Cultivation of Napier grass, Pennisetum purpureum, the most important livestock crop in East Africa is severely constrained by Napier Grass Stunt (NGS) disease. The disease spreads via an insect vector or vegetative propagation of infected plant material and is caused by a phytoplasma. This necessitates the development of an integrated management approach for the disease. Therefore, objectives of this study were to assess the incidence of the disease and its severity, to identify its wild hosts and farmers‟ knowledge on these hosts, to assess the threat of NGS disease to cultivated grasses and to establish the role of wild inoculum sources in its spread. The study showed NGS incidence ranging from 33% in Uganda to 95% in Kenya with 49% of the farmers interviewed, being able to discern NGS disease by its symptoms. Most farmers cited roguing and use of alternative fodder grasses as control measures, making these strategies the likely components of an integrated management approach for the disease. Responders named Sedge grass (Cyperus spp.) and Star grass (Cynodon dactylon) as the likely hosts of diseases caused by phytoplasma. Phytoplasmas were detected in leaves of 11 of 33 wild grass species collected using polymerase chain reaction (PCR) based on the highly conserved phytoplasma-specific 16S ribosomal DNA fragment. Sequence determination of amplified PCR fragments revealed the presence of NGS-related phytoplasmas in 11 grass species, Bermuda grass white leaf (BGWL) phytoplasmas in three and goosegrass white leaf (GGWL) in two wild grass species, showing that the geographical distribution and diversity of phytoplasmas and their grass hosts are greater than previously thought. The relationships between NGS and Hyparrhenia grass white leaf (HGWL) phytoplasmas were determined using sequences based on secA gene and immunodominant protein (imp). Results showed a very low genetic diversity between NGS and HGWL and produced a phylogenetic tree congruent to that produced by the 16S, affirming the inclusion of HGWL in the 16SrXI group. NGS phytoplasma was transmissible to food crops through Maiestas banda Kramer (Hemiptera: Cicadellidae) under screen-house conditions. With 56.3%, Saccharum officinarum showed the highest infection level followed by Eleusine coracana with 50%, Sorghum bicolor with 43.8%, Oryza sativa with 31.3% and Zea mays with 18.8%. All the phytoplasma-infected plants were asymptomatic except S. officinarum plants, which showed mild to moderate symptoms consisting of foliar yellow leaves and bright white or yellow midribs. This hints that besides wild hosts, food crops may also serve as alternative source of inoculum enabling a complex NGS disease cycle, which may add to challenges in the development of the disease control strategies. However, failure by M. banda to transmit HGWL and BGWL phytoplasmas back to Napier grass is an indication that it could be the exclusive vector of NGS. Therefore, there is need to initiate transmission trials using planthoppers and leafhoppers occurring on HGWL and BGWL phytoplasma-infected grasses to determine whether insect vectors capable of transmitting phytoplasmas from native grasses to Napier grass, are present in the region. / PhD (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

Background: In the management of metastatic colorectal cancer (mCRC), KRAS, NRAS and BRAF mutational status individualizes therapeutic options and identify a cohort of patients (pts) with an aggressive clinical course. We hypothesized that relapsed and refractory mCRC pts develop unique mutational signatures that may guide therapy, predict for a response and highlight key signaling pathways important for clinical decision making. Methods: Relapsed and refractory mCRC pts (N=32) were molecularly profiled utilizing commercially available next generation sequencing (NGS) platforms. Web-based bioinformatics tools (Reactome/Enrichr) were utilized to elucidate mutational profile linked pathways-networks that have the potential to guide therapy. Results: Pts had progressed on fluoropyrimidines, oxaliplatin, irinotecan, bevacizumab, cetuximab and/or panitumumab. Most common histology was adenocarcinoma (colon N=29; rectal N=3). Of the mutations TP53 was the most common, followed by APC, KRAS, PIK3CA, BRAF, SMAD4, SPTA1, FAT1, PDGFRA, ATM, ROS1, ALK, CDKN2A, FBXW7, TGFBR2, NOTCH1 and HER3. Pts had on average had >= 5 unique mutations. The most frequent activated signaling pathways were: HER2, fibroblast growth factor receptor (FGFR), p38 through BRAF-MEK cascade via RIT and RIN, ARMS-mediated activation of MAPK cascade, and VEGFR2. Conclusions: Dominant driver oncogene mutations do not always equate to oncogenic dependence, hence understanding pathogenic ` interactome(s)' in individual pts is key to both clinically relevant targets and in choosing the next best therapy. Mutational signatures derived from corresponding ` pathway-networks' represent a meaningful tool to (I) evaluate functional investigation in the laboratory; (II) predict response to drug therapy; and (III) guide rational drug combinations in relapsed and refractory mCRC pts.

The thesis The analysis of genetic factors of breast cancer by NGS deals with the current serious problematics of breast cancer from the perspective of genetic predisposition. Breast cancer is one of the most common tumors in women. Every year more than 7000 women are diagnosed with this disease and the mortality rate in the Czech Republic is nearly 2000 cases. Of the total number of patients diagnosed with breast cancer, approximately ten percent of patients have congenital mutations in one of the predisposing genes that cause a significantly increased risk of developing a cancer. More than half of these mutations occur in germline mutations of the BRCA1 or BRCA2 genes, others include a number of other genes, eg tp53, CDH1, PTEN, STK11, ATM, PALB2, CHEK2.Early diagnosis and identification of persons with increased risk of developing breast cancer is of key importance for their inclusion in preventive programs. Therefore, the thesis aims to testing genes that can cause a breast cancer. In the thesis, 219 known and candidate predisposition genes were analyzed in a group of 263 non-selected breast cancer patients using a targeted panel NGS, the Illumina platform. Selected identified suspect variants were further confirmed by Sanger sequencing. The aim of this work was also a mutational analysis of...

Metagenomic sequencing is an increasingly popular way of determining microbial diversity from environmental and clinical samples. By specifically targeting the 16S rRNA gene found in all bacteria, classifications of pathogens can be determined based on the variable and conserved regions found in the gene. Metagenomic sequencing can therefore highlight the vast difference in microbiological diversity between culture-dependent and culture-independent methods. Today, this has expanded into various next-generation sequencing platforms which can provide massively parallel sequencing of the target fragment. One of these platforms is Ion-torrent, which can be utilized for targeting the 16S rRNA gene and with the help of bioinformatics pipelines be able to classify pathogens using the bacteria’s own variable and conserved regions. The overall aim of the present work is to evaluate the clinical use of Ion-torrent 16S ribosomal RNA sequencing for determining pathogenic species from clinical samples, but also to set up a pipeline for clinical practice. Optimal DNA-extraction and quantification methods were determined towards each evaluated sample-type and DNA-eluates were sent for 16S rRNA Sanger and Next-generation sequencing. The result indicated that the next-generation sequencing shows a concordance in results towards the culturing-based method, but also the importance of experimental design and effective quality trimming of the NGS data. The conclusion of the project is that the Ion-torrent pipeline provided by the Public Health Agency of Sweden shows great promise in determining pathogens from clinical samples. However, there is still a lot of validation and standardisations needed for the successful implementation into a clinical setting.

Submitted by Ricardo Cedraz Duque Moliterno (ricardo.moliterno@uefs.br) on 2017-10-09T22:34:41Z No. of bitstreams: 1 MATHUES BRITO DE OLIVEIRA Disserta??ov.pdf: 5287293 bytes, checksum: 8d3e3b854b5799f16c0b61b6a5d33f1c (MD5) / Made available in DSpace on 2017-10-09T22:34:41Z (GMT). No. of bitstreams: 1 MATHUES BRITO DE OLIVEIRA Disserta??ov.pdf: 5287293 bytes, checksum: 8d3e3b854b5799f16c0b61b6a5d33f1c (MD5) Previous issue date: 2017-06-12 / The assembly of bacterial genomes consists of a process of reordering fragments so that the original genome can be represented. However, to maximize the results of genome assembly, some steps are required, for instance, read quality analysis and preprocessing, repetition identification and quality check. The process of assembly of genomes is a complex step that involves the type of sequencing that was used, there are several types of sequencers which imply different characteristics for each one for example: fragments size, throughput, among others. Analyzing these characteristics requires the use of several computational tools, to assist in all the processes mentioned above, and since the range of software available is quite broad and distinct, it is necessary for the user to learn to work with this computational diversity, dominating often knowledge that is not of the biological area, implying in less time for a deepening in biological questions. Based on this context, we developed a pipeline to perform an automated fragment analysis, read preprocessing, genome assembly and orientation of contigs, having as the assembly the main objective of the pipeline and that it will be managed by a Web application called GATOOL (Genome Assembly Tool). Aiming to evaluate the performance of the application, tests were carried out with two samples of prokaryotic organisms, which are: Bacillus amyloliquefaciens and Serratia marcescens. Also perform a test with seven SRA samples. Both organisms are sequenced on the Ion PGMTM platform. The tools used to perform the assembly were SPAdes and Velvet, both assemblers use de Bruijn graph algorithm as a paradigm for the assembly of the genome, after this stage the resulting set of contigs was ordered through the CONTIGuator, which is a reference ordering. We observed that the interface GATOOL allowed a quick and easy execution of several steps and processes in the field of genome assembly, including the assembly of two prokaryotic species in an automated way, thus facilitating the use and accomplishment of such processes by any user. / A montagem de genomas bacterianos ? um processo de reordena??o de fragmentos, de forma que se possa representar o genoma original. Entretanto, para que a montagem de um genoma seja realizada visando maximizar os resultados, ? preciso que algumas etapas sejam cumpridas, por exemplo: a an?lise dos fragmentos, o pr?-processamento destes fragmentos e novamente uma repeti??o do processo de an?lise, para verificar a efic?cia do pr?-processamento realizado. O processo de montagem de genomas ? uma etapa complexa, que envolve o tipo de sequenciamento que foi utilizado. Existem diversos tipos de sequenciadores, o que implica caracter?sticas distintas em cada um, como por exemplo: tamanho dos fragmentos, quantidade de fragmentos gerados por corrida, dentre outros. Analisando essas caracter?sticas, faz-se necess?ria a utiliza??o de diversas ferramentas computacionais para auxiliar a todos os processos citados anteriormente e, como a gama de softwares dispon?veis ? bem ampla e distinta, ? importante que o usu?rio domine essa diversidade computacional, contendo muitas vezes conhecimentos que n?o s?o da ?rea biol?gica, implicando menos tempo para um aprofundamento das quest?es biol?gicas. Com base neste contexto, prop?em-se um pipeline para a realiza??o da an?lise de fragmentos, pr?-processamento dos fragmentos, montagem de genomas e orienta??o de contigs, tendo como a montagem o objetivo principal do pipeline e este ser? gerenciado por uma aplica??o web chamada GATOOL (Genome Assembly Tool). Visando avaliar o desempenho da aplica??o, foram feitos testes com duas amostras de organismos procariontes, que s?o: Bacillus amyloliquefaciens e Serratia marcescens. Tamb?m foram realizados testes com sete amostras SRA. Ambos os organismos est?o sequenciados na plataforma Ion PGMTM. Os montadores usados foram o SPAdes e o Velvet, ambos montadores, utilizam o algor?tmo grafo de Bruijn como paradigma para a montagem do genoma; ap?s esta etapa, o conjunto de contigs resultante foi ordenado atrav?s do CONTIGuator, que ? uma ordena??o por refer?ncia. Observamos que a interface GATOOL permitiu uma execu??o r?pida e f?cil de diversas etapas e processos no campo da montagem de genomas, inclusive realizando a montagem de duas esp?cies procariontes de maneira automatizada, facilitando assim a utiliza??o e realiza??o de tais processos por qualquer usu?rio.

The broader purpose of the work is to find and interpret polymorphism in the genes of natural immunity of cattle to be used to improve disease resistance. The NGS method on the PacBio platform was applied for the resequencing of the gene for the key receptor of innate immunity TLR2 and two genes coding for the components of the downstream transcriptional factor NF-κB. In the population of 149 bulls of the Czech Simmental breed, 22 polymorphisms were found in the gene NFKB1 (5 new), while in the NFKB2 gene 13 SNP were found (10 new). 21 SNP were found in the TLR2 gene (3 new). Of the 56 found polymorphisms, 6 SNPs were nonsynonymous. One SNP leads to a change R474G in the NFKB1 product and five to changes E63D, R152Q, I211V, R563H and H665Q in the protein TLR2. Knowledge of the haplotypes facilitated the development of individual genotyping reactions. In TLR2, a high number of haplotypes was detected, both from the PacBio reads and the statistical reconstruction. In addition, two clusters of haplotypes were ditinguished inTLR2, possibly due to diversifying selection or introgression. The knowledge of genetic diversity in the population allows for the planned association studies with health data. Localization in functional domains allow to define the change with the greatest effect, in particular...

Falhas reprodutivas são importante causa de prejuízos econômicos na suinocultura. Elas implicam na diminuição do número de leitões nascidos vivos e aumentam o descarte de animais e as taxas de reposição de matrizes, levando à redução da produtividade do rebanho. Embora a maioria dos casos de natimortalidade sejam associados a fatores não infecciosos, os agentes infecciosos possuem um papel importante e ainda pouco conhecido na etiologia deste quadro. Até o presente, nenhum trabalho foi realizado visando o estudo do conjunto de vírus que possam estar presentes em matrizes com eventos de natimortalidade por ocasião do parto. Em função disso, o presente trabalho teve por objetivo examinar o viroma do soro de matrizes suínas com e sem casos de natimortalidade. Foram coletadas 94 amostras de soro de matrizes de seis granjas distribuídas em cinco municípios do Rio Grande do Sul. Em cada granja foram formados dois pools de soros: um composto por matrizes que pariram (um ou mais) natimortos e outro por matrizes que pariram leitegadas sem natimortos. Os pools foram submetidos à extração de ácido nucleico viral, enriquecimento e sequenciamento de alto desempenho, buscando a identificação de agentes que possam representar um fator de risco à natimortalidade em suínos Não foi possível identificar diferenças significativas nos viromas de matrizes correlacionadas à ocorrência de natimortalidade. Não obstante, foi possível identificar uma ampla variedade de genomas virais, a maioria deles correspondendo a vírus das famílias Anelloviridae. Este estudo permitiu ainda identificar 20 genomas completos de três espécies de vírus: torque teno vírus suíno 1a e 1b, circovírus suíno tipo 3 (PCV3) e vírus circulares DNA fita simples codificantes de replicase (CRESS), seis dos quais até o presente ainda não reportados em suínos. Em duas granjas, em matrizes que apresentaram natimortalidade, foram identificados genomas de PCV3, cuja participação como potencial causador de problemas reprodutivos precisa ser futuramente investigada. Não foram identificados vírus com genoma de RNA. Este estudo traz uma contribuição ao conhecimento do viroma em soros de matrizes suínas e, paralelamente, busca contribuir para o esclarecimento das possíveis causas de natimortalidade de origem infecciosa em suínos. / Reproductive failure in swine herds is an important cause of economic losses. It leads to a decrease in the number of piglets reared per sow and may imply in the need for replacement of sows, reducing the productivity in a herd. Although the majority of cases of stillbirths have been attributed to non-infectious causes, several infectious agents have been implicated in the etiology of such condition. Nevertheless, other as yet unknown agents may be involved in the pathogenesis of stillbirths. The aim of this work was to investigate the virome in sera of sows without and with one or more cases of stillbirth in the litter. Sera were collected from 94 sows of six commercial farms in five municipalities in the state of Rio Grande do Sul, Brazil. Two pools of sera were collected from each farm: one representative of sows that had at least on stillbirth in the last litter and another composed by sera of sows that had litters with no stillbirths. The pools were subjected to nucleic acid extraction, enrichment and high throughput sequencing. No significant differences were detected in the serum viromes of sows with or without stillbirth Nevertheless, it was possible to identify a wide variety of viral genomes, most of these representing viruses of Anelloviridae family. In addition, the present work allowed the identification of 20 complete genome sequences including torque teno sus virus 1a and 1b, porcine circovirus 3 (PCV3) and circular rep-encoding ssDNA viruses (CRESS), including six species not previously reported in swine. In two farms, PCV3 genomes were identified in the serum pools of sows which had cases of stillbirth. The role for this virus as a potential cause of reproductive failure needs additional investigations. No genomes of viruses with RNA genomes were identified. This study provides a contribution to the knowledge on the serum virome of pregnant sows. In addition, it is expected to aid in the identification of possible causes of stillbirth in swine.

Submitted by Maria Beatriz Vieira (mbeatriz.vieira@gmail.com) on 2017-10-18T12:09:03Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) dissertacao_frederico_schmitt_kremer.pdf: 1606431 bytes, checksum: 192db9fb559b24dfd0b3038659fdd5b7 (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2017-10-23T11:10:01Z (GMT) No. of bitstreams: 2 dissertacao_frederico_schmitt_kremer.pdf: 1606431 bytes, checksum: 192db9fb559b24dfd0b3038659fdd5b7 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2017-10-23T11:11:40Z (GMT) No. of bitstreams: 2 dissertacao_frederico_schmitt_kremer.pdf: 1606431 bytes, checksum: 192db9fb559b24dfd0b3038659fdd5b7 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-10-23T11:11:52Z (GMT). No. of bitstreams: 2 dissertacao_frederico_schmitt_kremer.pdf: 1606431 bytes, checksum: 192db9fb559b24dfd0b3038659fdd5b7 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-02-17 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / O advento do sequenciamento de DNA de nova geração (NGS) reduziu significativamente o custo dos projetos de sequenciamento de genomas. Quanto mais fácil é de obter novos dados genômicos, mais acuradas deve ser a etapa de anotação, de forma a se reduzir a perda de informações relevantes e efetuar o acúmulo de erros que possam afetar a acurácia das análises posteriores. No caso dos genomas bacterianos, um grande número de programas para anotação já foi desenvolvido, entretanto, muitos destes softwares não incorporaram etapas para otimizar os seus resultados, como filtragem de proteínas falso-positivas/spurious e a anotação mais completa de RNA não-codificantes. O presente trabalho descreve o desenvolvimento do Genix, uma nova pipeline automatizada que combina a funcionalidade de diferentes softwares, incluindo Prodigal, tRNAscan-SE, RNAmmer, Aragorn, INFERNAL, NCBI-BLAST+, CD-HIT, Rfam e Uniprot, com a intenção de aumentar a afetividade dos resultados de anotação. Para avaliar a acurácia da presente ferramenta, foram usados como modelo de estudo os genomas de referência de Escherichia coli K-12, Leptospira interrogans cepa Fiocruz L1-130, Listeria monocytogenese EGD-e e Mycobacterium tuberculosis H37Rv. Os resultados obtidos pelo Genix foram comparados às anotações originais e as obtidas pelas ferramentas de anotação RAST e BASys, considerando genes novos, faltantes e exclusivos, informações de anotação funcional e predições de ORFs spurious. De forma a se quantificar o grau de acurácia, uma nova métrica, denominada discrepância de anotação foi também proposta. Na análise comparativa o Genix apresentou para todos os genomas o menor valor de discrepância, variando entre 0,96 e 5,71%, sendo o maior valor observado no genoma de L. interrogans, para o qual RAST e BASys apresentaram valores superiores a 14,0%. Além disso, foram identificadas proteínas spurious nas anotações geradas pelos demais programas, e, em menor número, nas anotações de referência, indicando que a utilização do Antifam permite um melhor controle do número de genes falso positivos. A partir dos testes realizados, foi possível demonstrar que o Genix é capaz de gerar anotação com boa acurácia (baixo discrepância), menor perda de genes relevantes (funcionais) e menor número de genes falso positivos. / The advent of next-generation sequencing (NGS) significantly reduced the cost of genome sequencing projects. The easier it is to generate genomic data, the more accurate the annotation steps must to be to avoid both the loss of information and the accumulation of erroneous features that may affect the accuracy of further analysis. In the case of bacteria genomes, a range of web annotation software has been developed; however, many applications have not incorporated the steps required to improve the output (eg: false-positive/spurious ORF filtering and a more complete non-coding RNA annotation). The present work describes the implementation of Genix, a new bacteria genome annotation pipeline that combines the functionality of the programs Prodigal, tRNAscan-SE, RNAmmer, Aragorn, INFERNAL, NCBI-BLAST+, CD-HIT, Rfam and UniProt, with the intention of increasing the effectiveness of the annotation results. To evaluate the accuracy of Genix, we used as models of study the reference genomes of Escherichia coli K-12, Leptospira interrogans strain Fiocruz L1-130, Listeria monocytogenes EGD-e and Mycobacterium tuberculosis H37Rv. the results obtained by Genix were compared to the original annotation and to those from the annotation pipelines RAST and BASys considering new, missing and exclusive genes, functional annotation information and the prediction of spurious ORFs. To quantify the annotation accuracy, a new metric, called “annotation discrepancy” was developed. In a comparative analysis, Genix showed the smallest discrepancy for the four genomes, ranging for 0.96 to 5.71%, the highest discrepancy was bserved in the L. interrogans genome, for which RAST and BASys resulted in discrepancies greater than 14.0%. Additionally, several spurious proteins were identified in the annotations generated by RAST and BASys, and, in smaller number, in the reference annotations, indicating that the use of the Antifam database allows a better control of the number of false-positive genes. Based on the evaluations, it was possible to show that Genix is able to generate annotations with good accuracy (low discrepancy), low omission of relevant (functional) genes and a small number of false-positive genes.

Amphibians face an unknown future in a time of rapid environmental change due to global climate perturbations. Since amphibians are perceived to be indicators of ecosystem health, understanding the causes of their declines can improve our perception of threats to other species. Molecular techniques have allowed us to explore how environmental change affects genetic variation and to predict evolutionary adaptive potential of amphibian populations. The identification of populations with the greatest potential to respond to changing environmental variables may be an important conservation strategy to aid in future management efforts. I utilized targeted exon capture sequencing to identify adaptive variation in California tiger salamanders (CTS; Ambystoma californiense), a species threatened by land use change and hybridization with barred tiger salamanders (A. mavortium). I identified 17 and 26 outlier loci for balancing selection in historic and recent samples of CTS respectively. The outlier loci corresponded to genes of various functions, though none of the outliers associated significantly with the change in several tested environmental variables. Despite the lack of environmental correlations detected, it must also be considered that the outlier loci could be involved in epistatic interactions where many genes with small effects influence a single phenotype with fitness benefits. Additional hypotheses to explain the observed changes in allele frequencies and outliers may be the effects of UV-B radiation, pesticide use, or indirect effects of climate change.

Orientador: Carlos Augusto Araujo Valadão / Resumo: A microbiota bacteriana intestinal dos equinos é heterogênea e complexa, podendo ser alterada por variações introduzida na dieta. A ingestão excessiva de carboidrato solúvel altera a microbiota intestinal com possíveis consequências catastróficas sistêmicas. Com este estudo, buscou-se avaliar as implicações da sobrecarga dietética experimental com amido sobre a microbiota fecal, correlacionando-a com a indução de laminite aguda. Foram utilizados 10 equinos (fêmeas ou machos castrados) SRD, idade média de 13±5,6 anos, e peso médio de 353±28 kg. Os animais foram distribuídos num delineamento inteiramente casualizado em arranjo fatorial 2x2 com medidas repetidas no tempo, sendo quatro grupos: controle (GC) - água (10L) por sonda nasogástrica e, após oito horas, solução fisiológica 0,9% (5L) pela cânula cecal; controle-tampão (GCT) - água (10L) por sonda nasogástrica e, após oito horas, solução alcalinizante (3,5g de Al(OH)3, 65,6g de Mg(OH)2) e 1,2g de simeticona pela cânula cecal; amido-controle (GAC) - amido (17,6g/kg) diluído em água (10L) e, após oito horas, solução fisiológica 0,9% (5L) pela cânula cecal; amido-tampão (GAT) - amido (17,6g/kg) diluído em água (10L) e, após oito horas, solução alcalinizante (3,5g de Al(OH)3, 65,6g de Mg(OH)2) e 1,2g de simeticona pela cânula cecal. Amostras de fezes foram colhidas da ampola retal em seis intervalos de tempo: T0 (basal); T8; T12; T24; T48; T72 horas, respectivamente, após a indução com amido. Em período imediato à colheita, av... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The horses’ intestinal bacteria microbiota is heterogeneous and complex and can variate according to diet changes. The excessive intake of soluble carbohydrate changes the intestinal microbiota with possible consequences systemic catastrophic. The goal of this study is to evaluate possible changes by starch overload in the fecal microbiota, correlating it with acute laminitis. Ten mixed breed horses (females and geldings), with age 13±5,6 years and weighting 353±28 kg, were used. They were distributed in a completely randomized design in 2x2 factorial arrangement with repeated measurements over time, being four groups: control (GC) - water (10L) by nasogastric tube and, after eight hours, physiological solution 0,9% (5L) by cecal cannula; buffer-control (GCT) - water (10L) by nasogastric tube and, after eight hours, buffer solution (3,5g of Al(OH)3, 65,6g of Mg(OH)2) and 1,2g of simethicone by cecal cannula; starch-control (GAC) - starch (17,6g/kg) diluted in water (10L) and, after eight hours, physiological solution 0,9% (5L) by cecal cannula; and buffer-starch (GAT) - starch (17,6g/kg) diluted in water (10L) and, after eight hours, buffer solution (3,5g of Al(OH)3, 65,6g of Mg(OH)2) and 1,2g of simethicone by cecal cannula. The fecal samples were collected from rectal ampoule in six different times: T0 (basal); T8; T12; T24; T48; T72 hours, respectively, after the starch overload. Following this, the lameness, the abdominal pain sings, the water and hay intake, the quality ... (Complete abstract click electronic access below) / Mestre