Orientador: Lireny Aparecida Guaraldo Gonçalves / Texto em português e inglês / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-21T10:35:40Z (GMT). No. of bitstreams: 1 Conto_LeilaneCostade_D.pdf: 5195999 bytes, checksum: 05ac9b9628d2dacdf94c6fa8c8ba673f (MD5) Previous issue date: 2012 / Resumo: Óleos e gorduras são importantes na alimentação humana como fonte de energia,além de alguns serem considerados essenciais ao funcionamento dos organismos, tais como determinados ácidos graxos polinsaturados ômega-3. O ácido eicosapentaenóico (EPA) e o ácido docosahexaenóico (DHA), provenientes de fontes marinhas, são as principais formas de ingestão direta de ômega-3,porém estes são muito sensíveis à oxidação e apresentam flavors característicos que levam à rejeição por alguns consumidores. Uma alternativa para contornar estes problemas é a microencapsulação. Uma técnica muito difundida para este tipo de produto sensível é a coacervação, no entanto algumas novas técnicas vêm surgindo na busca de solução destas deficiências. A gelificação enzimática pode ser citada como uma nova tecnologia que objetiva reduzir algumas etapas do processo e tempo de produção, se comparado ao processo de coacervação.Neste trabalho buscou-se compreender o comportamento do material de recheio (éster etílico de óleo de peixe), visto que são encontrados poucos estudos referentes às análises da integridade dos materiais de recheio de natureza lipídica quando encapsulados, e dos materiais de parede (principalmente isolado protéico de soja e isolado protéico de soro) quando utilizados para a produção de microcápsulas por gelificação enzimática e por coacervação complexa, avaliando tanto as cargas eletrostáticas do meio pelo seu potencial zeta para a coacervação, quanto na caracterização completa das cápsulas produzidas por gelificação enzimática e coacervação. Entre os materiais de parede estudados, foram utilizados isolado protéico de soro e isolado protéico de soja, sendo que este último na concentração de 10% apresentou formação de microcápsulas com características superiores pela técnica de gelificação enzimática. Quando estudadas mais a fundo as características das microcápsulas produzidas por gelificação enzimática, a ánalise do material encapsulado constatou-se que ocorreu a encapsulação de óleo de milho da segunda emulsão, reduzindo assim a eficiência real de encapsulação, mostrando-se assim uma técnica não eficaz,mesmo se obtendo cápsulas com elevada resistência mecânica. Comparando-se os métodos de degradação destas cápsulas, foi observada a total degradação da parede para a metodologia de degradação ácida, e parcial para a metodologia de degradação enzimática alcalina. Entretanto a melhor metodologia de degradação para se determinar a composição do material encapsulado foi a degradação ácida com determinação direta da composição em ácidos graxos. No estudo estatístico de microcápsulas contendo éster etílico de óleo de peixe produzidas por coacervação complexa utilizando isolado protéico de soja e goma arábica como material de parede obteve-se cápsulas contendo mais de 20 g de EPA + DHA / 100 g microcápsulas, sendo necessária a adição de menos de 0,5 g de microcápsulas em porções de 100 g ou 100 mL de alimentos para este poder ser considerado funcional. Contudo, uma grande variação no processo foi observadalevando a um estudo mais aprofundado do processo de coacervação através do potencial zeta dos materiais de parede e de recheio separadamente e em diferentes misturas, onde foi constatado que o isolado protéico de soja, por possuir variação na sua constituição e baixa solubilidade, dificulta a determinação exata do potencial zeta zero das misturas, sendo a máxima eficiência de encapsulação encontrada quando as misturas de 1,5:1,0 (massa:massa) isolado protéico de soja:Goma arábica e 2,0:1,0 (massa:massa) material de parede:material de recheio em pH 4,0 foram testados / Abstract: Fats and oils are important energy sources in human feeding, and some, such as the omega-3 polyunsaturated fatty acids, are considered essential to the functioning of the organisms. Eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids from marine sources are the principal forms used for the direct ingestion of omega-3, but are highly sensitive to oxidation and present characteristic flavors leading to their rejection by some consumers. One alternative to overcome these problems is microencapsulation, and one well known technique for this type of sensitive product is coacervation, although some new techniques are currently appearing which also attempt to overcome these deficiencies.Enzymatic gelation could be cited as a new technology which aims to reduce some of the processing steps and production time when compared to coacervation. This work aimed to understand the behavior of the core material (fish oil ethyl ester),since few studies can be found referring to analyses of the integrity of the core materials of a lipid nature when encapsulated, and of the wall materials (principally soy protein isolate and whey protein isolate), when used in the production of microcapsules by enzymatic gelation and by complex coacervation, evaluating both the electrostatic charges in the medium from their zeta potential for coacervation, and a complete characterization of the resulting capsules produced by both enzymatic gelation and coacervation. Of the wall materials studied, whey protein isolate and soy protein isolate were used, the latter, at a concentration of 10%, producing microcapsules with the best characteristics by the enzymatic gelation technique. However, when the characteristics of the microcapsules produced by enzymatic gelation were studied at greater depth, the analysis of the core material showed that lipid material from another source had been coencapsulated due to the processing conditions, thus reducing the true efficiency of the encapsulation, showing that this technique was not efficient, despite the elevated mechanical resistance of the microcapsules. A comparison of the methods used to degrade the capsules showed total degradation of the wall by the acid degradation methodology, and only partial degradation for the enzymatic alkaline degradation methodology. Thus the best degradation methodology to determine the composition of the encapsulated material was acid degradation with the direct determination of the fatty acid composition. In the statistical study of the production of microcapsules containing fish oil ethyl ester by complex coacervation using soy protein isolate and gum Arabic as the wall materials, capsules were obtained containing more than 20 g EPA + DHA / 100 g of microcapsules, requiring the addition of less than 0.5 g of microcapsules to 100 g or 100 mL portions of foods for the food to be considered functional. However considerable process variation was observed, leading to a study in greater depth of the coacervation process as from the zeta potential of the wall and core materials separately, and in different mixtures. Thus it was shown that the soy protein isolate presented variation in its constitution and low solubility, which made it difficult to determine the exact zero zeta potential of the mixtures, the maximum encapsulation efficiency being found with mixtures of 1.5:1.0 (w:w) soy protein isolate: gum Arabic as the wall material and a ratio of 2.0:1.0 (w:w) for the wall material: core material at pH 4.0 / Doutorado / Tecnologia de Alimentos / Doutora em Tecnologia de Alimentos

Indiana University-Purdue University Indianapolis (IUPUI) / Each biological cell is surrounded by a membrane that consists of many different kinds of lipids. The lipids are mainly composed of phospholipids, which form a fluid bilayer that serves as the platform for the function of membrane bound proteins regulating cellular activity. In the research described in this thesis we employed solid state 2H NMR, complemented by DSC (differential scanning calorimetry) and MD (molecular dynamics) simulations, to study the effect of PUFA (polyunsaturated fatty acids) and TFA (trans fatty acids) on molecular organization in protein-free model membranes of controlled composition. These two classes of unsaturated fatty acid incorporate into membrane lipids and have, respectively, a beneficial and harmful impact on health. The aim is to gain insight into the molecular origin of this behavior. DHA (docosahexaenoic acid), which with 6 "natural" cis double bonds is the most highly unsaturated PUFA found in fish oils, and EA (elaidic acid), which with only a single "unnatural" trans double bond is the simplest manmade TFA often found in commercially produced food, were the focus. 2H NMR spectra for [2H31]-N-palmitoylsphingomyelin ([2H31]16:0SM) in SM/16:0-22:6PE (1-palmitoyl-2-docosahexaenoylphosphatidylethanolamine)/cholesterol (1:1:1 mol) mixed membranes were recorded. This system served as our PUFA-containing model. The spectra are consistent with lateral separation into nano-sized (< 20 nm) domains that are SM-rich/cholesterol-rich (raft), characterized by higher chain order, and DHA-rich/cholesterol-poor (non-raft), characterized by lower chain order. The aversion cholesterol has for DHA, as opposed to the affinity cholesterol has for predominantly saturated SM, excludes the sterol from DHA-containing PE-rich domains and DHA from SM-rich/cholesterol-rich domains. It is the formation of highly disordered membrane domains that we hypothesize is responsible, in part, for the diverse health benefits associated with dietary consumption of DHA. 2H NMR spectra for 1-elaidoyl-2-[2H35]stearoylphosphatidylcholine (t18:1-[2H35]18:0PC) and 1-oleoyl-2-[2H35]stearoylphosphatidylcholine (c18:1-[2H35]18:0PC) were recorded to compare membranes with respect to a trans vs. cis ("natural") double bond. The spectra indicate that while a trans double bond produces a smaller deviation from linear conformation than a cis double bond, membrane order is decreased by a comparable amount because the energy barrier to rotation about the C-C single bonds either side of a <italic>trans</italic> or <italic>cis</italic> double bond is reduced. Although EA adopts a conformation somewhat resembling a saturated fatty acid, the TFA is almost as disordered as its <italic>cis</italic> counterpart oleic acid (OA). We speculate that EA could be mistaken for a saturated fatty acid and infiltrate lipid rafts to disrupt the high order therein that is necessary for the function of signaling proteins.

No description available.

Thesis (PhD (Food Science))--University of Stellenbosch, 2006. / Long-chain polyunsaturated fatty acids (LCPUFA), especially the n-3 LCPUFA metabolic products eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) play an important role as regulators in many biological processes. To date hake (Merluccius capensis) heads, a rich source of EPA and DHA, have been discarded at sea. The South African Fisheries Policy Development Committee concerned with the environmental impact of this practice has rendered it undesirable. The high prevalence of under-nutrition amongst children in South Africa can be addressed by the supplementation of their diet with this unexploited fish source. The aim of the current study was to develop a microbiologically safe and sensory acceptable sandwich spread using fish flour prepared from fish heads, as a prime ingredient. The intervention trial aimed to compare the effects of an increased dietary intake of n-3 LCPUFA, specifically DHA, on the blood fatty acid levels and absenteeism (as indicator of immune function), as well as the cognitive status, of the subjects. The microbiological content of the sandwich spread was determined after storage for 20 d at 5°C and 15 d at 25°C. Sensory evaluation was performed by consumers (n = 95; M:F = 44:51; 6 – 9 yr) to determine acceptance of the five different flavours individually incorporated into the sandwich spread to mask the fishy note and to provide different flavour options. For the intervention trial subjects (n = 351) were stratified within class group (A - E) and gender and randomly assigned to two treatment categories, an experimental group (EG; n = 174) receiving 25 g sandwich spread.d-1 (191.66 mg DHA. d-1) and a control group (CG; n = 177) receiving an analogous placebo. On school days (104 d), each subject received two sandwiches consisting of two slices of bread (ca. 60 g), spread with 25 g of either the placebo or the experimental spread. Blood samples were drawn at baseline and post intervention. Plasma fatty acid and red blood cell (RBC) membrane status, C-reactive protein levels, as well as vitamin and micronutrient status, were determined. Trained test administrators conducted a battery of cognitive tests. According to South African Government health standards, the sandwich spread remained microbiologically safe after storage. Male and female consumer respondents revealed a significant difference between gender preferences of the five different spread flavours (p <0.05). Significant treatment effects (p <0.05) were observed in n-3 LCPUFA status of the EG, as well as for their absenteeism from school. The two subtests of the Hopkins Verbal Learning test, Recognition and Discrimination Index, showed significant differences between the EG and CG (p <0.05) post intervention in the Grade 2 subjects. The Spelling tests also showed a significant difference between the two groups (p <0.05). In the current study a microbiologically safe and sensory acceptable sandwich spread was developed and tested during an intervention trial, and could possibly in future, provide a healthier option in the School Nutritional Programme. This study proved that supplementation of children (6 - 9 yr) with n-3 LCPUFA, with specific reference to EPA and DHA from a marine source, could have a beneficial effect on their fatty acid status and absenteeism from school. Based on the outcomes of the Hopkins Verbal Learning test and Spelling test, the current study proved that an n-3 fatty acid-rich spread improved the learning ability and memory of children.

L‟acide docosahexaénoïque (DHA) s‟accumule principalement dans les membranes cérébrales humaines durant la période périnatale et les 2 premières années de la vie. Optimiser l‟incorporation des acides gras polyinsaturés à longue chaîne (AGPI-LC) n-3 dans le système nerveux central, notamment le DHA, constitue l‟un des objectifs majeurs de la nutrition néonatale et infantile. Ce projet étudie l‟effet de régimes à base de matière grasse laitière anhydre (MGLA) afin d‟améliorer la bioconversion des AGPI n-3 et l‟incorporation du DHA dans le cerveau. L‟autre objectif, au-delà des effets sur les acides gras, est d‟évaluer si l‟impact des apports destinés au jeune n‟exercent pas un effet plus large tels qu‟appréciés au niveau du lipidome du cerveau.Nous avons mis au point un modèle d‟expérimentation animale permettant d‟étudier les effets de mélanges de MGLA et d‟huiles végétales. Des mères sont nourries avec un régime déficient en acide α-linoléique (ALA) (0,4% des acides gras totaux (AGT)) pendant 6 semaines avant accouplement et pendant toute la gestation et la lactation. Après sevrage, quatre-vingts petits rats mâles et femelles ainsi carencés en AGPI n-3 sont séparés en 4 groupes et reçoivent des régimes à 10% de lipides pendant 6 semaines, soit à base d‟huile de palme mélangée avec des huiles vegétales pour un apport à 1,5%ALA (P1), ou 1,5% ALA supplementé avec 0,12%DHA et 0,4% acide arachidonique (ARA) (P2); soit à base de MGLA et d‟huiles végétales apportant 1,5%ALA (B1) ou 2,3%ALA (B2). Les acides gras cérébraux, plasmatiques et érythrocytaires ainsi que le profil lipidomique cérébral sont mesurés, et les résultats sont analysés en statistiques multivariées. Le régime B1 est supérieur aux deux régimes à base d‟huile de palme à 1,5 %ALA, pour restaurer la quantité de DHA du cerveau (augmentation de 14.38%, P < 0.05) ; le régime (B2) présente un bénéfice supplémentaire sur ce paramètre. Les concentrations cérébrales en DHA chez les rats mâles sont significativement plus faibles que chez les femelles en raison des interactions de l‟effet sexe sur l‟effet régime, mais cet effet s‟atténue avec les régimes MGLA ou l‟ajout de DHA préformés dans le régime palme (P2).Nous avons calculé un nouvel indice à l‟aide des profils en acides gras des globules rouges et du plasma pour prédire le contenu en DHA cérébral, et dont la performance est meilleure que celle des indices existants. Pour la première fois, nous avons pu mettre en évidence un effet majeur et inconnu jusqu‟alors, des régimes sur le lipidome du cerveau (analyse des espèces moléculaires de lipides), affectant près de 15% des espèces analysées. Ces changements semblent être liés, entre autres, au métabolisme du cholestérol, des acides gras et des messagers lipidiques.En conclusion, nos données sont susceptibles d„améliorer les formules infantiles. La première utilisation de l‟approche de lipidomique sans a priori que nous avons mise en oeuvre ouvre des perspectives nouvelles en nutrition infantile. / The accretion of docosahexaenoic acid (DHA) in brain membranes mainly occurs around delivery and during the first two years of life. One of the main goals of neonatal nutrition is to optimize the incorporation of n-3 long chain polyinsaturate fatty acids (LC-PUFA) into the central nervous system, including DHA. Our goal was to study the impact of several kinds of diets based on dairy-fat to improve the n-3 LC-PUFA bioconversion and DHA accretion into brain. The other endpoint was to assess if beyond the brain fatty acid profiles, the dietary intakes would bring about a wider effect such as the one that can be appreciated through a lipidomic approach.We compared the nutritional effect of dairy-fat based diets to that of palm-oil based diets in the rat reproductive model. Mother rats were made deficient in α-linoleic acid (ALA) (0.4% of fatty acids (FA) for 6 weeks prior to mating and throughout gestation and lactation. After weaning, the resulting deficient 40 rat pups of either gender were split into 4 groups and received 10% fat diets made with either 1.5%ALA palm oil blend (P1), same added with 0.12% DHA and 0.4% arachidonic acid (ARA) (P2) , 1.5% ALA dairy-fat blend (B1) or 2.5% ALA dairy-fat blend (B2). The brain, red blood cell (RBC) and plasma fatty acid profiles were analyzed and treated using multivariate statistics. B1 was superior to both palm-oil based diets to improve the brain DHA contents (14.4% increase, P < 0.05). B2 brought an additional benefit for this parameter. The brain DHA contents in males were significantly lower than for the female because of a diet x gender interaction. This effect was smoothed with the dairy-fat diets or the palm-oil based diet augmented with preformed DHA.We calculated a new fatty acid index to predict the brain DHA contents, based on the fatty acid profiles measured in RBC and plasma, and which demonstrated a better performance than the existing published index. For the first time, we showed a profound and yet unsuspected effect of diets until now on the brain lipidome (lipids molecular species), affecting about 15% of the features detected. These changes were ascribed to the cholesterol and fatty acid metabolism, and to the lipid messengers, among others.In conclusion, our data appear highly relevant to improve infant formulas. The first use of the lipidomic approach in neonatal nutrition open the paths of new researches in the area of infant nutrition

Les dernières données de consommation alimentaire de la population française démontrent que les apports nutritionnels en acide eicosapentaénoïque (EPA) et en acide docosahexaénoïque (DHA) sont nettement inférieurs aux recommandations fixées par l’Agence nationale de sécurité sanitaire, de l’alimentation, de l’environnement et du travail (ANSES). Compte tenu de leurs rôles physiologiques, l’amélioration de leur biodisponibilité est devenue une priorité nutritionnelle. La maitrise des formes de vectorisation des acides gras polyinsaturés à longue chaine de la série n-3 (AGPI-LC n-3) représente une piste d’intérêt afin de répondre à cette problématique. C’est dans ce contexte que s’inscrit ce travail de thèse, visant à étudier l’influence de la forme moléculaire (phospholipides (PL) vs triglycérides (TG)) et/ou supramoléculaire (phase continue, émulsion, liposomes) de vectorisation des AGPI-LC n-3 sur leur devenir métabolique.La démarche expérimentale adoptée a consisté, dans un premier temps, à caractériser les différentes formes de vectorisation des AGPI-LC n-3 par un couplage de méthodes d’analyse physico-chimiques (microscopie optique, granulométrie, mesure des produits primaires et secondaires d’oxydation, lipolyse enzymatique). Les données obtenues ont permis de poser des hypothèses mécanistiques pour l’étude de la biodisponibilité chez le rat. Ainsi, dans un deuxième temps, l’étude in vivo a permis d’aborder (1) l’absorption intestinale des acides gras (AG) suite à un apport en bolus de lipides et (2) l’accrétion tissulaire suite à un régime de 8 semaines.Les résultats indiquent que la forme moléculaire de vectorisation des AGPI-LC n-3 (TG marins vs PL marins, en phase continue) n’influence pas leur absorption intestinale mais plutôt leur incorporation dans les lipides lymphatiques, principaux transporteurs des AG alimentaires dans l’organisme. A l’inverse, la structuration des PL marins en milieu aqueux (émulsion ou liposomes), permet d’améliorer l’absorption de l’EPA et du DHA, de façon spécifique à la nature de la structuration supramoléculaire. Les résultats de l’accrétion tissulaire montrent qu’au terme des 8 semaines de régime, l’enrichissement tissulaire en AGPI-LC n-3 s’effectue de façon différente selon leur forme moléculaire de vectorisation. Ainsi, la consommation de TG marins favorise l’incorporation des AGPI-LC n-3 dans les lipides hépatiques, alors que la supplémentation des régimes en PL marins permet d’orienter le DHA vers le cerveau et la rétine.L’ensemble de ces résultats montre que le choix de la forme moléculaire de vectorisation des AGPI-LC n-3 (PL vs TG) peut être un moyen d'orienter leur incorporation tissulaire, alors que leur structuration supramoléculaire (émulsion ou liposomes), une stratégie pour moduler leur absorption intestinale. / The latest data from the cross-sectional national French dietary study show that dietary intakes of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are significantly lower than those recommended by the French Agency for Food, Environmental and Occupational Health & Safety (ANSES). Considering their physiological roles, improving their dietary intake has became a nutritional priority. The control of the different forms of n-3 long chain polyunsaturated fatty (n-3 LC-PUFA) intake represents an interesting way to address this issue. In this context, this thesis aims at studying the influence of the molecular form (phospholipids (PL) vs triglycerides (TG)) and/or supramolecular form (continuous phase, emulsion, liposomes) of n-3 LC-PUFA towards their bioavailability.The experimental approach consisted in characterizing the different forms of n-3 LC-PUFAs by coupling various physicochemical methods (optical microscopy, granulometry, measurement of primary and secondary oxidation products, enzymatic lipolysis). The data obtained made it possible to propose some mechanistic hypothesis for the bioavailability studies conducted in rat. Thus, in a second step, the in vivo study made addresses (1) the intestinal absorption of fatty acids following a single dose of lipids and (2) the lipid tissue accretion following an 8-week diet.The data obtained from the intestinal absorption study indicate that the molecular form of n-3 LC-PUFA targeting (marine TG vs marine PL, in continuous phase) does not influence their intestinal absorption but rather their incorporation into lymphatic lipids, which are the main carriers for dietary fatty acids in the organism. Conversely, structuring marine PL (emulsion or liposomes) improves the EPA and DHA absorption, but differently according to the supramolecular form. The results concerning tissue accretion show that, after 8-week diet, the tissue enrichment in n-3 LC-PUFA is different according to the molecular form of targeting. The consumption of marine TG favours the incorporation of n-3 LC-PUFA into hepatic lipids, while the supplementation of diets with marine PL targets DHA preferentially to brain and retina.All these results show that the molecular form of targeting (PL vs TG) of n-3 LC-PUFA can be a way for managing their tissue incorporation, whereas the supramolecular organization (emulsion or liposomes) can be envisaged to monitor their intestinal absorption.

Três experimentos foram conduzidos para determinar o efeito de fontes lipídicas nos desempenhos reprodutivo e zootécnico de lambaris e a comparação no perfil de ácidos graxos nos tecidos de lambaris selvagens e de cativeiro. Para o experimento de reprodução e de crescimento foram fornecidas, desde a fase larval até o período reprodutivo (11 meses), três dietas elaboradas com diferentes fontes de óleo: soja (SO); óleo de resíduos de tilápia (TI); óleo de resíduo de salmão (SA). No período reprodutivo, os peixes (36 fêmeas e 72 machos) foram induzidos à desova artificialmente e foram avaliados os parâmetros reprodutivos (volume e número total de ovos, taxas de fertilização e eclosão, diâmetro do ovo e comprimento da larva), bem como, o acompanhamento da regeneração ovocitária pós-desova. Observaram-se ovos e larvas maiores e taxas de fertilização superiores na progênie dos peixes alimentados com dietas contendo óleo de peixe, o que pode estar relacionado aos maiores valores da relação n-3/n-6 encontrados nos ovos. Para o experimento de desempenho zootécnico foram utilizados 192 lambaris sexados (espículas na nadadeira anal do macho), sendo 120 machos (peso médio 2,58 ± 0,13g) e 72 fêmeas (peso médio 4,00 ± 0,09g). O Delineamento utilizado foi o Inteiramente Casualizado em Esquema Fatorial 3 x 2, composto por três dietas (SO, TI, SA) e dois sexos. Verificou-se que as fêmeas apresentaram maior ganho em peso, taxas de conversão alimentar e taxa de eficiência protéica mais satisfatórias quando comparados com os machos, os quais apresentaram maior sobrevivência no final do experimento, independente da dieta fornecida. Para o terceiro experimento foram coletados 30 lambaris fêmeas selvagens e 30 fêmeas provenientes do cultivo. Extraíram-se os lipídios dos tecidos (músculo, ovários e fígado) de cada grupo, os quais foram separados (fases apolar e polar) e determinados os perfis de ácidos graxos. Os resultados foram submetidos a ANOVA e diferenciados pelo teste F. Os lambaris de ambos os grupos apresentaram em média 3,5g.100g-1 de teor de gordura no músculo. Os ovários dos peixes selvagens apresentaram a maior concentração de lipídios (14,447g.100g-1) quando comparados com os de cativeiro (13,181g.100g-1). A dieta não conseguiu suprir a quantidade mínima de importantes ácidos graxos no lipídio total e frações dos tecidos das fêmeas provenientes do cultivo em relação às selvagens. O ácido linolênico, considerado essencial para peixes de água doce, esteve presente em menores quantidades no lipídio total e nas frações polar e apolar nos tecidos dos lambaris cultivados, o que pode estar relacionado com deficiência em dietas comerciais para peixes onívoros. Com base nos resultados observados nos experimentos de reprodução e desempenho, sugere-se a inclusão de óleo de resíduos de tilápia e salmão na ração de peixes de lambaris. Ainda foi observado que os lambaris são capazes de elongar e dessaturar os ácidos graxos com 18 carbonos na cadeia, para a produção de Ácidos Araquidônico (AA), Eicosapentaenóico (EPA) e Docosahexaenóico (DHA), devido às baixas quantidades desses ácidos graxos na dieta e posterior aumento nos tecidos. / Three trials were conducted to determine the effect of lipid sources on lambari reproductive and growth performances as well as to make the comparison in the fatty acid profiles in tissues of lambari wild and captive. For the reproduction and growth performances were provided since the larval stage until the reproductive period (11 months), three diets containing different sources of oil: soybean oil (SO); tilapia waste oil (IT); salmon waste oil ( SA). During the reproductive period, fish (36 females and 72 males) were artificially induced to spawn and the reproduction parameters (volume and total number of eggs, fertilization and hatching rates, egg diameter and larval length) were evaluated, as well as monitoring of oocyte regeneration post-spawning. It were observed larger eggs and larvae and higher fertilization rate in the progeny of fish fed diets containing fish oil, which may be related to higher n-3/n-6 ratio values found in the eggs. For the trial of growth performance were used 192 sexed lambaris (male anal fin spines) with 120 males (mean weight 2.58 ± 0.13g) and 72 females (mean weight 4.00 ± 0.09g). The fish were separated on a random method in a factorial scheme 3 x 2, composed by three diets (SO, TI e SA) and two sexes. It was verified that females had higher weight gain, improved feed conversion and protein efficiency rates than males, which showed higher survival at the end of the trial, regardless of diet. In the third trial were collected 30 wild and 30 captive females. The lipids of tissues (muscle, liver and ovary) were extracted from each group and were separated (polar and non polar) and thus determined the fatty acids profiles. The results were analyzed by ANOVA and F test. The lambaris of both groups had mean of 3.5g.100g-1 in the muscle and the wild fish ovaries showed the highest concentration of lipids (14.447g.100g-1) than farming fish (13.181 g.100g-1). The diet failed to supply the minimum amount of important fatty acids in fractions and total lipids of cultivate females and these evidences were higher in the ovaries. Linolenic acid which is considered essential for freshwater fish, was present in smaller amounts in total lipids and polar and nonpolar fractions in all tissues of the cultivated lambari, which may be related to default in commercial diets for omnivores fish. In view of parameters observed in reproduction and growth trials, it can be suggest the inclusion of waste tilapia and salmon oil in lambari broodstock diet. Also it was observed that lambaris have the capacity elongation and desaturation of fatty acids with 18 carbons in the chain for the Arachidonic Acid (AA), Eicosapentaenoic Acid (EPA) and Docosahexaenoic Acid (DHA) production due to low amount of these fatty acids in the diet and the increase in the tissues.

Der globale Prävalenzanstieg allergischer Erkrankungen wird mit der westlichen Ernährung und einem sich ändernden Fettsäurespektrum assoziiert. Die omega-3 Fettsäure Docosahexaensäure (DHA) wurde bereits bei verschiedenen chronisch-entzündlichen Erkrankungen erfolgreich therapeutisch eingesetzt. Die dabei zugrunde liegenden Wirkmechanismen sind jedoch nicht vollständig geklärt. Deshalb wurde hier der molekulare Mechanismus der DHA-vermittelten Hemmung der IgE-Produktion in humanen B-Zellen sowie der verminderten Differenzierung IgE-produzierender Plasmazellen in vitro untersucht. Analysen der beteiligten Signaltransduktionswege offenbarten eine Reduktion der IL-4-abhängigen STAT6-Phosphorylierung und der CD40-vermittelten NFkappaB-Translokation, was zu einer Inhibition des IgE-Klassenwechsels auf dem Niveau des epsilon-Keimbahntranskriptes sowie der Aktivierungsinduzierten Desaminase führte. Weiterhin wurde in einer randomisierten, kontrollierten Doppelblindstudie die Supplementierung mit hochdosierter DHA bei Patienten mit atopischem Ekzem hinsichtlich klinischer und immunologischer Parameter geprüft. Dabei führte DHA zu einer Reduktion des Schweregrades der Erkrankung und zu einer verminderten IgE-Produktion anti-CD40/IL 4-stimulierter Blutzellen ohne Beeinflussung des Serum-IgE-Spiegels. Schließlich wurden die lokalen Prozesse nach DHA-Verabreichung in einem Mausmodell für proteininduzierte Dermatitis analysiert. Dabei war die Reduktion der klinischen Ekzemausprägung mit der verminderten Zahl dermaler CD8+ T-Zellen verbunden. Andere histologische Parameter und das Serum-IgE blieben jedoch unbeeinflusst. Durch die Fähigkeit von DHA, in den IgE-Klassenwechsel in B-Zellen einzugreifen, stellt die Supplementierung mit DHA somit eine mögliche präventive Maßnahme gegen allergische Erkrankungen dar. Ebenso ist DHA in der Lage, den Schweregrad des atopischen Ekzems durch die positive Beeinflussung lokaler inflammatorischer Prozesse signifikant zu verbessern. / The prevalence of allergic diseases has increased worldwide. Westernised diet with its changing polyunsaturated fatty acid (PUFA) proportions is considered to contribute to this development. The omega-3 PUFA Docosahexaenoic acid (DHA) has been reported to be antiinflammatory, but its way of action is not completely understood. Initially, the molecular mechanisms of DHA impact on IgE production in human B cells were examined in vitro. Thereby, DHA inhibited IgE production and the differentiation of IgE secreting cells. This was mediated through direct inhibition of the immunoglobulin isotype switching process by decreasing epsilon germline transcript and activation induced desaminase transcription. Analysis of involved signalling pathways revealed an inhibition of IL-4 driven STAT6 phosphorylation and a reduced NFkappaB translocation into nucleus upon CD40 ligation. Next, in a randomised, double bind, controlled clinical study the efficacy of high-dose DHA supplementation in atopic eczema was determined by investigating the impact on clinical and immunological parameters. In the DHA, but not in control group a clinical improvement of atopic eczema and a reduction of CD40/IL-4 mediated IgE synthesis of peripheral blood cells were observed whereas serum IgE levels remained unchanged. Finally, in a mouse model the impact of oral DHA application on allergen induced dermatitis as well as the underlying local mechanisms were investigated. Thereby, the DHA mediated reduction of clinical skin score was associated with decreased dermal CD8+ T cell numbers, whereas other histological parameters or serum IgE values were not affected. In summary the results indicate that dietary DHA may be effective in prevention of allergic diseases by interference with the IgE switching process and improve the clinical outcome of atopic eczema by its positive impact on local inflammatory processes.

L’acide docosahexaénoïque (DHA, 22:6n-3) est le principal acide gras oméga-3 des tissus cérébraux et est essentiel au développement et aux fonctions du cerveau. Une diminution de la concentration cérébrale du DHA est observée chez les patients souffrant de maladies neurodégénératives telles que les maladies d'Alzheimer et de Parkinson. Un apport ciblé du DHA au cerveau pourrait compenser ces carences. Le DHA sanguin est transporté à travers la barrière hémato-encéphalique (BHE) plus efficacement lorsqu’il est estérifié en position sn-2 de la lysophosphatidylcholine (lysoPC). Nous produisons au laboratoire une phosphatidylcholine structurée pour mimer la 2-docosahexaénoyl-lysoPC (lysoPC-DHA), nommée AceDoPC (1-acétyl,2-docosahexaénoyl-glycérophosphocholine), qui peut être considérée comme une forme stabilisée de la lysoPC-DHA physiologique et qui est neuroprotectrice dans l’accident ischémique cérébral. Le premier objectif de ce travail a été de comparer le passage du DHA marqué non estérifié ou estérifié dans l’AceDoPC ou dans une phosphatidylcholine (PC-DHA), lié au plasma, à travers un modèle in vitro de la BHE. Nous montrons un passage préférentiel à travers la monocouche endothéliale et une captation préférentielle par les cellules gliales de l’AceDoPC comparativement au DHA non estérifié et à la PC-DHA. Le deuxième objectif de ce travail a été de confirmer si cette préférence pour la forme AceDoPC était également observée in vivo. Nous avons donc étudié, chez des rats âgés de 20 jours, la captation cérébrale des différentes formes d’apport du DHA précédemment utilisées (DHA, AceDoPC, PC-DHA). Nous démontrons que l’AceDoPC apporte le DHA au cerveau plus efficacement que les autres formes d’apport de DHA et que cette préférence pour l’AceDoPC est spécifique au cerveau puisqu’elle n’est pas observée pour les autres organes étudiés. L’AceDoPC est trouvée, en partie, sous forme intacte dans le cerveau. L’autoradiographie ex vivo du cerveau de rat révèle que le DHA provenant de l’AceDoPC est localisé dans des régions cérébrales spécifiques jouant un rôle important dans la mémoire et les fonctions cognitives. Enfin, en utilisant des approches de modélisation moléculaire, nous démontrons que les potentiels électrostatiques et hydrophobes sont distribués de manière très similaire au niveau des surfaces de l’AceDoPC et de la lysoPC-DHA. En conclusion, nos études montrent que l’AceDoPC est un transporteur privilégié et spécifique du DHA au cerveau. En considérant les rôles essentiels du DHA pour le cerveau, cette nouvelle approche de ciblage cérébral du DHA offre des perspectives prometteuses dans le développement de stratégies préventives et thérapeutiques pour les maladies neurologiques. / Docosahexaenoic acid (DHA, 22:6n-3) is the main essential omega-3 fatty acid in brain tissues required for normal brain development and function. A decrease in the cerebral concentration of DHA is observed in patients suffering from neurodegenerative diseases such as Alzheimer’s and Parkinson’s. Targeted intake of DHA to the brain could compensate for these deficiencies. Blood DHA is transported across the blood-brain barrier (BBB) more efficiently when esterified at the sn-2 position of lysophosphatidylcholine (lysoPC). We produce in the laboratory a structured phosphatidylcholine to mimic 2-docosahexaenoyl-lysoPC (lysoPC-DHA), named AceDoPC (1-acetyl,2-docosahexaenoyl-glycerophosphocholine), that may be considered as a stabilized form of the physiological lysoPC-DHA and that is neuroprotective in experimental ischemic stroke. The first objective of this work was to compare the passage of either labeled unesterified DHA or DHA esterified in AceDoPC or in phosphatidylcholine (PC-DHA), bound to plasma, through an in vitro model of the BBB. This model is constituted of a co-culture of bovine brain capillary endothelial cells and glial cells from newborn rats. We show a preferential passage through the endothelial monolayer and a preferential uptake by glial cells of AceDoPC compared to unesterified DHA and PC-DHA. We also show that AceDoPC is hydrolyzed, partly, into lysoPC-DHA and that phosphatidylcholine (PC) and phosphatidylethanolamine (PE) are the most labeled lipid classes in endothelial cells and glial cells. AceDoPC is found, partly, as a whole molecule in the cells. The second objective of this work was to confirm whether this preference for AceDoPC was also observed in vivo. We studied, in 20 days old rats, the brain uptake of different forms of DHA previously used (DHA, AceDoPC, PC-DHA). We demonstrate that AceDoPC provided the brain with DHA more efficiently than the other forms of DHA and that this preference for AceDoPC is specific for the brain because it is not observed for other studied organs. AceDoPC is found, partly, intact in the brain. Ex vivo autoradiography of rat brain reveals that DHA provided from AceDoPC is localized in specific brain regions playing key roles in memory and cognitive functions. Finally, by using molecular modelling approaches, we demonstrate that electrostatic and hydrophobic potentials are distributed very similarly at the surfaces of AceDoPC and lysoPC-DHA. In conclusion, our studies demonstrate that AceDoPC is a privileged and specific carrier of DHA to the brain. Considering the essential roles of DHA for the brain, this new approach to target the brain with DHA offers promising perspectives in the development of preventive and therapeutic strategies for neurological diseases.

L'acide docosahexaénoïque (DHA, 22:6n-3) est un acide gras polyinsaturé (AGPI) oméga-3. Il est particulièrement abondant dans le cerveau et la rétine et est nécessaire pour le bon développement et fonctionnement du cerveau. Tandis qu'une déficience en DHA a été montrée être liée à l'émergence de maladies cérébrales (i.e. maladie d'Alzheimer ou maladie de Parkinson), des études ont également montré qu'un apport alimentaire en AGPI oméga-3 pouvait empêcher ou atténuer les perturbations neurologiques liées au vieillissement ou aux maladies neurodégénératives. Il est alors primordial de transporter efficacement le DHA au cerveau. Le laboratoire français a synthétisé auparavant une forme stabilisée de la lysophosphatidylcholine-DHA, qui est le vecteur principal d'apport de DHA au cerveau, de structure 1-acétyl,2-docosahexaénoyl-glycérophosphocholine, brevetée et nommée AceDoPC®. L'injection d'AceDoPC ou de DHA après un accident vasculaire cérébral ischémique provoqué expérimentalement a montré que ces deux molécules étaient neuroprotectrices. Ces effets sont supposés être dus en partie à la conversion du DHA en métabolites oxygénés. Notre étude vise à examiner les effets du DHA et de ses métabolites dérivés, estérifiés ou non dans des phospholipides structurés sur un modèle de neurogenèse in vitro en conditions physiologiques ou pathologiques. Le premier objectif de ce travail a été de synthétiser le phospholipide structuré contenant du DHA, l’AceDoPC®, la protectine DX (métabolite oxygéné du DHA), et un nouveau phospholipide structuré contenant la protectine: 1-acétyl,2-protectine DX-glycérophosphocholine (AceDoxyPC). Le second objectif était d’étudier les effets du DHA, de l'AceDoPC et de la PDX sur la neurogenèse en utilisant un modèle in vitro de neurogenèse, constitué de cultures de cellules souches progénitrices neurales (NSPCs) dérivées de cerveaux de souris adultes, dans des conditions physiologiques ou pathologiques (ischémiques ici). Enfin, le troisième objectif de cette thèse a été d'identifier les mécanismes impliqués dans la réponse des cellules aux conditions ischémiques. La synthèse du phospholipide structuré AceDoxyPC a été réalisée avec succès par une double lipoxygénation enzymatique de l'AceDoPC, et l'identification du produit a été possible grâce à l'utilisation de techniques avancées de chromatographie liquide couplée à la spectrométrie de masse (LC/ESI/MS). De futures études sur ce transporteur de molécule neuroprotectrice potentielle doivent être réalisées prochainement. Les cellules incubées en présence d’AceDoPC présentent une augmentation de neurogenèse comparativement à celles cultivées avec addition de DHA non estérifié ou du véhicule contrôle, notamment sous conditions pathologiques. Les études préliminaires des mécanismes potentiellement impliqués dans la neuroprotection indiquent que les effets neuroprotecteurs et régénératifs de l'AceDoPC pourraient être en partie dus à des effets anti-oxidants. / Docosahexaenoic acid (DHA, 22:6n-3) is an essential omega-3 polyunsaturated fatty acid (PUFA). It is specifically enriched in the brain and the retina and it is required for visual acuity, proper brain development and cerebral functions. While DHA deficiency in the brain was shown to be linked to the emergence of cerebral diseases (i.e. Alzheimer’s disease or Parkinson’s disease), studies showed that a dietary intake of omega-3 PUFA could prevent or attenuate neurologic disturbances linked with ageing or neurodegenerative diseases. In this context, it is primary to deliver DHA efficiently to the brain. Targeting the brain with DHA might offer great promise in developing new therapeutics for neurodegenerative diseases. The French host laboratory previously synthesized a stabilized form of lysophosphatidylcholine-DHA, which is main vector of DHA transportation to the brain, of structure 1-acetyl,2-docoshexaenoyl-glycerophosphocholine, patented and named AceDoPC®. Injection of AceDoPC or DHA after experimental ischemic stroke showed that both molecules also had neuroprotective effects. These potential neuroprotective effects are expected to be due, in part, to DHA conversion into oxygenated metabolites. This study aims to investigate the beneficial effects of DHA and its derived metabolites either unesterified or esterified within structured phospholipids on a model of neurogenesis in vitro under physiological or pathological conditions. The first objective of this work was then to synthesize the DHA-containing structured phospholipid AceDoPC®, DHA oxygenated derivative protectin DX (PDX) and a novel structured phospholipid of protectin: 1-acetyl,2-protectinDX-glycerophosphocholine (AceDoxyPC). The second objective was to investigate the effects of DHA, AceDoPC and PDX on neurogenesis using an in vitro model of neurogenesis, namely cultures of neural stem progenitor cells (NSPCs) derived from the adult mouse brain under physiological or pathological conditions (ischemic conditions). Following this, the third objective of this work was to identify the mechanisms involved in such response to stress induced under pathological conditions. Synthesis of the novel structured phospholipid AceDoxyPC was successfully performed by double enzymatic lipoxygenation of AceDoPC and identification of the product was possible using advanced techniques of liquid chromatography (LC)/electrospray ionization (/ESI)/mass spectrometry (/MS). Future studies on this potential neuroprotective molecule transporter are to be investigated in the near future. Neurogenesis study of cell cultures with AceDoPC showed enhanced neurogenesis compared to addition of unesterified DHA or vehicle control, especially under pathological conditions. Preliminary studies of the potential mechanisms involved in neuroprotection hinted that AceDoPC neuroprotective and regenerative effects might be due in part to its anti-oxidative effects.