Made available in DSpace on 2017-07-10T17:48:23Z (GMT). No. of bitstreams: 1 Leandro_Castilha.pdf: 563829 bytes, checksum: 6d297cffa932c5d373629232128d653e (MD5) Previous issue date: 2011-02-21 / Aiming to determine the digestible isoleucine requirement for female swines from 15 to 30 kg, two experiments were conducted, a performance one and a nitrogen balance. In the first experiment, 40 crossbreed female swines of high genetic potential and average performance were used, with 15.00 ± 0.52 kg initial weight, distributed in a randomized blocks design, consisting of five treatments (0.45, 0.52, 0.59, 0.66, 0.73% digestible isoleucine), four replicates and two animals. At the beginning and the end of the performance experiment one animal per experimental unit was bleed for determination of plasma urea. At the end of the experiment, the second animal of each experimental unit was slaughtered to determine carcass composition and organ weights. In the second experiment, 20 castrated crossbred pigs were used, averaging 22.26 ± 1.79 kg of initial weight, distributed individually in metabolism cages in a randomized blocks design, consisting of five treatments (0.45, 0.52, 0.59, 0.66, 0.73% digestible isoleucine) and four replications. In the first experiment, there was quadratic effect (P<0,05) of digestible isoleucine levels over the daily feed intake, with estimation of best feed intake at level 0,704%. There was quadratic effect (P<0,05) of digestible isoleucine levels over efficiency of isoleucine utilization for weight gain, with increase until 0.506% of digestible isoleucine. In the second experiment, only N intake (g/kg BW0,75/day) was influenced (P<0,05) by digestible isoleucine levels, with linear increase on N intake values as digestible isoleucine levels were increased in the rations. The level of 0.506% digestible isoleucine, for female swines from 15 to 30 kg, provided the best efficiency of isoleucine utilization for weight gain, which digestible isoleucine:lysine relation was 0,51. The daily requirement of digestible isoleucine was 4,94 g/day, providing 1,56g of digestible isoleucine/Mcal of metabolizable energy / Com o objetivo de determinar a exigência de isoleucina digestível para fêmeas suínas dos 15 aos 30 kg, foram realizados dois experimentos, um ensaio de desempenho e um balanço do nitrogênio. No primeiro experimento, foram utilizadas 40 fêmeas suínas, mestiças, de alto potencial genético e desempenho médio, com peso vivo inicial de 15,00 ± 0,52kg, distribuídas em um delineamento experimental de blocos ao acaso, constituído de cinco tratamentos (0,45; 0,52; 0,59; 0,66; 0,73% de isoleucina digestível), quatro repetições e dois animais por unidade experimental. No início e no final do experimento, foi realizada a coleta de sangue de um animal por unidade experimental, para determinação da ureia do plasma. Ao final do experimento, o segundo animal de cada unidade experimental foi abatido, para a determinação da composição de carcaça e peso de órgãos. No segundo experimento, foram utilizados 20 suínos, mestiços, machos castrados, com peso vivo inicial de 22,26 ± 1,79kg, distribuídos individualmente em gaiolas de metabolismo, em um delineamento experimental de blocos ao acaso, constituído de cinco tratamentos (0,45; 0,52; 0,59; 0,66; 0,73% de isoleucina digestível) e quatro repetições. No primeiro experimento, houve efeito quadrático (P<0,05) dos níveis de isoleucina digestível sobre o consumo diário de ração, com estimativas de melhor consumo para o nível de 0,704%. Obteve-se efeito quadrático (P<0,05) dos níveis de isoleucina digestível sobre a eficiência de utilização de isoleucina para ganho de peso, com aumento até o nível 0,506%. No segundo experimento, foi observada diferença linear (P<0,05) apenas para o nitrogênio ingerido (g/kg PV0,75/dia), em que o modelo linear apresentou aumento nos valores de N ingerido à medida que aumentaram os níveis de isoleucina digestível nas rações. O nível de 0,506% de isoleucina digestível, para fêmeas suínas dos 15 aos 30 kg, proporcionou a melhor eficiência de utilização de isoleucina para ganho de peso, conferindo uma relação isoleucina:lisina digestível de 0,51. A exigência diária de isoleucina digestível foi de 4,94 g/dia, proporcionando 1,56g de isoleucina digestível/Mcal de energia metabolizável

Made available in DSpace on 2017-07-10T17:48:26Z (GMT). No. of bitstreams: 1 Doglas_Lazzeri.pdf: 319692 bytes, checksum: ab1f14cee65939d583d1aaf7427d892d (MD5) Previous issue date: 2011-07-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Aiming to determine the digestible isoleucine requirement for barrows from 15 to 30 kg, two experiments were conducted, being one of digestibility and another of performance. Ten crossbreed barrows with average initial weight of 15.00 ± 0.27 kg were used to determine the ileal digestibility coefficient of amino acids from basal diet. The animals were housed individually in metabolic cages in a completely randomized design, with two treatments, five replicates and one animal per experimental unit. The treatments consisted of a basal diet with 14.13% crude protein and 0.45% isoleucine, and a free protein diet. Forty crossbreed barrows with average initial weight of 15.00 ± 0.87 kg were used to determine the digestible isoleucine requirement. The animals were distributed in a randomized block design with five treatments (0.45, 0.52, 0.59, 0.66 and 0.73% digestible isoleucine), four replicates and two animals per experimental unit. The coefficients of true ileal digestibility of essential amino acids were higher than the coefficients of apparent ileal digestibility and threonine, methionine+cystine and valine had the biggest increases. The true ileal digestibility of basal diet for lysine, threonine and tryptophan were higher than the true ileal digestible calculated amino acids. The same was not observed for true ileal digestibility of basal diet of arginine, histidine, isoleucine, leucine, methionine, methionine+cystine, phenylalanine and valine. The protein deposition rate had a quadratic effect (P<0.05) which the level of 0.600% digestible isoleucine had the highest protein deposition in carcasses of pigs. The daily isoleucine intake had quadratic effect (P<0.01), which level of 0.938% digestible isoleucine provided the higher intake. There was linear effect (P<0.01) on efficiency of isoleucine utilization for weight gain, with reduction on values of EIleUWG as levels of digestible isoleucine increased in rations. A quadratic effect (P=0.09) of digestible isoleucine levels on the final weight was observed, with better values for the level 0.599%. The level of 0.60% digestible isoleucine obtained in the present work provided a digestible isoleucine:lysine relation of 0.60. The daily requirement of digestible isoleucine was 5.86 g/day, providing 1.76g of digestible isoleucine/Mcal of metabolizable energy / Com o objetivo de determinar a exigência de isoleucina digestível para suínos machos castrados dos 15 aos 30 kg de peso vivo, foram realizados dois experimentos, um de digestibilidade e outro de desempenho. Para determinar o coeficiente de digestibilidade ileal dos aminoácidos da ração basal, foram utilizados 10 suínos, machos castrados, mestiços, com peso médio inicial de 15,00±0,27 kg, alojados individualmente em gaiolas de metabolismo, em um delineamento inteiramente ao acaso, com dois tratamentos, cinco repetições e um animal por unidade experimental. Os tratamentos consistiram de uma dieta basal, com 14,13% de proteína bruta e 0,450% de isoleucina, e uma dieta isenta de proteína. Na determinação da exigência de isoleucina digestível para suínos machos castrados, foram utilizados 40 suínos mestiços, com peso médio inicial de 15,00±0,87 kg, distribuídos em um delineamento experimental de blocos casualizados, com cinco tratamentos (0,45; 0,52; 0,59; 0,66 e 0,73% de isoleucina digestível), quatro repetições e dois animais por unidade experimental. Os valores dos coeficientes de digestibilidade ileal verdadeira dos aminoácidos essenciais foram maiores do que os coeficientes de digestibilidade ileal aparente, sendo a treonina, a metionina + cistina e a valina os aminoácidos que apresentaram os maiores aumentos. Os valores de digestibilidade ileal verdadeira da dieta basal para lisina, treonina e triptofano foram superiores aos valores de aminoácidos digestíveis ileais verdadeiros calculados. O mesmo não foi observado para os valores de digestibilidade ileal verdadeira da dieta basal dos aminoácidos arginina, histidina, isoleucina, leucina, metionina, metionina + cistina, fenilalanina e valina. A taxa de deposição de proteína apresentou efeito quadrático (P<0,05), em que o nível de 0,600% de isoleucina digestível proporcionou a maior deposição de proteína na carcaça dos suínos. Houve efeito quadrático (P<0,01) dos níveis de isoleucina digestível sobre o consumo diário de isoleucina, com estimativas de melhor consumo para o nível de 0,938%. Foi observada diferença linear (P<0,01) apenas para a eficiência de utilização de isoleucina para ganho, em que o modelo linear apresentou redução nos valores de eficiência à medida que aumentaram os níveis de isoleucina digestível nas rações. Foi observado efeito quadrático (P=0,09) dos níveis de isoleucina digestível sobre o peso final, com melhores valores obtidos para o nível de 0,599%. O nível de 0,60% de isoleucina digestível, obtido no presente estudo, proporcionou uma relação isoleucina:lisina digestível de 0,60. A exigência diária de isoleucina digestível foi de 5,86 g/dia, proporcionando um consumo de 1,76 g de isoleucina digestível/Mcal de energia metabolizável

Estudos em animais mostram que a desnutrição proteica intrauterina pode acarretar redistribuição do fluxo sanguíneo intraútero, podendo promover modificações permanentes na estrutura e funcionalidade de alguns órgãos, o que ocasiona modificações no metabolismo. Além disso, a desnutrição intrauterina pode afetar a secreção de hormônios que atuam no crescimento fetal, podendo conduzir à restrição do crescimento intrauterino. Esse fenômeno pode parcialmente ser explicado pela hipótese da programação fetal, na qual é sugerido que ocorra uma adaptação metabólica e fisiológica do feto a uma condição intrauterina adversa, que pode induzir o desenvolvimento de doenças crônicas não transmissíveis na vida adulta. Neste contexto, pesquisas com suplementação de aminoácidos de cadeia ramificada (BCAA) têm verificado a capacidade desses nutrientes promoverem a síntese proteica mesmo em condições catabólicas, por meio da ativação de uma via bioquímica intracelular intercedida pela proteína quinase Alvo da Rapamicina em Mamíferos (mTOR), a qual está envolvida no estímulo à etapa de tradução proteica. Assim, o presente trabalho avaliou o efeito da suplementação de BCAA em proles submetidas à desnutrição proteica materna. Para tanto, ratas Wistar foram acasaladas com ratos adultos de mesma raça. Uma vez constatada a gravidez, as matrizes foram distribuídas em grupos de acordo com a dieta que seria fornecida no decorrer da gestação: CON (20% proteína); VAL/ISO (5% proteína + 2% VAL + 2% ISO); AAE (5% proteína + 4% AAE); e BCAA (5% proteína + 4% BCAA). O protocolo de restrição proteica materna adotado causou redução no crescimento corporal e na massa de órgãos das proles. Embora a suplementação com VAL/ISO e AAE não tenha recuperado os efeitos mediados pela deficiência de proteína, foi constatado que a suplementação com BCAA reverteu parte do déficit observado no crescimento das proles, uma vez que foi eficaz em minimizar ou mesmo em restaurar plenamente diversos parâmetros como peso de órgãos, massa de gordura da carcaça e parâmetros indicativos do estado nutricional proteico, como as concentrações de proteína e RNA hepáticas e musculares. Estes efeitos podem parcialmente ser explicados pelo estímulo induzido pela suplementação com BCAA, na via de sinalização da mTOR, considerando que foi verificado no fígado das proles de matrizes que receberam esta suplementação, aumento na fosforilação desta proteína (P < 0,05), a qual é responsável por desencadear uma cascata de eventos biomoleculares que culminam, em última instância, no acréscimo da síntese proteica. Diante disto, torna-se relevante a realização de pesquisas que avaliem em longo prazo, os efeitos da suplementação com BCAA em proles submetidas à dieta materna restrita em proteína. / Animal studies show that intrauterine malnutrition may cause redistribution of blood flow in uterus, which may promote permanent changes in structure and function of some organs, which causes changes in metabolism. Furthermore, intrauterine malnutrition can affect the secretion of hormones that act on fetal growth and may lead to intrauterine growth restriction. This phenomenon can partly be explained by the hypothesis of fetal programming, which is suggested that occur a metabolic and physiological adaptation of the fetus to an adverse intrauterine condition, which can induce the development of chronic diseases in later life. In this context, researches with supplementation of branched chain amino acids (BCAA), especially leucine, have verified the ability of these nutrients to promote protein synthesis in catabolic conditions, through the activation of an intracellular biochemical pathway interceded by protein kinase Mammalian Target of Rapamycin (mTOR), which is involved in the stimulating of protein translation stage. Thus, this study evaluated the effect of BCAA supplementation in offspring subjected to maternal protein-restrict diet. To this, Wistar rats were mated with adult rats of the same race. Once was confirmed the pregnancy, the pregnants were distributed into groups according to the diet that would be provided during pregnancy: CON (20% protein); VAL/ISO (5% protein + 2% + 2% VAL/ISO), AAE (5% protein + 4% EAA) and BCAA (5% protein + 4% BCAA). The protocol adopted maternal protein restriction caused a reduction in body growth and weight of the offspring\'s organs. Although supplementation with VAL/ISO and AAE has not recovered the effects mediated by protein deficiency, it was found that supplementation with BCAA has reversed part of the deficit observed in the growth of the offspring, since it was effective in minimizing or even fully restoring various parameters such as organ weight, carcass fat mass and parameters indicative of nutritional protein, such as the concentrations of protein and RNA in liver and muscle. These effects may be partially explained by the stimulation induced by BCAA supplementation on the mTOR signaling pathway, considering that was verified in the liver of the offspring from dams that received this supplementation augment on the phosphorylation of this protein (P < 0,05), which is responsible for triggering a cascade of molecular events that culminate, ultimately, in increased protein synthesis. Given this, it becomes relevant to conducting research to assess long-term effects of supplementation with BCAA in offspring subjected to maternal protein-restricted diet.

A busca pelo aumento da força muscular, em paralelo à diminuição da gordura corporal e melhora do rendimento esportivo, tem levado muitas pessoas ao uso de suplementos de proteínas e/ou aminoácidos, associados com a prática de exercícios físicos. Dentre os inúmeros suplementos de proteínas ou aminoácidos disponíveis no mercado, têm merecido destaque nas últimas décadas os aminoácidos essenciais de cadeia ramificada, também chamados de branched chain amino acids (BCAA\'s). O suplemento chamado de BCAA é uma combinação de três aminoácidos essenciais - L-Leucina, L-Valina e L-Isoleucina. As alegações feitas a esses aminoácidos giram em torno de seus efeitos sobre a síntese proteica no músculo esquelético, diminuição dos danos musculares, redução da gordura corporal e melhora do desempenho físico. O presente estudo teve como objetivo realizar uma revisão sistemática de estudos clínicos na utilização desses aminoácidos no intuito de aumentar a massa muscular, reduzir a gordura corporal e aumentar o rendimento esportivo, avaliando os resultados obtidos e que comprovem seu uso e segurança. A busca dos artigos nas bases de dados resultou em 7502 artigos. Seguindo todos os critérios de inclusão e exclusão, 11 artigos foram selecionados para esta revisão sistemática. A performance foi avaliada em 6 artigos. A massa muscular foi avaliada em 5. Não foram encontrados artigos visando a redução de gordura corporal. A dose de BCAA utilizada foi de 1,2 g até 10g e os estudos ministraram os suplementos na forma de pó, cápsulas e infusão. A melhor relação entre leucina, valina e isoleucina foi de 2:1:1, respectivamente. Considerando que o número de estudos com resultados benéficos praticamente se iguala ao de resultados negativos, mais estudos são necessários para que se comprove os reais benefícios do uso de BCAA como suplemento estratégico para aumentar a massa muscular, reduzir a gordura corporal e aumentar o rendimento esportivo. / The search for increased muscle strength, in parallel to decreased in body fat and improved sports performance has led many people to use protein and/or amino acid supplements associated with the practice of physical exercises. Among the numerous supplements of proteins or amino acids available in the market, the branched chain amino acids (BCAA\'s) have deserved prominence in the last decades. The supplement called BCAA is a combination of three essential amino acids - L-Leucine, L-Valine and L-Isoleucine. The claims made to these amino acids revolve around their effects on protein synthesis in skeletal muscle, decreased muscle damage, reduced body fat and improved physical performance. The present study aimed to perform a systematic review of clinical studies in the use of these amino acids in order to increase muscle mass, reduce body fat and increase sports performance, evaluating the results obtained and proving its use and safety. Search for articles in databases resulted in 7502 articles. Following all the exclusion criteria, 11 articles were selected for the present systematic review. The performance was evaluated in 7 articles. The muscle mass was evaluated in 4. The used dose of BCAA ranged from 1.2 g to 10 g and studies have given supplements in the form of powder, capsules and infusion. The best ratio of leucine, valine and isoleucine was 2:1:1, respectively. Considering that the number of studies with beneficial results almost equals that of negative results, more studies are needed to prove the real benefits of using BCAAs as a strategic supplement to increase muscle mass, reduce body fat and increase sports performance.

Orientador: Jose Barreto Campello Carvalheira / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-25T02:56:20Z (GMT). No. of bitstreams: 1 Mendes_MariaCarolinaSantos_D.pdf: 2658779 bytes, checksum: 153ed5344815e7e59a41c04c4a965670 (MD5) Previous issue date: 2014 / Resumo: A proteína mTOR é um proteína reguladora chave de vários processos celulares, dentre eles proliferação, crescimento e sobrevivência celular. Fatores de crescimento, oxigênio, status energético e a presença de aminoácidos são fundamentais para que todos esses processos ocorram normalmente. Descobertas realizadas nas últimas décadas mostraram que a via da mTOR encontra-se ativada em vários processos celulares, incluindo formação tumoral e angiogênese. A leucina é um aminoácido de cadeia ramificada que tem o maior potencial em ativar a via da mTOR. Devido sua capacidade de promover a síntese proteica e ganho de massa muscular, seu uso é constantemente estimulado em pacientes com câncer. No entanto, seus efeitos no crescimento tumoral não está claro. Dessa forma, realizamos um estudo cujo objetivo principal foi investigar os efeitos da dieta suplementada com leucina na modulação do crescimento tumoral em diferentes linhagens de células tumorais que se diferenciem em relação à ativação constitutiva da via IRS1/Akt/mTOR. Estudos in vivo e in vitro realizados demonstraram que as células que se diferenciam em relação à ativação da via IRS1/AKT/mTOR respondem de maneira distinta à suplementação com leucina. Linhagens de células tumorais que possuem a via da mTOR constitutivamente ativada, PC-3 e MCF-7, quando suplementadas com doses elevadas de leucina in vitro reduziram a proliferação celular e causaram retenção das células na fase G1 do ciclo celular. Já o xenoenxerto tumoral da PC-3 reduziu sua proliferação e aumentou a morte celular quando os animais foram suplementados com leucina na dieta. Nós também observamos aumento da atividade da mTOR e da p70S6K em todas as linhagens celulares quando suplementadas com leucina. O aumento da atividade da proteína mTOR foi acompanhado de redução na fosforilação de AKTser473 nas células que possuíam a via da PI3K hiperativada (PC-3 e MCF-7). Esse fato pode estar ocorrendo devido a ativação das alças de contraregulação ocasionadas pela estimulação excessiva provocada pela suplementação com leucina, naquelas linhagens celulares que já possuem a via hiperativada. Fato este comprovado pelo aumento da fosforilação em serina 307 da proteína IRS1. Dessa forma, nossos resultados sugerem que a ativação da via da mTOR é central para determinar a sensibilidade de tumores à dieta suplementada com leucina, podendo modular o desenvolvimento tumoral naquelas células que já possuem a via IRS1/AKT/mTOR constitutivamente ativada. O mecanismo pelo qual a leucina pode retardar o desenvolvimento tumoral em células que possuem a via da mTOR hiperativada parece estar relacionado com o eixo de regulação negativa p70S6K-PI3K, com consequente redução da fosforilação de AKT e liberação das vias apoptóticas nos tecidos tumorais / Abstract: mTOR is a key regulatory protein in various cellular processes including proliferation, cell growth and survival. Growth factors, oxygen, energy status and amino acids are all essential to these processes. New findings in the last few decades have shown that the mTOR pathway is activated in many cellular processes, including tumorigenesis and angiogenesis. The branched chain amino acid leucine has the greatest potential to activate the mTOR pathway. Due to its ability to promote protein synthesis and muscle mass gain, use of leucine is frequently utilized in patients with cancer. However, the effect of leucine on tumor growth is not clear. The aim of this study is therefore to investigate the effect of diet-supplemented leucine on the modulation of tumor growth in several tumor cell lines that differ in the constitutive activation status of the insulin receptor substrate 1 (IRS1)/AKT/mTOR pathway. Both in vitro and in vivo experiments demonstrated different cell proliferation responses when cells were exposed to high doses of leucine. Tumor cell lines PC-3 and MCF-7, which have a constitutively activated mTOR signaling, displayed reduced cell proliferation and G1 phase cell cycle arrest when supplemented with high doses of leucine in vitro. Likewise, leucine-supplemented PC-3 cell tumor xenografts displayed reduced proliferation and increased cell death. We also observed increased activity of mTOR and its downstream substrate p70S6K in all cell lines supplemented with leucine. Increased mTOR activity was accompanied by a reduction in AKT serine 473 (ser473) phosphorylation in cell lines with a hyperactivated PI3K pathway (PC-3 and MCF-7). This most likely occurred because leucine supplementation further increased mTOR and p70S6K activity, triggering the inhibitory p70S6K/IRS1 axis. In fact, we found increased IRS1 ser307 phosphorylation in hyperactivated cell lines (PC-3 and MCF-7) supplemented with high doses of leucine. Therefore, our results suggest that mTOR pathway activation is central to determining the sensitivity of tumors to leucine supplementation. Furthermore, this could affect the response to leucine-supplemented therapies of those tumors in which the PI3K pathway is constitutively activated. The mechanism for this appears to be related to the negative p70S6K/IRS1 regulation axis, with consequent reduction of AKT phosphorylation and the release of apoptotic pathways in tumor tissues / Doutorado / Fisiopatologia Médica / Doutora em Ciências

Orientador: Jaime Amaya-Farfán / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-19T15:34:35Z (GMT). No. of bitstreams: 1 Moura_CarolinaSoaresde_M.pdf: 1533232 bytes, checksum: 1141b4840c5a0f9342072967abfece65 (MD5) Previous issue date: 2012 / Resumo: As heat shock proteins (HSPs), ou proteínas do estresse, correspondem a um importante sistema de defesa celular que é capaz de proteger e reparar danos causados ao organismo, conferindo à célula maior tolerância e resistência contra situações de alteração na homeostase, sendo também consideradas como um sistema antioxidante complementar. A glutamina é conhecida pelo seu potencial em promover o aumento na HSP70 contra diversas situações agressoras. As proteínas do soro do leite (PSL) contêm concentrações elevadas de aminoácidos de cadeia ramificada (BCAAs), sendo estes substratos para a síntese de glutamina, por meio da enzima glutamina sintetase. Objetivo: o objetivo deste trabalho foi observar a influência do consumo das proteínas do soro do leite (PSL), na forma concentrada (PSLC) e hidrolisada (PSLH), na concentração da HSP70 em ratos exercitados em esteira rolante. Metodologia: foram utilizados 48 ratos Wistar machos (290g ± 8g) divididos primeiramente pelo regime de atividade física em sedentários (S) e exercitados (E), e cada um desses, subdividido em outros três grupos, segundo a dieta. As dietas foram baseadas na AIN93-G, com substituição da fonte protéica da seguinte forma: PSLC, PSLH e caseína (CAS), como controle. O período em dieta experimental foi de 3 semanas, e os animais exercitados foram submetidos a 5 sessões de exercício a 22m/min durante 30 minutos como fonte de estresse térmico, na última semana de vida. Resultados: os resultados revelaram que o consumo da PSLH no grupo exercitado promoveu o aumento da HSP70 em pulmão, e nos músculos sóleo e gastrocnêmio. O consumo da PSLH aumentou os níveis de glutamato, isoleucina e leucina livres no plasma dos animais sedentários. Quando exercitado, o grupo PLSH teve redução no glutamato, leucina e valina (substratos envolvidos na síntese de glutamina) plasmáticos e aumento da enzima glutamina sintetase (GS) no sóleo, sugerindo o provável uso desses aminoácidos para proporcionar o aumento na HSP70. Em adição à elevação da GS, houve também aumento concomitante da concentração de corticosterona no grupo PSLH exercitado, sugerindo a influência do hormônio na enzima. Em relação ao possível dano oxidativo, avaliado pela geração de proteínas carboniladas, os grupos que consumiram PSLC e PSLH reduziram seus valores no plasma e, somente a PSLH, no gastrocnêmio. Houve preservação das proteínas totais e albumina nos grupos PSLC, PSLH exercitados. O ácido úrico aumentou no grupo PSLH exercitado, enquanto que a creatinina aumentou na PSLC, independente do exercício. A glicose foi reduzida nos animais sedentários que consumiram PSLH, porém as variações dos parâmetros sempre permaneceram dentro da normalidade. Nenhum efeito adverso ao consumo das diferentes fontes protéicas foi observado no rim ou no fígado, oriundo da mensuração das enzimas AST, ALT e o metabólito ureia respectivamente. Conclusão: os resultados indicam que o consumo da PSLH pode potencializar a resposta da HSP70, sugerindo aumento na proteção endógena e antioxidante, e que a PSLH possa ser mais estresse-responsiva em ratos submetidos ao exercício / Abstract: The heat shock proteins (HSPs), or stress proteins, correspond to an important cell defense system, whose function is to protect and repair injuries caused to the body, conferring the cell greater tolerance and resistance against altered homeostasis states, and for this reason they have been considered as a complementary antioxidant system. Glutamine in turn has been found to promote the increase of HSPs associated to various situations of stress. The milk whey proteins contain elevated concentrations of branched-chain amino acids (BCAAs), which can participate in the synthesis of glutamine via glutamine synthetase. Objective: the objective of this work was to assess the influence of the intake of the whey proteins either in the form of a concentrate (WPC) or a hydrolyzate (WPH) in enhancing the concentration of HSP70 in rats exercised in the treadmill. Methods: Forty-eight male Wistar rats (290 ± 8g) were divided, first, into two categories according to the level of physical activity: sedentary (S) and exercised (E), and each one subdivided into three groups according to the source of protein in the diet. The diets were based on the standard AIN93-G, formulated containing either WPC, WPH or casein (CAS), as the sole source of protein. The animals consumed the experimental diets for three weeks and those belonging to the exercised group were submitted to training 5 sessions on the last week of life. Results: the results showed that consumption of the WPH promoted the increase of HSP70 in lung, soleus and gastrocnemius in the exercised animals. Increases in plasma free glutamate, isoleucine and leucine of the sedentary rats were also observed. When exercised, the WPH group exhibited a reduction in the plasma levels of glutamate, leucine and valine (all involved in the synthesis of glutamine), plus an increase in the enzyme glutamine synthetase (GS) in the soleus muscle, thus suggesting a probable utilization of this amino acids, as a substrate, in the increase of HSP70. Considering that there was also an elevation of the corticosterone levels in the exercised cohorts that consumed the WPH, the concomitant increase of GS, suggested that the hormone exerted an influence on the enzyme. With regard to a possible oxidative damage, as assessed by the presence of carbonyls proteins, the group that consumed both of the whey proteins (WPC, WPH) exhibited lower plasma levels, but only the WPH reduced the levels in the gastrocnemius. Both total plasma proteins and albumin were preserved in the exercised animals. Uric acid was found to increase in the WPH exercised group, while creatinine increased in the WPC group, regardless of the exercise. Plasma glucose levels were also lowered in the sedentary animals that consumed the WPH diet, but at no time, did the increased or decreased levels of these parameters extrapolated normality. Additionally, from the AST, ALT and urea data, no adverse effects on either liver or kidney could be detected with the intake of the different proteins sources. Conclusion: from these results, it can be concluded that consumption of the WPH, in contrast to WPC or CAS, can enhance the HSP70 response suggesting a magnified endogenous and antioxidant protection, and that the hydrolyzed whey protein can be more stress-responsive / Mestrado / Nutrição Experimental e Aplicada à Tecnologia de Alimentos / Mestre em Alimentos e Nutrição

Duchenne Muscular Dystrophy (DMD) is an X-linked recessive, progressive muscle-wasting disease characterized by mutations in the dystrophin gene. Duchenne muscular dystrophy is the most common and most severe form of inherited muscle diseases, with an incidence of 1 in 3,500 male births1,2. Mutations in the dystrophin gene result in non-functional dystrophin or the complete absence of the protein dystrophin, resulting in necrosis and fibrosis in the muscle, loss of ambulation, cardiomyopathies, inadequate or failure of respiratory function, and decreased lifespan. Although there has been little research for effective nutritional strategies, dietary intervention may be effective as an adjuvant treatment. In this study, wild type (WT) and mdx animals were provided either a control or elevated branched chain amino acid (BCAA) diet nocturnally for 25 weeks to determine if the elevated BCAAs would attenuate muscle torque loss. Twenty-five weeks of chronic, elevated BCAA supplementation had no impact on muscle function measures. Interestingly, mdx and WT animals had the same torque responses in the low stimulation frequencies (1 Hz – 30 Hz) compared to higher stimulation frequencies. Tetanus was reached at a much lower stimulation frequency in mdx animals compared to WT animals (100 Hz vs +150 Hz). The mdx mouse consistently had more cage activity in the light cycle X- and Y-planes. Interestingly, animals on the BCAA diet increased X-, Y-, and Z-plane activity in the dark cycles at four weeks while animals on the control diet more Z-plane activity at 25 weeks, although not significant. All three BCAAs were elevated in the plasma at 25 weeks, although only Leu was significantly elevated. The BCAAs had no effect on. The diaphragm and skeletal muscle masses were larger in mdx animals, and WT animals had a significantly larger epididymal fat pad. The active state of BCKDC determined by phosphorylation of the E1α enzyme was greater in WT animals in white skeletal muscle, but not red skeletal muscle. Protein synthesis effectors of the mTORC1 signaling pathway and autophagy markers were similar among groups. Wild type animals had increased mTORC1 effectors and animals on the BCAA diet had decreased autophagy markers, although not significant. Although BCAAs did not affect muscle function, fibrosis, or protein synthesis effectors, this study illustrates the functionality of mdx muscles over time. It would be interesting to see how the different muscle fiber types are affected by DMD, noting the differences between the diaphragm, heart, red muscle, and white muscle fibrosis markers. Although there was no increase in mTORC1 effectors with an elevated BCAA diet, it would be interesting to determine muscle protein synthesis, myofibrillar protein synthesis, and total protein turnover in the mdx mouse with an elevated BCAA diet, although the dietary intervention started when mice arrived at 4 weeks of age, earlier intervention may be beneficial early in the disease process. / Doctor of Philosophy / Duchenne Muscular Dystrophy (DMD) is an X-linked recessive, progressive muscle-wasting disease characterized by mutations in the dystrophin gene. Duchenne muscular dystrophy is the most common and most severe form of inherited muscle diseases, with an incidence of 1 in 3,500 male births1,2. Mutations in the dystrophin gene result in non-functional dystrophin or the complete absence of the protein dystrophin, resulting in necrosis and fibrosis in the muscle, loss of movement and walking ability, cardiomyopathies, inadequate or failure of respiratory function, and decreased lifespan. Although there has been little research for effective nutritional strategies, dietary intervention may be effective as an adjuvant treatment and palliative care. The branched chain amino acids (BCAAs) are known to directly stimulate muscle protein synthesis by direct activation of the mechanistic target of rapamycin complex 1 (mTORC1). This study aimed to illustrate the differences between diseased and healthy mice and determine if BCAAs can reduce muscle torque loss. Twenty-five weeks of chronic, elevated BCAA supplementation had no impact on muscle function measures. Interestingly, mdx and WT animals had the same torque responses in the low stimulation frequencies (1 Hz – 30 Hz) compared to higher stimulation frequencies. Tetanus was reached at a much lower stimulation frequency in mdx animals compared to WT animals (100 Hz vs +150 Hz). The mdx mouse consistently had more cage activity in the light cycle X- and Y-planes. Interestingly, animals on the BCAA diet increased X-, Y-, and Z-plane activity in the dark cycles at four weeks while animals on the control diet more Z-plane activity at 25 weeks, although not significant. All three BCAAs were elevated in the plasma at 25 weeks, although only Leu was significantly elevated. The BCAAs had no effect on. The diaphragm and skeletal muscle masses were larger in mdx animals, and WT animals had a significantly larger epididymal fat pad. The active state of BCKDC determined by phosphorylation of the E1α enzyme was greater in WT animals in white skeletal muscle, but not red skeletal muscle. Protein synthesis effectors of the mTORC1 signaling pathway and autophagy markers were similar among groups. Wild type animals had increased mTORC1 effectors and animals on the BCAA diet had decreased autophagy markers, although not significant. Although BCAAs did not affect muscle function, fibrosis, or protein synthesis effectors, this study illustrates the functionality of mdx muscles over time. It would be interesting to see how the different muscle fiber types are affected by DMD, noting the differences between the diaphragm, heart, red muscle, and white muscle fibrosis markers. Although there was no increase in mTORC1 effectors with an elevated BCAA diet, it would be interesting to determine muscle protein synthesis, myofibrillar protein synthesis, and total protein turnover in the mdx mouse with an elevated BCAA diet, although the dietary intervention started when mice arrived at 4 weeks of age, earlier intervention may be beneficial early in the disease process.

Recent findings have shown an inverse association between the circulating levels of pentadecanoic acid (C15:0) and heptadecanoic acid (C17:0) with the risk of pathological development in type 2 diabetes, cardio vascular disease and neurological disorders. From previously published research, it has been said that both these odd chain fatty acids are biomarkers of their dietary intake and are significantly correlated to dietary ruminant fat intake. However, there are profound studies that show the contrary where they do not display this biomarker correlation. Additionally, several astute studies have suggested or shown odd chain fatty acid endogenous biosynthesis, most often suggested via alpha oxidation; the cleavage of a single carbon unit from a fatty acid chain within the peroxisomes. To better understand the correlations and interactions between these two fatty acids with pathological development, the origin of these odd chain fatty acids needed to be determined, along with confirming their association with the disease aetiology. To minimise animal & human experimentation we made use of existing sample sets made available through institutional collaborations, which produced both animal and human interventional study samples suitable for odd chain fatty acid investigations. These sample collaborations allowed us to comprehensively investigate all plausible contributory sources of these odd chain fatty acids; including from the intestinal microbiota, from dietary contributions, and derived from novel endogenous biosynthesis. The investigations included two intestinal germ-free studies, two ruminant fat diet studies, two dietary fat studies and an ethanol intake study. Endogenous biosynthesis was assessed through: a stearic acid infusion, phytol supplementation, and an Hacl1 knockout mouse model. A human dietary intervention study was used to translate the results. Finally, a study comparing circulating baseline C15:0 and C17:0 levels with the development of glucose intolerance. We found that the circulating C15:0 and C17:0 levels were not significantly influenced by the presence or absence of intestinal microbiota. The circulating C15:0 levels were significantly and linearly increased when the C15:0 dietary composition increased; however, there was no significant correlation in the circulating C17:0 levels with intake. Circulating levels of C15:0 were affected by the dietary composition and factors affecting the dietary intake, e.g. total fat intake and ethanol, whereas circulating C17:0 levels were found to be independent of these variables. In our studies, the circulating C15:0 levels were not significantly affected by any expected variations in alpha oxidation caused by pathway substrate inhibition or gene knockout. However, C17:0 was significantly related, demonstrating it is substantially endogenously biosynthesised. Furthermore, we found that the circulating C15:0 levels, when independent of any dietary variations, did not correlate with the progression of glucose intolerance when induced, but the circulating C17:0 levels did significantly relate and linearly correlated with the development of glucose intolerance. To summarise, the circulating C15:0 and C17:0 levels were independently derived; the C15:0 levels substantially correlated with its dietary intake, whilst the C17:0 levels proved to be separately derived from its endogenous biosynthesis via alpha oxidation of stearic acid. C15:0 was found to be minimally endogenously biosynthesised via a single cycle of beta oxidation of C17:0 in the peroxisomes, however, this did not significantly contribute to the circulating levels of C15:0. Additionally, only the baseline levels of C17:0 significantly correlated with the development of glucose intolerance. These findings highlight the considerable differences between both of these odd chain fatty acids that were once thought to be homogeneous and similarly derived. On the contrary, they display profound dietary, metabolic, and pathological differences.

In the human gut, bacterial fermentation of dietary fibers and proteins produces metabolites, primarily as short-chain fatty acids (SCFA), that are highly beneficial for host health. However, unlike dietary fiber, bacterial fermentation of protein additionally generates potentially toxic substances such as ammonia, hydrogen sulfide, amines, and indoles. It is believed that most gut bacteria favor utilization of dietary fiber over that of protein for energy. Therefore, when fermentable dietary fiber is readily available to colonic bacteria, protein fermentation, and its subsequent potentially toxic metabolites, remains relatively low. Dietary intake primarily determines the quantity of dietary fiber and protein substrate available to the gut microbiota and the resulting profile of metabolites produced. Increased protein consumption is associated with deleterious health outcomes such as higher risk of colorectal cancer and type II diabetes. Conversely, diets following US dietary recommendations are high in fiber, which promote a healthy microbiome and are protective against disease. Diets following the recommendation are also moderate in protein intake so that, ultimately, far more fiber than protein is available for colonic bacterial fermentation. On the contrary, dietary fiber intake is chronically low in a standard Western diet, while protein consumption is above dietary recommendations, which results in nearly equal amounts of dietary fiber and protein available for gut microbial fermentation. Furthermore, the popularity of high-protein diets for athletes, as well as that of high-protein low-carbohydrate diets for weight loss, may flip fiber and protein substrate proportions upside down, resulting in more protein than fiber available in the gut for fermentation. The objective of this study was to elucidate how substrate ratios in protein-fiber mixtures affect protein fermentation and metabolites, as well as examine the degree to which fiber source may influence these outcomes. Each dietary fiber source [fructooligosaccharides (FOS), apple pectin (Pectin), a wheat bran and raw potato starch mixture (WB+PS), and an even mixture of the three aforementioned fibers (Even Mix)] and protein were combined in three ratios and provided as substrate for in vitro fecal fermentation to understand how low, medium, and high fiber inclusion levels influence fermentation outcomes. They were compared to 100% protein and fiber (each different fiber) controls. Branched-chain fatty acids (BCFAs), metabolites produced exclusively from protein fermentation, were used as a measure of protein fermentation; the data were normalized based on the initial quantity of protein within the substrate. In protein-fiber substrate mixtures, only FOS and Even Mix inhibited BCFAs (mM/g protein basis) and only when they made up at least half of the substrate. Unexpectedly, the rate of protein fermentation was increased when the protein-fiber substrate contained 25% WB+PS fiber, possibly due to the starch component of the fiber. There was evidence that when pH drops during fermentation, as was the case for protein-FOS mixtures, it played a significant role in suppressing protein fermentation. Ammonia production was not largely affected by increasing the proportion of dietary fiber. A significant reduction did not occur until FOS made up at least 50% of the protein-fiber substrate; for Pectin, WB+PS, and Even Mix fibers, 75% inclusion was required for a significant decrease in ammonia. Interestingly, protein was butyrogenic. Protein as the sole substrate produced more butyrate than either Pectin or Even Mix as the sole substrates, and in fact, addition of Pectin to protein significantly reduced butyrate concentrations. However, the possible benefits of butyrate produced via protein fermentation needs to be tempered by the production of potentially toxic compounds and the association between protein fermentation and colorectal cancer. Overall, the thesis findings showed protein fermentation to be relatively stable and not easily influenced by increasing the availability of dietary fiber, and no clear evidence of microbial preference for carbohydrates over protein was found.

Les triacylglycérols d'algues (TAG) représentent une source prometteuse de biocarburants. Les principales étapes de la synthèse des acides gras et du métabolisme du TAG des algues ont été déduites de celles des plantes terrestres, mais on en sait peu sur les sources de carbones et d’énergie intervenant dans la synthèse de lipides de réserve. Nous avons donc étudié la synthèse des acides gras chez l’algue modèle Chlamydomonas reinhardtii en utilisant une combinaison d'approches génétiques, biochimiques et microscopiques. Plus précisément, j'ai d'abord examiné la localisation subcellulaire de gouttelettes de lipides dans des cellules d'algues exposées à une forte lumière, conditions où une plus grande quantité de pouvoir réducteur est produite. J'ai ensuite contribué à mettre en évidence que la bêta-oxydation des acides gras est un processus peroxysomal, et que pendant une carence en azote réalisée en conditions photoautotrophe, des mutants dépourvus de la malate déshydrogénase 2 peroxysomale (mdh2) accumulent 50% plus TAG que les souches parentales. Ces résultats nous ont permis de mettre en évidence l'importance du contexte redox cellulaire sur la synthèse lipidique. Cette étude a également permis de révéler l’existence d'un échange d’énergie entre le peroxysome et le chloroplaste. Enfin, en caractérisant des mutants déficients dans la dégradation des acides aminés à chaîne ramifiée (BCAA), j'ai montré que le catabolisme des BCAAs joue un double rôle dans la synthèse de TAG en fournissant des précurseurs carbonés et de l'ATP. L'ensemble de ces travaux ouvert de nouvelles pistes pour l'amélioration génétique future de souches d'algues pour la production de biocarburants. / Algal triacylglycerols (TAG) represent a promising source for biofuel. The major steps for fatty acid synthesis and TAG metabolism have been deduced based on that of land plants, but little is known about carbon and energy sources. To address this question, we investigated fatty acid synthesis in algal cells using a combination of genetic, biochemical and microscopic approaches in the model microalga Chlamydomonas reinhardtii. Specifically, I first examined subcellular localization of lipid droplets in algal cells exposed to high light, a condition favoring production of reducing power. Secondly, I contributed to put on evidence that the beta-oxidation of fatty acids is a peroxisomal process, and that during photoautotrophic nitrogen starvation, knock-out mutants of the peroxisomal malate dehydrogenase 2 (mdh2) made 50% more TAG than parental strains, highlighting the importance of cellular redox context on lipid synthesis. This study also revealed for the first time the occurrence of an energy trafficking pathway from peroxisome to chloroplast. And finally, by characterizing mutants defected in degradation of branched-chain amino acids (BCAAs), I showed that BCAA catabolism plays a dual role in TAG synthesis via providing carbon precursors and ATP. Taken together, this work highlighted the complex interplay between carbon and energy metabolism in green photosynthetic cells, and pointed future directions for genetic improvement of algal strains for biofuel productions.