsing het gewys dat die insluiting van sekere koolhidraat – en proteïen bronne in die voor-aanvangs diëete van braaikuikens, lei tot ‘n positiewe effek op die produksie van die kuikens, waar ander navorsing geen effek gevind het nie. Daarom was die doel van die huidige navorsing gewees om te toets wat die effek van die insluiting in die voor-aanvangs dieet van braaikuikens ‘n sekere produk met ‘n spesifieke koolhidraat –en proteïen bron samestelling op die produksie van die kuikens sal wees in die daaropvolgende fases. Dit was verwag dat die insluiting van hierdie produkte in die voor-aanvangs diëte van braaikuikens ‘n positiewe effek sou hê op die produksie van die kuikens. Spesiale klem was gelê op die parameters soos gemiddelde daaglikse toename (GDT) voer inname, kumulatiewe voer inname, voeromset verhoudings (VOV) Europese produksie doeltreffendheids- faktor (EPEF) en die proteïen doeltreffendheids faktor (PER). Verskillende insluitings vlakke van die verskillende produkte wat getoets is, is in die eerste proef ondersoek. Die drie produkte is deur middel van ‘n piek verdunnings proses by verhoudings van 100:0, 66:34, 50:50, 34:66 en 0:100 met mekaar vergelyk. Spesifieke produksie- parameters soos die GDT, lewende massa, weeklikse voer- inname, kumulatiewe voer- inname, VOV, EPEF en die PER is gemeet. Geen betekenisvolle verskille (P>0.05) was vir die 13 behandelings verkry nie. Die resultate het derhalwe getoon dat daar geen betekenisvolle verskille tussen die verskillende insluitings vlakke van die onderskeie produkte was nie en dat daar geen betekenisvolle tussen die produksieparameters van die kuikens wat die diëte met die verskillende insluitingspeile van die drie roumateriale ontvand het, was nie. Daarom is tot die slotsom gekom dat hierdie roumateriale suksesvol in die vooraanvangsdieet van braaikuikens aangewend kan word. Die effek van die bydrae van die suiker tot die metaboliseerbare energie (ME) van die produkte was in ‘n kommersiële groei proef getoets. Die drie rou materiale was by beide 12- en 18% ingesluit. Geen betekenisvolle verskille (P>0.05) was vir die sewe behandelings vir GDT, lewende massa, weeklikse voer- inname, kumulatiewe voer- inname, VOV, EPEF en PEF verkry nie.