Made available in DSpace on 2014-12-17T15:01:51Z (GMT). No. of bitstreams: 1 PriscillaDLS_TESE_Partes autorizadas.pdf: 314555 bytes, checksum: 661601c05f1dc510316e74f62a201622 (MD5) Previous issue date: 2011-02-25 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / This work targetet the caprine ice cream production added with probiotic bacteria Bifidobacterium animalis subsp. lactis. It is divided into two parts. In the first one, four caprine ice cream formulations were evaluated, in which it was used hydrogenated fat (F1 and F3) or fat substitute (F2 and F4) in two different flavors (F1 and F2, passion fruit, F3 and F4, guava). Statistical differences (p<0.05) were detected for their physical-chemical properties, mainly for total solids and fat, but no differences were observed for melting test results. When it went to sensory acceptance, all four ice cream formulations reached high acceptance indexes, mostly formulation F4, which was selected for further studies. In the second part, F4 formulation was prepared with the addition of probiotic bacteria Bifidobacterium animalis subsp. lactis. The growth kinetics was studied and it was observed that the cellular concentration peak was reached after four fermentation hours (10.14 log UFC/g). This time was selected for pre-fermentation procedure and posterior addition at ice cream syrup. In this part of the study, two experimental groups were evaluated: group G1, in which the probiotic addition occurred before the maturation step and group G2, which included a pre-fermentation step and probiotic addition after ice cream maturation. The physical-chemical properties of these two ice cream groups were similar, except for pH, which was higher for group G2 (p<0.05). G1 samples had superior melting rate (3.566 mL/min) and both groups presented microbiological and sanitary results in accordance to current Brazilian legislation. Also, G1 and G2 were considered sensory accepted due to their acceptance indexes higher than 70%. G1 and G2 sensory profiles were similar (p>0.05), and both ice cream samples exhibited high creaminess (6.76 to 6.91) and mouth melting sensation (6.53 to 6.67) scores, while low sandiness scores (0.85 to 0.86) were observed, positive characteristics for this kind of food product. During the first 24 hours after ice cream production, the population of B. animalis subsp. lactis decreased, reaching 7.15 e 6.92 log CFU/g for G1 and G2, respectively. Probiotic bacteria counts fluctuated in ice cream samples during the first 108 days at frozen storage, especially for G2 group. Decreased probiotic viability was observed for G1 samples during the first 35 days of frozen storage, mild variation between 35 and 63 days and stabilized counts were observed after this time. After 21 days at frozen storage, ice cream samples of G1 and G2 groups reached 1.2 x 109 and 1.3 x 109 CFU/portion, respectively. After 108 days under these storage conditions, the survival rate of B. animalis subsp. lactis was 94.26% and 81.10% for G1 and G2 samples, respectively. After simulation of gastroenteric conditions, G2 group reached 9.72 x 105 CFU/portion. Considering the current requirements of Brazilian legislation, which stipulates that functional foods must have minimum probiotic count between 108 and 109 CFU/portion and detectable probiotic bacteria after being submitted to gastroenteric conditions, it is concluded that the ice cream with the addition of Bifidobacterium animalis subsp. lactis made as shown in this work, can be considered as a dairy functional food / O presente trabalho teve o objetivo de estudar a produ??o de sorvete elaborado com leite caprino com adi??o da bact?ria probi?tica Bifidobacterium animalis subsp. lactis. Foi estruturado em duas etapas. Inicialmente foram avaliadas quatro formula??es de sorvete, nas quais foi utilizada gordura vegetal hidrogenada (F1 e F3) e substituto de gordura (F2 e F4) em dois sabores (F1 e F2, maracuj?; F3 e F4, goiaba). Os c?lculos de densidade aparente e overrun foram feitos levando em considera??o as especifica??es da RDC n?. 266 de setembro de 2005. Tamb?m foram realizadas determina??es de pH, acidez total titul?vel e s?lidos totais, s?lidos sol?veis e res?duo por incinera??o, m?todo Kjeldahl para determina??o de prote?na bruta, lip?dios, a??cares redutores e totais. Al?m destas an?lises foram realizados o teste de derretimento e as an?lises microbiol?gicas nos sorvetes elaborados. As formula??es apresentaram diferen?as significativas (p<0,05) quanto ? composi??o f?sico-qu?mica, sobretudo no que diz respeito ao teor de s?lidos totais e gordura, mas n?o foi observada influ?ncia da formula??o sobre o perfil de derretimento das amostras. Quanto ? avalia??o sensorial, as quatro formula??es apresentaram elevados ?ndices de aceita??o, sobretudo a formula??o F4. Essa formula??o foi selecionada para dar prosseguimento aos estudos, cujo objetivo foi estudar os procedimentos de elabora??o do sorvete de leite de cabra com adi??o de B. animalis subsp. lactis. O pico de concentra??o celular (10,14 log UFC/g) foi alcan?ado ap?s quatro horas de cultivo sendo esse ponto escolhido para o procedimento de pr?-fermenta??o e adi??o de B. animalis subsp. lactis na calda do sorvete. Foram avaliados dois grupos experimentais de sorvete caprino com adi??o de probi?ticos: o grupo G1, com adi??o das bifidobact?rias antes da matura??o e G2, com etapa de pr?-fermenta??o e adi??o ap?s a matura??o. As propriedades f?sico-qu?micas dos dois grupos foram similares, com exce??o do pH, cujo valor foi superior no grupo G2 (p<0,05). O grupo G1 apresentou maior (p<0,05) taxa de derretimento (3,566 mL/min) e ambos os tratamentos apresentaram padr?es microbiol?gicos e sanit?rios dentro do exigido pela legisla??o vigente. Os dois grupos foram considerados aceitos sensorialmente, por exibirem n?veis de aceita??o superiores a 70% em todos os atributos verificados. Os perfis sensoriais das amostras G1 e G2 foram semelhantes (p>0,05), com elevados escores para os atributos cremosidade (6,76 a 6,91) e derretimento na boca (6,53 a 6,67), al?m de pontua??o reduzida para o quesito arenosidade (0,85 a 0,86), resultados considerados positivos para esse tipo de alimento. Foi observado decr?scimo da popula??o de B. animalis subsp. lactis ap?s as primeiras 24 horas de produ??o com contagens de 7,15 e 6,92 log UFC/g para G1 e G2, respectivamente. A contagem de bact?rias probi?ticas apresentou varia??es ao longo do armazenamento congelado por 108 dias, sobretudo para o grupo G2. O grupo G1, por sua vez, apresentou queda de viabilidade durante os primeiros 35 dias de congelamento, leve varia??o entre 35 e 63 dias de armazenamento e tend?ncia ? estabiliza??o ap?s esse ponto. Ap?s 21 dias sob armazenamento congelado, as amostras G1 e G2 apresentaram contagem de 1,2 x 109 e 1,3 x 109 UFC/por??o, respectivamente, conforme determina a legisla??o para contagens m?nimas por por??o de comest?veis gelados. Por sua vez, ao final de 108 dias sob essas condi??es, as taxas de sobreviv?ncia do B. animalis subsp. lactis do grupo G1 e G2 foram respectivamente, 94,26% e 81,10%. Ap?s ser submetido a condi??es g?stricas e ent?ricas simuladas in vitro, o sorvete com quatro meses de armazenamento do tratamento G2 apresentou contagem 9,72 x 105 UFC/por??o. Considerando o disposto pela legisla??o nacional vigente, segundo a qual um alimento com alega??o funcional deve possuir contagem m?nima probi?tica entre 108 e 109 UFC/por??o e exist?ncia de microrganismos vi?veis ap?s exposi??o ?s condi??es gastroent?ricas, conclui-se que o sorvete com adi??o de B. animalis subsp. lactis, produzido no presente estudo, constitui alimento l?cteo funcional

Submitted by (edna.saturno@ufrpe.br) on 2016-07-29T11:50:01Z No. of bitstreams: 1 Allan Vieira dos Santos Marques.pdf: 717930 bytes, checksum: aa978139a85c2cfa9f5a7df5d8379ad4 (MD5) / Made available in DSpace on 2016-07-29T11:50:01Z (GMT). No. of bitstreams: 1 Allan Vieira dos Santos Marques.pdf: 717930 bytes, checksum: aa978139a85c2cfa9f5a7df5d8379ad4 (MD5) Previous issue date: 2010-02-26 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The aim of this research was to know serum and liver concentrations of Cu, Mo, Fe and Zn in sheep and goats slaughtered in the semiarid region of the state of Pernambuco, Northeastern Brazil, during the rainy and dry seasons, and to determine if Cu deficiency that occurs in the region is primary or secondary to high levels of Mo and/or Fe. Serum and liver samples from 141 goats and 141 sheep were submitted to wet digestion in nitric-percloric acid and analyzed by coupled plasma atomic absorption spectrophotometry. The mean concentration of serum Cu in sheep was 9.22±2.34 μmol/L in the dry period and 10.03±2.89 μmol/L in the rainy period, but females had significantly higher values (10.92±2.56 μmol/L) than males (9.42±2.67 μmol/L). Mean Cu concentrations in the liver were 185.1±88.28 mg per kg of dry matter (mg/kg) in the dry period and 137.95±87.04 mg/kg in the rainy period, and females had significantly higher concentrations (218.61±93.49 mg/kg) than males (133.45±92.37 mg/kg). In goats serum concentrations of Cu were of 11.74±2.36 μmol/L in the dry period and 11.05±2.74 μmol/L in the rainy period, and females (12.10±2.67 μmol/L) had higher concentrations than males (10.14±1.80 μmol/L). Liver concentrations were 155.2±93.40 mg/kg in the dry period and of 149.37±62.33 mg/kg in the rainy period. Mean serum concentrations of Cu in sheep (9.85±2.71 μmol/L) were significantlyt lower than in goats (11.37±2.57 μmol/L), but there were no differences in liver concentrations of Cu between sheep (158.45±83.05 mg/kg) and goats (152.46±79.58 mg/kg). Based in Cu serum and liver concentrations, and in the sporadic occurrence of enzootic ataxia, Cu suplementation is recommended in grazing sheep and goats during the dry and the rainy seasons. In sheep, serum concentrations of Fe were 36.99±15 μmol/L in the dry season and 34.52±14.86 μmol/L in the rainy season, with significant differences between females (29.92±11.06 μmol/L) and males (37.85±15.68 μmol/L). Liver Fe concentrations were significantly lower in the dry season (186.20±30.02 mg/kg) than in the rainy season (229.25±83.15 mg/kg), with no differences between females and males. In goats, serum concentrations of Fe were 25.61±9.35 μmol/L in the dry season and 24.57±6.96 μmol/L in the rainy season, and liver concentrations were of 170.52±56.91 mg/kg in the dry season and 139.73±51.30 mg/kg in the rainy season; there were no significant differences between females and males. Serum levels of Fe were significantly higher in sheep (35.58±14.89 μmol/L) than in goats (25.06±8.10 μmol/L). Also Fe concentrations of the liver were higher in sheep (210.53±121.99 mg/kg) than in goats (156.1±55.99 mg/kg). Considering that serum and hepatic concentrations of Fe are between normal ranges or marginal it is suggested that the low Cu concentrations are not related with high Fe ingestion. In sheep serum concentrations of Mo were 0.33±0.18 μmol/L in the dry season and 0.3±0.15 μmol/L in the rainy season and liver concentrations were 8.27±3.97 in the dry season and 7.96±4.07 in the rainy season. In goats, serum concentrations of Mo were 0.31±0.12 μmol/L in the dry season and 0.26±0.10 μmol/L in the rainy season, and liver concentrations were 7.17±4.09 mg/kg in the dry season and 5.8±4.14 mg/kg in the rainy season. There were no significant differences in serum and liver Mo concentrations between sheep and goats and between males and females. Despite the variations found in this study and also in reference values, it is suggested that the low or marginal Cu concentrations are not due to high Mo intake. In sheep serum concentrations of Zn were significantly lower during the dry season (9.79±3.02 μmol/L) than in the rainy season (13.48±7.22 μmol/L). Also Zn concentrations in the liver were significantly lower in the dry season (109.96±30.23 mg/kg) than in rainy season (139.1±60.45 mg/kg). In goats, serum Zn concentrations were 12.01±9.61 μmol/L in the dry season and 11.6±4.93 μmol/L in the rainy season, and liver concentrations were 134.2±26.58 mg/kg in the dry season and 131.45±76.55 mg/kg in the rainy season. There were no significant differences between serum and liver concentrations of Zn between sheep and goats or between males and females. Taking into account that serum and liver Zn concentrations in sheep and goats are considered marginal, supplementation with this mineral it suggested in grazing sheep and goats, mainly during the dry season. / Objetivou-se conhecer os teores de Cu, Mo, Fe e Zn em soro e fígado de ovinos e caprinos, nas épocas de chuva e seca, criadas no semi-árido do estado de Pernambuco, e estabelecer se a carência de Cu é causada por deficiência primária de Cu ou secundária à ingestão de quantidades excessivas de Fe ou Mo. Amostras de soro e fígado de 141 ovinos e 141 caprinos foram submetidas à digestão úmida em ácido nítrico-perclórico e analisados em espectrofotômetro de absorção atômica acoplado a plasma. A concentração sérica média de Cu em ovinos foi de 9,22±2,34 μmol/L na seca e 10,03±2,89 μmol/L na chuva, sendo que as fêmeas tiveram valores significativamente maiores (10,92±2,56 μmol/L) do que os machos (9,42±2,67 μmol/L). Os valores de Cu em fígado foram de 185,1±88,28 mg/kg da MS na seca e 137,95±87,04 mg/kg na chuva e as fêmeas tiveram valores significativamente maiores (218,61±93,49 mg/kg) do que os machos (133,45±92,37 mg/kg). Em caprinos os valores séricos de Cu foram de 11,74±2,36 μmol/L na seca e 11,05±2,74 μmol/L na chuva, sendo que as fêmeas tiveram maiores valores (12,10±2,67 μmol/L) que os machos (10,14±1,80 μmol/L). Os teores do fígado foram de 155,2±93,40 mg/kg na seca e 149,37±62,33 mg/kg na chuva. Os teores séricos de cobre em ovinos foram significativamente menores que o dos caprinos, mas não se observaram diferenças nos teores hepáticos de Cu entre ovinos e caprinos. Baseado nesses valores, considerados marginais, e na ocorrência de surtos de ataxia enzoótica em caprinos e ovinos na região, recomenda-se a suplementação com Cu, em animais a campo, tanto na seca quanto na chuva. Os teores séricos de Fe em ovinos foram de 36,99±15 μmol/L na seca e de 34,52±14,86 μmol/L na chuva, diferindo entre fêmeas (29,92±11,06 μmol/L) e machos (37,85±15,68 μmol/L). Os teores do fígado foram significativamente menores na seca (186,20±30,02 mg/kg) do que na chuva (229,25±83,15 mg/kg), não havendo diferenças entre machos e fêmeas. Em caprinos os teores séricos de Fe foram de 25,61±9,35 μmol/L na seca e de 24,57±6,96 μmol/L na chuva e os teores do fígado de 170,52±56,91 mg/kg na seca e de 139,73±51,30 mg/kg na chuva. Nesta espécie não houve diferenças nos teores séricos e hepáticos de Fe entre machos e fêmeas. Os teores séricos e hepáticos de Fe foram significativamente maiores em ovinos do que em caprinos. Considerando que as concentrações séricas e hepáticas de Fe encontram-se dentro da normalidade ou são marginais sugere-se que as concentrações marginais de Cu não estejam diretamente relacionadas com o excesso de Fe. Os teores séricos de Mo em ovinos foram de 0,33±0,18 μmol/L na seca e 0,3±0,15 μmol/L na chuva e os teores no fígado de 8,27±3,97 na seca e 7,96±4,07 na chuva. Os teores séricos de Mo em caprinos foram de 0,31±0,12 μmol/L na seca e de 0,26±0,10 μmol/L na chuva e os do fígado de 7,17±4,09 mg/kg na seca e 5,8±4,14 mg/kg na chuva. Os teores médios de Mo de soro e fígado em ovinos, 0,31±0,17 μmol/L e 8,10±4,01 mg/kg, respectivamente, foram semelhantes aos teores séricos e hepáticos de caprinos, de 0,28±0,11 μmol/L e 6,53±4,13 mg/kg, respectivamente. Tanto em ovinos quanto em caprinos não houve diferenças significantes nos teores do soro e fígado entre machos e fêmeas. Apesar das variações encontradas tanto neste trabalho quanto nos dados da literatura os resultados sugerem que os teores marginais de Cu não são devidos a teores altos de Mo. Em ovinos os valores de Zn no soro foram significativamente diferentes na seca (9,79±3,02 μmol/L) do que na chuva (13,48±7,22 μmol/L). No fígado os valores de Zn foram, também, significativamente diferentes na seca (109,96±30,23 mg/kg) do que na chuva (139,1±60,45 mg/kg). Em caprinos os teores de Zn no soro foram de 12,01±9,61 μmol/L na seca e 11,6±4,93 μmol/L na chuva e os do fígado foram de 134,2±26,58 mg/kg na seca e 131,45±76,55 mg/kg na chuva. Os teores séricos e hepáticos de Zn foram semelhantes em caprinos e ovinos. Considerando que os teores de Zn sérico encontram-se abaixo dos valores considerados como marginais e os hepáticos dentro do limite de normalidade, embora próximos ao limite inferior da referência, recomenda-se a suplementação com Zn, principalmente durante o período da seca.

O objetivo do presente estudo foi estabelecer os valores de referência do proteinograma de soro lácteo por meio da técnica de eletroforese SDS-PAGE para a lactação plena e avaliar os efeitos do processo de secagem da glândula mamária, fase colostral e primeiro mês de lactação, fase de lactação, número de lactações, isolamento bacteriano e infecção pelo VCAE nas proteínas da secreção láctea de cabras da raça Saanen. Foram analisadas, entre 2007 e 2010, 545 amostras de leite provenientes de 185 cabras em diversas fases da lactação. Durante a lactação plena, baseado nos resultados dos intervalos de confiança, foram determinados os seguintes valores de referência: proteína total entre 2.940,0 e 3.050 mg/dL; proteína do soro lácteo entre 903,0 e 973,0 mg/dL; lactoferrina entre 68,0 e 77,0 mg/dL; albumina entre 88,0 e 97,0 mg/dL; imunoglobulina cadeia pesada entre 93,3 e 103,0 mg/dL; imunoglobulina cadeia leve entre 132,7 e 146,0 mg/dL; &beta;-lactoglobulina entre 299,0 e 329,0 mg/dL e &alpha;-lactoalbumina entre 213,0 e 229,5 mg/dL. Os valores absolutos de proteína total, proteína do soro e frações protéicas aumentam durante a secagem da glândula. Antes da secagem predominavam as frações de &beta;-Lg e &alpha;-La, a partir do 3&ordm; dia, ocorre o surgimento das novas frações e a alteração do perfil protéico sem que haja o predomínio de nenhuma fração. A fase colostral, primeiras 24 horas de lactação, determinam as maiores concentrações de proteína total, proteína do soro e frações protéicas que diminuem após as primeiras 12 horas de lactação estabilizando após o 5&ordm; dia. No colostro as imunoglobulinas são predominantes, e após o período de transição do colostro para o leite as frações &beta;-Lg e &alpha;-La são predominantes. Nos primeiros 15 dias de lactação, devido à influência da fase colostral, observa-se que as concentrações de proteína total e proteína do soro lácteo são maiores. A partir desse momento permanecem estáveis voltando a aumentar no final da lactação. As frações protéicas do soro de leite (lactoferrina, albumina sérica, imunoglobulina de cadeia pesada, imunoglobulina de cadeia leve, &beta;-Lg e &alpha;-La) também são máximas nos primeiros 15 dias de lactação e diminuem ao longo do período. A concentração de proteína do soro e suas frações em cabras primíparas foi menor quando comparadas com cabras pluríparas. O isolamento bacteriano não influencia as concentrações de proteína total do leite e proteína do soro lácteo de cabras, contudo a concentração de lactoferrina é maior e as concentrações de &beta;-Lg e &alpha;-La são menores em amostras com isolamento bacteriano. O CAEV não influencia as concentrações de proteína total do leite e proteína do soro lácteo de cabras, contudo a concentração de lactoferrina é maior e a concentração de e &alpha;-La é menor em cabras sororeagentes positivas ao VCAE. / The aim of this study was to establish reference values of the whey protein through the technique of SDS-PAGE for the full lactation and to evaluate the effects of the dry period of the mammary gland, colostral phase and first month of lactation, lactation, lactation number, bacterial isolation and VCAE infection in proteins of milk secretion in Saanen goats. Were analyzed between 2007 and 2010, 545 milk samples from 185 goats at different stages of lactation. During full lactation, based on the results of the confidence intervals were determined the following reference values: total protein between 2,940.0 and 3,050 mg / dL; whey protein between 903.0 and 973.0 mg / dL; lactoferrin between 68.0 and 77.0 mg / dL, serum albumin between 88.0 and 97.0 mg /dL, immunoglobulin heavy chain between 93.3 and 103.0 mg / dL, immunoglobulin light chain between 132.7 and 146, 0 mg / dL, &beta;-lactoglobulin between 299.0 and 329.0 mg / dL and &alpha;-lactalbumin between 213.0 and 229.5 mg / dL. The absolute values of total protein, whey protein and protein fractions increase during the dry period. Prevailed prior to dry period the fractions of &beta;-Lg and &alpha;-La from the 3rd day, occurs the emergence of new fractions and protein profile changes without the predominance of any fraction The colostral phase, the first 24 hours of lactation, determine the highest concentrations of total protein, whey protein and protein fractions that decrease after the first 12 hours of lactation stabilized after the 5th day. Immunoglobulin in colostrum is prevalent, and after the period of transition from colostrum to milk fractions &beta;-Lg and &alpha;-La are predominant. In the first 15 days of lactation, due to the influence of colostral phase, it is observed that the concentrations of total protein and whey protein are higher. From then remain stable before rising again in late lactation. The protein fractions of whey (lactoferrin, serum albumin, immunoglobulin heavy chain, immunoglobulin light chain, &beta;-Lg and &alpha;-La) are also maximal in the first 15 days of lactation and decrease during the period. The concentration of whey protein and protein fractions in heifers are smaller when compared with multiparous goats. Bacteria isolation does not influence the concentrations of total protein from milk and whey protein of goats, but the concentration of lactoferrin is increased and the concentrations of &beta;-Lg and &alpha;-La is smaller in samples with bacterial isolation. The CAEV does not influence the concentrations of total protein and whey protein in goat, but the concentration of lactoferrin is higher and concentration of &alpha;-La is less in goat positive by the CAEV.

Infant formula (IF) is a commonly used replacement whenever mother’s own milk is not available. Most IFs are based on cow milk (powders, liquids). Alternatives, based on other sources such as goat milk or plants, exist. Independent of the source, IF production and composition are strictly regulated. Besides proteins, minerals, and lipids, milk contains a variety of endogenous peptides. Whereas the human milk peptidome has been studied intensively, the peptidomes of IFs have been mostly neglected. This study investigated the peptidomes of different types of first stage IF, including cow milk-based powders and liquids, and powdered goat milk-based IF, highlighting major similarities and differences to human milk. Extracted native peptidomes were analyzed by nanoRPC-ESI-MS/MS using two different fragmentation techniques allowing the confident identification of 1587 peptides. β-Casein peptides dominated in all samples. Interestingly, powdered and liquid cow milk-based IFs differed in the numbers of β- and αS1-casein peptides, indicating processing-derived variations. However, the peptidomes of cow and goat milk-based IF appeared to be more comparable to each other than to human milk. Despite an overlap in the major source proteins, many peptide sequences were different, i.e., species-specific. Remarkably, the data indicate that the human milk peptidome might be donor-specific as well.

Le groupe ‘M. mycoides’ constitue une branche phylogénétique homogène des mycoplasmes regroupant 6 taxons pathogènes des ruminants, responsables pour la plupart de maladies inscrites sur la liste de l’OIE. L’identification taxinomique sur laquelle repose le diagnostic reste délicate à cause de réactions antigéniques et génétiques croisées et d’un manque d’universalité intra-taxon des PCR, notamment pour les taxons Mcc, MmmLC et Mbg7. Une approche par hybridation soustractive sélective a été développée pour 1) appréhender les différences moléculaires entre ces 3 taxons ; 2) analyser globalement la diversité au sein du groupe ‘M. mycoides’ et 3) rechercher de nouveaux marqueurs d’intérêt diagnostique. Nos résultats montrent un important partage de séquences entre ces taxons, MmmLC et Mcc étant très polymorphes par rapport à Mbg7, plus homogène et qui représente une sorte de chimère entre les taxons Mcc et MmmSC. Nos données nous ont permis de développer un test PCR spécifique pour Mcc mais la diversité génétique du groupe ‘M. mycoides’ dépasse les frontières entre taxons rendant difficile et peu pertinente l’identification taxinomique. Un typage des souches en fonction de la virulence indépendamment de l’espèce serait l’approche diagnostique alternative. La faisabilité d’une telle approche a été explorée dans le cas du taxon MmmLC mais aucun critère susceptible de différencier les souches issues de foyers de celles issues de portage dans des troupeaux sans antécédent clinique n’a pu être mis en évidence. Ce continuum génétique entre souches, probablement lié à des transferts génétiques horizontaux, imposera à l’avenir une surveillance globalisée des mycoplasmoses / The ‘M. mycoides’ cluster, a homogenous phylogenetic branch of the Mollicutes, includes 6 taxa which are responsible for diseases in ruminants, most of which are listed by the OIE. Their taxonomic identification, on which current diagnosis is based, is impaired by antigenic and genetic cross-reactivity and by the lack of a universal, intra-taxon PCR assay, especially for the Mcc, MmmLC and Mbg7 taxa. A suppression subtractive hybridization approach was developed to: 1) define molecular differences between these 3 taxa; 2) analyze the overall genetic diversity within the ‘M. mycoides’ cluster and 3) search for new markers useful for diagnosis. Results obtained here showed that several sequences are shared across taxa, with Mcc and MmmLC being very polymorphic compared to Mbg7 which is more homogeneous, representing a sort of chimera between Mcc and MmmLC. From these analyses, a specific PCR assay was designed for Mcc identification but, because of the genetic diversity existing within the ‘M. mycoides’, the taxonomic identification of new strain appears less and less relevant. Instead, regardless of their species, strain typing on the basis of their virulence would offer an alternative approach for diagnosis. We assessed this type of approach for the MmmLC taxon but so far, our attempts to uncover markers that would distinguish pathogenic strains from carrier strains, isolated from herds with no clinical history, have failed. The genetic continuum observed between strains is remnant of horizontal gene transfers and imposes the development of a more global approach for mycoplasmosis surveillance

Le virus Schmallenberg (SBV) appartient au genre Orthobunyavirus, au sein de la famille des Bunyaviridae. Ce nouveau virus, découvert en 2011 au nord-ouest de l’Europe, affecte les ruminants domestiques. Il est responsable de signes cliniques discrets chez les adultes et de malformations congénitales chez les nouveau-nés. Ces travaux de thèse s’inscrivent dans les projets d’étude de la pathogenèse de l’infection à SBV et de l’épidémiologie de la maladie, dans le cadre d’un programme de recherche européen sur le virus. Ce manuscrit inclut de nouvelles données, telles les cinétiques de la virémie et de la séroconversion chez les ovins et caprins, après infection expérimentale par SBV. La possibilité d’infection par SBV par voie vaginale est démontrée expérimentalement chez la chèvre. Après infection expérimentale de chèvres gestantes entre 28 et 42 jours de gestation, une mortalité fœtale ou des lésions du système nerveux central des fœtus peuvent survenir. Enfin, la sensibilité de plusieurs espèces de ruminants sauvages et exotiques de parcs zoologiques vis-à-vis de SBV est démontrée pour la première fois. / Schmallenberg virus (SBV) belongs to the genus Orthobunyavirus in the family Bunyaviridae. This new virus was discovered in 2011 in Northwestern Europe in domestic ruminants. Infection by SBV is associated with mild clinical signs in adult and congenital malformations in the progeny. In the scope of the European research program on SBV in the pathogenesis and epidemiology areas, the works included in this thesis provide new data about SBV infection in livestock and wild and exotic ruminants. The kinetics of viremia and seroconversion after experimental SBV infection are described in sheep and goats. This manuscript includes evidence of SBV infection via vaginal route in goats. Experimental SBV infection in pregnant goats between 28 and 42 days of gestation can lead to death or central nervous system lesions in fetuses. Evidence of susceptibility to SBV in several species of wild and exotic ruminants kept in zoos is described for the first time.