Inflammatory bowel disease (IBD) comprises diseases that are characterized by chronic or relapsing inflammation of the gastrointestinal tract. Primary sclerosing cholangitis (PSC) is an extraintestinal manifestation in IBD. Immunoreactivity against an autoantigen that is expressed both in the gastrointestinal tract and the biliary tract could be the link between these diseases. A possible source of such an antigen is goblet cells. Immunostainings of normal human tissues using IBD patient sera showed goblet cell immunoreactivity against goblet cells in all parts of the gastrointestinal tract. The most frequent immunostaining was found against goblet cells in the appendix against which 84% (42/50) of IBD patients compared to 8% (4/50) of healthy blood donors showed immunoreactivity. To identify the corresponding antigen we used three different approaches, investigation of immunoreactivity to different candidate proteins compared to IBD sera, immunoscreening of an appendiceal cDNA library, and immunoprecipitation of protein lysates from mucin producing cells followed by SDS-PAGE and 2D gel electrophoresis. These approaches led to the identification of several candidate autoantigens of which complement C3 is the most promising. A novel staining pattern with strong immunoreactivity to granules and the apical membrane of biliary epithelial cells was identified with 35% (12/34) of PSC sera compared to none of healthy controls (n=28). Screening of a cDNA library from normal human choledochus identified PDZ domain containing 1 (Pdzk1) and Glutathion S transferase theta 1 (GSTT1) as potential candidates. Pdzk1 is an interesting candidate which is expressed in the intestinal tract and bile ducts. GSTT1 antibodies were not specific for PSC and are thought to develop as an alloimmune response in patients with the GSTT1-null genotype. In conclusion, we have identified specific immunoreactivity to goblet cells and biliary epithelial cells using sera from patients with IBD and PSC respectively. We have also identified several potential autoantigens.

Intravenous application of a high dose of endotoxin, such as lipopolysaccharide (LPS), results in endotoxemia and sepsis in experimental animals. LPS induces production of cytokines and free radicals, plasma leakage and systemic inflammation. But the relationship between LPS-induced plasma leakage and endothelial gap formation is still unknown. Under normal physiological and pathological conditions, the mucus of intestine plays an important role in host defense mechanism as a barrier to prevent invasion of bacteria and endotoxin. The integrity of the intestinal epithelium is an important determinant of clinical outcome in septic patients. It is reported that, after LPS application, ileal mucosa is injured consequently. Necrosis of epithelial cells is also prominent feature in the villus epithelium. However, the response of mucin-secreting goblet cells is often ignored. The present study was designed to prove (1) whether LPS application increased plasma leakage by endothelial gap formation in rat intestinal tract, (2) whether LPS application increased goblet cell secretion by compound exocytotic activity in mucosal villi of small intestine; and (3) whether hydroxyl radicals were involved in LPS-induced compound exocytosis in goblet cells and plasma leakage. First, the microcirculation of large intestine in rats was shown by using silver nitrate staining method, and India ink was used to label the leaky microvessels to express the magnitude of plasma leakage. Endothelial gaps formed between endothelial cells in the venules after LPS-induced inflammation were investigated by light and scanning electron microscopy. In saline control, the number of endothelial gaps per 1000 £gm2 endothelium of postcapillary and collecting venules was 0.2 ¡Ó 0.1 ~ 0.4 ¡Ó 0.1 / 1000 £gm2 (n = 5). At 5 minutes after LPS application, the endothelial gap density drastically increased to 12.1 ¡Ó 1.6 ~ 27.5 ¡Ó 2.2 / 1000 £gm2 (n = 5 or 6), about 43-69 times (P < 0.01) as much as control. At the same time, the magnitude of plasma leakage, expressed by area density of India ink-labeled blood vessels, in the cecum and colon of LPS-treated rats increased to 7.8-8.2 times (P < 0.01) as much as control. Unusually high degree of plasma leakage and high number of endothelial gaps persisted for at least 30 minutes after treatment. Then, a significant reduction to the baseline level occurred at 60 minutes after LPS application (P > 0.05). The results evidently indicated that LPS-induced intestinal plasma leakage and the endothelial gap formation of venules were closely related. In the following experiment, in order to obtain an actual number of goblet cells in the mucosal epithelium, an innovative and effective experimental method was developed and adopted to prepare small intestine specimens in this study. Tissue pieces with two rows of mucosal villi were taken under a dissecting microscope. Then, scanning electron microscope was used to observe goblet cells and histochemistry staining was applied to further identify mucosubstance. The degree of goblet cell secretion in the villus epithelium of the duodenum and ileum was expressed by the number of cavitated goblet cells undergoing compound exocytosis. Digital morphometric software SimplePCI was employed to measure the epithelial surface area of sampled villi and to count the number of goblet cells. In addition, hydroxyl radical scavenger ¡V dimethylthiourea (DMTU) was also applied to explore the role of hydroxyl radicals involving in LPS-induced goblet cells secretion and plasma leakage. From scanning electron microscopy study, the numbers of cavitated goblet cells per mm2 of ileal villus epithelium in rats at 5 and 30 minutes after LPS injection were 693 ¡Ó 196 (n = 6) and 547 ¡Ó 213 (n = 6), respectively, which were 5.1 and 8.4 times (P < 0.05) compared with the number of saline control. The percentage of villus cavitated goblet cell numbers, in both duodenum and ileum 5 minutes after LPS and in the ileum 30 minutes after LPS, increased significantly (P < 0.05). When DMTU was given prior to LPS, the number of cavitated goblet cells and the amount of plasma leakage was inhibited and remained at the level as control (P > 0.05). It is concluded that the mechanism of the LPS-induced increase in compound exocytotic activity of goblet cells and increase in plasma leakage during acute phases of inflammatory response in rat small intestine was associated with hydroxyl radicals.

This project has provided a better understanding of the human conjunctiva, the glistening tissue covering the white of the eye, at the cellular level. The observations of this study may serve as a useful marker against which changes in conjunctival tissue due to disease, surgery, drug therapy or contact lens wear can be assessed. Laser scanning confocal microscopy was used to observe and measure characteristics the conjunctiva of healthy human volunteer subjects. It was concluded that this technique is a powerful tool for studying the human conjunctiva and assessing key aspects of the structure of this tissue. The effects of contact lens wear on the conjunctiva can be investigated effectively at a cellular level using this technology.

Thesis (M.Sc.). / Written for the Dept. of Human Genetics. Title from title page of PDF (viewed 2009/07/02). Includes bibliographical references.

Mucociliary epithelia are found in the human airways and act as the first line of defence against inhaled foreign agents. Mucus traps potentially damaging particles and the cilia transport the mucus away from the airways to remove the threat. Modelling mucociliary epithelia for research purposes is challenging. This is because the airways are enclosed and are thus difficult to study directly. Instead, tissue is extracted or in vitro techniques are employed. Whilst these systems are useful, there is a need for accessible in vivo models to complement them. In this thesis I assess a new model system for studying mucociliary epithelia. This system is the larval epidermis of the amphibian, Xenopus tropicalis. Its epidermis comprises multi-ciliated cells that beat in a polarised direction reminiscent of those found in the human airways. It is also proposed to have a number of other cell types including mucus-secreting cells, but very little is known about them. The epidermis is open and accessible to manipulation meaning that it has great potential to be used in the study of mucociliary epithelia in live, native conditions. Such a system would be a valuable addition to the current models employed. However, the epidermis has not been thoroughly characterized before so its utility as a model system remains speculative.To develop and evaluate this new model, I fully characterize the epidermis, showing that it has five distinguishable cell types. This includes a population of cells called ionocytes that are shown to be essential for the health and function of the epidermis. I also test for the presence of mucins, the structural component of mucus, secreted from the epidermis in order to evaluate the proposal that mucus-secreting cells are present in the epidermis. A mucin-like protein called otogelin is identified. After characterizing the epidermal cell types, I compare them to the human mucociliary epithelium and consider potential applications and future perspectives for this model.

O estresse causa modificações no epitélio intestinal, tais como o aumento de células caliciformes e da taxa de apoptose. O uso de alimentos nutracêuticos tem sido uma alternativa para amenizar essas modificações sobre o tecido epitelial. Desta forma, este trabalho teve como objetivo avaliar se a inclusão de colostro bovino, o qual é constituído de fatores antioxidantes, imunes e de crescimento, seria capaz de amenizar as consequências do estresse crônico sob o intestino. Para isso, juvenis de pacu (Piaractus mesopotamicus) adensados a 50 kg/m3 foram alimentados duas vezes ao dia até a saciedade com ração peletizada e semi-purificada sem (0%CBL) e com a inclusão de colostro bovino liofilizado em concentrações crescentes (10, 20 e 30%CBL), (n=4). Após 28 dias, foram coletados segmentos do intestino médio, S1 e S2, e reto. Os tecidos foram marcados com corantes histológicos para a quantificação de células caliciformes contendo mucinas neutras, ácidas (incluindo sialo e sulfomucinas) e ácidas-neutras. Também foram mensurados o volume (Vv) e a densidade da superfície (Sv) da mucosa, por análise estereológica, e a espessura da camada muscular. A razão do número de cada tipo e subtipo de célula caliciforme sobre o Vv e Sv foi calculada para estimar a densidade de células caliciformes, Dv e Ds, respectivamente. A taxa apoptótica foi analisada qualitativamente através da intensidade (alta, média e baixa) da imunomarcação da caspase-3 nas células epiteliais. As dietas não influenciaram os parâmetros zootécnicos analisados (P>0,05). No reto, os grupos que receberam 20 e 30%CBL apresentaram menor número de células caliciformes contendo sulfomucinas e menor Ds em relação a 0 e 10% (P=0,0148 e 0,0198, respectivamente). No RT, Dv total e Dv de células caliciformes contendo mucinas ácidas foi maior em 0 e 30%CBL em relação a 20%CBL (P=0,0155 e 0,225, respectivamente). No S1, 10 e 30%CBL apresentaram maior Dv em relação a 20%CBL (P=0,0540). A espessura da camada muscular, o Vv e a Sv não diferiram entre os tratamentos (P>0,05). No S2 e RT, a taxa de apoptose teve relação inversa à concentração de colostro bovino liofilizado adicionado na ração. Nos três segmentos, houve maior proporção de células caliciformes contendo mucinas ácidas do que neutras, sendo a maioria representada por sulfomucinas. Assim, a inclusão de colostro bovino liofilizado nas rações de juvenis de pacu adensados diminuiu a apoptose nos segmentos intestinais S2 e RT e também diminuiu o número de células caliciformes contendo sulfomucinas no RT, indicando que o colostro bovino liofilizado pode ser utilizado como alimento nutracêutico para pacus (Piaractus mesopotamicus) adensados, a fim de diminuir a taxa apoptótica e proteger o intestino contra enzimas bacterianas, uma das principais funções das sulfomucinas. / The stress causes changes in the intestinal epithelium, such as the increase in the number of goblet cells and on the rate of apoptosis. The use of nutraceutical foods has been an alternative to soften these modifications on the epithelial tissue. Thus, this study aimed to evaluate if the inclusion of bovine colostrum, which is composed of antioxidant, immune and growth factors, would be able to attenuate the consequences of chronic stress on the intestine. For this, pacu juveniles (Piaractus mesopotamicus), stocked at density of 50 kg/m3, were fed twice daily until satiety with pelleted and semi-purified diet without (0% LBC) and with the inclusion of lyophilized bovine colostrum in increasing concentrations (10, 20 and 30% LBC), (n = 4). After 28 days, segments of the middle gut, S1 and S2, and rectum (RT) were collected. The tissues were stained with histological dyes for the quantification of goblet cells containing neutral, acidic (including sialo and sulphomucins) and acid-neutral mucins. The volume (Vv) and surface density (Sv) of the mucosa were also measured by stereological analysis and the thickness of the muscular layer. The ratio between the number of each goblet cell type and subtype and the Vv or Sv was calculated to estimate the density of goblet cells, Dv and Ds, respectively. The apoptotic rate was analyzed qualitatively according to the intensity (high, medium and low) of caspase-3 immunostaining in epithelial cells. The diets did not influence the zootechnical parameters analyzed (P> 0.05). In the rectum, the groups that received 20 and 30% LBC presented lower number of goblet cells containing sulphomucins and lower Ds in relation to 0 and 10% (P = 0.0148 and 0.0198, respectively). In RT, total Dv and Dv of goblet cells containing acid mucins were higher in 0 and 30% LBC in relation to 20% LBC (P = 0.0155 and 0.225, respectively). In S1, 10 and 30% LBC presented higher Dv in relation to 20% LBC (P = 0.0540). Muscle layer thickness, Vv and Sv did not differ between treatments (P> 0.05). In S2 and RT, the rate of apoptosis was inversely related to the concentration of lyophilized bovine colostrum added in the diet. In the three segments, there was higher proportion of goblet cells containing acidic than neutral mucins, most of them being sulphomucins. Thus, the inclusion of lyophilized bovine colostrum in diets of pacu juveniles reduced apoptosis in the intestinal segments S2 and RT and also decreased the number of goblet-containing sulphomucins in the RT, indicating that lyophilized bovine colostrum can be used as a nutraceutical feed for pacus (Piaractus mesopotamicus) under high stocking density to decrease the apoptotic rate and protect the intestine against bacterial enzymes, one of the main functions of sulphomucins.

O objetivo deste trabalho foi avaliar o efeito do colostro bovino liofilizado (CBL), utilizado como fonte parcial da dieta protéica, sobre as características histológicas do epitélio intestinal de juvenis de pacu (Piaractus mesopotamicus) e dourado (Salminus brasiliensis). Os juvenis foram distribuídos num delineamento experimental inteiramente casualizado em esquema fatorial 3x2. Foram utilizadas dietas com três níveis de inclusão de CBL (0%, 10% e 20%) e dois períodos experimentais (30 e 60 dias), oferecidas duas vezes ao dia até a saciedade aparente. Para o estudo histológico, o intestino foi dividido em três segmentos, S1, S2 e reto para pacu e S1, S2 e intestino posterior para dourado. Foram avaliadas a espessura da camada muscular; o volume parcial da mucosa absortiva (Vv); o número das células caliciformes contendo mucinas ácidas e neutras e totais, e os subtipos ácidas - sialomucinas e sufomucinas. Nos juvenis de pacu, a inclusão de 20% de CBL alterou a distribuição das células caliciformes contendo as mucinas ácidas, neutras e totais, os subtipos sialomucinas e sulfomucinas, e a espessura da camada muscular, enquanto o Vv foi afetado apenas pelo período experimental. Nos juvenis de dourados, efeito de período experimental foi observado para células caliciformes contendo mucinas ácidas, neutras e totais e os subtipos sialomucinas e sulfomucinas, espessura da camada muscular e Vv. A adição de 10% de CBL afetou apenas o Vv no segmento S1. Considerando os aspectos avaliados no presente estudo, a presença do colostro bovino liofilizado na dieta influenciou, no período estudado, as características histológicas entéricas de juvenis de pacu, enquanto que nos juvenis de dourado influencia desta secreção láctea não foi observada. / The aim of this study was to evaluate the effect of lyophilized bovine colostrum (LBC), used as partial source of protein in the diet, on the histological characteristics of the intestinal epithelium of juvenile pacu (Piaractus mesopotamicus) and juvenile dourado (Salminus brasiliensis). Juveniles were distributed in a completely randomized design in a factorial scheme 3x2. Three diets were used with different levels of LBC inclusion (0%, 10% and 20%) and two experimental periods (30 and 60 days) offered twice daily until apparent satiation. For the histological study, the intestine was divided into three segments, S1, S2 and rectum to the pacu and S1, S2 and posterior intestine to the dourado. The muscle layer thickness; the mucosal absorptive volume (Vv); the number of goblet cells containing acidic and neutral mucins and the acidic subtypes - sialomucin and sulphomucin were evaluated. In juvenile pacu, the inclusion of 20% of LBC changed the distribution of goblet cells containing acidic, neutral and total mucins, the subtypes sialomucins and sulphomucins, and the thickness of the muscle layer, while the Vv was affected only by the experimental period. In juvenile dourado, effect of experimental period was observed for goblet cells containing acidic, neutral and total mucins and subtypes sialomucins, sulphomucins, thickness of muscle layer and Vv. The addition of 10% of LBC affected only Vv in the segment S1. Considering the aspects studied, the presence of lyophilized bovine colostrum in the diet influenced, in the period studied, the enteric histological characteristics of juvenile pacu, while the juvenile dourado influence of this lacteal secretion was not observed.

In this study, we demonstrated that the CSKSSDYQC-peptide ligand which was identified from a random phage-peptide library through an in vivo phage display technique with rats could prominently improve the transport efficiency of macromolecules, such as large filamentous phage particles (M13 bacteriophage), across the intestinal mucosal barrier. Synthetic CSKSSDYQC-peptide ligands significantly inhibited the binding of phage P1 encoding CSKSSDYQC-peptide ligands to the intestinal mucosal tissue and immunohistochemical analysis showed that the CSKSSDYQC-peptide ligands could be transported across the intestinal mucosal barrier via goblet cells as their specific gateway. Thus, we inferred that CSKSSDYQC-peptide ligand might have a specific receptor on the goblet cells and transported from intestinal lumen to systemic circulation by transcytosis mechanism. These results suggest that CSKSSDYQC-ligand could be a promising tool for development of an efficient oral delivery system for macromolecular therapeutics in the carrier-drug conjugate strategy.

The incubation period is crucial for development and overall quality of a chick. The selection for fast growing broilers has allowed the birds to reach market weight at a faster rate making the incubation period a larger portion of a broiler's life. A faster growth rate can lead to the release of more metabolic heat inside of the egg toward the second half of incubation because the embryo shifts to a homeothermic state. More heat being released into the incubator can cause the incubation temperature to rise if the incubator is not electronically regulated or cannot be ventilated properly due to malfunction. A high incubation temperature can impact the hatchability, growth, and development of the chick. This thesis provides a more in-depth analysis of the effects of high incubation temperature (37.5°C versus 39.5°C) on the developing small intestine and yolk sac, which provide the chick with nutrients posthatch and during embryogenesis. Studying these organs and mechanisms occurring during this time could potentially indicate why chicks from eggs subjected to a higher incubation temperature are not developing and growing properly. Chicks from eggs incubated at a higher temperature had lower body weights, lower hatchability and lower villus height in the duodenum, jejunum, and ileum. There were also differences seen in the depth of the crypt, which is the site for stem cells. Chicks from eggs incubated at a higher temperature had a lower crypt depth in the duodenum and jejunum. There was no difference in the expression of the intestinal stem cell marker olfactomedin 4 (Olfm4) and mucin 2, which is secreted by goblet cells and forms mucus. In the yolk sac, heat shock proteins (HSP) 70 and 90 were elevated at embryonic day 15, and HSP90 still remained elevated at embryonic day 17. Chicks from eggs incubated at a higher temperature showed greater expression of peptide transporter 1 and avian beta-defensin 10 mRNA at embryonic day 13. Even though small intestinal morphology was impacted early posthatch and expression of genes in the yolk sac were elevated at embryonic day 13, there does not seem to be a long-lasting effect on the development of the small intestine or the yolk sac. It is still important to study the impact of the incubation environment to understand the development and growth of the chicks and how different incubation factors can impact the overall hatchability and health of the chick. / Master of Science / The incubation period is crucial for development and overall quality of a chick. The selection for fast growing broilers has allowed the birds to reach market weight at a faster rate making the incubation period a larger portion of a broiler’s life. A faster growth rate can lead to the release of more metabolic heat inside of the egg toward the second half of incubation because the embryo shifts to a homeothermic state. More heat being released into the incubator can cause the incubation temperature to rise if the incubator is not electronically regulated or cannot be ventilated properly due to malfunction. A high incubation temperature can impact the hatchability, growth, and development of the chick. This thesis provides a more in-depth analysis of the effects of high incubation temperature (37.5°C versus 39.5°C) on the developing small intestine and yolk sac, which provide the chick with nutrients posthatch and during embryogenesis. Studying these organs and mechanisms occurring during this time could potentially indicate why chicks from eggs subjected to a higher incubation temperature are not developing and growing properly. Chicks from eggs incubated at a higher temperature had lower body weights, lower hatchability and lower villus height in the duodenum, jejunum, and ileum. There were also differences seen in the depth of the crypt, which is the site for stem cells. Chicks from eggs incubated at a higher temperature had a lower crypt depth in the duodenum and jejunum. There was no difference in the expression of the intestinal stem cell marker olfactomedin 4 (Olfm4) and mucin 2, which is secreted by goblet cells and forms mucus. In the yolk sac, heat shock proteins (HSP) 70 and 90 were elevated at embryonic day 15, and HSP90 still remained elevated at embryonic day 17. Chicks from eggs incubated at a higher temperature showed greater expression of peptide transporter 1 and avian beta-defensin 10 mRNA at embryonic day 13. Even though small intestinal morphology was impacted early posthatch and expression of genes in the yolk sac were elevated at embryonic day 13, there does not seem to be a long-lasting effect on the development of the small intestine or the yolk sac. It is still important to study the impact of the incubation environment to understand the development and growth of the chicks and how different incubation factors can impact the overall hatchability and health of the chick.

<p>Препарати ћелијског зида квасца користе се у исхрани домаћих животиња са<br />циљем побољшања њихових производних резултата и здравља. Ћелијски зид<br />квасца садржи две врсте бета глукана и алфа манан чијим разлагањем настају<br />мананолигосахариди. Овим једињењима се приписују бројна корисна дејства<br />као што су везивање непожељних бактерија и микотоксина, имуномодулаторно<br />дејство итд. Огледи обухваћени овом дисертацијом испитивали су утицај једног<br />новог препарата ћелијског зида квасца на бројлерске пилиће. У првом огледу,<br />два нивоа препарата су поређена са стандардном смешом и праћен је утицај на<br />телесне масе пилића, конверзију хране, морталитет пилића, дужине и масе<br />црева, масе различитих органа, бактеријске популације црева, морфометрију<br />црева, пехарасте ћелије у епителу црева и стање простирке. У наредном огледу<br />три концентрације препарата су поређене са контролном групом и праћени су<br />исти параметри као у првом огледу, осим бактеријских популација, дужина и<br />маса црева и стања простирке. У трећем и четвртом огледу, испитивања<br />препарата су вршена на пилићима који су са 13 дана старости раздвојени у<br />тежинске групе. Трећи оглед је, уз праћење производних параметара, обухватио<br />испитивања цревних ресица и пехарастих ћелија епитела црева, док су се у<br />четвртом огледу испитивали само производни резултати. Добијени резултати,<br />тумачени у контексту бројних других истраживања на ову тему, указују да<br />додатак препарата ћелијског зида квасца може довести до побољшања<br />производних параметара бројлерских пилића. Просечно побољшање које се<br />добија употребом новог препарата слично је или благо боље од просечних<br />побољшања до којих доводе ранији слични препарати. Завршна телесна маса је<br />просечно већа за око 40 g, утрошак хране по тони произведене живе масе<br />смањен је за око 34 kg хране, а преживљавање пилића је веће за око 1,5%. Од<br />испитиваних концентрација препарата, најефикаснијом се показала 0,04%,<br />односно 400 g препарата по тони хране. Ова концентрација је неколико пута<br />нижа од уобичајено коришћених концентрација претходних сличних препарата,<br />што потврђује да је нови препарат концентрисанији од претходних. Утврђена је<br />велика варијабилност дејства препарата ћелијског зида квасца која се кретала од<br />потпуног изостанка утицаја до веома снажних ефеката. Део ове варијабилности<br />се може објаснити различитим условима узгајања пилића. У четири огледа<br />обухваћена дисертацијом потврђена је хипотеза да се дејство препарата јаче<br />испољава када су пилићи у неповољнијој ситуацији. Најјаче дејство је<br />забележено у огледу у коме су постигнути најслабији производни резултати, а<br />најслабије у огледу са најбољим производним резултатима. Трећи и четврти<br />оглед су показали да се пилићи чија телесна маса одступа од просека суочавају<br />са различитим проблемима. Додатак препарата је делимично успео да ублажи<br />уочене проблеме код пилића малих и великих телесних маса, не мењајући при<br />томе битно резултате просечних пилића. Ово указује да препарат испољава<br />своје дејство првенствено на пилићима угроженим одређеним проблемима, што<br />је веома важно за његову практичну примену. Додатак препарата није изазвао<br />промене у броју укупних аеробних и анаеробних бактерија, лактобактерија,<br />бифидобактерија, ентерокока и Е. coli у садржају слепих црева бројлерских<br />пилића. Утицаји додатка препарата на дужину танког црева и његових поједних<br />делова, масе црева, масе органа, висину и ширину цревних ресица, дубину<br />цревних крипти и остале везане параметре били су варијабилни. Није утврђено<br />да постоји директна повезаност ових промена са производним резултатима, па<br />се може претпоставити да се ради о ефектима који се јављају паралелно се<br />побољшањем производних резултата, а не као узрок тог побољшања. Најјачи<br />утицај препарата утврђен је на пехарасте ћелије црева бројлерских пилића.</p> / <p>Preparati ćelijskog zida kvasca koriste se u ishrani domaćih životinja sa<br />ciljem poboljšanja njihovih proizvodnih rezultata i zdravlja. Ćelijski zid<br />kvasca sadrži dve vrste beta glukana i alfa manan čijim razlaganjem nastaju<br />mananoligosaharidi. Ovim jedinjenjima se pripisuju brojna korisna dejstva<br />kao što su vezivanje nepoželjnih bakterija i mikotoksina, imunomodulatorno<br />dejstvo itd. Ogledi obuhvaćeni ovom disertacijom ispitivali su uticaj jednog<br />novog preparata ćelijskog zida kvasca na brojlerske piliće. U prvom ogledu,<br />dva nivoa preparata su poređena sa standardnom smešom i praćen je uticaj na<br />telesne mase pilića, konverziju hrane, mortalitet pilića, dužine i mase<br />creva, mase različitih organa, bakterijske populacije creva, morfometriju<br />creva, peharaste ćelije u epitelu creva i stanje prostirke. U narednom ogledu<br />tri koncentracije preparata su poređene sa kontrolnom grupom i praćeni su<br />isti parametri kao u prvom ogledu, osim bakterijskih populacija, dužina i<br />masa creva i stanja prostirke. U trećem i četvrtom ogledu, ispitivanja<br />preparata su vršena na pilićima koji su sa 13 dana starosti razdvojeni u<br />težinske grupe. Treći ogled je, uz praćenje proizvodnih parametara, obuhvatio<br />ispitivanja crevnih resica i peharastih ćelija epitela creva, dok su se u<br />četvrtom ogledu ispitivali samo proizvodni rezultati. Dobijeni rezultati,<br />tumačeni u kontekstu brojnih drugih istraživanja na ovu temu, ukazuju da<br />dodatak preparata ćelijskog zida kvasca može dovesti do poboljšanja<br />proizvodnih parametara brojlerskih pilića. Prosečno poboljšanje koje se<br />dobija upotrebom novog preparata slično je ili blago bolje od prosečnih<br />poboljšanja do kojih dovode raniji slični preparati. Završna telesna masa je<br />prosečno veća za oko 40 g, utrošak hrane po toni proizvedene žive mase<br />smanjen je za oko 34 kg hrane, a preživljavanje pilića je veće za oko 1,5%. Od<br />ispitivanih koncentracija preparata, najefikasnijom se pokazala 0,04%,<br />odnosno 400 g preparata po toni hrane. Ova koncentracija je nekoliko puta<br />niža od uobičajeno korišćenih koncentracija prethodnih sličnih preparata,<br />što potvrđuje da je novi preparat koncentrisaniji od prethodnih. Utvrđena je<br />velika varijabilnost dejstva preparata ćelijskog zida kvasca koja se kretala od<br />potpunog izostanka uticaja do veoma snažnih efekata. Deo ove varijabilnosti<br />se može objasniti različitim uslovima uzgajanja pilića. U četiri ogleda<br />obuhvaćena disertacijom potvrđena je hipoteza da se dejstvo preparata jače<br />ispoljava kada su pilići u nepovoljnijoj situaciji. Najjače dejstvo je<br />zabeleženo u ogledu u kome su postignuti najslabiji proizvodni rezultati, a<br />najslabije u ogledu sa najboljim proizvodnim rezultatima. Treći i četvrti<br />ogled su pokazali da se pilići čija telesna masa odstupa od proseka suočavaju<br />sa različitim problemima. Dodatak preparata je delimično uspeo da ublaži<br />uočene probleme kod pilića malih i velikih telesnih masa, ne menjajući pri<br />tome bitno rezultate prosečnih pilića. Ovo ukazuje da preparat ispoljava<br />svoje dejstvo prvenstveno na pilićima ugroženim određenim problemima, što<br />je veoma važno za njegovu praktičnu primenu. Dodatak preparata nije izazvao<br />promene u broju ukupnih aerobnih i anaerobnih bakterija, laktobakterija,<br />bifidobakterija, enterokoka i E. coli u sadržaju slepih creva brojlerskih<br />pilića. Uticaji dodatka preparata na dužinu tankog creva i njegovih pojednih<br />delova, mase creva, mase organa, visinu i širinu crevnih resica, dubinu<br />crevnih kripti i ostale vezane parametre bili su varijabilni. Nije utvrđeno<br />da postoji direktna povezanost ovih promena sa proizvodnim rezultatima, pa<br />se može pretpostaviti da se radi o efektima koji se javljaju paralelno se<br />poboljšanjem proizvodnih rezultata, a ne kao uzrok tog poboljšanja. Najjači<br />uticaj preparata utvrđen je na peharaste ćelije creva brojlerskih pilića.</p> / <p>Yeast cell wall products are used in animal nutrition to improve their performance and<br />health. The yeast cell wall contains two beta glucans and alpha mannan that can be<br />degraded into mannan-oligosaccharides. Numerous positive effects are attributed to<br />these compounds, like binding unwanted bacteria and mycotoxins, modulating<br />immune response etc. Trials within this PhD thesis focused on testing effect of a new<br />yeast cell wall product on broiler chickens. In first trial, diets containing two levels of<br />product were compared to a standard diet, and following parameters were recorder:<br />body weight, feed conversion ratio, chicken mortality, lengths and weights of<br />intestine, organ weights, bacterial populations of digesta, small intestine<br />morphometrics, goblet cells of intestinal epithelium and litter quality. Next trial<br />compared three concentrations of the product with a control group. Same parameters<br />to that in first trial were recorded, except lengths and weights of intestine, bacterial<br />populations of digesta and litter quality. In the third and the fourth trial, the yeast cell<br />wall product&rsquo;s effect was tested on broiler chickens grouped according to their 13th<br />day body weight. Performance, intestinal villi and goblet cells were monitored in the<br />third trial, and only performance data in the fourth trial. Results, interpreted in the<br />context of numerous other studies on this subject, indicate that feeding the yeast cell<br />wall product can improve performance of broiler chickens. Average improvement<br />observed using the new product is similar to, or slightly better than, average<br />improvements observed using earlier similar products. Final body weight was<br />increased by 40 g, feed consumption per tonne of live weight was reduced by 34 kg of<br />feed, and survival rate of chicks was 1.5% higher. The most effective concentration<br />was 0.04% (400 g/t). This concentration is several times lower than usual<br />concentrations of previous similar products, confirming that the new product is more<br />concentrated than the previous ones. Effects were very variable, ranging from the<br />complete absence of influence to very strong effects. Part of this variability can be<br />explained by the different conditions of broiler growing. In four experiments covered<br />by the thesis, the hypothesis that the effects are stronger when chickens are facing<br />certain challenges was confirmed. The strongest effect was observed in the<br />experiment when the worst performance was achieved, and the weakest effect was<br />observed in the trial with the best production results. The third and fourth trial showed<br />that the broilers with low or high body weight face different problems. Feeding the<br />yeast cell wall product partially alleviated problems identified in chickens with low<br />and high body weight, without changing results of average chicks. These results<br />suggest that this product exerts its effect mainly on chickens challenged with certain<br />problems. This conclusion is very important for product&rsquo;s practical application. The<br />yeast cell wall product did not cause changes in the number of total aerobic and<br />anaerobic bacteria, lactobacteria, bifidobacteria, enterococci and E. coli in the digesta<br />of broiler chickens. Effects on the length of the small intestine and certain parts of it,<br />the weight of the intestine, organs weight, height and width of the intestinal villi,<br />depth of intestinal crypts and other related parameters were variable. It seems that<br />there is not a direct correlation of these parameters with the performance results. It<br />can be assumed that these effects are not the cause of observed performance<br />improvements. The strongest effect of yeast cell wall product was observed on the<br />goblet cells in the intestine of broiler chickens.</p>