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- Programming the metabolic gene expression in zebrafish juveniles (Danio rerio) by supra-physiological glucose level during embryogenesisPublication . Rocha, F.; Dias, J.; Engrola, S.; Gavaia, Paulo J.; Geurden, Inge; Dinis, Maria Teresa; Panserat, S.Using zebrafish as a model organism, assess the effect of high glucose levels during early embryonic stages as a lifelong moderator of metabolic pathways.
- Tolerance of zebrafish embryos to supra-physiologic yolk levels of glucosePublication . Rocha, F.; Dias, J.; Engrola, S.; Gavaia, Paulo J.; Dinis, Maria Teresa; Panserat, S.Once spawned and fertilized the oviparous fish eggs operate as closed systems; only respiratory gases, heat and negligible amounts of solutes and water are exchanged freely, as a result of an extremely low permeability of the egg surface membranes. Currently, the opportunities to exert a nutritional stimulus during a stage of high metabolic plasticity, such as fish embryogenesis, are restricted to maternal transfer and the onset of exogenous feeding.
- Age and growth of megrim, Lepidorhombus boscii, Risso of the portuguese continental coastPublication . Castilho, Rita; Dinis, Maria Teresa; Erzini, KarimThe first study of age and growth of four-spotted scaldfish, more commonly known as megrim (Lepidorhombus boscii, Risso), an important (by catch ) species of the Portuguese trawl fishery from the Atlantic coast is presented. The analysis was based on data obtained from a total of 609 specimens sampled between 1985 and 1986. Otoliths were used for age determination. The Von Bertalanf~, growth parameters were estimated using the non-linear fitting method: Lt (females)=440[ 1 -e -°-14(t+ 1.32) ] and Lt= 375 [ 1 -e -°~4(t+ 1.93) ] for males. L~ and to values are significantly different. The megrim grows allometrically (slope of length-weight regressions > 3 ). Females live longer and gain weight at a faster rate than males. Differences in growth between sexes become more apparent from the second year onwards.
- Evaluation of candidate probiotic strains for gilthead sea bream larvae (Sparus aurata) using an in vivo approachPublication . Makridis, P.; Martins, S.; Vercauteren, T.; Van Driessche, K.; Decamp, O.; Dinis, Maria TeresaAims: The aim of this study was to evaluate the effect of six bacterial strains on gilthead sea bream larvae (Sparus aurata). Methods and Results: Six bacterial strains isolated from well-performing live food cultures were identified by sequencing fragments of their 16s rDNA genome to the genus level as Cytophaga sp., Roseobacter sp., Ruergeria sp., Paracoccus sp., Aeromonas sp. and Shewanella sp. Survival rates of gilthead sea bream larvae transferred to seawater added these bacterial strains at concentrations of 6 +/- 0.3 x 10(5) bacteria ml(-1) were similar to those of larvae transferred to sterilized seawater and showed an average of 86% at 9 days after hatching, whereas, survival rates of larvae transferred to filtered seawater were lower (P < 0.05), and showed an average of 39%, 9 days after hatching. Conclusion: Several bacterial strains isolated from well-performing live food cultures showed a positive effect for sea bream larvae when compared with filtered seawater. Significance and Impact of the Study: The approach used in this study could be applied as an in vivo evaluation method of candidate probiotic strains used in the rearing of marine fish larvae.
- Osteological development and abnormalities of the vertebral column and caudal skeleton in larval and juvenile stages of hatchery reared solea senegalensis (kaup)Publication . Gavaia, Paulo J.; Dinis, Maria Teresa; Cancela, LeonorThe Senegal sole is a species recently adapted to aquaculture for which little information on larval development is available. This study was designed to describe normal skeletal development and the occurrence of skeletal malformations in Senegal sole reared in captivity. Eggs were collected from natural spawning, incubated until hatching and larvae reared to the juvenile stage in a closed recirculating system. Samples were collected throughout development at regular intervals from hatching to fully formed juveniles. Specimens were stained with alcian blue and alizarin red and observed for skeletal development and detection of anomalies. A high number of malformations were detected, both in the caudal complex and the vertebral column. About 44% of the individuals observed showed at least one malformation and the highest occurrence of deformities was observed in the caudal region and in the vertebral column. Accordingly, 28% of the total deformities identified in this study were detected at those sites and in adjacent arches and spines. The causes were not identified in this study, but the high incidence of malformations may reflect culture problems due to rearing and/or feeding conditions that affect skeletal development.
- Changes in plasma amino acid levels in a euryhaline fish exposed to different environmental salinitiesPublication . Aragão, C.; Costas, B.; Vargas-Chacoff, L.; Ruiz-Jarabo, I.; Dinis, Maria Teresa; Mancera, J. M.; Conceição, L. E. C.Previous studies have shown that Senegalese sole is partially euryhaline in the juvenile phase, being able to adapt to a wide range of salinities in a short-time period, due to changes at the osmoregulatory and metabolic level. This study aimed to assess the effects of acclimation of sole to a wide range of salinities, with a special emphasis on the role of plasma amino acids during this process. Sole juveniles were acclimated for 2 weeks to different salinities: 5, 15, 25, 38, and 55 g L−1. Plasma levels of cortisol, glucose, osmolality, and free amino acids were assessed at the end. Changes in plasma levels of cortisol, glucose, and amino acids indicate that fish reared at 5 and 55 g L−1 were facing extra energy costs. Amino acids seem to play an important role during salinity acclimation, either as energy sources or as important osmolytes for cell volume regulation.
- Cryopreservation of germ cells for the production of marine speciesPublication . Cabrita, Elsa; Martinez-Paramo, Sonia; Dinis, Maria TeresaGerm cell cryopreservation is a safe method to store and preserve genetic material. Cryobanks in aquatic species were developed with different aims, benefiting fish farming, from management of reproduction to genetic selection of sperm from males with high reproductive value. Research has been conducted on the development of protocols for new/problematic species, for commercial species to improve gamete quality during storage or for conservation purposes.
- Intra-adrenal interactions in fish: Catecholamine stimulated cortisol release in sea bass (Dicentrarchus labrax L.)Publication . Rotllant, J.; Ruane, N. M.; Dinis, Maria Teresa; Canario, Adelino V. M.; Power, DeborahThe effect of the catecholamines, adrenaline and noradrenaline, on sea bass (Dicentrarchus labrax) and sea bream (Sparus auratus) interrenal cortisol production was studied in vitro using a dynamic superfusion system technique. Increasing concentrations of catecholamines (10−6, 10−8 and 10−10 M) stimulated cortisol production in a dose-dependent manner, in sea bass only. The increase in cortisol production stimulated by adrenaline (10−6 M) and noradrenaline (10−6 M) was inhibited by sotalol (2×10−5 M), but not by prazosin suggesting that catecholamines stimulate cortisol release through the β-receptor subtype. To evaluate catecholamine-induced signal transduction in head kidney cells, measurements of cAMP production and [H3]myo-inositol incorporation were determined in head kidney cell suspensions. Adrenaline and noradrenaline (10−6 M) increased cAMP production, but had no effect on total inositol phosphate accumulation. These results indicate that catecholamines released from the chromaffin cells within the interrenal tissue may act as a paracrine factor to stimulate interrenal steroidogenesis in the sea bass.
- Farmed fish as a functional food: Perception of fish fortification and the influence of origin - Insights from PortugalPublication . Ribeiro, Ana Ramalho; Altintzoglou, Themistoklis; Mendes, Júlio; Nunes, Maria Leonor; Dinis, Maria Teresa; Dias, JorgeBeing a rich source of important nutrients, including highly digestible proteins, vitamins (A, D3), trace minerals (iodine, selenium) and n-3 long chain polyunsaturated fatty acids (n-3 LCPUFA), fish consumption is generally regarded as part of a healthy dietary pattern. Exogenous feeding in aquaculture unlocks the possibility to tailor fish composition with healthy valuable nutrients. However, the use of supplements in the fish feed during fish production may undermine consumers' perception opinion of these fortified products. The effectiveness success of a functional food is a combination of its efficacy and meeting consumers' expectations. A self-administered questionnaire was designed to assess consumers' preferences regarding fish consumption, and their perception of farmed seabream as a functional food. A high consumption rate of fish, (between daily, and a minimum of three times a week), was reported by 47% of the respondents. Freshness, flavour, quality and price were the four most valued attributes. Good acceptance of the fish fortification concept was observed (53%), as well as positive receptiveness to its consumption (50%). Anti-oxidants and omega-3 fatty acids were the most accepted compounds for fish fortification. Additionally, two consumer groups were established based on their high (HIG) or low (LIG) interest in fish origin (wild vs aquaculture). The LIG was more receptive to all aspects of fish fortification and showed willingness to buy and consume it. This suggests that fortified fish could be targeted to the LIG profile group, which represents 42% of the studied population. With appropriate communication, farmed fish may be a good candidate for functional food.
- Optimization of monoclonal production of the glass anemone Aiptasia pallida (Agassiz in Verrill, 1864)Publication . Leal, M. C.; Nunes, Carla; Engrola, S.; Dinis, Maria Teresa; Calado, RicardoSea anemones of genus Aiptasia are commonly used as biologicalmodels for biotechnological and molecular research. They are also employed to study the symbiotic interactions between cnidarians and zooxanthellae. In addition, Aiptasia is an important prey for the culture of the highly priced ornamental nudibranch Aeolidiella stephanieae. The purpose of this study was to determine the best culture conditions for establishing large monoclonal populations of this anemone. This study analyzed the effect of the following factors on Aiptasia pallida propagation and biomass increase throughout 60 days: initial anemone stocking density, light regimes, water temperature and different live diets. The best results were achieved at a higher water temperature (26 °C) and in darkness. Artemia nauplii were a better live prey than Artemia metanauplii to maximize biomass production, with lower initial anemone stocking densities maximizing propagation ratios. This research provides initial data that enables a large-scale production of monoclonal A. pallida, either to be used as a biological model, for the screening of new natural products or in the aquaculture of ornamental sea slugs.