Foram utilizadas 168 galinhas poedeiras Hisex White em delineamento experimental inteiramente casualizado, com duração de cinco semanas. As aves foram distribuídas em sete tratamentos com três repetições cada, com o objetivo de verificar a influência da suplementação de três fontes marinhas de PUFAs n-3 - óleos de salmão (SA) e de atum e sardinha (A/S) e mistura de algas marinhas (AL), bem como sua combinações (SA+A/S, AL+SA, AL+A/S) - em relação ao grupo controle alimentado com ração basal de milho e soja (CON), sobre a qualidade do ovo e a composição lipídica da gema. A qualidade externa e interna do ovo não foi alterada significativamente pela adição de fontes de PUFAs n-3 na dieta das aves. A relação entre os lípides saturados : monoinsturados : poliinsaturados da gema (3,5 : 4,5 : 2,0) manteve-se constante com a adição dos suplementos de PUFAs n-3 na ração. Os óleos de salmão (SA) e de atum e sardinha (A/S) revelaram-se mais efetivos no enriquecimento da gema do ovo em PUFAs n-3, em especial o DHA. A relação PUFAs n-6/ PUFAs n-3 sofreu redução significativa com a adição das fontes marinhas de ômega-3 à dieta das galinhas. O EPA, embora em teores mais baixos que o DHA na gema do ovo, apresentou incremento significativo com o uso dos óleos de peixes (SA e A/S) adicionado à dieta em relação ao CON. O consumo de dois ovos enriquecidos com DHA do presente estudo, por dia, provavelmente atenderia os requerimentos diários deste PUFA n-3 para o ser humano / To investigate the influence of three PUFAs n-3 marine sources - salmon oil (SA), tuna and sardine oil (A/S), marine algae (AL) and combinations (SA+A/S, AL+SA, AL+A/S) - on egg quality and egg lipid composition, compared to a corn/soy control group (CON), 168 Hisex White laying hens were assigned into seven treatments with three repetitions in a randomized design during a experimental period of five weeks. The external and internal egg quality were not significantly affected by the addition of PUFAs n-3 marine sources into the hen diets. The saturated : monounsaturated : polyunsaturated ratio (3.5:4.5:2.0) remained constant by the supplementation of the marine sources into the diets. The salmon oil and the tuna and sardine oil showed the best results of PUFAs n-3 egg yolk enrichment, mainly the DHA. The PUFAs n-6/PUFAs n-3 ratio was significantly reduced by the inclusion of PUFAs n-3 sources into the hen diets. The EPA, although with lower levels than DHA into the egg yolk, showed a significant increase by the use of salmon oil and tuna and sardine oil added to the diet as compared to the control group (CON). The consumption of two DHA enriched eggs from this study per day probably would reach the daily requirements of this PUFA n-3 for the human been

Le métabolisme énergétique cérébral via l’utilisation du glucose est fortement impliqué dans la production d’énergie nécessaire au fonctionnement du neurone en situation basale et d’activation. Des travaux précédents ont mis en évidence chez le rat chroniquement déficient en acides gras polyinsaturés (AGPI) de la série n-3 une altération de ce métabolisme en situation basale (diminution de l’utilisation cérébrale du glucose et de la densité des transporteurs de glucose GLUT1). Pour cerner les différentes étapes du métabolisme énergétique pouvant être modifiées par les AGPI n-3, l’expression des gènes clés a été mesurée par approche transcriptomique (cartes microfluidiques) chez l’animal déficient en AGPI n-3 ou supplémenté en acide docosahexaénoïque (DHA, 22 :6n-3). Ces mesures ont été réalisées sur deux zones cérébrales (cortex fronto-pariétal et couche CA1 de l’hippocampe) chez les animaux en situation basale et soumis à un environnement enrichi activant ces deux zones cérébrales. Pour ces 2 situations, le niveau d’utilisation cérébrale de glucose a été quantifié par la technique du fluoro-2-déoxyglucose couplée à l’imagerie de tomographie par émissions de positons (18FDG-TEP) chez les animaux déficients en AGPI n-3. L’analyse de la teneur cérébrale en AGPI membranaire a été réalisée par chromatographie en phase gazeuse et une approche in vitro sur culture primaire d’astrocytes a été développée pour apprécier l’impact du DHA sur les paramètres métaboliques de ces cellules.Les principaux résultats montrent que :- la déficience en n-3 diminue de 67% la teneur membranaire en DHA dans les deux zones cérébrales étudiées. Si la déficience induit principalement une diminution spécifique de l’expression de GLUT1 (-33%) dans le cortex fronto-pariétal en situation basale et d’activation, en revanche elle perturbe la neurotransmission glutamatergique dans l’hippocampe en augmentant l’expression des 2 transporteurs de glutamate (GLAST et GLT1). Par ailleurs, les données d’imagerie TEP mettent en évidence un hypométabolisme général du glucose chez les animaux déficients en n-3 en situation basale. Les données recueillies sur le modèle astrocytes soulignent un effet direct du DHA sur l’utilisation du glucose et l’expression de GLUT1 ;- La supplémentation en DHA ne modifie pas de façon appréciable la teneur membranaire en DHA dans les deux zones cérébrales étudiées. Au contraire de la déficience, il apparaît clairement pour la couche CA1 de l’hippocampe que l’expression de l’ensemble des gènes codant pour les complexes enzymatiques du cycle de krebs et de la voie de phosphorylation oxydative est significativement augmentée.Ces résultats originaux laissent ainsi entrevoir la possibilité que les acides gras de cette famille d’AGPI puissent intervenir sur l’énergétique et le fonctionnement de la synapse glutamatergique en modulant 1) le métabolisme glucidique (captage de glucose) et du glutamate en situation de déficit d’apport et 2) la production d’ATP (phosphorylation oxydative) en situation de supplémentation en DHA. L’altération de ces paramètres métaboliques au cours du vieillissement et dans certains désordres neurologiques, liée à un déficit de statut en DHA, mettent en avant les potentialités nutritionnelles des AGPI n-3 comme facteur préventif. / Cerebral energy metabolism via glucose utilization is heavily involved in the production of energy required to the neuron in basal conditions and activation. Previous work has shown in rats chronically deficient in n-3 polyunsaturated fatty acids (PUFA) altered the metabolism in basal condition (decrease of cerebral glucose use and density of glucose transporters GLUT1). To identify the different stages of energy metabolism may be modified by n-3 PUFA, the expression of key genes was measured by transcriptomic approach (Taqman Low Density Arrays) in animals deficient in n-3 PUFA or docosahexaenoic acid supplementation (DHA, 22:6n-3). These measurements were performed on two brain areas (fronto-parietal cortex and layer CA1 of the hippocampus) in animals in basal condition or submit to an enriched environment. For these two situations, the level of cerebral glucose utilization was quantified by the technique of fluoro-2-deoxyglucose imaging coupled with positron emission tomography (18FDG-PET) only in deficient n-3 PUFA animals. Analysis of brain PUFA content of membrane was performed by gas chromatography and an in vitro approach to primary culture of astrocytes was developed to assess the impact of DHA on metabolic parameters of these cells.The main results show that: - n-3 Deficiency decreases from 67% in membrane DHA content in both brain areas studied. If the deficiency induces mainly a decrease in the specific expression of GLUT1 (-33%) in the fronto-parietal cortex in basal and activation conditions, however it disrupts glutamatergic neurotransmission in the hippocampus by increasing the expression of two glutamate transporters (GLAST and GLT1). In addition, PET data show a general hypometabolism of glucose in animals deficient in n-3 in basal situation. Data collected on the model astrocytes point to a direct effect of DHA on glucose utilization and expression of GLUT1; - DHA supplementation does not alter significantly the membrane content of DHA in both brain areas studied. Unlike the n-3 deficiency, it is clear for the layer CA1 of the hippocampus that the expression of all genes encoding the enzyme complexes of the Krebs cycle and oxidative phosphorylation pathway is significantly increased. These original results suggest the possibility that the fatty acids of the n-3 PUFAs family can act on the energy and functioning of the glutamatergic synapse by modulating 1) glucose metabolism (glucose uptake) and glutamate in deficit intake situation and 2) the production of ATP (oxidative phosphorylation) in DHA supplementation. The alteration of these metabolic parameters during aging and certain neurological disorders, related to a deficit of DHA status, highlight the potential of dietary n-3 PUFA as a preventive factor.

Notre étude a montré l’implication de la déficience de PPARα dans la modulation de latranscription des gènes de l’insuline et de l’inflammation des adipocytes chez les sourisadultes C57BL/6J (WT) et PPARα-null. A jeun, les souris PPARα-null sont hypoglycémiquespar rapport aux animaux témoins WT. La concentration en insuline et l’expression de sesARNm pancréatiques, par rapport aux animaux témoins, sont diminuées chez les sourisPPARα-null, suggérant que la suppression du gène de PPARα contribuait à la faibletranscription de ces gènes. De plus, la suppression du gène de PPARα aboutit à la diminutiondes facteurs de transcription des gènes de l’insuline comme Pdx-1, Nkx6.1 et MafA. En outre,la capacité pancréatique fonctionnelle est aussi détériorée par la suppression du gène dePPARα puisque le pancréas des souris PPARα-null exprime de faibles taux de Glut2 et deglucokinase. Les souris PPARα-null expriment des taux élevés d’adiponectine et de leptinecomparées aux souris témoins. Dans les tissus adipeux, les souris PPARα-null présentent uneaugmentation de l’expression de CD14 et CD68 généralement exprimés par les macrophages.La suppression du gène de PPARα diminue, au niveau des adipocytes, l’expression de MCP-1, TNFα, IL-1β, IL-6 et RANTES, alors que l’expression de TLR-2 et de TLR-4 (récepteurspro-inflammatoires) était élevée dans les tissus adipeux. Ces résultats suggèrent qu’encondition normale, la déficience en PPARα, chez les souris est impliquée dans la modulationde la transcription des gènes de l’insuline et le statut inflammatoire du tissu adipeux.En outre, l'invalidation du gène de PPARα dans les cellules T a abouti àl'augmentation de T-bet et la diminution de GATA-3 tant aux niveaux de la protéine que del’ARNm. Comme prévu, l’acide Docosahexaénoïque (DHA) a exercé non seulement un effetinhibiteur sur la prolifération des cellules T, mais aussi a diminué la sécrétion d’IFN-γ etstimulé la sécrétion de l’IL-4 dans les deux types cellulaires. Le DHA a aussi diminué T-bet etaugmenté GATA-3 tant au niveau de la transcription qu’au niveau de la protéine. Quoique lescellules T des souris PPARα-null ont exprimé un plus fort niveau de phosphorylation de p38MAP kinase que les cellules T de WT, le DHA a diminué la phosphorylation des MAPkinases (p38 et ERK1/2) dans tous les deux les types cellulaires. Les inhibiteurspharmacologiques des MAP kinases ont aussi diminué T-bet et augmenté GATA-3 dans lescellules T. Ces résultats démontrent que le DHA, via son action sur les MAP kinases, modulel'expression des facteurs de transcription. Ces résultats expliquent aussi le mécanisme d'actionde cet acide gras sur la différenciation des cellules T dans la maladie et la santé / We assessed, in this study, the effects of PPARα deficiency on the expression of mRNAencoding for insulin gene transcription factors in pancreatic β-cells along with thoseimplicated in inflammation in adipose tissues. On fasting, the adult PPARα-null mice werehypoglycemic. Serum insulin concentrations and its pancreatic mRNA transcripts weredownregulated in PPARα-null mice, suggesting that PPARα gene deletion contributes to lowinsulin gene transcription. The PPARα gene deletion downregulates the mRNA expression ofinsulin gene transcription factors, i.e., Pdx-1, Nkx6.1 and MafA. Besides, the pancreaticfunction was diminished by PPARα deficiency as PPARα-null mice expressed low pancreaticGlut2 and glucokinase mRNA. PPARα-null mice also expressed high adiponectin and leptinmRNA levels compared to wild type animals. Adipose tissues of PPARα-null mice exhibitedupregulation of CD14 and CD68 mRNA, generally expressed by macrophages. PPAR-a genedeletion downregulates the adipocyte mRNA of certain pro inflammatory agents, like MCP-1,TNF-a, IL-1b, IL-6, and RANTES, though pro-inflammatory TLR-2 and TLR-4 mRNAswere upregulated in the adipose tissues. Our results suggest that PPAR-a deficiency, in mice,is implicated in the modulation of insulin gene transcription and inflammatory status inadipose tissues.The another part of the study was conducted on CD4+ T-cells, isolated from wild type(WT) and PPARα-null mice, in order to assess the mechanismof action of docosahexaenoicacid (DHA), an n-3 fatty acid, in the modulation of two transcription factors, i.e., T-bet andGATA-3, implicated in T-cell differentiation towards, respectively, TH1 and TH2 phenotype.The T-cells from PPARα-null mice secreted higher IFN-γ and lower IL-4 concentrations thanWT T-cells. Furthermore, the deletion of PPAR-α gene in T-cells resulted in the upregulationof T-bet and downregulation of GATA-3 both at mRNA and protein levels. DHA exerted notonly an inhibitory effect on T-cell proliferation, but also diminished IFN-γ and stimulated IL-4 secretions in both cell types. DHA also downregulated T-bet and upregulated GATA-3 bothat transcription and protein levels. Though the T-cells from PPARα-null mice expressedhigher p38 phosphorylation than WT T-cells, DHA diminished the MAP kinasephosphorylation (p38 and ERK1/2) in both the cell types. The pharmacological inhibitors ofMAP kinases also downregulated T-bet and upregulated GATA-3 in T-cells. Altogether, theseresults demonstrate that DHA, via its action on MAP kinases, modulates the expression oftranscription factors. These results also explain the mechanism of action of this fatty acid onT-cell differentiation in disease and health

The important factor in regulation of metabolic processes is regulatory proteins, which are able to react by feed-back to energetic state of the cell. Big attention is focused on the AMP activated kinase (AMPK) and NAD+ activated deacetylase SIRT1. These enzymes interact together and their stimulation increases mitochondrial biogenesis and fatty acid oxidation. Due to this it functions beneficially against the onset of obesity, insulin resistance and ageing. Fasting, exercise and some antidiabetogenic drugs act by these regulators. n-3 polyunsaturated fatty acids (PUFA) are also known because of their stimulative effects on mitochondrial biogenesis and -oxidation. Previous work of our group have showed that intake of higher dose of n-3 polyunsaturated fatty acids (PUFA) in diet lead to increase in activity of AMPK in white adipose tissue. New results presented in this thesis show that SIRT1 is essential for increase in expression of stimulators of -oxidation (PPAR etc) in response to n-3 PUFA in diet. n-3 PUFA futher improve the metabolic profile synergistically with calorie restriction probably through SIRT1.

Adipose tissue plays a crucial role in nutrient and energy homeostasis. At the time of worldwide pandemy of obesity and consequent metabolic syndrome, a great effort is made to find new treatments with potential to preserve insulin sensitivity, or even counteract development of obesity and type 2 diabetes. There are three principal possibilities how the adipose tissue biology can contribute to this goal: 1) induction of UCP1-dependent energy dissipation in brown adipose tissue; 2) conversion of white adipose depots to brown-like tissue (i.e. "browning"); and 3) stimulation of UCP1-independent thermogenesis in white adipose tissue. This thesis is based on two published works and one article under preparation. Generaly, it is focused on three different approaches targeting the above mentioned processes in adipose tissue of laboratory mouse: 1) diet supplementation with bile acids; 2) combination treatment of ω-3 polyunsaturated fatty acids and calorie restriction; and 3) cold exposure. In the experiments with administration of bile (specifically chenodeoxycholic) acid to mice, we confirm specific induction of UCP1 in both brown and subcutaneous white adipose tissue, as well as reversion of obesity in the response to the treatment. Nevertheless, most of the acute beneficial effects are mediated by...

A presente pesquisa foi conduzida utilizando-se 288 galinhas poedeiras da linhagem Hisex White com 32 semanas de idade, pelo período de 10 semanas, com o objetivo de estudar o enriquecimento da gema do ovo em ácidos graxos a partir de rações suplementadas com óleo de peixe (OP) ou alga marinha (AM) em cinco níveis de DHA (120, 180, 240, 300 e 360 mg/100 g dieta). Foi aplicado modelo fatorial 2 x 5, inteiramente casualizado, com três repetições de oito aves por tratamento, de modo a constituir os grupos: OP120, OP180, OP240, OP300, OP360, AM120, AM180, AM240, AM300 e AM360. Um grupo controle submetido à ração basal de milho e soja (CON) e outro, acrescido de AM, contendo 420 mg de DHA/100 g dieta (AM420) foram também utilizados. Os seguintes parâmetros foram avaliados: postura, peso do ovo, consumo alimentar, conversão alimentar, qualidade externa e interna dos ovos e qualidade organoléptica dos mesmos. O peso médio do ovo assinalado para o grupo CON (63,30 g) decresceu linearmente de forma significativa (Y = - 0,0051X + 63,8560, R2 = 0,97) em resposta à suplementação de níveis crescentes de DHA da fonte OP, atingindo valor mínimo de 62,13 g no grupo OP360. O índice de postura das aves de 88,10% (CON) não foi influenciado pelas fontes de DHA na ração. A qualidade interna do ovo, avaliada em unidades Haugh, apresentou melhora significativa (P<0,05) com a adição de teores crescentes de AM igual ou superior a 1% na dieta das aves. Quanto aos teores de DHA na gema do ovo de aves suplementadas com OP, foi observado aumento significativo de 22,64 mg/ gema (CON), para 187,91 mg/ gema no grupo OP360. Os PUFAs n-3 apresentaram acréscimo significativo no contraste entre CON (62,16 mg/gema) e OP360 (218,62 mg/gema). Para a fonte AM, as médias de DHA também mostraram linearidade (Y = 0,23X + 1,27, R2 = 0,86), oscilando entre 22,64 mg/gema (CON) e 149,75 mg/gema (AM420), enquanto que o total de PUFAs n-3 oscilou de 104,18 mg/gema (AM120) a 175,32 mg/gema (AM420). O inverso ocorreu com os ácidos araquidônico, linoléico e PUFAs n-6 que mostraram decréscimos significativos (P<0,05) com o aumento de OP na dieta, variando, respectivamente, de 98,71 mg, 987,70 mg e 1108,92 mg/ gema na dieta CON a 38,87 mg, 734,22 mg e 802,79 mg/ gema, para o grupo OP360. O percentual de incorporação de DHA na gema dos ovos decresceu linearmente com o aumento dos níveis de DHA na ração suplementada com OP e AM, de 85,11% (OP120) e 65,28% (AM120) para 49,45% (OP360) e 34,06% (AM420). Melhora significativa (P<0,05) foi consignada na relação n-6/n-3, variando de 17,50 no grupo CON para 3,72 e 6,36 para tratamentos OP360 e AM420, respectivamente. A avaliação sensorial não detectou qualquer sabor ou odor estranho nos ovos dos diferentes tratamentos ou fontes utilizados, exceto para a análise qualitativa do grupo OP360 onde foi detectado grau de intensidade regular de sabor de peixe, diferindo significativamente (P<0,05) do grupo CON. / This experiment was conducted using two hundreds eighty eight 32-wk-old Hisex White laying hens for a period of ten weeks, with the objective of studying the fatty acid enrichment of the egg yolk of hens fed diets supplemented with fish oil (OP) or marine algae (AM) to provide five levels of DHA (120, 180, 240, 300 and 360 mg/100 g diet) for each source. A 2 X 5 completely randomized factorial design with three replicates of eight birds per treatment was applied in order to have the following groups: OP120, OP180, OP240, OP300, OP360, AM120, AM180, AM240, AM300 and AM360. A control group submitted to a corn/soy basal diet (CON) and another one supplemented with AM at the level of 420 mg of DHA/100 g diet (AM420) were also used. Egg production, egg weight, feed intake, feed conversion, external and internal egg quality and the organoleptic quality of the eggs were evaluated. The egg weight mean obtained for group CON (63.30 g), decreased linearly (Y = - 0.0051X + 63.8560, R2 = 0.97) as the supplemented DHA levels from the OP source increased, reaching the lowest egg weight mean of 62.13 g for the group OP360. The egg production of the control group hens (88.10%) was not influenced by the source of DHA. The internal quality of the egg evaluated by Haugh units presented significant improvement (P<0.05) with the increase of the AM source to 1% or more. The amounts of DHA into the egg yolk in birds fed OP diets, were significantly increased from 22.64 mg/egg yolk (CON), to 187.91 mg/egg yolk (OP360). The egg yolk PUFAs n-3 of the control group (62.16g) increased significantly as compared to the OP360 group (218.62 mg/yolk). The AM source showed DHA means also linear (Y = 0.23X + 1.27, R2 = 0.86), ranging from 22.64 mg/yolk (CON) to 149.75 mg/yolk (AM420), while the PUFAs n-3 ranged from 104.18 mg/yolk (AM120) to 175.32 mg/yolk (AM420). The araquidonic acid, linoleic acid and PUFAs n-6 showed significant decrease (P<0.05) with the increase of OP into the diet, ranging from 98.71 mg, 987.70 mg and 1108.92 mg/egg yolk for the CON group to 38.87 mg, 734.22 mg and 802.79 mg/egg yolk, for the OP360 group. The percentage of DHA incorporation into the egg yolk decreased linearly as the DHA levels increased into the diet. Thus, for the OP and AM sources, mean values of 85.11% (OP120) and 65.28% (AM120) decreased to 49.45% (OP360) and 34.06% (AM420). Significant improvement (P<0.05) was found in the ratio n-6/n-3, ranging from17.50 (CON) to 3.72 (OP320) and 6.36 (AM420). The sensorial evaluation of eggs did not detect any different flavor or odor in eggs among treatments or sources, except for the qualitative analysis of group OP360 which showed fish flavor, significantly different (P<0.05) from the control group.

Submitted by Angela Maria de Oliveira (amolivei@uepg.br) on 2018-04-20T12:04:40Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Karla Miky.pdf: 833137 bytes, checksum: 4aac692850a86aaeabe93d6bbcf5af02 (MD5) / Made available in DSpace on 2018-04-20T12:04:40Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Karla Miky.pdf: 833137 bytes, checksum: 4aac692850a86aaeabe93d6bbcf5af02 (MD5) Previous issue date: 2018-03-09 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O óleo de linhaça tem se destacado como alimento funcional para humanos, sendo a fonte mais rica de ácido graxo α-linolênico. Quatro dietas isentas de farinha de peixe foram formuladas para serem isoproteicas (321,2 g/kg de proteína brua), isocalóricas (17,1 Mcal/kg de energia bruta) e isolipídicas (73,1 g/kg de lipídios totais), contendo duas fontes de óleos vegetais (óleo de soja ou óleo de linhaça) suplementadas em dois níveis (15 ou 30 g / kg). Foram distribuídos ao acaso 144 peixes (1076,3 ± 37,2 g) em esquema fatorial 2x2, em 12 gaiolas flutuantes de 1000 L cada, alimentadas manualmente até saciedade aparente. Observou-se maior aumento de peso, consumo de ração e melhor conversão alimentar em peixes alimentados com 30 g/kg de óleo de linhaça em comparação com peixes alimentados com 15 e 30 g/kg de óleo de soja. O rendimento de filé foi maior em peixes alimentados com 30 g/kg de óleo de linhaça em relação aos peixes alimentados com 30 g/kg de óleo de soja. Não foram observadas diferenças no peso corporal inicial, índice hepatosomático e composição próxima dos filés. Peixes alimentados com 30 g/kg de óleo de linhaça apresentaram maior teor de 18: 3 n-3 e menor teor de 18:2n-6 nos filés em comparação com peixes alimentados com 15 e 30 g/kg de óleo de soja. As maiores somas de SFA, MUFA e AG n-3 foram observados em filés de peixes alimentados com 15 g/kg de óleo de soja. Peixes alimentados com 30 g/kg de óleo de linhaça apresentaram maiores somas de ácidos graxos PUFA e de ácidos graxos n-3 nos filés. Filés de peixes alimentados com óleo de linhaça apresentaram menor relação de ácidos graxos n-6/n-3 em comparação com peixes alimentados com óleo de soja. A cor, capacidade de retenção de água, pH e a dureza dos filés não foram afetados. A adesividade dos filés analisada um e sete dias pós mortem foi maior em peixes alimentados com óleo de linhaça, enquanto observou-se menor mastigabilidade em filés de peixes alimentados com 30 g/kg de óleo de soja e de linhaça em relação aos peixes alimentados com 15 g/kg de óleo de soja e linhaça. Em conclusão, o óleo de linhaça demonstrou ser um alimento funcional como fonte de AG α-linolênico e para aumentar a relação de ácidos graxos n-6/n-3 nos filés. Além disso, recomenda-se 30 g/kg de óleo de 8 linhaça em dietas de terminação para melhorar o desempenho produtivo de tilápias do Nilo em terminação. / Linseed oil has emerging as functional food for human being one richest source of α-linolenic fatty acid. Four fishmeal-free diets were formulated to be isonitrogenous (321.2 g/kg of crude protein), isocaloric (17.1 Mcal/kg of gross energy) and isolipidic (73.1 g/kg of total lipids), containing two sources of vegetable oils (soybean oil or linseed oil) supplemented at two levels (15 or 30 g/kg). A hundred and forty-four fish (1076.3 ± 37.2 g) were distributed in a completely randomized in a 2x2 factorial scheme, into twelve 1000 L each floating cage, hand fed until apparent satiety and reared at 18 to 24 oC, during 6 wk. Higher weight gain, feed intake and improved feed conversion ratio were observed in fish fed 30 g/kg of linseed oil compared to fish fed 15 and 30 g/kg of soybean oil. Fillet yield of fish fed 30 g/kg of linseed oil was higher compared to observed in fish fed 30 g/kg of soybean oil. No differences on initial body weight, hepatosomatic index and proximate composition of fillets were observed. Fish fed 30 g/kg of linseed oil showed higher 18:3 n-3 and lower 18:2 n-6 content in the fillets compared to fish fed 15 and 30 g/kg of soybean oil. Higher sum of SFA, MUFA and n-3 FA were observed in fillets of fish fed 15 g/kg of soybean oil. Fish fed 30 g/kg of linseed oil showed higher sum of PUFA and sum of n-3 fatty acids in the fillets. Fillet of fish fed linseed oil showed lower ratio of n-6/n-3 fatty acids compared to fish fed soybean oil. Color, water holding capacity, pH and hardness of fillets were not affected. The adhesiveness of fillets analyzed at one and seven days post-mortem was increased in fish fed linseed oil, while lower chewiness was observed in fillet of fish fed 30 g/kg of soybean or linseed oil compared to observed in fish fed 15 g/kg of soybean or linseel oil. In conclusion, linseed oil was demonstrated to be functional food as α-linolenic source to enhance n-6/n-3 ratio of the fillets. In addition, linseed oil at 30 g/kg is recommended in finishing diets

La bactérie Helicobacter pylori est responsable de l’infection la plus répandue dans la population mondiale. Cette bactérie est considérée comme le principal agent étiologique de la gastrite chronique, de l’ulcère duodénal et du cancer gastrique non-héréditaire. La thérapeutique prescrite pour l’éradication de cette infection est inefficace pour un nombre de plus en plus élevé de patients, dû à l’induction constante de souches résistantes aux antibiotiques habituellement prescrits.H. pylori a aussi d’autres façons d’assurer sa survie dans le milieu gastrique que l’induction de résistances aux antibiotiques. En particulier en intéragissant avec le cholestérol des cellules épithéliales gastriques. De ce fait, l’utilisation de molécules inhibitrices de la croissance de H. pylori, autres que les antibiotiques classiques, est une stratégie importante pour combattre cette infection.L’objectif majeur de ce travail a été de mettre en évidence de nouvelles molécules inhibitrices de la croissance et de la viabilité de H. pylori, permettant ainsi le développement de solutions alternatives à la thérapeutique classiquement utilisée. Les acides gras polyinsaturés et l’acide docosahexaenoic (DHA) se mettre en lumière pour réunir incontestable propriété anti-inflammatoires et anti-tumoral. Nous avons émis l’hypothèse que le DHA influence la survie de H. pylori, et peut moduler la disponibilité des acides gras et du cholestérol cellulaires.Nos résultats montrent que le DHA inhibe la croissance de H. pylori in vitro et affecte sa capacité à coloniser la muqueuse gastrique dans le modèle souris. Dans ces conditions, le DHA diminue la réponse inflammatoire gastrique induite par l’infection. Au niveau des cellules épithéliales gastriques, des modifications du profil des acides gras et du cholestérol avec des conséquences sur le métabolisme et la signalisation cellulaire sont observées. De plus, un traitement antibiotique classique combiné à une administration de DHA aux souris infectées diminue de façon drastique la récidive de l’infection. En conclusion, cette étude démontre un effet inhibiteur du DHA sur l’infection par H. pylori et sa récidive. Ces résultats justifient la proposition du DHA comme coadjuvant thérapeutique, constituant ainsi une stratégie prophylactique alternative de l’éradication de l’infection par H. pylori. / H. pylori infection is extremely common worldwide and is recognized as a major etiological factor in chronic active gastritis, gastric duodenal ulcers and gastric cancer development. H. pylori eradication treatment has not changed to a large extent in the last decades and can raise some concern mainly due to recurrence of infection, and most importantly, acquired resistance to classically used antibiotics. In this context, the use of compounds other than antibiotics that could decrease H. pylori infection in a safe way could provide an alternative to tackle this problem. It is known that H. pylori extracts cholesterol from host cell-membrane rafts, modifies it into an α-glycosylated form, and uses this mechanism to increase its survival. The main aim of this thesis work was to explore the role of different non-antibiotic molecules in inhibiting H. pylori growth. Among molecules known to affect in vitro H. pylori growth and viability are certain polyunsaturated fatty acids (PUFAs). Within the many molecules available, we concentrated our efforts on the study of docosahexaenoic acid (DHA). We also pursued the hypothesis that DHA affects survival of H. pylori by modulating the host epithelial cell levels of fatty acids and cholesterol availability.Our results show that DHA inhibits H. pylori growth both in vitro and in vivo, and attenuates the host inflammatory response. Additionally, we demonstrate that DHA induces morphological and cell wall protein composition changes that altogether decrease bacteria-gastric epithelial cell adherence, inflammation and survival. Also, we demonstrated that DHA alters cholesterol levels in epithelial cells, thereby influencing H. pylori ability to uptake and use epithelial cholesterol. This will ultimately impair H. pylori survival. Importantly, the combination of DHA and antibiotic standard treatment decreased the recurrence of H. pylori infection in a mouse model. Our results have gathered important evidence to pave the way for DHA use in the clinical setting and in prophylactic/preventive strategies against H. pylori infection.

Les acides gras polyinsaturés à longue chaîne (AGPI-LC) de la série n-3 jouent un rôle essentiel dans le fonctionnement cérébral, notamment dans le maintien des processus de plasticité synaptique et de mémoire au cours du vieillissement. Il est maintenant bien admis que ces acides gras peuvent moduler la transcription de gènes impliqués dans les processus de plasticité synaptique sous-tendant les performances mnésiques via leur liaison à des récepteurs nucléaires tels que les PPAR (peroxisome proliferator-activated receptor) et les RXR (retinoid X receptor). Les RXR sont les partenaires communs d’hétérodimérisation de nombreux autres récepteurs, dont le récepteur nucléaire de l’acide rétinoïque (AR), RAR (retinoic acid receptor), métabolite actif de la vitamine A. Ainsi, les RXR jouent un rôle majeur dans la régulation des voies de signalisation des AGPI n-3 et des rétinoïdes.Dans ce contexte, l’objectif de notre travail était de mieux comprendre les mécanismes mis en jeu dans l’action des AGPI-LC n-3 sur les processus neurobiologiques qui sous-tendent les performances mnésiques au cours du vieillissement, notamment en abordant de manière spécifique les mécanismes mis en jeu dans les interactions entre les voies de signalisation des AGPI-LC n-3 et des rétinoïdes. Les approches expérimentales mises en place ont consisté notamment à évaluer chez le rat âgé les effets de supplémentations nutritionnelles en AGPI-LC n-3 et/ou vitamine A sur les performances de mémoire, ainsi que l’action du DHA administré seul sur différents types de mémoire dépendants de l’hippocampe.Nos principaux résultats montrent une altération du métabolisme des acides gras et de la vitamine A au cours du vieillissement. Ces changements métaboliques sont associés à une hypoexpression des voies de signalisation des AGPI n-3 et des rétinoïdes, accompagnée de déficits mnésiques. Nous montrons par ailleurs un effet synergique d’une supplémentation nutritionnelle en AGPI-LC n-3 et en vitamine A sur le maintien des performances de mémoire chez l’animal âgé. De plus, cette supplémentation permet de prévenir, dans l’hippocampe, les changements de composition en AGPI n-3 ainsi que l’hypoexpression des ARNm de RXRγ et de kinases régulées par l’AR et les AGPI n-3.Ces résultats plaident en faveur d’une action synergique des AGPI-LC n-3 et de la vitamine A sur le maintien des performances mnésiques au cours du vieillissement, via une action combinée sur leurs voies de signalisation, lesquelles participeraient ainsi au maintien de certains processus de plasticité synaptique sous-tendant la mémoire et qui se trouvent être altérés avec l’âge. / N-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFAs) play a critical role in brain functioning, notably in the maintenance of synaptic plasticity and memory processes during aging. It is now well accepted that n-3 PUFAs can modulate transcription of genes involved in synaptic plasticity processes underlying the memory performances through binding and activating nuclear receptors such as PPARs (peroxisome proliferator-activated receptors), and RXRs (retinoid X receptors). RXRs are the common heterodimerization partner of numerous nuclear receptors, among them the retinoic acid receptor (RAR), which binds retinoic acid (RA), the active metabolite of vitamin A. Thus, RXRs play a key role in the regulation of n-3 PUFA and retinoid signaling pathways.In this context, the aim of this work was to study the mechanisms involved in the action of n-3 PUFAs on neurobiological processes underlying the memory performances during aging, and more particularly by assessing specifically the molecular mechanisms involved in interactions between n-3 PUFA and retinoid signaling pathways. For this purpose, we studied the effects of dietary supplementations in n-3 PUFAs and/or vitamin A on memory performances in aged rats. We also studied the specific effect of unesterified DHA pharmacological treatments on different hippocampal-dependent memory tasks.Our main results showed impairments in fatty acid and vitamin A metabolism during aging. These modifications were associated with an hypoexpression of n-3 PUFA and retinoid signaling pathways, and memory deficits. Furthermore, we demonstrated a synergetic effect of the joint n-3 LC-PUFA and vitamin A dietary supplementation on the maintenance of memory performances in aged rats. Moreover, in the hippocampus, this supplementation prevented the n-3 PUFA compositional changes, and also the mRNA hypoexpression of RXRγ and of several kinases regulated by RA and n-3 PUFAs which were observed during aging.These results suggest a beneficial synergetic effect of n-3 LC-PUFAs and vitamin A on the maintenance of memory performances during aging, through a combined action on their signaling pathways, which could be involved in the maintenance of synaptic plasticity processes underlying memory performances impaired during aging.

Dans une stratégie de diversification des apports en acides gras polyinsaturés très longue chaîne n-3 (AGPI TLC n-3), essentiels à la santé de l'Homme et majoritairement apportés par les produits de la mer, l'objectif de la thèse était de mieux comprendre les mécanismes cellulaires pouvant expliquer la faible teneur en AGPI TLC n-3 présente dans le muscle de bovin, ceci en explorant trois voies métaboliques de ces acides gras potentiellement limitantes (biosynthèse, captage facilité et peroxydation non-enzymatique) par des approches de qPCR ou de transcriptomique. Les principaux résultats montrent que le foie et les muscles de bovin possèdent tout le matériel génétique nécessaire à la synthèse des AGPI TLC n-3 et pourraient donc assurer leur synthèse, sauf chez le mâle entier où l'expression du gène de l'élongase 5 est réprimée par la présence d'hormones sexuelles mâles. D'autre part, les teneurs musculaires en AGPI TLC n-3 plus élevées avec un régime base d'herbe par rapport à de l'ensilage de maïs et dans un muscle glycolitique par rapport à un muscle oxydatif ne semblent pas s'expliquer par une modulation de l'expression des gènes impliqués dans leur biosynthèse, ni dans leur captage facilité et dans la régulation endogène de leur lipoperoxydation. En conclusion, ce travail de thèse a permis de considérablement faire progresser la compréhension des mécanismes impliqués dans la régulation des dépôts d'AGPITLC n-3 dans les muscles de bovin. Toutefois, ces régulations sont certainement plus complexes et probablement multifactorielles. De nombreuses pistes restent encore à explorer avant d'envisager augmenter la teneur en AGPI TLC n-3 dans la viande bovine. / N-3 very long chain polyunsaturated fatty acids (n-3 VLC PUFA) are essential for human health but are almost exclusively present in seafood. Thus, in a strategy of diversification of n-3 VLC PUFA sources for human, the aim of this thesis was to better understand the cellular mechanisms that may explain the low n-3 VLC PUFA content in bovine muscle, by exploring three potentially limiting metabolic pathways of these fatty acids (biosynthesis, facilited uptake and non-enzymatic peroxidation) by qPCR or transcriptomic approaches. The main results indicate that the liver and muscles of cattle possess all the genetic material necessary for the synthesis of n-3 VLC PUFA and may therefore ensure their synthesis, except in entire males where gene expression of the elongase 5 is suppressed by the presence of male sex hormones. On the other hand, the higher n-3 VLC PUFA content in muscle of cattle with a grass based diet compard to corn silage and in glycolytic muscle compared to oxidative muscle do not seem to be explained by a modulation of gene expression of proteins involved in their biosynthesis or in their facilited uptake or in the endogenous regulation of their lipoperoxidation. In conclusion, this thesis has greatly advance our understanding of mechanisms involved in the regulation of n-3 VLC PUFA deposits in muscles of cattle. However, these regulations are certainly more complex and probably multifactorial. Many tracks remain to be explored before considering increasing n-3 VLC PUFA content in beef.