Concepción integral y aplicación experimental de procesos de membranas en la reutilización de aguas depuradas

[ES] El estudio enfoca el manejo de los procesos de membranas en la regeneración de aguas residuales y su utilización. Se especifican criterios de reuso y reciclo de agua y su proyección con un estudio de los fundamentos teóricos de la tecnología de membranas y nos guía a la aplicación real. En el apartado práctico exponemos el diseño, ensamblaje y operación de la planta semiindustrial de 860 m3/d que se desarrolla a través de dos líneas de actuación con aplicación en el campo agrícola, conceptos de reconversión y reuso de unidades que han cumplido su ciclo de vida útil en función del factor económico que se ha aplicado. Obtención de ocho calidades de agua para diversas aplicaciones con sistemas de clarificación, filtración multicapa, microfiltración, ultrafiltración, ósmosis inversa, intercambio iónico, electrodesionización y desinfección U. violeta y cloro.

PepT1 mRNA expression levels in sea bream (Sparus aurata) fed different plant protein sources

[EN] The expression and regulation of intestinal oligopeptide transporter (PepT)-1 when vegetable sources are used as a substitute for fish meal in the diet of marine fish has not yet been explored. In the present study, as part of our ongoing work on elucidating PepT1 gene expression in relation to different dietary treatments, we have now isolated and deposited in Genbank database (accession no. GU733710) a cDNA sequence representing the PepT1 in the sea bream (Sparus aurata). The ?de novo? prediction of the three-dimensional structure of PepT1 protein is presented. We also analyzed diet-induced changes in the expression of PepT1 mRNA via real-time RT-PCR using the standard curve method. Sea bream were fed for 140 days with one of the following four diet formulations (43% protein/21% lipid): a control fast growth-promoting diet (C), and three diets with the same formulation but in which 15% of the fish meal was substituted by protein concentrates either from lupine (LPC), chick pea (CPC), or green pea (PPC). Fish fed PPC had significantly (p < 0.05) lower levels of PepT1 transcripts in the proximal intestine than the controls, whereas PepT1 transcript levels in fish fed LPC or CPC were not significantly different from the controls. Although growth was similar between fish fed with different diets during the first 72 days of feeding, growth of the fish fed with PPC was reduced during the second part of the trial and was significantly (p < 0.05) lower than fish fed LPC and CPC diets by the end of the experiment. Correlation between these results and fish growth performances highlights that the intestinal PepT1 mRNA level may serve as a useful marker of the dietary protein quality and absorption efficiency.