Stress during slaughter increases lipid metabolites and decreases oxidative stability of farmed rainbow trout (Oncorhynchus mykiss) during frozen storage

6 páginas, 1 figura, 3 tablasThe consequences of slaughter on the formation of lipid metabolites and oxidative stability of fish muscle during long term frozen storage (−10 °C) were evaluated using farmed rainbow trout killed by asphyxia in air or percussion. The level of major adenine nucleotides and their related compounds was determined in order to check the stress level during slaughter. Plasma lipid metabolites were studied through the determination of eicosanoids and docosanoids such as prostaglandins, leukotrienes, thromboxanes, isoprostanes, resolvins, hydroxides, hydroperoxides, coming from eicosapentaenoic (EPA), arachidonic (ARA), and docosahexaenoic (DHA) acids. In addition, lipid oxidative stability of fillets was monitored. Results revealed that stress during slaughter can greatly influence oxidative stress and oxidative stability of rainbow trout fillets. In fact, asphyxia, which was the most stressful, induced a higher production of some lipid mediators such as hydroperoxides and EPA-derived prostaglandins, such as 12-HpHEPE/15-HpHEPE and PGD3/PGE3. As a consequence, fillets derived from asphyxiated fish were less stable in terms of oxidative stability and showed lower shelf-lifeThe authors gratefully acknowledge the Erasmus Placement Project for Giulia Secci’s grant, the Consejo Superior de Investigaciones Científicas (CSIC) for the doctoral fellowship to Gabriel Dasilva, the ASTRO Company for the project financial supporting and the Fondazione Edmund Mach for kindly providing rainbow troutPeer reviewe

Non-targeted LC-MS/MS assay for screening over 100 lipid mediators from ARA, EPA, and DHA in biological samples based on mass spectral fragmentations

A non-targeted strategy to simultaneously screen for over 100 lipid mediators from ω-6 ARA and ω-3 EPA and DHA fatty acids is presented. The method based on an extensive study of fragmentation patterns obtained by SPE-LC-MS/MS analysis-provided fingerprints to comprehensively elucidate and identify lipid mediators in biological samples. Many of these metabolites are associated to metabolic disorders, inflammatory, immune and oxidative stress. The methodology consisted of a three-step procedure. (1) SPE extraction of compounds from plasma and adipose tissue was followed by LC-MS/MS analysis operating in full scan mode. The methodology was validated for a group of 65 metabolites using standards. SPE recoveries ranged from 29–134% and matrix effect from 10–580%. LOD and LOQ ranged from 0.01 to 1765 ng/mL and 0.03 to 5884 ng/mL respectively, similarly than current analytical strategies based on MRM mode. (2) An extensive study of the mass spectra of a wide range of compounds was done to stablish a specific fragmentation pattern. Interestingly, illustrative fragmentations and new specific transitions to identify EPA and DHA lipid mediators have been innovatively established. (3) After analysis, 30 lipid mediators were tentatively identified in plasma and 35 in adipose tissue of rats according to the pre stablished fragmentation patterns. The hypothetical identification of compounds was validated by using reference standards. Around 85–90% of proposed identifications were correctly assigned and only 4 and 3 identifications failed in adipose tissue and plasma, respectively. The method allowed the identification of these metabolites without losing information by the use of predefined ions list. Therefore, the use of full scan mode together with the study of fragmentation patterns provided a novel and stronger analytical tool to study the complete profile of lipid mediators in biological samples than the analysis through MRM based methods. Importantly, no analytical standards were required at this qualitative screening stage and the performance and sensitivity of the assay were very similar to that of a MRM method.This research was funded by the Spanich Ministerio de Economía y Competitividad (MINECO), grant number: AGL2013-49079-C2-1.2-RS

Analyzing how Atomic Models are being introduced in Secondary School textbooks

Presentamos en este trabajo un análisis de como los libros de texto de Secundaria abordan los contenidos referidos a los modelos atómicos (Thomson, Rutherford, Bohr y el actual). Dicho estudio se ha desarrollado para cuatro editoriales muy conocidas y en los últimos cursos de la secundaria en España (desde 3º E.S.O hasta 2º Bachillerato). Hemos establecido diferentes criterios de análisis atendiendo a las consideraciones actuales de la Didáctica de las Ciencias. Los resultados coinciden en general con lo esperado, detectándose numerosos errores conceptuales, un escaso desarrollo en espiral de los modelos y un tratamiento enfocado principalmente desde una perspectiva de enseñanza memorística. Creemos, además, que esta situación está también presente en muchos otros sistemas educativos.We show in this work an analysis about how secondary school textbooks are considering Atomic Models (Thomson, Rutherford, Bohr and the current model). For this study we have analysed different publishing houses for the last four Spanish secondary school courses. The analysis was set according to current science didactic considerations. The results have detected some conceptual mistakes, a poor spiral development and a didactic strategy focused in a memoristical way to teach these models

Estudiando cómo los modelos atómicos son introducidos en los libros de texto de Secundaria.

Presentamos en este trabajo un análisis de como los libros de texto de Secundaria abordan los contenidos referidos a los modelos atómicos (Thomson, Rutherford, Bohr y el actual). Dicho estudio se ha desarrollado para cuatro editoriales muy conocidas y en los últimos cursos de la secundaria en España (desde 3º E.S.O hasta 2º Bachillerato). Hemos establecido diferentes criterios de análisis atendiendo a las consideraciones actuales de la Didáctica de las Ciencias. Los resultados coinciden en general con lo esperado, detectándose numerosos errores conceptuales, un escaso desarrollo en espiral de los modelos y un tratamiento enfocado principalmente desde una perspectiva de enseñanza memorística. Creemos, además, que esta situación está también presente en muchos otros sistemas educativos.Palabras clave: enseñanza de los modelos atómicos; estudio en espiral; aprendizaje significativo.Analyzing how Atomic Models are being introduced in Secondary School textbooksWe show in this work an analysis about how secondary school textbooks are considering Atomic Models (Thomson, Rutherford, Bohr and the current model). For this study we have analysed different publishing houses for the last four Spanish secondary school courses. The analysis was set according to current science didactic considerations. The results have detected some conceptual mistakes, a poor spiral development and a didactic strategy focused in a memoristical way to teach these models.Keywords: Atomic Models teaching, Spiral study, Significant learning

Lipidomics to analyze the influence of diets with different EPA:DHA ratios in the progression of Metabolic Syndrome using SHROB rats as a model

8 páginas, 4 tablasThe role of specific proportions of ω-3 EPA and DHA, in the modulation of inflammation and oxidative stress markers associated to the progression of Metabolic Syndrome was investigated. Potential inflammatory eicosanoids and docosanoids were discussed together to biomarkers of CVD, obesity, inflammation and oxidative stress in an animal model of metabolic disorders. Results evidenced a noteworthy health effect of 1:1 and 2:1 EPA:DHA proportions over 1:2 EPA:DHA based diets through a down-regulation in the production of strong pro-inflammatory ω-6 eicosanoids, a decrement of biomarkers of oxidative stress, and a modulation of fatty acid desaturase activities and plasma and membrane PUFAs towards greater anti-inflammatory profiles. Outcomes contribute to the general knowledge on the health benefits of marine lipids and their role on the progress of MetS, inflammation and oxidative stress. Results shed light on controversial protective mechanisms of EPA and DHA to better design dietary interventions aimed at reducing MetSThis work was supported by the Spanish Ministerio de Economía y Competitividad (AGL2009-12374-C3-1, -2, and -3, and AGL2013-49079-C2-1,2-R). The Consejo Superior de Investigaciones Científicas (CSIC) and the University of Santiago de Compostela (USC) are gratefully acknowledged for the doctoral fellowship to Gabriel Dasilva. Xunta de Galicia and European Social Fund are also thankfully recognized for the financial support of the postdoctoral contracts to M. P and E.G.-E., and ISCIII for the postdoctoral contract “Sara Borrell” to J.P.-J. (CD09/00068)Peer reviewe

Targeting hepatic protein carbonylation and oxidative stress occurring on diet-induced metabolic diseases through the supplementation with fish oils

The present study addressed the ability of long-chain ω-3 polyunsaturated fatty acids (ω-3 PUFA), i.e., eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), to ameliorate liver protein damage derived from oxidative stress and induced by consumption of high-caloric diets, typical of Westernized countries. The experimental design included an animal model of Sprague-Dawley rats fed high-fat high-sucrose (HFHS) diet supplemented with ω-3 EPA and DHA for a complete hepatic proteome analysis to map carbonylated proteins involved in specific metabolic pathways. Results showed that the intake of marine ω-3 PUFA through diet significantly decreased liver protein carbonylation caused by long-term HFHS consumption and increased antioxidant system. Fish oil modulated the carbonylation level of more than twenty liver proteins involved in critical metabolic pathways, including lipid metabolism (e.g., albumin), carbohydrate metabolism (e.g., pyruvate carboxylase), detoxification process (e.g., aldehyde dehydrogenase 2), urea cycle (e.g., carbamoyl-phosphate synthase), cytoskeleton dynamics (e.g., actin), or response to oxidative stress (e.g., catalase) among others, which might be under the control of diet marine ω-3 PUFA. In parallel, fish oil significantly changed the liver fatty acid profile given by the HFHS diet, resulting in a more anti-inflammatory phenotype. In conclusion, the present study highlights the significance of marine ω-3 PUFA intake for the health of rats fed a Westernized diet by describing several key metabolic pathways which are protected in liver

Functional effects of the buckwheat iminosugar D-fagomine on rats with diet-induced prediabetes

Scope: The goals of this work were to test if D-fagomine, an iminosugar that reduces body weight gain, can delay the appearance of a fat-induced prediabetic state in a rat model and to explore possible mechanisms behind its functional action. Methods and results: Wistar Kyoto rats were fed a high-fat diet supplemented with D7 fagomine (or not; for comparison) or a standard diet (controls) for 24 weeks. The variables measured were: fasting blood glucose and insulin levels; glucose tolerance; diacylglycerols as intracellular mediators of insulin resistance in adipose tissue, liver and muscle; inflammation markers (plasma IL-6 and leptin, and liver and adipose tissue histology markers); eicosanoids from arachidonic acid as lipid mediators of inflammation; and the populations of Bacteroidetes, Firmicutes, Enterobacteriales and Bifidobacteriales in feces. We found that D-fagomine reduces fat-induced impaired glucose tolerance, inflammation markers and mediators (hepatic microgranulomas and lobular inflammation, plasma IL-6, prostaglandin E2 and leukotriene B4) while attenuating the changes in the populations of Enterobacteriales and Bifidobacteriales. Conclusion: D-Fagomine delays the development of a fat-induced prediabetic state in rats by reducing low-grade inflammation. We suggest that the anti-inflammatory effect of D-fagomine may be linked to a reduction in fat-induced overpopulation of minor gut bacteria

Mechanistically different effects of fat and sugar on insulin resistance, hypertension and gut microbiota in rats

Insulin resistance (IR) and impaired glucose tolerance (IGT) are the first manifestations of diet-induced metabolic alterations leading to type-2 diabetes, while hypertension is the deadliest risk factor of cardiovascular disease. The roles of dietary fat and fructose in the development of IR, IGT and hypertension are controversial. We tested the long-term effects of an excess of fat or sucrose (fructose/glucose) on healthy male Wistar Kyoto (WKY) rats. Fat affects IR and IGT earlier than fructose through low-grade systemic inflammation evidenced by liver inflammatory infiltration, increased levels of plasma interleukin-6, prostaglandin E2 and reduced levels of protective short-chain fatty acids without triggering hypertension. Increased populations of gut Enterobacteriales and Escherichia coli may contribute to systemic inflammation through the generation of lipopolysaccharides. Unlike fat, fructose induces increased levels of diacylglycerols (lipid mediators of IR) in the liver, urine F2-isoprostanes (markers of systemic oxidative stress) and uric acid, and triggers hypertension. Elevated populations of Enterobacteriales and E. coli were only detected in rats given an excess of fructose at the end of the study. Dietary fat and fructose trigger IR and IGT in clearly differentiated ways in WKY rats: early low-grade inflammation and late direct lipid toxicity, respectively; gut microbiota plays a role mainly in fat-induced IR; and hypertension is independent of inflammation55 mediated IR. The results provide evidence which suggests that the combination of fat and sugar is potentially more harmful than fat or sugar alone when taken in excess

Marcadores de peroxidación lipídica asociados al consumo de PUFAs ω-3 en estudios de alteración metabólica inducida por la dieta

El objetivo del presente trabajo es caracterizar los derivados de la oxidación enzimática y no enzimática de los PUFAs ω-3 y ω-6, y relacionar el perfil de estos mediadores lipídicos con la potencial prevención del desarrollo de la inflamación, estrés oxidativo y otras alteraciones asociadas a la dieta en modelos animales de desórdenes metabólicos. Para realizar este trabajo se emplean modelos animales de ratas alimentadas con dietas enriquecidas con PUFAs de origen marino, EPA y DHA, y se estudian los posibles efectos sinérgicos de combinar estos PUFAs con antioxidantes naturales en un contexto dietario sano y uno alto en grasa y azúcares. Para el análisis de los mediadores lipídicos se desarrolla una metodología basada en la extracción en fase sólida y cromatografía líquida con detección por espectrometría de masas

Lipidomic methodologies for biomarkers of chronic inflammation in nutritional research: ω-3 and ω-6 lipid mediators

20 pages, 4 figures, 3 tablesThe evolutionary history of hominins has been characterized by significant dietary changes, which include the introduction of meat eating, cooking, and the changes associated with plant and animal domestication. The Western pattern diet has been linked with the onset of chronic inflammation, and serious health problems including obesity, metabolic syndrome, and cardiovascular diseases. Diets enriched with ω-3 marine PUFAs have revealed additional improvements in health status associated to a reduction of proinflammatory ω-3 and ω-6 lipid mediators. Lipid mediators are produced from enzymatic and non-enzymatic oxidation of PUFAs. Interest in better understanding the occurrence of these metabolites has increased exponentially as a result of the growing evidence of their role on inflammatory processes, control of the immune system, cell signaling, onset of metabolic diseases, or even cancer. The scope of this review has been to highlight the recent findings on: a) the formation of lipid mediators and their role in different inflammatory and metabolic conditions, b) the direct use of lipid mediators as antiinflammatory drugs or the potential of new drugs as a new therapeutic option for the synthesis of antiinflammatory or resolving lipid mediators and c) the impact of nutritional interventions to modulate lipid mediators synthesis towards antiinflammatory conditions. In a second part, we have summarized methodological approaches (Lipidomics) for the accurate analysis of lipid mediators. Although several techniques have been used, most authors preferred the combination of SPE with LC-MS. Advantages and disadvantages of each method are herein addressed, as well as the main LC-MS difficulties and challenges for the establishment of new biomarkers and standardization of experimental designs, and finally to deepen the study of mechanisms involved on the inflammatory responseThe authors thank the Spanish Ministry of Science and Innovation (grants AGL2013-49079-C2-1-R), and Consejo Superior de Investigaciones Científicas (CSIC) for the financial supportPeer reviewe