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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
471

Efeitos da suplementação de probióticos na prevenção da obesidade e suas complicações em camundongos Swiss / Effects of probiotics supplementation on the prevention of obesity and its complications in Swiss mice

Zambon, Renata Alvares Bagarolli, 1984- 23 August 2018 (has links)
Orientador: Mario Jose Abdalla Saad / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-23T21:44:54Z (GMT). No. of bitstreams: 1 Zambon_RenataAlvaresBagarolli_D.pdf: 7972972 bytes, checksum: 0c4feccde8df219c21aef1c3e8740fc0 (MD5) Previous issue date: 2013 / Resumo: A obesidade é caracterizada por processo inflamatório crônico e resistência à insulina (RI), os quais são responsáveis por grande parte de suas doenças associadas. Sabe-se que diversas moléculas do sistema imune inato estão associadas à RI e obesidade, destacando-se o receptor toll-like-receptor 4 (TLR4). Sua via de sinalização está ativada na obesidade, devido à presença aumentada na circulação de seu principal ligante, lipopolissacarídeo (LPS). Acredita-se que esta endotoxemia metabólica seja causada por alterações na microbiota e na permeabilidade intestinais, o que torna o intestino e as bactérias que o habitam, grandes alvos para o tratamento da obesidade. O objetivo deste presente trabalho foi avaliar os efeitos dos probióticos (PB) na sensibilidade à insulina e na sinalização de TLR4 em tecidos insulino-sensíveis, além de verificar suas possíveis ações na microbiota intestinal. Dessa forma, camundongos Swiss foram divididos em 4 grupos: controles (C), controles tratados com PB (C+PB), obesos (DIO) e obesos tratados com PB (DIO+PB). O tratamento teve a duração de 5 semanas. O uso de PB em animais obesos proporcionou grandes melhoras nos parâmetros fisiológicos e moleculares de RI, além de atenuar a ativação da via de sinalização do TLR4, provavelmente pela redução dos níveis circulantes de LPS. O grupo DIO+PB ainda mostrou mudanças positivas na distribuição dos filos de bactérias intestinais e menor permeabilidade intestinal, quando comparado com o grupo DIO. Analisando o hipotálamo, observou-se que o uso de PB nesse modelo de obesidade regulou de forma favorável os mecanismos centrais de controle da fome, bem como alguns parâmetros de inflamação. Assim, conclui-se que a regulação da microbiota intestinal promovida pela administração de probióticos pode trazer benefícios no controle da obesidade, por reduzir ou atenuar mecanismos moleculares de resistência à insulina / Abstract: Obesity is the main risk factor to the development of insulin resistance and type 2 diabetes. The common basis among these events is an inflammatory process characterized by the activation of toll-like receptor 4 (TLR4) by its main ligand lipopolysaccharide, LPS. Its concentration is higher in obese people and it is believed that changes in composition of the gut microbiota and epithelial functions may play a role in the inflammation associated with obesity. The aim of the study was to evaluate the effects of probiotic on the insulin sensitivity, TLR4 signaling, intestinal permeability and microbiota composition in diet-induced obese mice. Male adult Swiss mice composed randomly 2 groups: chow diet (CTL) and high-fat diet by 5 consecutive weeks (DIO). During these 5 weeks, some mice of the DIO and CTL groups received daily a pool of probiotics. The DIO animals that received probiotic presented an expressive improvement in their glucose tolerance test, fasting glucose and in parallel a significant increase in the phosphorylation levels of insulin induced IR, IRS1 and Akt in muscle, liver and adipose tissue. There was a relevant reduction in the TLR4-Myd88 interaction, IKK? and JNK phosphorylation and iNOS expression in DIO mice treated with probiotic. This treatment also improved the expression of ileal tight-junctions proteins (ZO-1, Occludin), decreased LPS portal levels and the concentrations of bacteria of the phylum Firmicutes (associated with obesity) in feces. Analyzing the hypothalamus, it was observed that the use of probiotics in this model of obesity favorably regulated central mechanisms of food intake, as well as some inflammation parameters. In conclusion, our results show that probiotics, through their effects on intestinal permeability and microbiota composition, can improve insulin sensitivity and signaling of DIO mice, reducing their inflammation and suggesting potential beneficial effects in the treatment of insulin resistance and type 2 diabetes / Doutorado / Medicina Experimental / Doutora em Ciências
472

17β-hydroxysteroid dehydrogenase types 1 and 2 in human normal and malignant breast and gastrointestinal tract

Oduwole, O. (Olayiwola) 02 July 2003 (has links)
Abstract 17β-hydroxysteroid dehydrogenases (17HSDs) catalyze the interconversion of high-activity 17β-hydroxysteroids and low-activity 17-ketosteroids. In the present study, the mRNA of the 17HSD type 1 and 2 enzymes, catalyzing opposite reactions of estrogen metabolism, was analyzed in normal and malignant breast and gastrointestinal tract by in situ hybridization. Further, the activities of these enzymes were measured in normal and adenomatous intestinal cell lines. Markers of the main mesenchymal cell types were also used to study the cell-type specific expression of the 17HSD type 2 enzyme in the gastrointestinal tract. The mRNA of the 17HSD types 1 and 2 was expressed in normal breast tissues of premenopausal, but not postmenopausal women. In breast cancer, varied mRNA expressions of the enzymes were seen in both groups of women. Variable mRNA expressions of the reductive 17HSD type 5 enzyme were also seen in breast cancer tissues. Patients with tumors expressing 17HSD type 1 mRNA had significantly shorter overall survival and disease-free interval than those without 17HSD type 1 expression, suggesting that inhibition of the enzyme may be beneficial in the prevention or treatment of hormone-dependent breast cancers. In normal gastric tissues, 17HSD type 2 mRNA was expressed mainly in the surface and foveolar epithelium. Expression was weak or absent in glandular epithelium. Gender did not have any effect on expression, but there was a decrease with increasing age. Chronic gastritis was associated with decreased expression, while upregulation was observed in intestinal metaplasia. In gastric malignancy, downregulation was observed in most specimens. 17HSD type 2 mRNA was expressed mainly in absorptive epithelia cells and the upper parts of crypts in normal intestinal tissues. In the lamina propria, expression was detected in endothelial cells and mononuclear phagocytes. In colon cancer, the enzyme was downregulated in most, but not all cases. 17HSD type 1 and 2 activity measurements in normal and colon cancer cell lines showed a predominant oxidative activity. Northern analysis also revealed the transcript for the 17HSD type 2 enzyme. Female subjects had significantly more colon cancers with high 17HSD type 2 mRNA than males; however, low 17HSD type 2 mRNA expression was associated with survival in females with cancer of the distal colon and rectum. These data indicate the presence of gender- and location-related differences in the pathogenesis of colon cancer and suggest that low 17HSD type 2 mRNA expression is a marker of a favorable prognosis.
473

Exprese ubiquitinových ligáz v gastrointestinálním traktu / Expression of ubiquitin ligases in gastrointestinal tract

Pícková, Markéta January 2017 (has links)
Ubiquitin (Ub) ligases are important regulatory and signalling molecules, which are involved in majority of cellular processes such as differentiation, DNA repair, and regulation of energetic metabolism or immune response. E3 Ubiquitin ligases are also responsible for pathophysiological changes in the organism and their activity is associated with many human diseases including cancers. This makes E3 Ubiquitin ligases to be new diagnostic markers and interesting pharmaceutical targets. Based on previous studies, these enzymes evince very specific expression in the level of tissues or cell populations. Determination of this specific expression is important for a better understanding of their biological function. In this diploma thesis we systematically screened presence of 370 genes of E3-Ub ligases in gastrointestinal tract under physiological conditions and during acute inflammatory damage of distal colon. Obtained data allowed us to select genes, which can play important role in homeostasis as well as pathophysiology and regeneration of gastrointestinal tract. The screening was based on the expression profiling using qPCR, followed by in situ hybridization to determine the exact localization of the gene expression within tissues. From qPCR analysis was predicted hundred thirty seven candidates for...
474

International Delphi study to assess the need for multiaxial criteria in diagnosis and management of functional gastrointestinal disorders

Austin, Philip Daniel January 2015 (has links)
Purpose: While there are diagnostic criteria for functional gastrointestinal disorders (FGIDs), their evaluation is challenging. This is because criteria are based on symptoms, and the underlying pathophysiology is not clear; as such, there are no gold standard tests. Diagnosis is further challenged by considerable clinical overlap between different FGIDs as well as other organic diseases, while many people with FGIDs have more anxiety and depression than healthy individuals. I hypothesised that assessment of separate components of FGIDs that also indicate their effect on the patient could improve diagnosis. My aim was to investigate the evolution of opinions from experts involved in the development of FGID diagnostic criteria on the proposal for the development of multiaxial assessment criteria (MAC) for FGIDs. Methods: I conducted a web-based Delphi study using a group of purposively sampled experts identified from committees of the Rome Foundation and the International Foundation for Gastrointestinal Disorders. From a systematic search of relevant articles, I generated132 items that were sent to experts as a first round survey. The items assessed risk and contributing factors, the therapeutic relationship, areas of evaluation and the advantages and disadvantages of multiaxial assessment. Consensus on an item was reached when 75% of experts indicated that they agreed or strongly agreed with the statement. Key results: 36 of 68 eligible participants (52%) responded to the first round. Consensus was reached on 96 items. Using participant feedback, thematic analysis was used to generate 33 additional items for round two. Thirty-one of 36 participants (86%) replied to rounds two and three. In round two, 19 items gained consensus, and in round three, nine items gained consensus. Participants agreed that multiaxial assessment was needed, using a systematic approach to establish the physiological and psychosocial components of FGIDs. Participants were unable to agree on the importance of physical risk factors such as previous surgery and genetic association. Overall, 124 of the 167 items achieved consensus. Conclusion and inferences: The key finding from my study shows that experts agree that multiaxial assessment of FGIDs is needed. I also identified expert agreement on the consideration of psychological risk factors and the importance of the impact of FGID symptoms on daily life. Findings also show that experts disagreed on the impact of physical risk factors, socioeconomic status and spirituality on people with FGIDs. While experts could not agree on genetic and gender-based risk factors, they considered that these areas are important and require further research.
475

Modulatory effect of magnolol in colonic motility dysfunction induced by neonatal maternal separation in rats

Zhang, Man 01 January 2010 (has links)
No description available.
476

Cell immobilization techniques for the preservation of probiotics

Thantsha, Mapitsi Silvester 28 January 2008 (has links)
Incorporation of probiotic cultures in products in order to replenish or supplement the normal gastrointestinal microflora is a well known and accepted practice. However survival of these cultures is a problem due to a number of reasons including effects of storage conditions. Various researchers from different countries around the world have reported probiotic product instability. Microencapsulation has been used in an attempt to solve this problem. However, most methods involve the use of organic solvents which is not ideal because their toxicity may cause destruction of the microbial cells. A novel encapsulation method for probiotics, which excludes the use of organic solvents, was developed by the Council for Scientific and Industrial Research (CSIR) (US Patent Application no. 20050112205). This thesis investigated the efficiency/potential of this new method for increasing stability of sensitive probiotic cultures, specifically bifidobacteria. Early studies using both culture dependent and culture independent techniques showed reduced numbers of viable cultures in probiotic products, mainly yoghurts, from all around the world. These results were confirmed in this study for similar products sold in South Africa. Most of the product labels did not specify viable numbers of probiotics nor the identity (genus and species names) of the microorganisms incorporated. Successful encapsulation of bifidobacteria was achieved using the CSIR patented method. Complete encapsulation was indicated by absence of cells on surfaces of the encapsulated particles and production of a product with an acceptable particle size distribution was obtained. It was also demonstrated that the encapsulation process produced no visible morphological changes to the bacterial cells nor did it have a negative effect on cell viability over time. The potential of interpolymer complex formation in scCO2 for the encapsulation of sensitive probiotic cultures was demonstrated for the first time. Once ingested, probiotic cultures are exposed to unfavourable acidic conditions in the upper gastrointestinal tract. It is desired that these cultures be protected from this in order to increase the viability of the probiotics for efficient colonization. Interpolymer complex encapsulated B. longum Bb-46 cells were therefore exposed to simulated gastric fluid (SGF) and subsequently to simulated intestinal fluid (SIF). It was found that the interpolymer complex protected bifidobacteria from gastric acidity, displaying pH-responsive release properties, with little to no release in SGF and substantial release in SIF. Thus the interpolymer complex demonstrated desirable characteristics retaining the encapsulated bacteria inside when conditions were unfavourable and only releasing them under favourable conditions. Survival was improved by the incorporation of glyceryl monostearate (GMS) in the matrix and by use of gelatine capsules. Protection efficiency of the interpolymer matrix was better when higher loading of GMS was used. Use of polycaprolactone (PCL) as an alternative to poly (vinylpyrrolidone) (PVP) and incorporation of ethylene oxide-propylene oxide triblock copolymer (PEO-PPO-PEO) affected the interpolymer complex negatively, rendering it swellable in the low pH environment exposing the bifidobacteria to gastric acidity. The use of beeswax seemed to have a more protective effect though results were inconclusive. Probiotic cultures must also remain viable in products during storage. Encapsulated bacteria were either harvested from the reactor after 2 h of equilibration followed by depressurization, and then ground to a fine powder or after 2 h of equilibration the liquefied product was sprayed through a capillary tube with a heated nozzle at the end, into the product chamber. Encapsulated bacteria were stored in either sterile plastic bags or glass bottles under different conditions and then viable counts were determined over time. Survival of bacteria was generally better when the products were stored in glass bottles than in plastic bags. Bacteria encapsulated in an interpolymer complex formed between PVP and vinyl acetate-crotonic acid copolymer (VA-CA), (PVP:VA-CA) survived better than non-encapsulated bacteria under all storage conditions when the product was recovered from the reaction chamber. When the product was recovered from the product chamber, numbers of viable non-encapsulated bacteria were higher than the encapsulated bacteria for all interpolymer complex formulations. This was probably due to some exposure to high shear during spraying into the product chamber. The interpolymer complex between PCL and VA-CA i.e. PCL:VA-CA seemed weaker than the PVP:VA-CA nterpolymer complex as viable counts of bacteria released from it were lower than those from the latter complex. Addition of PEO-PPO-PEO to both the PVP:VA-CA and PCL:VA-CA complexes decreased the protection efficiency. However, results indicated that sufficient release of encapsulated bacteria from the interpolymer complexes was obtained when the encapsulated material was incubated in SIF rather than in Ringer’s solution. When SIF was used for release of encapsulated bacteria, the shelf life of B. longum Bb-46 was doubled. Encapsulation in an interpolymer complex therefore provided protection for encapsulated cells and thus has potential for improving shelf life of probiotic cultures in products. Further studies will investigate the effects of encapsulating probiotics together with prebiotics in the interpolymer complex as well as effects of encapsulating combinations of different probiotic strains together, both on survival in simulated gastrointestinal tract and during storage. The unique particles produced using the patented encapsulation technique increased the stability of probiotic cultures. This technique may find significant application in industries manufacturing probiotic products, especially food and pharmaceuticals, thereby improving the well being of consumers. / Thesis (PhD(Microbiology))--University of Pretoria, 2008. / Microbiology and Plant Pathology / PhD / unrestricted
477

The effect of pancreatic duct ligation on the gastric inhibitory polypeptide (GIP), gastric acid secretion and glucose metabolism in dogs

Nakayasu, Akira January 1982 (has links)
(A) Gastric Secretion The present study was performed to investigate the canine post-pancreatic duct ligation GIP secretion in response to fat ingestion using a meat meal mixed with unhydrolyzed or hydrolyzed whipping cream, and to determine whether GIP plays a role in the production of hyperacid secretion in the pancreatic duct ligated dogs. Four mongrel female dogs were prepared with Heidenhain pouch (HP) and gastric fistula (GF), and daily acid secretion from the HP was measured before and after pancreatic duct ligation (PDL). HP acid output, serum immunoreactive gastrin (IR-Ga) and serum immunoreactive gastric inhibitory polypeptide (IR-GIP) concentrations during five hours following oral ingestion of a meat meal alone, a meat meal mixed with 125g of unhydrolyzed cream and meat meal mixed with 125g of hydrolyzed cream were measured before and after PDL. Twenty four hour HP acid outputs increased significantly in each of the four dogs after PDL. Five hour HP acid outputs in response to a meat meal alone and a meat meal plus unhydrolyzed cream were modestly increased, while those in response to a meat meal plus hydrolyzed cream were rather reduced after PDL. Serum IR-Ga responses to all stimulants were lowered after PDL and those to meat meal plus hydrolyzed cream lowered most markedly. Serum IR-GIP responses to a meat meal alone were significantly increased, while those to a meat meal plus unhydrolyzed and hydrolyzed cream were reduced. The results of the present study demonstrate serum IR-GIP in response to a meat meal is increased by PDL in dogs, suggesting augmented acid juice passing into the intestinal lumen is responsible for the increased GIP response. It is indicated that hypo-secretion of GIP is not the cause of hypersecretion of gastric acid in the PDL dogs. (B) Glucose Metabolism. Functional alteration in glucose homeostasis especially concerning the early onset of diabetes after PDL was studied in dogs. Intravenous (i.v.) and intragastric glucose tolerance tests were performed at two to ten weeks and two weeks after PDL respectively. Serum glucose, IRI, and IR-GIP in response to a meat meal with and without unhydrolyzed or hydrolyzed fat were estimated at six weeks after PDL. Significantly impaired glucose tolerance and early phase IRI secretion after i.v. glucose were shown at two to ten weeks after PDL. Intragastric glucose load revealed delayed pattern of serum glucose and IRI (no evidence of glucose intolerance or diminished IRI secretion), indicating decreased gastric motility after PDL. Serum IR-GIP response to intragastric glucose load was not attenuated by the operation but showed a similar pattern to IRI response. Serum IRI responses to meat meals with and without unhydrolyzed or hydrolyzed cream were impaired after PDL. It is indicated that dogs after PDL show early onset (two to ten weeks) of diabetes, i.e. blunted early phase insulin secretion, 2 the mechanism of GIP secretion as an insulinotropic enterohormone remains intact after PDL if sufficient stimulants are given. / Surgery, Department of / Medicine, Faculty of / Graduate
478

Estudo da interferencia da alimentação na absorção de fluor ingerido sob a forma de dentifricio fluoretado

Del Fiol, Fernando de Sa 19 July 2018 (has links)
Orientador: Pedro Luiz Rosalen / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-07-19T15:53:46Z (GMT). No. of bitstreams: 1 DelFiol_FernandodeSa_M.pdf: 1505001 bytes, checksum: 265a879fb9127a4758242b8ad95fd302 (MD5) Previous issue date: 1994 / Resumo: A proposta do presente estudo foi avaliar a interferência da alimentação na absorção gastrointestinal de flúor ingerido através de dentifrício fluoretado. Dezoito voluntários adultos jovens foram submetidos a três situações de conteúdo estomacal, jejum, café da manhã e almoço e à ingestão de um dentifrício em 3 concentrações; placebo, 550 e 1100 ppmF, ou seja, em ocasiões diferentes ingeriram um dentifrício em cada situação de conteúdo gástrico. Foram feitas coletas de urina 24 horas anteriores e posteriores ao experimento e a partir da ingestão do dentifrício, amostras de saliva foram coletadas nos tempos (hora) 0; 0,25; 0,5; 0,75; 1,0; 2,0; 3,0; 8,0 e 24. Através da área de concentração salivar e da quantidade de flúor excretada em cada tratamento e pôde-se notar uma queda na absorção em torno de 19% quando da ingestão de flúor após o café da manhã e de aproximadamente 33% quando da ingestão de flúor após uma refeição tipo almoço / Abstract: The aim of the present study was to determine the influence of feed in the gastrointestinal absorption of fluoride ingested as fluoride dentifrices. Eighteen young volunteers were submited to three situations of stomachal contents; fasting stomach, breakfast and lunch and then to ingest some fluoride dentifrice in three different concentrations; placebo, 550 and 1100 ppmF, i.e., in different occasions they ingested one dentifrice in a situation of stomachal content. Urine was colected 24h before and after the experiment and as soon they ingested the dentifrice, saliva samples were colected in time (hour) 0; 0,25; 0,5; 0,75; 1,0; 2,0; 3,0, 8,0 and 24,0. Data from salivary fluoride concentration (ASC) and F urinary output was determined. In the present study it was found that breakfast and lunch consumed prior to ingestion of fluoride reduces fluoride absorption by 19% and 33% respectiviJy, compared to ingestion on a fasting stomach / Mestrado / Farmacologia / Mestre em Odontologia
479

Prevalencia de sobrecrecimiento bacteriano intestinal en pacientes con trastornos funcionales gastrointestinales en el Hospital Nacional Daniel Alcides Carrión

Chávez Gonzáles, Rocío del Carmen January 2014 (has links)
El documento digital no refiere asesor. / Manifiesta que los trastornos funcionales del tracto digestivo han sido definidos como una combinación de síntomas digestivos crónicos y recurrentes, en ausencia de patología orgánica. Un grupo de expertos ha establecido diversos subgrupos dependiendo del posible origen de los síntomas, de acuerdo a los denominados Criterios de Roma. (3) El síndrome de intestino irritable (SII) definido de acuerdo a estos criterios, constituye uno de los cuadros clínicos más frecuentes en el mundo, es motivo de un elevado número de consultas a gastroenterólogos y médicos. Los síntomas producidos por el sobrecrecimiento bacteriano intestinal (SOBIA) pueden ser similares y confundirse con trastornos funcionales como síndrome de intestino irritable (SII), distensión abdominal funcional (DAF) o dispepsia (DF) (4, 5). En la práctica clínica, SOBIA se caracteriza por un amplio espectro de las manifestaciones, que van desde síntomas abdominales inespecíficos (balonamiento, dolor o disconfort abdominal, flatulencia) a síntomas graves con menos frecuencia como malabsorción y deficiencia de nutrientes (diarrea, esteatorrea, pérdida de peso). / Trabajo de investigación
480

The effect of dietary energy and protein interaction on the physiological plasticity of the small intestine of the young ostrich

Viljoen, Mariaan 06 May 2012 (has links)
The study includes separate papers, which are all linked by their emphasis on the effect of different diets on the impact of the development of the small intestine of the young ostrich. This abstract is intended to provide readers with a broad overview of the outcomes of the study. Part 1: Yolk utilisation and the development of the small intestines Chapter 2 deals with the composition of egg yolk as it is absorbed by starved ostrich Struthio camelus L. ) chicks from one to seven days post-hatching and for ostrich (Struthio camelus L.) chicks from one to sixteen days post-hatching on a pre-starter broiler diet. Chapter 3 provides information on the intestinal enzymes of ostrich (Struthio camelus L. ) chicks from one to sixteen days post-hatching on a pre-starter broiler diet. The effect of growth on enzyme activity immediately post-hatching up to sixteen days of age was studied. Chapter 4 details a histological and morphological study of the gastrointestinal tract of ostrich (Struthio camelus L.) chicks from two to sixteen days post-hatching on a pre-starter broiler diet. The effect of growth on histological and morphological changes in the various parts of the small intestines was examined. Part 2: Influence on various pre-starter diets on growth and the development of the intestinal tract Chapter 5 discussed a growth and digestibility study of ostrich (Struthio camelus L.) chicks on eight different pre-starter diets. The performance, growth and physiological development of the chicks on high and low variations of different nutritional components were examined. Chapter 6 provides information on certain intestinal enzymes of ostrich (Struthio camelus L.) chicks on the eight different pre-starter diets. Chapter 7 dealt with the histological and morphological changes of the gastrointestinal tract of ostrich (Struthio camelus L.) chicks as a result of high and low variations of different nutritional components in prestarter diets. Implications The first part of this study revealed that although it appeared that yolk content was absorbed faster in starved ostrich chicks, intake of external feed had a positive influence on the absorption of fat from the yolk. The changes in the fatty acid composition of the yolk fat content that were observed may indicate that ostrich chicks have the ability to withdraw certain fatty acid components, especially unsaturated fatty acids. The digestive tract of ostrich chicks was compared with that of broiler chicks and differences observed in amylase and lipase activity between the birds in this trial and in poultry could be due to genetic differences between species. It could also be due to the genetic homogeneity of the poultry chicks that were used in the trials, whereas ostrich chicks have not been subjected to the same extent of advanced breeding improvement to date. Results on histological and morphological growth of the small intestines of the ostrich chick indicate increased absorption with an increase in age. The second part of this study revealed that ostrich chicks performed differently on diets formulated with different nutritional components. It appears that a high fat and low sugar content in the diet is advantageous in ostrich pre-starter diets. Although there were a few mortalities during the trials, there is no clear indication as to why the chicks died, as the causes of mortalities were not investigated. Differences in composition of the eight pre-starter diets did not seem to have an influence on the protein content or enzyme activity of the small intestines of ostrich chicks. An anti-nutritional factor within certain feedstuffs may, however, have had an influence on enzyme activity. Similar results were obtained for the histological and morphological parameters which were measured in chicks fed the different diets. There was no single diet that promoted intestine development, although it seemed as if the small intestines of the chicks fed the high protein diet were under higher digestive stress than those of the chicks fed the other diets. / Thesis (PhD)--University of Pretoria, 2011. / Anatomy and Physiology / Unrestricted

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