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Microalgae are one of the most promising groups of functional ingredients for inclusion in microdiets for Senegalese sole (Solea senegalensis) larvae, supplying components with anti-oxidant effects that may be important during an accelerated stage of development where excessive reactive oxygen substance production leading to oxidative stress may occur. The diatom Phaeodactylum tricornutum complies with such potential since it is rich in fucoxanthin, a carotenoid with demonstrated antioxidant activity. This study aimed at determining the effect of dietary P. tricornutum supplementation on the growth performance, survival and levels of oxidative stress of Senegalese sole postlarvae. Four dietary treatments were tested: a commercial microdiet, used as control, and three experimental variants where P. tricornutum was included (1) whole cells at 5%-WP5, (2) broken cells at 5%-BP5 and (3) broken cells at 10%-BP10. At the end of the trial, no significant differences were found in growth performance of larvae fed diets where P. tricornutum was included at 5% (WP5 and BP5) and the commercial control. However, larvae from the BP10 treatment had a significantly higher dry weight than larvae from the remaining treatments. Moreover, the experimental diets had no significant effects on oxidative stress. Nonetheless, lipid peroxidation levels were significantly higher in smaller larvae fed diets where P. tricornutum whole cells were included, relatively to the commercial control. The results of the present study demonstrate that P. tricornutum broken cell biomass has the potential for inclusion in weaning microdiets for Senegalese sole, increasing larval growth performance at an inclusion level of 10 %. European Union European Commission [613588] info:eu-repo/semantics/publishedVersion

Senegalese sole (Solea senegalensis) production presents several nutritional challenges, making this species a good candidate to study the dietary potential of bioactive compounds. Since proper nutrition plays a fundamental role in fish biology, it is necessary to further investigate species-specific and well-balanced diets in order to improve Senegalese sole juvenile farming. Algae have antioxidant properties, high-quality dietary protein, and are a source of bioactive compounds. This study evaluates the effects of dietary microalgal inclusion in both health status and growth performance of Senegalese sole post-larvae. Individuals 41 days after hatching (DAH) were randomly distributed among 12 tanks and four experimental diets were randomly distributed by triplicate groups. A basal diet served as CTRL and the experimental diets were formulated to include 3% of each of the algal biomass (CHLO, Chlorella sp. from heterotrophic production; PHAEO, Phaeodactylum sp.; and NANNO, Nannochloropsis sp.). At 50 DAH, 20 post-larvae/tank were collected and homogenized for analysis of immune and oxidative status, and at 61 DAH the total length, dry weight, and survival were assessed. No changes were observed in survival and total length of individuals, post-larvae fed NANNO, and CHLO dietary treatments increased dry weight at 61 DAH compared with those fed CTRL. While post-larvae immune status was apparently not altered by dietary treatments at 50 DAH, the total glutathione content decreased in fish fed PHAEO and CHLO dietary treatments compared to control diet. The observed results on improvement of growth performance without adverse effects on the immune status and decrease of endogenous total glutathione point to the fact that Nannochloropsis sp., Phaeodactylum sp., and Chlorella sp. could work as potential candidates for inclusion in microdiets for Senegalese sole. VALORMAR project - Compete 2020 [POCI-01-0247-FEDER-024517]; Lisboa 2020; CRESC Algarve 2020; Portugal 2020; European Union through European Regional Development Fund; Foundation for Science and Technology (FCT)Portuguese Foundation for Science and TechnologyEuropean Commission [UIDB/04423/2020, UIDP/04423/2020]; FCT, PortugalPortuguese Foundation for Science and TechnologyEuropean Commission [SFRH/BD/108243/2015, PD/BDE/129262/2017, IF/00197/2015] info:eu-repo/semantics/publishedVersion

Senegalese sole (Solea senegalensis) is a highly valuable flatfish species targeted for aquaculture diversification in Southern-European countries. Although its adaptation to captivity was foreseen in the 1970´s, its commercial production at a relevant industrial scale is extremely recent. One of the factors causing this delay in commercialisation was a severe bottleneck occurring during weaning, where incipient larval growth performances and survivals were impairing farming during the first decades of farming. However, a significant evolution has recently occurred for Senegalese sole weaning, with larval growth rates, survivals and quality drastically increasing, and good results becoming more reproducible. These progresses were only possible following significant R&D efforts leading to increased knowledge on larval nutritional physiology, weaning strategies, feeding practices and microdiet formulation and production. To this end, this work reviews the advancements that contributed for the evolution occurring in Senegalese sole weaning during the last decades. This overview shows that, for instance, while in the year 2000 larval weaning would only be achieved at around 60 days after hatching (DAH), with fish achieving 1 g (wet weight basis) at around 120 DAH, nowadays it is possible to perform an early weaning starting immediately after settling (15 DAH) and achieving 1 g at 65 DAH. Future perspectives on Senegalese sole weaning should target an optimisation of microdiet nutritional and physical properties to a further adequacy for the pelagic larvae, where the predatory capacity is reduced and lower particle sizes lead to fast and high nutrient leaching. Nevertheless, this work shows that early life-feed replacement is a reality for Senegalese sole, although it remains uncertain if it will ever occur at the onset of exogenous feeding.

Dietary phospholipids' (PLs) content, origin, and profile are known to affect fish development and reproductive performance, but their effects in zebrafish (Danio rerio) nutrition are still poorly investigated. Therefore, this study aimed to assess the effect of practical microdiets containing plant-based and marine PL sources in zebrafish growth, survival, skeletal development, and reproductive performance. Reproductive performance was evaluated according to sperm motility, number of eggs, egg morphometry, hatching rate, and offspring standard length at 5 days postfertilization (dpf). For this purpose, seven microdiets were used, where two control diets were tested along with a supplementation with soybean lecithin (SL) as a plant-based PL source, and krill oil (KO) and copepod oil (CO) as marine PL sources, or in combinations (SLCO and SLKO). KO supplementation decreased larval growth performance and induced severe skeletal anomalies. SL supplementation reduced sperm total motility but improved offspring length at 5 dpf. CO supplementation increased sperm motility and the number of spawned eggs. Our results showed that a careful selection of the origin of dietary PL sources for microdiet formulation is critical to ensure adequate skeletal development and reproductive success. This study contributes to the improvement of zebrafish microdiet formulation and optimization of zebrafish husbandry practices. FEDER through PO Algarve 21 [23000-ZEBRAFEEDS] Portuguese Foundation for Science and Technology (FCT)Portuguese Foundation for Science and Technology [SFRH/BD/97466/2013] Foundation for Science and Technology (FCT)Portuguese Foundation for Science and Technology [UID/Multi/04326/2019] CRESC Algarve 2020 [EMBRC.PT ALG-01-0145-FEDER-022121] COMPETE 2020 [EMBRC.PT ALG-01-0145-FEDER-022121] info:eu-repo/semantics/publishedVersion

Larvae and early juveniles of fast-growing fish species show tremendous growth potential, leading to higher requirements for protein, high-unsaturated fatty acids, and other nutrients. Several commercial weaning diets with relatively high success have been developed for low/moderate-growing species; however, additional challenges are outlined to meet growth potential and energy requirements of such fast-growing species. The objective of the present study was to evaluate two commercial microdiets for marine fish, one having simultaneously a very high protein and high lipid contents (HIGH), and another (MOD) with a high protein and moderate lipid content, in a growth performance trial with greater amberjack post-larvae from 33 to 78 days after hatching. Moreover, histological preparations of liver, anterior and posterior intestine were assessed for hepatic and intestinal lipid inclusions quantification and gut epithelial brush height measurement. Activities of the digestive enzymes: pepsin, trypsin, chymotrypsin, lipase and amylase were also analyzed. Post-larvae fed HIGH microdiet exhibited higher final weight and lower feed conversion ratio that those fed on MOD microdiet. Liver displayed a higher level of lipid inclusions for the MOD diet than for HIGH diet. Moreover, enterocytes of posterior intestine presented a much higher level of supranuclear vacuoles for the HIGH diet compared to MOD diet. The lower Trypsin/Chymotrypsin ratio observed at the end of the experiment in larvae fed on MOD diet may indicate a deficiency in protein of this diet. Together, these results support that larvae of greater amberjack, and likely other fast-growing marine fish species, require high protein–high lipid microdiets. The use of microdiets developed targeting slower growing marine species may lead to sub-optimal performances in fast-growing larvae., This study was undertaken by Project WEANTUNA supported by Eurostars (E! 7994) and co-financed by FEDER through PO Algarve 21 in the framework of QREN 2007-2013 (30200).

Zebrafish is a model species with a high variability of feeding regimes among fish facilities. The use of live feeds for early life stages is a common practice, and few studies have focused early weaning into microdiets. The lack of standardized feeding protocols among research facilities promotes discrepancies in biological performances, and few studies relate dietary regimes to zebrafish development. The objective of this work was to assess the effect of an early transition into microdiets in zebrafish development by evaluating growth, survival, reproductive performance, and skeletal anomalies. These parameters were assessed in one group exclusively fed on Artemia nauplii and two groups fed on microdiets (commercial and experimental). Results showed that an early weaning with the two microdiets significantly improved zebrafish growth and reproductive performance, while a decrease in incidence of vertebral column anomalies was observed. A high survival was also maintained in fish fed microdiets at an early developmental stage when comparing to exclusive Artemia nauplii feeding. In conclusion, early weaning with high quality microdiets is beneficial for zebrafish growth, reproductive performance, and skeletal development, contributing to the standardization of zebrafish husbandry practices. FEDER through PO Algarve 21 in the framework of QREN - 3000-ZEBRAFEEDS. Portuguese Foundation for Science and Technology -SFRH/BD/974662013. info:eu-repo/semantics/publishedVersion

Broodstock rearing conditions and handling procedures should be optimized in aquaculture species in order to benefit fish welfare and guarantee optimal conditions for spawning. In teleosts, basal cortisol levels display daily rhythms, oscillating along the 24 h of the day. In this sense, handling fish at different moments of the day may lead to different stress responses. The present study aimed at investigating the optimal rearing conditions for Senegalese sole broodstock, considering ambient light intensity and handling time. The optimal light intensity (50, 100 or 200 lx) was investigated by measuring fish cortisol levels and monitoring locomotor activity rhythms under each intensity tested. Results showed a significant increase in cortisol levels of fish exposed to 200 lx, when compared to values obtained under 100 lx, accompanied by changes in locomotor activity rhythms in both tanks under study. These results suggested that 200 lx may be too high as light intensity for this species, whereas 100 lx seems to be more adequate. Also, daily rhythms of stress response were investigated in breeders from different origins (Wild and first generation, G1). Basal cortisol levels and cortisol stress response after an acute stressor (air exposure) were monitored at two distinct moments of the day (Mid-Light and Mid-Dark). Basal levels were higher during the day in the wild group, while G1 fish seemed to have lost the daily fluctuations in basal cortisol plasma levels, as well as their daily rhythms of locomotor activity. Both groups showed lower stress responses during night-time, an indication that this is an adequate period of the day to handle this species. Senegalese sole breeders born in captivity presented more pronounced stress responses when compared to wild fish, reflecting their different life history in terms of stress challenges. FP7/SME/2008/1; UID/Multi/04326/2019; DL 57/2016/CP1361/CT0007; DL 57/2016/CP1361/CT0033 info:eu-repo/semantics/publishedVersion

Summary The objectives of this study were to determine the effects of a tailor made purified diet (PUR) supplemented with phosphatidylcholine (PC) or phosphatidylethanolamine (PE) on the reproductive performance, gamete quality, embryo development and growth as well as skeletal malformations of the larvae in zebrafish, Danio rerio. The PUR diet was tested against a commercial diet as a negative control (CD). For each diet, one experimental group of eight adult zebrafish (three males, five females) was maintained in 3-L tanks in a water recirculating system under continuously controlled conditions (photoperiod 14 h light: 10 h dark; water flow rate 7.3 L h−1; 28°C; pH 7.5; 700 μS). Two trials were performed to confirm the results. The CD treatment resulted in the highest final weight of the breeders (0.60 ± 0.18 g); however, the fish failed to spawn. The PC supplemented diet promoted a reasonable final weight of the breeders (0.48 ± 0.10 g) similar to the CD and with a mean hatching rate of 93.80 ± 6.9%. Nevertheless, the PC treatment induced the highest rate of skeletal malformations in progeny (82.40 ± 4.1%), which could be related to the low larval survival at 28 days post-fertilization (dpf) (48.00 ± 11.3%). In comparison to the control groups, broodstock fed the PE diet showed the best results in sperm quality, which was revealed by higher total and progressive motility and higher velocities than sperm from males fed the CD and PUR diets. Furthermore, the PE group produced significantly higher egg diameters (1.20 ± 0.05 mm) when compared to the PUR diet (1.14 ± 0.03 mm). This study highlights the importance of phospholipids in zebrafish gamete quality, and that supplying PE in broodstock diets can improve the reproductive performance of zebrafish.

The present study reveals the first characterization of the plasma melatonin rhythms of the meagre (Argyrosomus regius) under aquaculture conditions. Melatonin levels were monitored during a 24 h cycle under a photoperiod of 16 L:8D and under constant darkness (DD), respectively to characterize the daily rhythm of this indoleamine and to test its endogenous origin. Besides, to identify which light intensities are perceived as night or day by this species, the degree of inhibition of nocturnal melatonin production caused by increasing intensities of light was tested (3.3, 5.3, 10.5, and 120 μW/cm2), applying 1 h light pulses at Mid-Dark. The result for melatonin daily rhythm in plasma showed a typical profile: concentration remained low during all daytime points, increasing greatly during dark points, with maximum values at 16:00 and 22:00 h, zeitgeber time. Under DD conditions, the plasma melatonin profile persisted, with a similar acrophase but with a lower amplitude between subjective day and night periods, indicating this rhythm as being endogenously driven. Moreover, meagre seemed to be very sensitive to dim levels of illumination during the night, since an intensity of just 3.3 μW/cm2 inhibited melatonin production. However, only the pulse of 5.3 μW/cm2 caused a melatonin drop till daytime concentrations. Thus, the threshold of light detection by the pineal organ was suggested as being located between 3.3 and 5.3 μW/cm2. Such results are an added value for this species biology knowledge, and in consequence to its adaptation to aquaculture conditions, allowing the improvement of culture husbandry protocols.

In diet formulation for fish, it is critical to assure that all the indispensable amino acids (IAA) are available in the right quantities and ratios. This will allow minimizing dietary AA imbalances that will result in unavoidable AA losses for energy dissipation rather than for protein synthesis and growth. The supplementation with crystalline amino acids (CAA) is a possible solution to correct the dietary amino acid (AA) profile that has shown positive results for larvae of some fish species. This study tested the effect of supplementing a practical microdiet with encapsulated CAA as to balance the dietary IAA profile and to improve the capacity of Senegalese sole larvae to utilize AA and maximize growth potential. Larvae were reared at 19 A degrees C under a co-feeding regime from mouth opening. Two microdiets were formulated and processed as to have as much as possible the same ingredients and proximate composition. The control diet (CTRL) formulation was based on commonly used protein sources. A balanced diet (BAL) was formulated as to meet the ideal IAA profile defined for Senegalese sole: the dietary AA profile was corrected by replacing 4 % of encapsulated protein hydrolysate by CAA. The in vivo method of controlled tube-feeding was used to assess the effect on the larvae capacity to utilize protein, during key developmental stages. Growth was monitored until 51 DAH. The supplementation of microdiets with CAA in order to balance the dietary AA had a positive short-term effect on the Senegalese sole larvae capacity to retain protein. However, that did not translate into increased growth. On the contrary, larvae fed a more imbalanced (CTRL group) diet attained a better performance. Further studies are needed to ascertain whether this was due to an effect on the voluntary feed intake as a compensatory response to the dietary IAA imbalance in the CTRL diet or due to the higher content of tryptophan in the BAL diet.

Senegalese sole (Solea senegalensis) is a highly-valuable flatfish species with interest for diversification of aquaculture in Mediterranean countries. Unlike other fish species known to have a high dietary DHA requirement during the larval stage, several studies have suggested dietary DHA could play a minor role for Senegalese sole during the early developmental stages. This suggestion was recently supported by studies that indicated an ability of Senegalese sole to biosynthesise DHA from its precursors during the larval period. However, it is still uncertain if Senegalese sole post-larvae can effectively grow on low dietary DHA levels during weaning. Moreover, recent studies focusing on the juvenile phase of Senegalese sole have suggested a possible impairment of this species to efficiently digest or absorb high dietary lipid levels. Yet, if a reduction of dietary lipid levels would affect a normal development of Senegalese sole during the early stages remains to be established. Therefore, this study aimed at determining if a reduction of dietary DHA and lipid levels would affect Senegalese sole performance and lipidme-tabolism duringweaning and post-larval period. In this study, Senegalese sole post-larvae were reared according to four dietary treatments: low lipid levels (treatments LFAT and LFAT_DHA) and moderate lipid levels (MOD-FAT and MODFAT_DHA). DHA levels in LFAT_DHA and MODFAT_DHA diets were higher than in LFAT and MOD-FAT diets, respectively. Subsequently, effects of experimental diets on Senegalese sole post-larval growth, survival, fatty acid composition and histopathological condition of intestinal and liver tissues were evaluated. Results showed that feeding on diets with low DHA and lipid levels significantly reduced the growth performance of Senegalese sole post-larvae. However, at the end of the experimental period, no significant differences were observed for post-larval survival in response to dietary treatments. In overall, this study disadvises that weaning diets for Senegalese sole post-larvae should contain low DHA and lipid levels, as a reduction of these levels may compromise post-larval growth performance.Statement of relevance: Determining essential fatty acid requirements in marine fish larvae is of utmost importance for the aquaculture industry, contributing to fulfil the growth potential of farmed species. In the case of Senegalese sole, a highly valued species farmed in Mediterranean countries, it may have the capacity to biosynthesise DHA from its precursors during the larval stage. However, the inclusion of DHA-rich oils in weaning diets is costly, considerable savings could be achieved by replacing DHA-rich oils by common fish oils in weaning diets for this species. Furthermore, Senegalese sole has also been shown a poor ability to deal with high dietary lipid levels during the juvenile stage. However, no studies have addressed this capacity in Senegalese sole larvae. This study comprises an evaluation on the effects of reducing dietary DHA and lipid levels during Senegalese sole weaning by integrating an assessment of these effects on post-larval growth, survival, fatty acid composition and histopathological condition. (C) 2016 Elsevier B.V. All rights reserved. Project SOLEAWIN (310305/FEP/71)

Mestrado em Engenharia Física The main objective of this work is the development of a hardmetal components (WC-6%Co) recovery method by thermal deposition process. The thermal deposition technique used was HVOF (high velocity oxygen-fuel). The HVOF enables depositions of thick coatings (100-500 µm) with low porosity levels, high hardness and excellent adhesion. Before deposition, hardmetal samples with different geometries (plates and cylinders) were finished in order to have different roughness. The influence of these parameters in adhesion was studied. After this step, different re-sintering temperatures were used, in order to determine which one allows to obtain the maxima densification, elements distribution and metallurgical bonding. The re-sintering promotes the densification of the coating, with an increase of its hardness and metallurgical bonding formation. The inclusion of an intermetallic layer was tested along with different layer parameters. In liquid phase sintering (1383 and 1455 ºC) a complete densification of the coating occurred, while a bonding between the substrate and the coating only partially happened. The results of SEM/EDS show low levels of porosity and a complete and uniform distribution of the elements of the alloy. The cylindrical samples without intermetallic layer showed the lowest level of porosity and best metallurgical bonding. When the substrate surface was polished (Ra = 0.05 mm) lower levels of porosity and greater metallurgical bonding were found for both geometries. Taking into account the results obtained in this study, we can conclude that the implementation of this process is appropriate for cylindrical components with a polished surface. In these components the intermetallic layer is unnecessary and punctual defects like pores can be repaired with this process. O presente trabalho teve como objetivo o desenvolvimento de um processo de recuperação de componentes de metal duro (WC-6%Co) por projeção térmica, especificamente por HVOF (high velocity oxygenfuel). Esta técnica possibilita a obtenção de revestimentos espessos (100-500 µm) com baixos níveis de porosidade, elevada dureza e excelente adesão ao substrato. Foram testados diferentes tipos de acabamentos superficiais de modo a avaliar qual a superfície onde se obtém melhor adesão do filme e diferentes temperaturas de ressinterização, para garantir a ligação metalúrgica. A ressinterização permitiu a densificação do filme e o consequente aumento da sua dureza bem como a ligação metalúrgica do filme ao substrato. Procedeu-se também à variação da geometria dos provetes (placas e cilindros) e estudou-se ainda a variação da espessura e rugosidade de uma camada de interligação de níquel-alumínio (NiAl). Nas placas, a sinterização na presença de fase líquida (1383 e 1455 °C) deu origem a uma densificação completa do filme e apenas uma ligação metalúrgica parcial entre o revestimento e o substrato. Os resultados obtidos por SEM/EDS mostram um baixo nível de porosidade e uma difusão completa e uniforme dos elementos de liga. Nas amostras cilíndricas sem camada de interligação ocorreu uma ligação metalúrgica perfeita não sendo detetada qualquer porosidade, tendo sido observada uma elevada uniformidade no revestimento. Os melhores resultados a nível de porosidade e ligação metalúrgica foram obtidos nas superfícies polidas (Ra= 0,05 mm) em ambas as geometrias. Face aos resultados obtidos, é possível concluir que a implementação do processo desenvolvido a nível industrial, pode ser realizada em componentes cilíndricos e com superfície polida. Nesta geometria e com acabamento polido foram obtidas ligações metalúrgicas perfeitas e sem presença de porosidade, não sendo necessária a inclusão da camada de interligação de NiAl. O estudo realizado também permitiu verificar que esta técnica se poderá implementar em defeitos localizados, nomeadamente poros superficiais.

(Tesis) Ingeniero en Computación e Informática Actualmente en la empresa Anglo American División El Soldado, se presentan problemas al momento del desarrollo de los procesos de capacitación correspondiente tanto a trabajadores que deben realizarla, como a los encargados de tramitar los documentos (administración, supervisores y gerentes),por lo que como proyecto informático tenemos el objetivo reducir el tiempo que el personal de la organización ocupa en los procesos de capacitación (generación, toma y resultados), a partir de una solución informática propia para la empresa con el fin de tener un producto diferenciador de otro que se pueda implementar y que cumpla con las expectativas del cliente.