Effect of dietary free fatty acid content on growth and hepatic morphology in sole (Solea Senegalensis) juveniles

Utilization in aquaculture of unusual meals with unbalanced lipid content or inadequate previous treatment may result in harmful state for fish. This research studied the effects caused by different dietary free fatty acid (FFA) content on growth performance and hepatic morphology in liver in sole juveniles. Results revealed an inverse relationship between dietary FFA content and ability of fish to grow. Moreover, hepatic morphology analysis indicated an overall healthier status in hepatocytes of fish fed with low dietary FFA content. Dietary fatty acids must be esterified to glycerols seem an absolutely necessary requisite in sole, allowing a proper energy storing and its latter mobilisation to gain biomass.This work was supported by Interreg Project 0251_ECOAQUA_5_E, financed by the EDRF (European Regional Development Fund). www.juntadeandalucia.es/agriculturaypesca/ifapa/ecoaquaLa utilizaci&oacute;n en la acuicultura de dietas inusuales con contenido lip&iacute;dico desequilibrados o tratamientos previos inadecuados puede resultar nocivo para los peces. Esta investigaci&oacute;n estudi&oacute; los efectos causados por distintas dietas con diferente contenido en &aacute;cidos grasos libres (FFA) en el crecimiento y la morfolog&iacute;a hep&aacute;tica en juveniles de lenguado. Los resultados revelaron una relaci&oacute;n inversa entre el contenido de FFA en la dieta y la capacidad de los peces para crecer. Por otra parte, el an&aacute;lisis de la morfolog&iacute;a hep&aacute;tica indic&oacute; un estado m&aacute;s saludable en los hepatocitos de los peces alimentados con una dieta baja en FFA . La esterificaci&oacute;n con glicerina de &aacute;cidos grasos es un requisito indispensable en lenguados, lo que permite un adecuado almacenamiento de energ&iacute;a y su posterior movilizaci&oacute;n para ganar biomasa.Este trabajo fue apoyado por el proyecto Interreg 0251_ECOAQUA_5_E , financiado por el FEDER (Fondo Europeo de Desarrollo Regional). www.juntadeandalucia.es/agriculturaypesca/ifapa/ecoaqua.</p

Salinity tolerance as a factor controlling spatial patterns in composition and structure of zooplankton in the Guadalquivir estuary

Trabajo presentado en ECSA 56 (Coastal systems in transition: From a 'natural' to an 'anthropogenically-modified' state), celebrado en Bremen del 4 al 7 de septiembre de 2016.N

Spatial distribution and estuarine sources of dissolved organic matter export to the coastal zone in the Gulf of Cádiz, Spain

Trabajo presentado en el XVIII Seminario Ibérico de Química Marina, celebrado en Alicante (España) de 20 al 22 de julio de 2016.Dissolved organic matter (DOM) is a major component of the organic matter transported to the coastal zone by rivers. It controls ecosystem-level processes (e.g. food web) and constitutes an important pathway for nutrients transport from land to coastal waters. We know that estuarine discharges affect the primary production and nutrient composition in the adjacent coastal area. For instance, the current hypernutrification of the Guadalquivir estuary may benefit primary production on adjacent coasts. However, studies on DOM in the Gulf of Cádiz waters are unknown despite its importance in the global ocean functioning. The Gulf of Cádiz is under the estuarine influence of three main estuaries: Guadiana, Tinto-Odiel and Guadalquivir. The present study evaluates the relevance of DOM and the estuarine influence and environmental factors which determine its distribution in the Gulf of Cádiz. Our results suggest that the Gulf of Cádiz water mass is receiving large amounts of dissolved organic transported by the Guadiana and Guadalquivir rivers and much lesser from Tinto-Odiel. Thus, the estuarine influenced area explained the fDOM variability in the Gulf of Cadiz and this variability was shaped by turbidity, water depth and distance from the coast. Within the estuarine ecosystems, salinity and turbidity were the main factors explaining the fDOM variability.This work was financed by the MICCIN grants DILEMA (CTM2014-59244-C3-2-R).N

Population dynamic and trophic position of mysid community demonstrates its key role for nursery function in a temperate estuary

Guadalquivir Estuary is a main nursery ground of marine goal species for Gulf of Cadiz fisheries. It is a well-mixed temperate estuary with horizontal salinity gradient and clear seasonal water temperature trend. Mysid community with Mesopodopsis slabberi, Neomysis integer and Rhopalophthalmus tartessicus make up to over 80% of total macrofauna biomass in the estuary. Life history, population structure, secondary production, trophic level and community spatio-temporal dynamic were unravelled combining analysis of long term 16y monitoring data with 2y of in depth population analysis and trophic biomarker studies. Results show a key trophic role in food web, a seasonal trend showing density peaks ( 23, 3 and 6 mg/m3, respectively) in spring-summer and winter marine coastward migration. Despite being euryhaline, the three species of showed unevenly spatial distribution, being salinity the variable best explaining structure changes of mysid assemblage. Inter- and intra-specific euryhalinity differences both for prey and predators seem to determine the entire spatial estuarine community distribution. High secondary production (P/B rates 38.2, 10.3 and 10.7) and food web studies confirm key role of mysids transferring energy up to juveniles (fish and crustaceans) arriving yearly in spring to their nursery area

Hormonal control of tryptic enzyme activity in Atlantic cod larvae (Gadus morhua): Involvement of cholecystokinin during ontogeny and diurnal rhythm

Highlights • We describe the ontogenetic development of CCK and tryptic enzyme activity in larval cod • CCK is known to play a key role in regulating digestive processes • CCK concentrations increased during ontogeny suggesting a growing role in regulating digestive processes • A short-term experiment reveals a feedback mechanism between CCK and tryptic enzyme activity • Cod larvae have limited regulatory and digestive capacity to handle several meals in a short period The ontogenetic development of the gut hormone cholecystokinin (CCK) and the key proteolytic enzyme trypsin was described in Atlantic cod larvae (Gadus morhua) from first-feeding until 38 days post first-feeding (dpff). CCK is known to play a major role in the endocrine control of digestive processes in mammals and adult fish, but its regulatory role in the larval stages of marine fish is largely unknown. Only small amounts of CCK were found in the body (excluding head) in cod larvae at first-feeding, but CCK levels increased exponentially with development, suggesting a more pronounced role of CCK during ontogeny. Tryptic enzyme activity increased slightly until a standard length of ca. 8 mm (approx. 33 days dpff) with a significant increase in larvae larger than 8 mm standard length, indicating limited digestive capacity in the early stages. To entangle the short-term feedback mechanism between CCK and tryptic enzyme activity, we conducted a 12 hour feeding experiment at 21 dpff. Cod larvae receiving only algae revealed a noticeable response in tryptic enzyme activity within two hours in the morning, whereas larvae fed algae and rotifers at the same time showed a slightly delayed response up to four hours. Tryptic enzyme activity remained low in the group receiving only algae as well as the two fed groups in the afternoon. No reaction in tryptic enzyme activity was observed in larvae that received a second meal of rotifers in the afternoon, indicating limited regulatory and digestive capacity to handle several meals in a short period. CCK levels remained relatively constant throughout the day but increased in the afternoon in all three groups when tryptic enzyme activity was low, suggesting that a negative feedback mechanism between CCK and tryptic enzyme activity is present in larval cod at least from 21 dpff

Cultivation of larval of Pargo and Sarge in CICEM The Toruño

Presentación de resultados y métodos empleados en el CIFPA El Toruño para el cultivo larvario del Pargo y del Sargo

Alevinaje of flounder in Cicem The Toruño CIFPA. The Toruño

El lenguado senegalés (Solea senegalensis) es una especie de gran interés en acuicultura. Se han logrado grandes avances en su cultivo larvario y en los mecanismos que controlan la metamorfosis. En este proyecto se realiza un estudio acerca de los alevines obtenidos en criadero