Influence of alpha-tocopherol on arachidonic acid deposition and peroxidation in Atlantic salmon (Salmo salar L.) fingerlings

The synergistic effect of arachidonic acid (ARA) (20:4n-6) and alpha-tocopherol on the accumulation of fatty acids and the peroxidation of lipids in liver and muscle was evaluated in Atlantic salmon (Salmo salar) juveniles. Triplicate groups were fed during 12 weeks with eight experimental diets with different levels of ARA and alpha-tocopherol. In all experimental diets the productive parameters were not affected (P > 0.05). ARA accumulation in muscle and liver showed significant differences (P < 0.05) between treatments. The synergic relationship between ARA/alpha-tocopherol was influenced (P < 0.05) only in the liver, showing that high levels of alpha-tocopherol and ARA favored the fatty acids accumulation in this organ. Results indicate that a dietary concentration up to 0.6% ARA, the increment of alpha-tocopherol is not necessary. The data obtained in this study demonstrated that the interaction between the ARA and alpha-tocopherol influenced the accumulation of fatty acids in the live

Identification of a low digestibility δ-Conglutin in yellow lupin (Lupinus luteus L.) seed meal for atlantic salmon (Salmo salar L.) by coupling 2D-PAGE and mass spectrometry.

The need of quality protein in the aquaculture sector has forced the incorporation of alternative plant proteins into feeding diets. However, most plant proteins show lower digestibility levels than fish meal proteins, especially in carnivorous fishes. Manipulation of protein content by plant breeding can improve the digestibility rate of plant proteins in fish, but the identification of low digestibility proteins is essential. A reduction of low digestibility proteins will not only increase feed efficiency, but also reduce water pollution. Little is known about specific digestible protein profiles and/or molecular identification of more bioavailable plant proteins in fish diets. In this study, we identified low digestibility L. luteus seed proteins using Atlantic salmon (Salmo salar) crude digestive enzymes in an in vitro assay. Low digestibility proteins were identified by comparing SDS-PAGE banding profiles of digested and non-digested lupin seed proteins. Gel image analysis detected a major 12 kDa protein band in both lupin meal and protein isolate digested products. The 12 kDa was confirmed by 2D-PAGE gels and the extracted protein was analyzed with an ion trap mass spectrometer in tandem mass mode. The MS/MS data showed that the 12 kDa low digestibility protein was a large chain δconglutin, a common seed storage protein of yellow lupin. Comparison of the protein band profiles between lupin meal and protein isolates showed that the isolatation process did not affect the low digestibility of the 12 kDa protein

Protein band profiles of non-digested and digested yellow lupin products.

<p>Meal, the dehulled seed meal extracts; Isolate, the protein isolate extracts; Casein, casein extracts; N, non-digested product; D, digested product; B Blank, only digestive enzymes; E, Blank, empty lane. The position of the main low digestibility lupin protein is shown by a leftward-pointing arrow.</p

2D-PAGE gel images of yellow lupin digested products.

<p>Meal, the dehulled seed meal extracts; Blank, only digestive enzymes. The leftward-pointing arrow and the leftward-pointing dotted arrow point the 12 kDa and other minor indigestible yellow lupin proteins, respectively. The circle shows a protein from the digestive enzymes.</p

Protein digestibility for yellow lupin meal and protein isolate.

<p>Meal, the dehulled seed meal extracts; Isolate, the protein isolate extracts. (*) significantly different (p = 0.043).</p

Educación. Contextos sociales y propensión a aprender

Nuestras sociedades están inmersas, desde hace algunos años, en interminables debates y movilizaciones en torno a la educación. Se ha ido configurando una creciente demanda ciudadana exigiendo una educación de calidad e igualdad de oportunidades en el acceso a ella. Por otra parte se han instaurado prácticas recurrentes de medición de los logros educativos, haciendo uso de patrones de carácter universal, que permiten a los distintos actores involucrados cotejar lo que está ocurriendo en sus respectivos países comparándolo con lo que ocurre en otros países