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Docosahexaenoic acid (DHA) is a well-known dietary n-3 polyunsaturated fatty acid (PUFA) found in marine fish and organisms whose beneficial effects for human health are widely reported. However, the supply of food containing DHA is currently becoming critical due to the overexploitation of fisheries worldwide. Consequently, searching for alternative sources of DHA is a relevant issue nowadays. Viscera from cultured fishes is considered a by-product by the fishery industry and therefore discarded after fish processing. In this work, viscera from farmed marine fish (Sparus aurata and Dicentrarchus labrax) and also oil extracted from such by-products have been studied to assess their suitability as DHA sources by obtaining their fatty acid profiles. Viscera oil was used as a source for DHA purification by a simple and easily scalable chromatographic method. As a result, a highly purified DHA fraction (>99.0% DHA on total fatty acids) was obtained.Practical applications: This DHA concentrate obtained from viscera oil could be potentially used for alimentary or pharmaceutical purposes due to its lower cholesterol content compared with other known marine sources and also because only safe and legally allowed food-grade solvents have been used throughout the whole process. This way, by obtaining a high added-value product, a revaluation is given to fish by-products which are usually discarded. Abbreviations: DHA, docosahexaenoic acid; EE, ethyl ester; EPA, eicosapentaenoic acid; FA, fatty acid; FAME, fatty acid methyl ester; FID, flame ionization detector; MUFA, monounsaturated fatty acids; PCB, polychlorinated biphenyls; PUFA, polyunsaturated fatty acids; SFA, saturated fatty acids 724Eur.

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Although a subskills approach to reading instruction is merited in improving the reading skills of readers often deemed "struggling," these readers also benefit from balanced literacy instruction. Overemphasis on reading subskills arguably minimizes students' enjoyment of and motivation to read and may inevitably result in the formation of marginalized readers. In turn, the self-efficacies of marginalized readers may be diminished. Framed by social cognitive theory, the author designed an embedded multiple case study to explore the potential influence of peer-led, text based discussion groups on the reader self-efficacies of marginalized readers in Grades 4-6. In terms of reader self-efficacy, marginalized readers appeared to benefit more from participating in peer-led, text based discussion groups than their classmates (i.e. students with initially higher reader self-efficacies). This study is significant in providing support for a more balanced approach to reading instruction, particularly for marginalized readers.