No description available.

Conjugated linoleic acids (CLA) have been shown to have remarkable yet inconsistent metabolic effects in mice, rats, hamsters, chickens, cattle, and humans. In particular, effects on lipogenesis vary with tissue, physiological state and specie. In this study we tested the hypothesis that CLA would differentially affect ducks of the same genetic background but of differing age. Growing (7 wk) and maintenance (11 wk) Moulard ducks were grouped by age and fed a standard diet supplemented with either 5% soybean oil (control) or 5% CLA isomer mixture. Animals were harvested after 3 weeks or 6 weeks for assessment of body composition including adipose, liver, viscera, and empty carcass weight. Serum nonesterified fatty acid (NEFA) and glucose concentrations were evaluated, and gene targets were cloned from the duck to use in quantifying mRNA abundance for genes involved in lipogenesis (fatty acid synthase, FAS; acetyl-CoA carboxylase, ACC) and lipid oxidation (carnitine palmitoyl transferase-1, CPT-1) in liver tissue from maintenance animals. After 3 weeks, the growing CLA group exhibited a 24% decrease in dissectible adipose tissue (P < 0.05) while maintenance animals showed no significant diet effect. After 6 weeks, the growing CLA group exhibited a 20% increase in liver mass compared to the control (P < 0.05), but no diet effect on adipose tissue. Maintenance animals receiving dietary CLA had a 42% decrease in adipose tissue mass after 6 weeks, increased serum NEFA, ACC and CPT-1 mRNA after 3 and 6 weeks (P < 0.05), and increased FAS mRNA after 3 weeks of treatment (P < 0.05). These data indicate that CLA have potent effects on lipid metabolism in ducks, but that these effects differ dependent on physiological age.

No description available.

No description available.

The main source of omega-3 (n-3) long-chain polyunsaturated fatty acids (LC-PUFA) in our diet is supplied by fish, and an ever-increasing proportion of these are being produced by aquaculture. The drive for the growing market demand and production from sustainable sources has led to the use of high-energy (fat) diets and, recently, to the replacement of fishmeal and fish oil with non-marine components, such as plant meals and vegetable oils that are devoid of n-3 LC-PUFA. Both changes impact greatly on lipid and fatty acid metabolism in fish, with health implications for the fish and the human consumer. This impact highlights the need to investigate the basic molecular mechanisms underlying the regulation of lipid and fatty acid metabolism in fish, specifically focussing on the pathways of lipid homeostasis and LC-PUFA synthesis. The aim of this study was to develop and utilise Chinook salmon embryo (CHSE-214) cell line as a model for Atlantic salmon, Salmo salar L., to enable an integrated approach to study the biochemical and molecular regulation of lipid metabolism in fish. In particular, α-linolenic acid (LNA, 18:3n-3) and linoleic acid (LOA, 18:2n-6), which are essential fatty acids abundantly found in vegetable oils, and are precursors of LC-PUFA, were supplemented in combination with other fatty acids, to explore the effect of these on total lipid content, lipid class, FA composition and gene expression of CHSE-214 cell line. Total lipid content was extracted, followed by determination of lipid class and fatty acid analyses. Gene expression analyses of transcription/nuclear factors and various target genes in Atlantic salmon, including those involved in pathways of LC-PUFA synthesis and fatty acid oxidation, were carried out. The results demonstrated that CHSE-214 cell line, under experimental conditions, is able to convert LNA to eicosapentaenoic acid (EPA, 20:5n-3), and LOA to arachidonic acid (ARA, 20:4n-6), but not LNA and/or EPA to docosahexaenoic acid (DHA, 22:6n-3), highlighting the activity of elongase and desaturase enzymes during the conversion process. Changes occurring on the fatty acid profile and also at molecular level were observed. Understanding the role that transcription factors play in the regulation of lipid biosynthesis in fish will allow endogenous LC-PUFA synthesis to be optimised. The results from this study could be used to improve the efficiency of alternative, sustainable diets in aquaculture, while maintaining the nutritional quality of farmed fish for the final consumer. CHSE-214 cell line can therefore be used as a model to study the molecular mechanisms involved in the LC-PUFA biosynthesis, particularly in the conversion of LNA to EPA, which can then be reproduced in vivo, saving time and money.

La biohydrogénation (BH) ruminale des acides gras polyinsaturés (AGPI) est à l'origine de la production d'intermédiaires trans retrouvés dans les productions de ruminants (essentiellement le lait). Il existe deux voies de BH produisant des acides gras (AG) trans qui auraient des propriétés différentes : les isomères t11 auraient des effets bénéfiques pour la santé des consommateurs et les isomères t10 seraient responsables d'une forte diminution du taux butyreux du lait, représentant une contrainte majeure pour les éleveurs. Dans des conditions physiologiques normales, la voie t11 est fortement majoritaire, par contre avec des rations à base d'ensilage de maïs, riches en concentrés et surtout si elles comprennent des suppléments lipidiques riches en AGPI, une déviation de la voie t11 à la voie t10 peut se produire avec une augmentation significative des isomères t10 au détriment des isomères t11. L'objectif de cette thèse est d'expliquer les modalités de cette déviation, afin de mieux la maîtriser en élevage. Nos travaux permettent de conclure que les facteurs alimentaires de maîtrise de la déviation de la voie t11 vers la voie t10, sont la teneur en amidon rapidement fermentescible et la teneur en c9,c12-C18:2. Lorsque la quantité de c9,c12-C18:2 présente dans le rumen est faible, même avec une ration riche en amidon et un pH bas dans le rumen, la déviation n'a pas lieu, la voie t11 suffisant à assurer l'hydrogénation des AGPI puisque dans ces conditions, la ∆9 isomérisation est elle aussi peu efficace à pH bas. En revanche, lorsqu'en plus de l'amidon, du c9,c12-C18:2 est ajouté dans la ration, la voie t11 devient insuffisante et c'est la voie t10 qui prend le relais. Le pyroséquençage 454 couplé à une régression multiple SPLS nous ont permis d'établir des corrélations entre les taxons identifiés et la proportion d'AG (t10 ou t11) dans le rumen. Il s'avère que les genres bactériens corrélés fortement et positivement aux AG t10 sont plus ou moins impliqués dans le métabolisme ruminal du lactate ainsi qu'au faible pH ruminal. Cependant, l'identification des taxons les plus corrélés aux AG t11 était moins précise, elle s'arrête à l'ordre des Clostridiales. Enfin, dans des conditions de déviation de la voie t11 à la voie t10, l'addition de vitamine E dans la ration des vaches n'a pas permis de restaurer un ratio déjà élevé. Ces résultats ont abouti à une meilleure compréhension de cette déviation et orientent vers une meilleure maîtrise en élevage. / Rumen biohydrogenation (BH) of polyunsaturated fatty acids (PUFA) is responsible of the production of trans intermediates found in ruminant products (mainly milk). There are two BH pathways leading to trans fatty acids (FA) with different biological properties: t11 isomers have beneficial effects for consumer's health and t10 isomers result in low milk fat content, representing a major constraint for farmers. In most conditions, t11 FA are the major trans FA, but in some conditions, especially with diets based on corn silage and including lipid supplements rich in PUFA, a shift from t11 to t10 pathway can occur with a significant increase of t10 isomers at the expense t11 isomers. The objective of this work was to explain modalities of this shift to better control it in animal production. Our results demonstrated that dietary factors responsible of the shift from t11 to t10 pathway are starch rapidly fermentable and c9, c12-C18:2 contents. When the amount of c9, c12-C18:2 present in the rumen is low, even though the diet is rich in starch and the pH is low in the rumen, the shift does not occur, t11 pathway being sufficient to ensure the hydrogenation of PUFA since in these conditions, the 9 isomerization is also poorly effective at low pH. However, when c9, c12-C18:2 is supplemented to the diet in addition to starch, t11 pathway becomes insufficient for FA BH, and t10 pathway becomes dominant. 454 pyrosequencing coupled to a multiple sPLS regression allowed us to establish correlations between some identified taxa and FA proportions (t10 or t11) in the rumen. It appears that bacterial genera that are strongly and positively correlated with t10 FA are more or less involved in the metabolism of ruminal lactate and also positively correlated with a low ruminal pH. However, identification of taxa correlated with t11 FA was less accurate, stopping at Clostridiales order. Finally, once the shift occurred, the subsequent addition of vitamin E was not able to counteract this process. These results lead to a better understanding of this shift to better control it in animal livestock.

Este trabalho investigou os efeitos do CLA sobre o metabolismo lipídico na caquexia. Grupos controle ou tumor foram suplementados com CLA, óleo de girassol ou salina, por gavagem, por 14 dias. O peso corporal, ração, glicose, colesterol, TAG, insulina e leptina plasmáticos, glicogênio, proteína, TAG, expressão gênica da CPT I and II, MTP, L-FABP, PPAR-&#945 e apoB, o conteúdo proteíco da apoB e a atividade máxima da CPT I e II no fígado, o conteúdo de gordura no TAE e TARP e a concentração proteíca e de IL-1&#946,IL-6,TNF-&#945 e IL-10 desses tecidos foram determinados. A atividade da CPT II mostrou-se reduzida em todos os grupos em relação a C. o mRNA da MTP, apoB e FABP foi inferior em todos os grupos TB, mas no TBCLA esta redução foi maior. Todos os grupos mostraram expressão diminuída de proteína apoB em relação a C. TBCLA aumentou o TAG hepático e plasmático, assim como colesterol e glicose quando comparado com os grupos TB. O TAG no TAE diminuiu em TBCLA em relação a C, TBSF e CCLA. Houve diminuição de IL-1&#946 no CCLA em relação a C, mas em TBCLA a IL-1&#946 foi superior em relação a C, TB e TBSF. TBCLA mostrou um aumento de IL-6 em relação a TB e CCLA. O TBCLA mostrou aumento de TNF-&#945 quando comparado com TB e CCLA. O CLA falhou em promover a recuperação do metabolismo lipídico em animais caquéticos. / We investigated the effects of CLA upon lipid metabolism in cachexia. Male Wistar rats were assigned to a control or cachetic rats, supplemented with CLA, sunflower oil or saline, for 14 days. Body weight, dietary intake, plasma glucose, cholesterol, insulin and leptin, and liver TAG, glycogen and protein, CPT I and II, MTP, L-FABP, PPAR-&#945, apoB gene expression, apoB protein content and the maximal activity of CPT I and II, were assessed. The fat content of EAT and RPAT, and adipose tissue IL-1&#946,IL-6,TNF-&#945 and IL-10 content were assessed. CPT II activity was reduced in all groups when compared with C. mRNA expression of MTP, apoB and FABP were reduced in all TB groups, but TBCLA showed the greatest reduction of apoB and MTP mRNA and apoB protein content. TBCLA increased liver and plasma TAG, cholesterol and glucose content, when compared with TB groups. TAG in EAT decreased in TBCLA group when compared with C, with TBSF, and with CCLA. Decreased IL-1&#946 in CCLA was found in relation to C, TBCLA enhanced IL-1&#946 in relation to C, TB and TBSF. TBCLA, increased IL-6 when compared with TB and CCLA. TBCLA showed higher TNF-&#945 in relation to TB and CCLA. We conclude that CLA fails promoting the re-establishment of lipid metabolism in cachexia.

A manipulação da dieta constitui uma prática efetiva e rápida de alteração da composição do leite, especialmente do seu teor de gordura. Entretanto, os mecanismos envolvidos não são ainda completamente conhecidos, embora muito se tenha avançado na última década. Sabe-se hoje que certo tipo de ácido graxo (CLA trans-10 cis-12) formado no rúmen sob condições específicas de alimentação é capaz de inibir a síntese de gordura do leite. Entretanto, depressão da gordura do leite (DGL) tem sido observada em casos (e.g. dietas contendo óleo de peixe) onde não há formação deste inibidor. Embora o efeito do CLA sobre a secreção de gordura do leite já esteja bem caracterizado, estudo prévio conduzido pelo nosso grupo mostrou ainda um aumento do teor de proteína do leite em resposta a este tratamento. Dois experimentos foram conduzidos com os seguintes objetivos principais, respectivamente: 1) determinar se um maior suprimento de proteína através da dieta afeta a secreção de proteína do leite de vacas recebendo CLA e 2) Estudar os mecanismos envolvidos na DGL de vacas recebendo dietas contendo óleo de peixe (OP) e níveis distintos de fibra. No primeiro experimento, 48 vacas em lactação receberam os seguintes tratamentos: 1) Dieta controle (DC) + Lac100, 2) DC + CLA, 3) Dieta com alta proteína (DAP) + Lac100 e 4) DAP + CLA. O Lac100 (sais de cálcio de óleo de soja) foi utilizado como placebo. O CLA foi protegido por encapsulação e o produto utilizado continha ~16% de CLA. No segundo experimento, 12 vacas em lactação foram avaliadas em 3 períodos: a) Basal: os animais receberam uma dieta com alto teor de fibra sem OP (dieta basal) por 12 dias; b) Suplementação: 4 vacas/grupo receberam os seguintes tratamentos: 1) Dieta com alta fibra + OP (AF+OP), 2) Dieta com baixa fibra sem OP (BF) e 3) Dieta com baixa fibra + OP (BF+OP); c) Pós-suplementação: todos os animais passaram a receber novamente a dieta basal por 12 dias. Os resultados obtidos no primeiro experimento mostraram que o CLA não foi eficientemente protegido, de forma que a redução da secreção de gordura do leite foi de pequena magnitude em relação a outros trabalhos. Da mesma forma, a proteção dos sais de cálcio de óleo de soja foi pequena, resultando em maior concentração de CLA cis-9 trans-11 (P<0,05) e menor concentração de ácido linoléico (P<0,05) no leite dos animais. Apesar da concentração do CLA trans-10 cis-12 no leite ter aumentado igualmente em resposta ao CLA e ao Lac100, o teor de gordura do leite foi menor (P<0,05) no primeiro tratamento, sugerindo a presença de outros inibidores (ou precursores) no produto utilizado. A concentração de CLA trans-10 cis-12 no leite explicou ~50% da variação da DGL, sugerindo que outros fatores afetaram a síntese de gordura do leite. Os resultados do segundo experimento demostraram, de forma inédita, que o CLA trans-9 cis-11 e o C18:1 cis-11 estão estreitamente relacionados à DGL dos animais que receberam OP. A DGL foi causada por uma ampla redução (P<0,01) da secreção tanto dos ácidos graxos sintetizados de novo quanto dos pré-formados, sugerindo que o mecanismo da DGL pode envolver a inibição de diferentes enzimas lipogênicas. O menor (P<0,01) índice de atividade da enzima &#8710;-9 dessaturase em animais que receberam OP é consistente com a idéia acima. Diferentemente do observado em resposta ao OP, a secreção de gordura do leite não foi afetada pelo tratamento BF (P>0,1). Os teores de proteína e lactose aumentaram na dieta BF e nas dietas contendo OP, respectivamente. / Diet manipulation is an effective and rapid way to change milk composition, mainly for fat content. However, mechanisms are not fully undestood in despite of progress in the area over the last decade. Nowadays, it is known that a molecule of fatty acid (CLA trans-10 cis-12) which is formed in the rumen under specific feeding situations is capable of inhibiting milk fat synthesis. However, milk fat depression (MFD) has been observed even at conditions where there is no formation of trans-10 cis12 CLA (e.g. fish oil-supplemented diets). Although CLA effects on milk fat synthesis are well-established, previous study from our group also showed an increase on milk protein content in cows fed CLA. Two trials were conducted with two main objectives: 1) to determine if an additional supply of diet protein affects milk fat synthesis in cows fed CLA and 2) to study the mechanisms involved in MFD of cows fed diets with fish oil (FO) and different fiber levels. In the first trial, 48 lactating cows received the treatments as follow: 1) Control Diet (CD) + Lac100, 2) CD + CLA, 3) High Protein Diet (HPD) + Lac100 and 4) HPD + CLA. The Lac100 (calcium salts of soybean oil) was used as a placebo. CLA was protected by encapsulation (prills) and the product contained 16% CLA. In the second trial, 12 lactating dairy cows were evaluated in three periods: a) Basal: for 12 days, all cows received a baseline diet (High fiber without FO); b) Suplementation: 4 cows/group received the treatments for 21 days: 1) High fiber diet + FO (HF+FO); 2) Low fiber diet without FO (LF) and 3) Low fiber diet + FO (LF+FO); c) Post-supplementation: cows returned to baseline diet on 12 days. Results from the first trial showed that CLA protection method was innefficient. Thus, milk fat reduction was smaller than in other studies. Protection of calcium salts of soybean oil was also small which resulted in higher cis-9 trans-11 CLA and lower linoleic acid concentrations (P<0.05) in milk from cows fed Lac100. In despite of similar milk trans-10 cis-12 CLA increase in response to CLA and Lac100, milk fat content was lower (P<0.05) in cows fed CLA. It suggests the presence of other fat inhibitors (or precursors) in the product containing CLA isomers. Moreover, concentration of milk trans-10 cis-12 CLA explained ~50% of MFD suggesting others factors influencing milk fat synthesis. Results of the second trial were inedit in showing the close association of milk trans-9 cis-11 CLA and C18:1cis-11 concentrations and FO-induced MFD. MFD resulted from a lower (P<0,01) secretion of both de novo and preformed milk fatty acids. It suggests that mechanisms of FO-induced MFD must involve the inhibition of different lipogenic enzymes. The lower (P<0.01) dessaturase activity index in cows fed FO is consistent with this hypothesis. In contrast to FO, milk fat secretion was unchanged (P>0.1) by LF diet which is consistent with low CLA trans-10 cis-12 and C18:1trans-10 concentrations in milk from cows fed this diet. Contents of milk protein and milk lactose increased (P<0.05) in cows fed LF and FO diets, respectivelly.

O objetivo deste estudo foi avaliar os efeitos do ácido linoléico conjugado (CLA), especificamente do isômero trans-10, cis-12 em culturas de explante de tecido adiposo de suínos, em crescimento. / The objective of this study was to evaluate the effects of conjugated linoleic acid (CLA), specifically the tnas-10, cis-12 isomer on cultures of adipose tissue explants from growing pigs.

O presente trabalho está inserido dentro de um estudo que pretende entender os mecanismos químicos e bioquímicos envolvidos na biodegradação da madeira por Ceriporiopsis subvermispora. Particularmente avaliou-se a relação entre a atividade redutora de Fe3+ presente em extratos aquosos de cultivos de Ceriporiopsis subvermispora sobre madeira com a iniciação de reações de peroxidação de ácido linoleico. A madeira foi biotratada por períodos de 7, 14 e 28 dias. Após a biodegradação, os cavacos foram extraídos com água e os extratos gerados foram caracterizados quanto a atividade redutora de Fe3+ e a capacidade de peroxidar ácido linoleico in vitro. As reações de peroxidação foram avaliadas a partir do monitoramento do consumo de O2 em um oxímetro. A partir desses ensaios foi possível determinar que tanto a oxidação de íons Fe2+ adicionados diretamente ao meio reacional ou a adição de íons Fe3+ e extratos com atividade redutora foram capazes de gerar radicais hidroperoxila que podem iniciar a peroxidação de ácido linoleico. As reações controle indicaram que a peroxidação não ocorre na presença de Fe3+. A adição de metanol às reações contendo Fe2+ não proporcionou menor capacidade de peroxidação de lipídeos, indicando que a reação não deve ser iniciada por OH radical. Tanto a atividade redutora de Fe+3 como a capacidade de iniciar a peroxidação de ácido linoleico dos extratos aumentaram em função do tempo de cultivo. A ultrafiltação dos extratos através de membranas seletivas associada com estudos de cromatografia de permeação em gel (CPG) indicaram que a maior parte da atividade redutora e da capacidade peroxidativa pode ser atribuída a compostos menores que 5kDa. Entre os compostos orgânicos identificados nas frações menores que 5 kDa, foram identificados, por cromatografia gasosa acoplada à espectrometria de massas (CG/EM), alguns ácidos graxos como o palmítico e o ácido esteárico, além de glicerol e ácido oxálico e compostos aromáticos como a vanilina, e os ácidos vanílico, siríngico e gálico. A vanilina, detectada em todas as amostras em estudo, foi usada como padrão para um estudo comparativo das atividades redutoras de Fe3+ detectadas nos extratos. As concentrações estimadas de vanilina nos extratos foram de 5 a 22 ? moles/L de extrato ultrafiltrado. Soluções padrão de vanilina foram então preparadas em concentrações de 5 a 30 ? M e avaliadas quanto a capacidade de reduzir Fe3+ na presença de ferrozina. Essas misturas levaram à formação de Fe2+ nas concentrações de 0,5 a 0,7 ? M de Fe2+ , após 10 min de reação. A comparação desses dados com a capacidade redutora de Fe3+ encontrada nos ultrafiltrados da amostra de madeira biotratada por 14 dias, 43 ?M de Fe2+ em 10 min, sugeriu que a maior parte da capacidade redutora dos extratos não pode ser atribuída aos compostos detectados por CG/EM e sim deve ser atribuída a compostos que apresentam massa molar próxima àquela obtida pela calibração do sistema de CPG, entre 3 e 5 kDa. Isso sugere que a atividade redutora não estaria presente em compostos de baixa massa molar compatíveis com estruturas contendo 1 ou, no máximo, 2 anéis aromáticos e sim em derivados fenólicos maiores, oriundos da biodegradação da lignina. / The present work is inserted in a broad study aiming to understand the chemical and biochemical mechanisms involved in wood biodegradation by Ceriporiopsis subvermispora. Particularly, the relationship between the Fe3+-reducing activity present in aqueous extracts recovered from Ceriporiopsis subvermispora cultures on wood with the initiation of linoleic acid peroxidation reactions was evaluated. Wood chips were biotreated for periods varying from 7 to 28 days. After biotreatment, the wood chips were extracted with water and the resulting extracts were characterized according to their Fe3+-reducing activity, as well as their capacity to initiate linoleic acid peroxidation reactions in vitro. The peroxidation reactions were monitored through O2 consumption by using an appropriated Oximeter. Based on these assays, it was possible to show that Fe2+ ions added directly to the reaction media or the addition of Fe3+ ions plus aqueous extracts were able to generate hidroperoxil radicals that initiated linoleic acid peroxidation. The control reactions indicated that the peroxidation did not occur in the presence of Fe3+ ions alone. Addition of methanol to the reaction media containing Fe2+ did not diminish the lipid peroxidation extent, suggesting that the reaction should not depend on the formation of hydroxyl radical. The Fe3+-reducing activity and the capacity to initiate linoleic acid peroxidation increased in the aqueous wood extracts as a function of culturing time. The ultrafiltration of the extracts associated with gel permeation chromatography (GPC) studies indicated that most of the reducing activity and the peroxidation capacity present in the extracts were assigned to compounds presenting molecular mass lower than 5 kDa. In the fraction lower than 5 kDa some organic compounds were identified by using gas chromatography coupled to mass spectrometry (GC/MS). Palmitic and estearic acids, glycerol, oxalic acid and some aromatic compounds such as vanillin, vanillic, gallic and syringic acids were identified. Vanillin, detected in all the studied samples, was used as a standard for comparative evaluation of the Fe3+-reducing activities detected in the extracts. The estimated concentrations of vanillin in the extracts varied from 5 to 22 &#956;mol/L of ultrafiltrated extract. Therefore, 5 to 30 &#956;M standard solutions of va nillin were assayed for their Fe3+-reducing activity. These solutions reduced 0.5 to 0.7?M of Fe3+ after 10 min reaction. The comparison of these data with the Fe3+-reducing capacity found in the ultrafiltrated aqueous extract from the 14-day biotreated sample, 43 ? M of Fe3+ reduced after 10 min reaction, suggested that most of the reducing capacity in the extracts could not be attributed to compounds detect by GC/MS. Conversely, the Fe3+-reducing capacity could be assigned to compounds with higher molar mass as already observed in the GPC studies (3 to 5 kDa). These data suggest that the reducing activity detected in the aqueous extracts would not be compatible with low molar mass compounds containing 1 or, at least 2, aromatic rings. Instead, the Fe3+-reducing capacity should be assigned to high molar mass phenolic derivatives produced during the lignin biodegradation.