Caracterización histológica del desarrollo del sistema visual en larvas de Dorada Sparus aurata (Linnaeus 1758)

[ES] El objetivo del presente estudio es aportar nuevos conocimientos sobre el desarrollo del sistema visual en los primeros estadios larvarios de dorada. El entendimiento de la ontogenia del sistema visual puede contribuir a la mejora en las condiciones de iluminación en el cultivo, las cuales podrían tener repercusiones en la obtención de larvas de mejor calidad y unas mayores tasas de supervivencia en el cultivo larvario. Las larvas de la mayoría de los peces son predadores visuales, lo que indica la gran importancia que juega el sistema visual en desarrollo (BLAXTER, 1986). El comportamiento trófico de la larva estará intimamente ligado al desarrollo de su capacidad visual, que depende directamente de la organogénesis de la retina. El estudio muestra que durante el desarrollo post-embrionario y en las primeras etapas de vida larvaria, el sistema visual de dorada Sparus aurata, histologicamente, es muy similar al descrito por otros autores para especies similares, Pagrus major (KAWAMURA,1984), Pagrus auratus (PANKHURST, 1996) y Pagrus pagrus (L. 1758 ) (ROO et al.,1998). El tercer día de vida de la larva es uno de los mas importantes, necesita estar preparada para capturar y digerir sus presas. En este día la larva muestra todas las estructuras necesarias para la función visual. El epitelio pigmentario bien definido, el músculo de la lente esta presente y el iris esta completamente formado. Las condiciones de iluminación que se utilizan en los criaderos comerciales difieren bastante de las condiciones naturales, pudiendo ser un factor a tener en cuenta para la obtención de una mejor calidad de larvas así como unas mejores tasas de supervivencia.

Development of skeletal deformities in Gilthead sea bream (Sparus aurata) reared under different larval culture and dietary conditions

[EN] Main deformities such as lordosis, opercular deformities and upper/lower jaws shortening are considered as quality descriptors in commercial marine fish fry production and seem to be related at least with larval culture conditions in early larval stages. The aim of this work was to obtain information about the contribution of the diet and rearing system to the apparition of these abnormalities in gilthead sea bream (Sparus aurata) larvae in semi-industrial scale facilities. For that purpose, two different larval rearing systems semi-intensive and intensive were compared by duplicate and with the same live feed enrichments; besides, two different rotifer enrichments were tested in an intensive system. Biochemical composition of larvae, preys and commercial products was analysed. At 50 days post hatching six hundred fish per treatment were individually studied under stereoscope and abnormalities frequency recorded. At 95 days post hatching fry were soft X ray monitored as well. Survival and malformation frequency were significantly different between treatments, the effect of diet and system are discussed. A significantly lower percentage of deformity rates together with better survival and growth were obtained in the semi-intensive system, whereas the rotifer enrichment significantly affected larval survival.

Detección de QTLs de deformidades esqueléticas en dorada (Sparus aurata L.): herramientas moleculares y análisis de segregación

Programa de doctorado: Acuicultura: producción controlada de organismos acuáticos

Indagine sull’influenza di differenti sistemi d’allevamento sui connotati nutrizionali, tecnologici, sensoriali e di freschezza dell’orata (Sparus aurata) allevata in Italia

On account of the commercial importance of gilthead sea bream (Sparus aurata) in Italy the aim of the present study is the evaluation of the quality of nutritional, technological, sensory and freshness aspects. Sea bream production is growing in the Mediterranean and the evaluation of its quality concerns both producers and consumers alike. The culture system greatly influences final product quality. In Italy most of sea bream culture is carried out in cages but there is also a production in land based facilities and in lagoons. In this study external appeareance differentiations are pronounced. Different results were found for nutritional aspects, for fatty acids and for mineral content. Some differences in the freshness indices are also found. Furthermore, organoleptic differences have been described between culture system.

Stato sanitario di Spigole (Dicentrarchus Labrax) ed Orate (Sparus Aurata) allevate in Grecia e in Italia in relazione alla presenza di agenti di Zoonosi ed Ectoparassiti patogeni

Le attività di ricerca della presente tesi di dottorato si sono focalizzata principalmente sulla parassitofauna dei pesci marini allevati in Grecia ed in Italia con particolare attenzione allo studio degli ectoparassiti di maggior rilievo sanitario in maricoltura ed alla ricerca di endoparassiti di potenziale interesse zoonosico, in particolare larve di nematodi Anisakidae del genere Anisakis. Nel corso del triennio sono stati sottoposti ad esami parassitologici 916 spigole (Dicentrarchus labrax) e 462 orate (Sparus aurata) prelevate presso diverse tipologie di allevamenti greci ed italiani. Per quanto concerne le spigole, la presenza di ectoparassiti è stata riscontrata nel 29,2% e nel 61,9% dei soggetti provenienti rispettivamente da impianti siti in Grecia ed in Italia, mentre le orate hanno presentato percentuali di positività rispettivamente del 87,5% e del 26,7%. Gli ectoparassiti dominanti sono risultati essere il monogeneo Diplectanum aequans nelle spigole ed il ciliato Cryptocaryon irritans e il monogeneo Furnestinia echeneis nelle orate, sebbene sia stato possibile studiare anche il coinvolgimento di altri ectoparassiti, quali il monogeneo Sparicotyle chrysophrii ed il dinoflagellato Amyloodinium ocellatum, nel determinismo di alcuni episodi morbosi. Le osservazioni istopatologiche hanno permesso di caratterizzare le lesioni causate dagli ectoparassiti a diverse intensità d’infestazione. Per quanto concerne la ricerca di parassiti zoonosici, con particolare riferimento agli stadi larvali di nematodi Anisakidae del genere Anisakis, si sono condotti esami parassitologici a livello di cavità viscerale e di muscolo laterale in tutti i soggetti provenienti da allevamenti in gabbia (626 soggetti, di cui 441 spigole e 185 orate). Tutti i soggetti esaminati sono risultati negativi, indicando come il rischio di infestazione da larve di nematodi anisakidi possa essere considerato trascurabile in spigole ed orate allevate in gabbia, come già dimostrato per il salmone atlantico (EFSA, 2010).

Acute stress regulates vasotocinergic and isotocinergic systems in the gilthead sea bream (Sparus aurata L.).

The hypothalamus-pituitary-interrenal axis is involved in stress response regulation. In addition, arginine vasotocin (AVT) and isotocin (IT) are also considered as important players in this stress regulation. The present study assessed, using the teleost gilthead sea bream (Sparus aurata) as a biological model, hypothalamic mRNA expression changes of AVT and IT and their receptors at hepatic level after an acute stress situation. Specimens were submitted to air for 3 min and place back in their respective tanks after that, being sampled at different times (15 min, 30 min, 1, 2, 4 and 8 hours post-stress) in order to study the time course response. Plasma cortisol values increased after few minutes post-exposure, decreasing during the experimental time while a metabolic reorganization occurred in both plasmatic and hepatic levels. At hypothalamic level, acute stress affects mRNA expression of AVT and IT precursors, as well as hepatic expression of their receptors, suggesting the involvement of both vasotocinergic and isotocinergic systems in the acute stress response. Our results demonstrate the activation and involvement of both endocrine pathways in the regulation of metabolic and stress systems of Sparus aurata, which is stated, at least, through changes in mRNA expression levels of these genes analysed.

Utilização de glúten de trigo na alimentação de dourada, Sparus aurata (Linnaeus, 1758)

A incorporação de fontes proteicas alternativas à farinha de peixe na alimentação de espécies piscícolas tem sido objecto de variados estudos no âmbito da nutrição animal. Neste contexto realizou-se o presente trabalho, cujo objectivo foi determinar o nível de substituição ideal de farinha de peixe por glúten de trigo na alimentação de dourada. Foram realizados dois ensaios, um de crescimento e um de digestibilidade. O ensaio de crescimento efectuou-se para determinar qual o nível máximo de substituição sem que os animais apresentassem diferenças significativas em termos de taxa de crescimento. O ensaio de digestibilidade teve como principal objectivo determinar qual das dietas testadas proporcionaria melhores valores de utilização digestiva por parte dos animais. Tendo em conta os resultados dos ensaios e as condições experimentais em que se realizaram, verificou-se que a substituição até 40% não afecta significativamente o desempenho zootécnico das douradas. ABSTRACT; The incorporation of alternative protein sources in fish diets has been the aim of many scientific experiments in animal nutrition. ln this study, the main objective was to evaluate the ideal level of wheat gluten incorporation in substitution of fishmeal in diets for gilthead sea bream (Sparus aurata L). To reach this objective, two experiments were carried out, in which growth and digestibility were studied. The aim of the growth experiment was to evaluate the maximum level of fish meal substitution by wheat gluten (20%, 40%, 60% and 80%), without affecting significantly the animals growth rate. The digestibility experiment took place to evaluate which animals presented better food utilization with the tested diets (20%, 40%, 60% and 80%). Observing the results of these two experiments, it was concluded that the substitution until 40% did not affect significantly the performance of the fishes.

Formação e desenvolvimento da bexiga gasosa em larvas de dourada (Sparus aurata Linnaeus 1758)

Tese de dout., Unidade de Ciências e Tecnologias dos Recursos Aquáticos, Univ. do Algarve, 1995

Estudo da doença de inverno em dourada (Sparus aurata L.) de cultivo a sul de Portugal

Dissertação de mest. em Aquacultura, Faculdade de Ciências do Mar e do Ambiente, Univ. do Algarve, 2003

Molecular biology of prolactin and prolactin receptor in a marine teleost: the sea bream(Sparus aurata)

Tese de dout. em Biologia, especialidade de Biologia Molecular, Unidade de Ciências e Tecnologias dos Recursos Aquáticos, Univ. do Algarve

Site fidelity and movements of gilthead sea bream (Sparus aurata) in a coastal lagoon (Ria Formosa, Portugal)

Short-time site fidelity and movements of gilthead sea bream (Sparus aurata) in a coastal lagoon were determined using passive acoustic telemetry. Nine fish, ranging from 20.1 to 32.5 cm total length, were surgically implanted with acoustic transmitters and monitored for up to 179 days. Minimum convex polygon areas ranged from 18,698.6 m(2) to 352,711.9 m(2). Home range sizes were small, with individuals using core areas on a daily basis. However, these core areas shifted within the study site over time towards the opening to the sea. Two different diel behaviors were recorded, with some individuals more active at night and others during day time. Some individuals also demonstrated homing abilities, returning to the capture site after being released more than 4 km away. (C) 2008 Elsevier Ltd. All rights reserved.

1H NMR-based metabolomics investigation on the impacts of feeding in aquaculture of Gilthead sea bream (Sparus aurata)

In questo lavoro di tesi sono stati analizzati campioni di orate (Sparus aurata) da acquacoltura allevate con differenti diete, commerciali o innovative, con lo scopo di verificare se le diverse formulazioni dei mangimi hanno un effetto sul profilo molecolare dei pesci. A tal proposito, è stata utilizzata la spettroscopia di Risonanza Magnetica Nucleare (1H NMR) accoppiata ad un approccio metabolomico poiché, rispetto ad altre tecniche, consente la determinazione simultanea di un’ampia classe di metaboliti che caratterizzano il campione attraverso la generazione di spettri che contengono un ampio spettro di informazioni. Questo lavoro di tesi si sposa bene con l’attuale tendenza di sviluppo dell’acquacoltura, che viene vista come uno strumento interessante per fornire cibo e migliorare la sicurezza alimentare, ma allo stesso tempo esso è in accordo anche con la sempre più elevata attenzione verso sostenibilità, qualità e conformità alle richieste dei consumatori, che sono oggi le principali tendenze nel settore alimentare. Negli ultimi anni si è assistito ad un ampio sviluppo dell’acquacoltura e questo ha portato alla necessità di ricercare strategie per migliorare l’efficienza, la produttività, ma anche la sostenibilità di questi sistemi. Questo ha condotto ad un elevato aumento delle ricerche riguardanti questi aspetti dell’acquacoltura, e l’impatto che la dieta ha sul metabolismo dei pesci è uno di questi. I dati spettroscopici sono stati interpretati attraverso analisi statistica multivariata, nello specifico attraverso l’analisi delle componenti principali, PCA, per individuare eventuali differenze significative tra i tre gruppi a seguito della diversa tipologia di alimentazione. Dal presente lavoro di tesi è stato possibile concludere che i campioni vengono distribuiti e classificati in funzione della dieta. Inoltre, è stato possibile individuare i metaboliti che maggiormente determinano questa separazione.

The effects of stocking density in physiological parameters and growth of the endangered teleost species piabanha, Brycon insignis (Steindachner, 1877)

This study investigated the effects of stocking density on the growth and fatty acid (FA) of Brycon insignis metabolism. Fingerlings (360) were distributed into eight ponds at two stocking densities (105 and 210 g/m(3)). The analysis of growth showed that the condition factor (K) and the coefficient of variation (CV) for body mass were not affected by stocking density. However, final body mass and length, specific growth rate (SGR), and weight gain (WG) were higher in the low stocking density group, which also presented a higher feed efficiency (FE) and survival (S). By contrast, muscle protein levels were higher in the high stocking density group. The plasma and muscle lipid content were not affected by stocking density, but fish reared at lower stocking density presented higher lipid concentration in the liver, with no differences in hepatosomatic index values. Even with the differences observed in metabolic and growth parameters, plasma cortisol was not affected by stocking density. The FA profile in the muscle and liver neutral fraction were not affected by stocking density, but the FA in the polar fractions differed between the two stocking densities. In the liver, total polyunsaturated fatty acids (PUFA) and PUFA n - 3 increased in higher stocking density, mainly due to an increase in docosahexaenoic acid (DHA). In addition, PUFA n - 6 were also increased in the higher stocking density group, mainly due to an increase in arachidonic acid (AA) and docosadienoic acid (22:2n - 6). In the muscle polar fraction, the saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) decreased in the animals from the higher stocking density group, and this reduction was compensated by an increase in PUFA n - 3 and PUFA n - 6, mainly the FA with 20-22 carbons (20:4n - 6: 22:4:n - 6; 22:5n - 6, 22:5n - 3, and 22:6n - 3). A different profile was observed for the C18 PUFAs, mainly 18:2n - 6 and 18:4n - 6, which were higher in the lower density stocking group. The data suggest that when living in high stocking density, B. insignis differentially utilizes the hepatic lipids as energy source and remodels the membrane fatty acids, with higher amounts of DHA in the polar muscle fraction compensated for by a decrease in MUFA. The zootechnical and physiological indices reveal that the lower stocking density group achieve overall better performance. (C) 2010 Elsevier B.V. All rights reserved.