Simultaneous measurements of energy and protein metabolism can provide valuable information about their interactions. Dietary lysine is limiting in typical feedstuffs fed to swine and, therefore, limits protein synthesis. Current recommendations for dietary amino acid and energy intakes may not be reflective of the requirements for modern, highly productive sows and, therefore, invalidate requirement estimates determined according to the factorial approach. Current feeding recommendations suggest a constant amino acid intake throughout gestation. However, the demands for amino acids changes from maternal tissue accretion in early-gestation to fetal, conceptus, and mammary tissue development in late-gestation. This thesis reports the method development associated with simultaneous measurements of energy and protein metabolism and its application to determine dietary lysine requirements in non-pregnant and pregnant sows using the indicator amino acid oxidation method. Two indirect calorimetry systems and an experimental feeding regimen were tested and validated for use in studies of amino acid requirements by stable isotope dilution. Protein and energy balance studies were performed in non-pregnant sows fed two distinct levels of energy and protein intake. The systems reacted appropriately to changes in gas concentrations induced by sow respiration. Protein and energy balance studies were also performed in pregnant and lactating sows fed typical diets. Sows appeared more anabolic during mid-gestation and were catabolic by late-gestation and through lactation, where additional energy intake provided by ad libitum feed intake increased milk energy output. The dietary lysine requirement in non-pregnant sows at maintenance was determined as 49 mg/kg0.75, 30% greater than current recommendations. The dietary lysine requirement was determined to be 10.1 g/d and 16.5 g/d, in early- and late-gestation, respectively. These results suggest that a constant diet formulation for the entirety of gestation is not appropriate. In conclusion, simultaneous measurements of energy and protein metabolism combining indirect calorimetry and stable isotope techniques may be used to define requirements for dietary amino acids in sows. Basic assumptions of the factorial approach to estimate requirements require further investigation, including the dietary lysine requirement. Application of phase feeding for sows during gestation can more correctly meet the demands for amino acids and energy, improving sow longevity. / Animal Science

Thèse d'université : Sciences de la vie et de la santé. Pharmacologie et pharmacochimie : Strasbourg 1 : 2006. / Titre provenant de l'écran-titre. Bibliogr. 8 p.

No description available.

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No. of bitstreams: 1 santos_vjc_dr_jabo.pdf: 2568509 bytes, checksum: 8b023c0739ebd8dfa28bf7b7c3a5ab64 (MD5) Previous issue date: 2017-11-09 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O entendimento acerca da fisiologia do processo gestacional e desenvolvimento embrionário/fetal oferece conhecimento para que se tome decisões acertadas em relação ao manejo da fêmea gestante, além destes animais serem utilizados como modelo experimental para a medicina humana, o que reforça a importância do estudo da gestação em ovinos. Nesse contexto, a ultrassonografia se apresenta como melhor opção para avaliar o desenvolvimento da gestação. É uma tecnologia segura que permite que se façam avaliações repetidas durante todo o processo gestacional. Objetivou-se estudar o desenvolvimento fisiológico embrionário/fetal durante a gestação de ovelhas por meio da ultrassonografia a fim de se obter parâmetros de normalidade que possam ser utilizados como referência para o diagnóstico de possíveis alterações do desenvolvimento embrionário/fetal e desenvolver fórmulas para predição de idade gestacional. Foram utilizadas 30 ovelhas Santa Inês pesando 45,4±4,3 kg, entre 2 e 5 anos e realizados exames ultrassonográficos semanais desde a 3ª, até a 21ª semana gestacional. Para a análise estatística, realizou-se teste de “Shapiro” para normalidade, com medidas reais ou transformadas correlacionadas com as semanas gestacionais pelo teste de “Spearman”. Quando significativo, foram testados os ajustes dos parâmetros e semanas gestacionais à modelos de regressão. Foi utilizado nível de significância de 5% e os resultados apresentados como média±DP (desvio padrão). Foram avaliados os diâmetros da vesícula gestacional (VG), abdominal (DA), torácico (DT), biparietal (DBP), da órbita ocular (OO) e dos placentônios (PL), além dos comprimentos crâniocaudal (CC), da nuca ao focinho (NF), da escápula (ESCA), do úmero (UME), do rádio (RD), do metacarpo (MCAR), do fêmur (FEM), da tíbia (TI), do metatarso (MTAR) e dos rins (RIM); mensuração da frequência cardíaca (FC em bat/min) obtida por meio do “Doppler” Pulsado e as medidas de comprimento da base ao ápice do coração (CCOR) e de largura da parede esquerda à direita na região mais próxima à base (LCOR). Os maiores coeficientes de determinação (R²) foram obtidos para o diâmetro biparietal foi de 96,5% e para o metacarpo de 93%. O diâmetro abdominal apresentou 91,7% e a largura do coração 90,2%. Estes últimos podem ser usados para estimar o período gestacional com precisão comparável da 4ª à 21ª semana, permitindo que o Médico Veterinário faça inferências quanto à normalidade do desenvolvimento da gestação. As avaliações ultrassonográficas permitiram acompanhar o desenvolvimento gestacional nas ovelhas, obtendo-se resultados com alta correlação com o desenvolvimento das estruturas materno-fetais, que podem ser utilizados como valores de referência para o acompanhamento gestacional e detecção de anormalidades no desenvolvimento embrionário/fetal. / The understanding about the physiology of the gestational process and embryonic/fetal development offers tools to make wise decisions regarding the management of the pregnant female, besides, these animals are used as experimental models, which reinforces the importance of the study of gestation in sheep. In this context, ultrasonography is the best option for the evaluation of gestation. It is safe and allows repeated evaluations to be made throughout the gestational process. The objective of this study was to assess the embryonic/fetal physiological development during pregnancy of sheep by means of ultrasonography in order to obtain normality parameters that can be used as a reference for the diagnosis of embryonic/fetal development alterations and to develop formulas for estimate gestational age. Thirty Santa Ines sheep weighing 45.4±4.3kg, between 2 and 5 years old were used. Ultrasound examinations were performed weekly from the 3rd to the 21st gestational week. For the statistical analysis Shapiro test was performed for normality with real or transformed measurements correlated with the gestational weeks by the Spearman test. When significant, parameter adjustments and gestational weeks were tested for regression models. A significance level of 5% was used and the results presented as mean ± SD (standard deviation). The gestational vesicle (GV), abdominal (AD), thoracic (TD), biparietal (BPD), ocular orbit (OO) and placentonium (PL) diameters were evaluated, as well as the crown-rump (CR), head-nose (HN), shoulder-blade (SB) umerus (UM), radius (RD), femur (FEM), tibia (TI), metatarsus (MTT), metacarpal (MCAR), heart rate (HR in beat/min) measurements obtained with Pulsed Doppler and measurements of the length of the base to the apex of the heart (LCOR) and width in the region closest to the base (WCOR). The highest coefficients of determination (R²) were obtained for the biparietal diameter was 96.5% and for the metacarpal 93%. The abdominal diameter had 91.7% and the heart width 90.2%. The latter can be used to estimate the gestational period from the 4th to the 21st week, allowing the Veterinarian to make inferences about the normality of the development of gestation. Ultrasonographic evaluations allowed the monitoring of gestational development in sheep, resulting in high correlation with the development of maternal-fetal structures, which can be used as reference values for gestational follow-up and detection of abnormalities in embryo/fetal development. / FAPESP 14/15422-0

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Organochalcogens are important intermediates and the main applied reagents in organic synthesis and in industrial processes, which can increase human exposure risk to these chemicals in the workplace. The effects of single subcutaneous (s.c.) injection of diphenyl ditelluride ((PhTe)2) at days 6, 10 or 17 of gestation were evaluated in Wistar rats. No alterations were observed in maternal organism at the end of the experimental period. Maternal injections at day 10 of gestation resulted in appearance of malformation in the inferior and superior limbs, absent or short tail, subcutaneous blood clots, exophthalmia, hydrocephalus and exposed brain in fetuses on day 20 of gestation. Besides, (PhTe)2 reduced the fetal body and cerebral weight, kidneys length, measurements of body dimension and provoked 73% of fetal mortality. The administration of (PhTe)2 at day 17 of gestation induced appearance of hydrocephalus and evident edema in fetuses on day 20 of gestation. This administration caused 94% of fetal mortality and alterations at measurements of body dimension. Histological evaluations demonstrated alterations in GD10 and GD17. Thus, (PhTe)2 can be teratogenic to the rat fetuses. The two last fetal periods of development in the rat are the critical periods for induction of anomalies induced by (PhTe)2. Other focus of this study was the evaluation of effect of organochalcogens on the fertility and reproductive system of male rats. Adult male rats were exposed acutely (single dose) to diphenyl diselenide ((PhSe)2 and diphenyl ditelluride prior to mating. Clinical signs of toxicity following administration of drug were evidenced for reduction of body weight of rats. However, eight days after compounds exposure the mating and fertility indices were not affected in treated groups. A number of biochemical parameters in rat testes were examined, such as δ-aminolevulinic acid dehydratase (δ-ALA-D) activity, lipid peroxidation, glycogen content and components of the antioxidant defenses (superoxide dismutase (SOD) activity and ascorbic acid concentration). Except for a decrease in testes glycogen content on (PhSe)2-treated group, no alterations were found on treated groups. Histological evaluation revealed that no modification were found on the testicular tissue after drugs administration. Based on these results, there was no observed reproductive toxicity in male Wistar rats exposed acutely to (PhTe)2 and (PhSe)2. / Os organocalcogênios são importantes intermediários e reagentes utilizados em síntese orgânica e em processos industriais, portanto o risco de intoxicação por exposição ocupacional a estes compostos aumenta. O efeito da administração s.c., única, de ditelureto de difenila ((PhTe)2 ) foi avaliado nos dias 6, 10 ou 17 da gestação de ratas Wistar. No final do período experimental não foram observadas alterações no organismo materno. O (PhTe)2. induziu o aparecimento de malformações fetais, tais como deformações nos membros inferiores e superiores, ausência de cauda ou cauda diminuída, coágulos sangüíneos subcutâneos, exoftalmia, hidrocefalia e presença de cérebro exposto, quando as ratas mães receberam este composto no dia 10 da gestação. Além disso, essa mesma administração reduziu os pesos corporal e cerebral, o comprimento dos rins, as medidas de dimensão corporal e provocou uma taxa de mortalidade fetal de 73%. A administração de (PhTe)2 no dia 17 da gestação induziu o aparecimento de hidrocefalia e edema nos fetos, além de 94% de mortalidade e alterações nas medidas de dimensão corporal fetal. Avaliações histológicas demonstraram as alterações acima descritas. Então, o (PhTe)2 pode ser teratogênico para fetos de rato. Dessa forma, os dois últimos períodos gestacionais em ratas são os períodos críticos para a indução de anormalidades, no modelo experimental estudado. Outro foco deste estudo foi a avaliação do efeito de organocalcogênios sobre o sistema reprodutivo e a fertlidade de ratos machos. Os ratos receberam (PhTe)2 ou disseleneto de difenila ((PhSe)2 ), em doses únicas antes do acasalamento. Sinais clínicos da toxicidade das drogas foram evidenciados pela redução do peso corporal dos ratos. Entretanto, oito dias depois da exposição aos compostos, os índices de acasalamento e fertilidade não foram afetados. Vários parâmetros bioquímicos foram testados nos testículos desses animais, tais como as atividades das enzimas ácido δ-aminolenulínico desidratase e superóxido dismutase, a peroxidação lipídica, o conteúdo de glicogênio e a concentração de ácido ascórbico. Exceto por uma diminuição no conteúdo de glicogênio testicular no grupo tratado com (PhSe)2, não houve alteração nos outros parâmetros bioquímicos estudados. A avaliação histológica revelou que o tecido testicular não sofreu mudanças após a administração das drogas. Baseados nesses resultados, não foi observada toxicidade reprodutiva em ratos machos expostos agudamente ao (PhTe)2 ou (PhSe)2.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-07-28T13:48:12Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação para biblioteca- Versão digital.pdf: 3924060 bytes, checksum: 99b5d3f2c655eb2094f3e4cf887ae8c9 (MD5) / Made available in DSpace on 2016-07-28T13:48:12Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação para biblioteca- Versão digital.pdf: 3924060 bytes, checksum: 99b5d3f2c655eb2094f3e4cf887ae8c9 (MD5) Previous issue date: 2016-02-29 / CNPq / Descendentes adultos de mães esquistossomóticas demonstraram alteração da imunidade para antígenos homológos e heterólogos, devido á gestação ou amamentação nestas mães. A gestação em descendentes, sob infecção pós-natal concomitantemente imunizados com OA(ovalbumina)+adjuvante, demonstrou maior número de granulomas e alta deposição de colágeno enquanto que a amamentação diminuiu o tamanho. Para o antígeno heterólogo, ambas a gestação e a amamentação levaram à imunossupressão anti-OA. Contudo, sabe-se pouco sobre os efeitos da sensibilização materna com antígenos parasitários do verme do S. mansoni (SWAP). Aqui, as mães foram sensibilizadas com SWAP e foi avaliada a imunidade em descendentes nascidos e/ou amamentados. Para isto, descendentes adultos foram divididos em: animais nascidos de mães sensibilizadas e amamentados em mães não-sensibilizadas (MI), animais nascidos em mães não-sensibilizadas e amamentados em mães sensibilizadas (AI) ou nascidos e/amamentados (MIAI) em mães sensibilizadas e mães não-sensibilizadas (Controle). Estes descendentes foram infectados (80 cercárias de S. mansoni) e uma parte foi imunizada com OA+adjuvante. Realizou-se a dupla marcação para linfócitos T e coestimulatórias (CD4 e CD28, CD154 ou CTLA-4) e macrófagos (CD14 e CD40) em esplenócitos, sob estimulação com OA ou mitógeno (ConA). Foi realizada a dosagem das citocinas (IL-4, IL-10, IL-5 e IFN-γ), e anticorpos IgG1 e IgG2a anti-SWAP e antiOA, bem como a histomorfometria do granuloma hepático. Em relação ao Controle, os grupos AI e MIAI, sob infecção pós-natal apresentaram menor grau de fibrose e não houve diferença no grupo MI. Houve maior produção de IL-10 nos grupos MIAI, AI e MI, com diminuição de IL-5 e maior frequência de células CD14+CD40+ no primeiro e menor produção de IFN- e maior frequência de células CD4+CD28+ no segundo. No grupo MI, houve maior frequência basal de células CD4+CD28+ e CD14+CD40+, porém estiveram diminuídas em resposta ao mitógeno. Houve maior produção de isótipo IgG2a anti-SWAP em todos os grupos experimentais e de IgG1 anti-SWAP apenas no grupo AI.Para a imunidade anti-OA, no grupo MIAI, houve maior frequência de células CD14+/CD40, menor produção de IL-5 sem diferença na produção de anticorpos anti-OA. Amamentação induziu maior frequência de células CD4+/CD28, CD4+/CTLA-4, CD14+/CD40, maiores níveis de IL-4 e menos IFN-γ basal e em resposta à OA e maior produção de IgG1 anti-OA. A gestação induziu maior frequência basal de células CD14+/CD40+ e menor frequência em resposta à OA e ConA, maiores níveis de IL-4, em resposta à OA, sem diferença para IFN-γ. Em resposta ao mitógeno, menos células CD4+CD28+, alta frequência de células CD40/CD154, e altos níveis de IL-10. Assim, a amamentação, e não a gestação, em mães sensibilizadas com SWAP, seguida de infecção pós-natal ameniza a inflamação granulomatosa. Para o antígeno heterólogo, ambos gestação e amamentação desviam a resposta para Th2, porém a amamentação melhora os status de ativação de linfócitos e macrófagos, acompanhada de melhor resposta de anticorpos anti-OA. / Descendants adult schistosome mothers had alterations of immunity to homologous and heterologous antigens due to pregnancy or breastfeeding these mothers. The pregnancy in offspring in postnatal infection concomitantly immunized with OA (ovalbumin) + adjuvant, demonstrated great number of granulomas and high deposition of collagen, while suckled decreased size. For the heterologous antigen, both pregnancy and breastfeeding led to anti-OA immunosuppression. However, little is known about the effects of maternal sensitization with worm parasite antigens of S. mansoni (SWAP). Here, mothers were sensitized with SWAP and immunity was evaluated in born and / or breastfed offspring. For this, adult descendants were divided into animals born sensitized mothers and breastfed in non-sensitized mothers (BIM), animals born in nonsensitized and breastfeeding mothers sensitized mothers (SIM) or born and / breastfed (BSIM) in mothers sensitized mothers and non-sensitized (CONTROL). These offspring were infected (80 cercariae of S. mansoni) and a part was immunized with adjuvant + OA. Was performed for double labeling T lymphocytes and co-stimulatory (CD4 and CD28 or CTLA-4 CD154) and macrophages (CD14 and CD40) in splenocytes, OA or upon stimulation with mitogen (ConA). the dosage of cytokines was performed (IL-4, IL-10, IL-5 and IFN-γ) and IgG1 and IgG2a anti-SWAP and anti-OA and histomorphometry of hepatic granuloma. In relation to control, SIM and BSIM groups under postnatal infection had lower degree of fibrosis and no difference in BIM group. There was a greater IL-10 production in BSIM groups, SIM and BIM, with decreased IL-5 and increased frequency of CD14+ CD40+ in the first and lowest IFN-γ and increased frequency of CD4+ CD28+ in the second. In the BIM group had higher baseline frequency of CD4+CD28+ and CD14+CD40+ cells, but were reduced in response to mitogen. There was a higher production of isotype IgG2a anti-SWAP in all experimental groups and anti-IgG1 SWAP only in the SIM group. For the anti-OA immunity in BSIM group had a greater frequency of CD14+/ CD40 cells, decreased production of IL-5 with no difference in the production of anti-OA antibodies. Breastfeeding induced higher frequency of CD4+/CD28+ CD4+/CTLA-4+, CD14+/ CD40+ increased IL-4 levels under basal and IFN-γ and in response to OA and increased production of anti-OA IgG1. Pregnancy induced basal frequency of CD14+/ CD40+ and lower frequency in response to OA and Con-A, increased IL-4 levels in response to OA was no difference for IFN-γ. In response to mitogen less CD4+ CD28+ cells, CD40 high-frequency cells CD154, and high IL-10 levels. Thus, breastfeeding, and not pregnancy in mothers sensitized with SWAP, followed by postnatal alleviates granulomatous inflammation infection. For the heterologous antigen, both pregnancy and breastfeeding divert the response towards Th2, but breastfeeding enhances activation status of lymphocytes and macrophages, together with better anti-OA antibody response.

No / Gestational stress (GS) produces profound behavioural impairments in the offspring and may permanently programme hypothalamic¿pituitary¿adrenal (HPA) axis function. We investigated whether or not GS produced changes in the maternal behaviour of rat dams, and measured depression-like behaviour in the dam, which might contribute to effects in the progeny. We used the Porsolt test, which measures immobility in a forced-swim task, and models depression in rodents, while monitoring maternal care (arched-back nursing, licking/grooming, nesting/grouping pups). Pregnant rats underwent daily restraint stress (1 h/day, days 10¿20 of gestation), or were left undisturbed (control). On post-parturition days 3 and 4, dams were placed into a swim tank, and time spent immobile was measured. GS significantly elevated immobility scores by approximately 25% above control values on the second test day. Maternal behaviours, in particular arched-back nursing and nesting/grouping pups, were reduced in GS dams over post-natal days 1¿10. Adult offspring showed increased immobility in the Porsolt test, and also hypersecreted ACTH and CORT in response to an acute stress challenge. These data show that GS can alter maternal behaviour in mothers, and this might contribute to alterations in the offspring. GS may be an important factor in maternal post-natal depression, which may in turn detrimentally effect the offspring because depressed mothers do not sufficiently care for their offspring.

No description available.

L’immaturité pulmonaire caractérisée par un défaut en surfactant est très fréquente chez le nouveau-né prématuré, particulièrement chez les plus jeunes. La sévérité du syndrome de détresse respiratoire (SDR) et le taux de mortalité qui y est associé ont été considérablement réduits par l’administration anténatale de glucocorticoïdes. En plus, les traitements administrant du surfactant exogène, qui compense l’immaturité, et l’amélioration des protocoles de ventilation assistée ont contribué à ces progrès. Toutefois, le SDR reste plus fréquent chez les enfants de sexe masculin que féminin. Le sexe fœtal est alors un facteur déterminant dans les processus de développement et de maturation pulmonaire où la maturation des pneumocytes de type II marque le début de la montée de synthèse et de la sécrétion du surfactant. Chez l’enfant né prématurément, la structure du poumon est simplifiée. Les saccules distales sont indifférenciées, les parois paraissent plus larges et on observe un faible développement microvasculaire. Le poumon verra sa surface alvéolaire augmenter vers la 30e semaine de gestation tandis que la septation alvéolaire des saccules distales commencera vers la 32e semaine de gestation. Durant cette maturation structurale du poumon, des interactions entre le mésenchyme et l’épithélium vont être impliquées dans la régulation de différents processus via des facteurs paracrines. Chez le garçon, la maturation est retardée par les androgènes, conduisant à un délai dans la synthèse du surfactant pulmonaire. Dans le but de développer de nouvelles cibles pharmacologiques, nous avons étudié les différences temporelles et sexuelles dans les transcriptomes des cellules fibroblastiques et épithéliales pulmonaires chez la souris durant les jours de gestation 17 .5, 18.0 et 18.5. Nous avons utilisé une approche de biopuce ADN durant une fenêtre de gestation qui encadre la montée de synthèse du surfactant, qui est asynchrone entre femelles et mâles en défaveur de ces derniers. Différents profils d’expression des gènes du poumon ont été obtenus entre les jours de gestation 17.5, qui correspond au stade canaliculaire, et 18.5, qui correspond au début du stade sacculaire. Les résultats ont montré que 347 gènes présentaient une différence d’expression en fonction du temps dans les cultures de fibroblastes contre 116 gènes dans les cultures épithéliales. Le gène Cox-1, impliqué dans la synthèse des prostaglandines présentait une expression qui diminuait entre les jours de gestation 17.5 et 18.5. Pour le gène Sema3A impliqué dans la différenciation des cellules épithéliales, et le gène Lemd2, un régulateur négatif de la signalisation PI3K/MAP kinase, on observait une augmentation de leur niveau d’expression entre les jours de gestation 17.5 et 18.5. De plus, nos résultats indiquent que le nombre de gènes exprimé avec des différences sexuelles évolue à la hausse en fonction du temps de gestation. Dans les cellules épithéliales, 3276 transcrits présentant une différence sexuelle dans leur niveau d’expression au jour gestationnel 18.5 ont été identifiés. Ils sont principalement impliqués dans la prolifération et la croissance cellulaire, les interactions cellulaires, le métabolisme des lipides et l’apoptose. Plusieurs voies de signalisation, dont celles de TGF, FGF, IGF et WNT présentaient des différences sexuelles. Des modulations temporelles et sexuelles spécifiques aux types cellulaires ont été observées pour plusieurs gènes, ce qui pave la voie au développement de nouvelles cibles pharmaceutiques. / Pulmonary immaturity characterized by the deficiency absence of surfactant is frequent for premature babies, especially for those who born before the 32nd week of gestation. The severity of respiratory distress syndrome of the neonate (RDS) and the related mortality rate have been reduced substantially by antenatal administration of glucocorticoids. Moreover, exogenous surfactant therapy and ventilation strategies also have contributed to this progress. However, RDS is still more frequent for boys than girls. Fœtal sex is thus a critical factor for fœtal lung maturation. For babies born prematurely, lungs structure is simplified. The distal saccules are undifferentiated. Pulmonary walls seem thicker and the microvasculature is underdeveloped compared with normal lungs. Alveolar surface of normal lungs increases from the 30th week of gestation, while saccularization starts around the 32nd week of gestation. During this lung structural maturation, interactions between mesenchymal and epithelial cells involving paracrine factors are involved in the regulation of different processes. For males, maturation is delayed by androgens, leading to a delay in the surge of surfactant synthesis in type II pneumocytes. In order to develop novel pharmaceutical targets, we have studied the effect of sex and gestation time on the transcriptome of cultured mouse pulmonary fibroblasts and epithelial cells isolated on gestation day 17.5, 18.0 and 18.5. We used DNA microarrays during a gestation period overlapping the surge of surfactant synthesis, which occurs later in males. Different expression profiles were obtained on gestation day 17.5, corresponding to the canalicular stage, compared with gestation day 18.5, corresponding to the beginning of the saccular stage. Our data indicated that 347 genes were expressed differently according to gestation time in lung fibroblast cultures, while only 116 genes presented such a variation in epithelial cell cultures. The expression levels of Cox-1, involved in prostaglandin synthesis, decreased from gestation day 17.5 to 18.5. For Sema3A, involved in epithelial cell differentiation, and Lemd2, encoding for a negative regulator of PI3K/MAP kinase signalling, we observed an increase in expression from gestation day 17.5 to GD 18.5. Moreover, our results show that the number of genes expressed with a sex difference increased according to gestation time. In epithelial cells, 3,276 transcripts presenting a sex difference in their expression level on gestation day 18.5 have been identified. They are mainly involved in cell proliferation and growth, cell-cell interaction, lipid metabolism, and apoptosis. Several signalling pathways including those of TGF, FGF, IGF and WNT showed sex differences. Time- and sex-related modulations were observed for various genes in specific cells, which pave the way to the development of novel pharmaceutical targets.

The interaction between the embryo and fetus with the maternal environment can have both short- and long-term consequences on health and development after birth. In some cases, these changes may be detrimental to the individual, but in other cases these developmental changes may be beneficial and manipulated to produce desired effects. Our interest is to use this concept of fetal programming to improve skeletal muscle development and meat production in ruminants. To achieve this, we targeted the period of gestation when fetal muscle fiber formation occurs. Primary muscle fibers form during embryonic development, and it is this small number of primary muscle fibers that will serve as templates for secondary fiber formation that occurs in the fetus during mid-gestation. Supplementing amino acids that influence blood flow within the reproductive tract is one potential way to provide fetuses with added nutrients during gestation, and this supplementation strategy may be especially useful when the maternal diet is compromised. L-citrulline was chosen for this work because of its long half-life in maternal circulation. This work utilized twin-bearing ewes with a moderate dietary energy restriction to assess the effects of mid-gestational L-citrulline supplementation on umbilical blood flow, placental function, neonatal lamb size, and lamb performance. We hypothesize that i.v. administration of L-citrulline will increase uterine and placental blood flow in gestating ewes and this will improve fetal growth, development, and overall postnatal performance. Blood flow parameters were not influenced by treatment (P>0.05). Circulating levels of progesterone and pregnancy-specific protein B (PSPB) were used as indicators of placental function and were unaffected by treatment administration (P>0.05). A treatment by time interaction was detected in both analyses, but no differences between treatments were detected within any time points. There was no effect of treatment on lamb weights or survival to weaning (P>0.05). Lamb sex effects are absent with the exception that body weights were greater in ewe lambs (P>0.05). There was no effect of treatment on any carcass traits or visceral organ weights assessed, though there was an effect of sex on dressing percentage and pancreas weight with wethers having a greater dressing percentage and heavier pancreases per kg body weight than that of ewes (P<0.05). In summary, contrary to our hypothesis L-citrulline supplementation to pregnant ewes under a minor to moderate metabolic challenge had no impact on blood flow and provided no programming benefit to the lambs. / Master of Science / The global population continues to grow, along with the consumption of animal protein. This can be met with increasing the numbers of animals within our food production systems, however, there is also increasing pressure for livestock production systems to produce more while utilizing less space and resources. And simultaneously, we face growing concerns about climate change, its impacts on agriculture, and the role of agriculture in both the cause and any future solution. To combat both these issues, the efficiency of our livestock systems needs to improve with each individual animal becoming much more efficient. This increase in efficiency can occur in many ways including reproductive efficiency, feed efficiency, and in overall producing more meat per individual. The improvement in efficiency of an animal can begin in the womb. Livestock in meat production spend 35-40% of their life within the uterus being nourished by their mother. The interactions the embryo and fetus have with the maternal environment during this time can have both short- and long-term impacts on health and development after birth. In some cases, these changes may be detrimental to the individual, but in other cases these developmental changes may be beneficial and manipulated to produce the desired effects. Thus, it is important to understand the impact of these fetal-maternal interactions as it directly affects both fetal growth and growth and development after birth. This concept is known as fetal programming. Our interest is to use this concept to improve skeletal muscle development and meat production in cattle and sheep. To achieve this, we targeted the period of pregnancy when fetal muscle formation occurs. Primary muscle fibers form early in pregnancy, and it is this small number of primary muscle fibers that will serve as templates for secondary fiber formation that occurs in the fetus during mid-pregnancy. Supplementing amino acids that influence blood flow within the reproductive tract is one potential way to provide fetuses with added nutrients during pregnancy, and this supplementation strategy may be especially useful when the maternal diet is compromised. L-citrulline was chosen for this work because of its long half-life in maternal circulation. This work utilized twin-bearing ewes with a moderate dietary energy restriction to assess the effects of L-citrulline supplementation on blood flow, placental function, newborn lamb size, and lamb performance. We hypothesize that intravenous administration of L-citrulline will increase uterine and placental blood flow in pregnant ewes and this will improve fetal growth, development, and overall postnatal performance. There was no beneficial effect on blood flow to the fetus and on placental function. Additionally, there were very minimal effects on carcass traits or internal organ weights assessed. In summary, contrary to our hypothesis L-citrulline supplementation to pregnant ewes under a moderate metabolic challenge had no impact on blood flow and provided no programming benefit to the lambs. We can conclude that the potential benefit of amino acid supplementation was not realized in our sheep model.