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- Optimisation of algorithms to predict biomass and size distribution of fish reared in cages, using the Aquanetix production management softwarePublication . Soares, Diogo Alexandre Marques; Cabrita, Elsa Alexandra Martins e Silva; Thomaz, Diogo FernandesThis Thesis aims to optimise the algorithms used to estimate actual biomass and weight distribution in gilthead sea bream (Sparus aurata) and European sea bass (Dicentrarchus labrax) cages by the Aquanetix Software. For this, we first try to understand the practical functioning of a fish farm that uses cages and how can the used procedures affect the collection of data or its veracity. Then, we use the data collected by the company and the observations made on the field in order to attempt the optimization of the algorithms that estimate biomass and weight distribution of the Aquanetix Software. The data parameters analysed were the moving average of the estimated biomass, mortality, density, number of fish and mean weight. Two time periods were tested for the moving average of the estimated biomass, at fourteen and thirty days prior to the first harvest. Between these two periods, the one at thirty days seemed to provide the better biomass estimation. Mortality and density showed to have no apparent influence in the deviations found between the biomass estimations and the total biomass harvested. The number of fish was found to be overestimated in the majority of the studied cages (n=7), with the exception of only cage 109. The mean weight was found to be underestimated in the majority of the studied cages, with the exception of only cage 03. At the end, all proposed goals were achieved. In conclusion, every cage of sea bream studied (n=4) shows an under estimation of the mean weight of fish at first harvest, which in turn leads to an underestimation of the biomass. This suggests that every sea bream cage is currently being under fed, most likely, due to a fault on the feeding model which is probably overestimating the specific feeding rate (SFR) for this species. Alterations should be made to the feeding model in order to resolve this unbalance. The results for the sea bass cages were shown to be more inconclusive since all of the studied cages for this species (n=3) appear to have no common reason to explain the errors found for the estimation of their biomass.
- Vertebrate SLRP family evolution and the subfunctionalization of osteoglycin gene duplicates in teleost fishPublication . Costa, Rita; Brazona, Rute Sofia Tavares Martins; Capilla, E.; Anjos, Liliana; Power, DeborahBackground Osteoglycin (OGN, a.k.a. mimecan) belongs to cluster III of the small leucine-rich proteoglycans (SLRP) of the extracellular matrix (ECM). In vertebrates OGN is a characteristic ECM protein of bone. In the present study we explore the evolution of SLRP III and OGN in teleosts that have a skeleton adapted to an aquatic environment. Results The SLRP gene family has been conserved since the separation of chondrichthyes and osteichthyes. Few gene duplicates of the SLRP III family exist even in the teleosts that experienced a specific whole genome duplication. One exception is ogn for which duplicate copies were identified in fish genomes. The ogn promoter sequence and in vitro mesenchymal stem cell (MSC) cultures suggest the duplicate ogn genes acquired divergent functions. In gilthead sea bream (Sparus aurata) ogn1 was up-regulated during osteoblast and myocyte differentiation in vitro, while ogn2 was severely down-regulated during bone-derived MSCs differentiation into adipocytes in vitro. Conclusions Overall, the phylogenetic analysis indicates that the SLRP III family in vertebrates has been under conservative evolutionary pressure. The retention of the ogn gene duplicates in teleosts was linked with the acquisition of different functions. The acquisition by OGN of functions other than that of a bone ECM protein occurred early in the vertebrate lineage.
- Influence of sperm density on cryopreservation outcomes in sturgeonPublication . Nascimento, João Pedro Oliveira; Pedro, Paulo Zaragoza; Dzyuba, BorysThe goals of this experiment were the establishment of procedure for variation of spermatozoid concentration without compromising quality, establishment of highest cell concentration without decreasing post-thaw motility by routine freezing protocol and influence of ploidy level. It was used sperm from sterlet sturgeon (Acipenser ruthenus, n=6), Siberian sturgeon (Acipenser baerii, n=6) and from Russian sturgeon (Acipenser gueldenstaedii, n=4). It was tested a method of increasing concentration of spermatozoa by centrifuging with the following conditions (300 x g, 10 min, 4ºC and 300 x g, 20 min, 4ºC). To find the ideal concentration, it was tested 4 dilutions (1:1, 1:4, 1:9 and 1:49) and 2 controls (one control with spermatozoa without being centrifuged and another control with concentrated spermatozoa without the addition of seminal fluid). To perform these 4 dilutions, the concentrated spermatozoa was diluted with seminal fluid (SF). Then, the sperm was diluted in a cryoprotective medium containing 10% methanol and frozen by a conventional freezing protocol. It was measured the concentration of spermatozoa and motility parameters. It was determined the critical concentration of sperm in the straw where it was known that relative motility was 50% by performing a simple regression line. Spermatozoa after centrifugation had no changes in its quality and it was possible to increase concentration up to 10 times the initial concentration. For post-thaw spermatozoa, the highest motilities were obtained in samples with concentrations lower than 1 x 109 spz mL-1 for all three species (57.5 % for sterlet sturgeon, 40% for Siberian sturgeon and 20% for Russian sturgeon). The critical concentrations in the straw for when we know the relative post-thaw motility is 50% was 1.05 x 109 spz mL-1 for sterlet, 0.92 x 109 spz mL-1 for Siberian sturgeon and for Russian sturgeon was 1.17 x 109 spz mL-1. Regarding motility parameters, the concentrations lower than the critic level had higher VCL values (164 μm s-1 for sterlet sturgeon, 179.26 μm s-1 for Siberian sturgeon and 145.48 μm s-1 for Russian sturgeon). There was significant difference (p < 0.05) when comparing the velocities between the spermatozoa with concentration lower than critic level and higher than critic level in sterlet sturgeon and Siberian sturgeon but not in Russian sturgeon. Our results show a dependency of the concentration and spermatozoa size in cryopreservation outcomes.
- Optimization of a sperm cryopreservation protocol for spotted wolffish (Anarhichas minor Olafsen, 1772)Publication . Santana, João Paulo Ribeiro Proença; Cabrita, Elsa; Santos, José Beirão dosSpotted wolffish is a potential candidate for cold water aquaculture, presenting high growth rates in captivity, good fillet yielding and a valuable and tasty meat. Reproduction in captivity is dependent on in vitro fertilization, however, low sperm volume with relatively low cell concentration and the lack of gametes synchronization (simultaneous availability of mature eggs and sperm) represent a challenge for the aquaculture industry. In this context, it is crucial the development of protocols, such as sperm cryopreservation, that allow sperm storage and maximization of its use. Sperm was diluted in a solution described by Kime and Tveiten (2002), and four sequential experiments were conducted. First, three different cryoprotectants (DMSO; 1, 2-propanediol; and methanol) at different concentrations (5, 10, and 20%) were tested for their toxicity. Second, sperm was cryopreserved in 0.5ml straws, at different distances from the liquid nitrogen (1.5, 2.5, 4.5, and 7.5cm) that correspond to different freezing rates. Afterwards, two different thawing rates (1min at 5ºC; and 25s at 10ºC) were tested. Finally, the fertilization capacity of cryopreserved sperm was tested against fresh, and cryopreserved and then washed sperm. The ratio of eggs with normal cell divisions, abnormal divisions or undeveloped were counted at the two-cell division stage. The trial on cryoprotectants toxicity revealed no differences between the control samples and cryoprotectants at concentration up to DMSO 10%, 1, 2-propanediol 10%, and methanol 20%, thus, these were chosen to use on the freezing trial. Motility values after freezing decreased for all the cryoprotectants, however, methanol revealed to have the lowest protective capacity and DMSO the highest throughout all the freezing rates, while propanediol presented the best results when freeze at 4.5 cm from liquid nitrogen. The thawing trial was carried using only DMSO 10% and 1, 2-propanediol 10%, revealing slight differences between the two temperatures. However, the best results were obtained using DMSO 10%. For the fertilization trial we selected the aforementioned cryoprotectant and thawing at 5ºC for 1min. Cryopreserved sperm showed lower fertilization capacity at a concentration of 5x104 spz/egg compared with fresh sperm. Nevertheless, at a concentration of 5x105 spz/egg, similar fertilizations rates to the fresh sperm were obtained. There was no improvement in the fertilization rates after washing the sperm to remove the cryoprotectant. An over dosage of DMSO revealed minor effects in abnormal divisions and lower number of developed eggs. To cryopreserve spotted wolffish sperm it is recommended that sperm is diluted on the extender described by Kime and Tveiten (2002), containing 10% DMSO, loaded on 0.5ml straws, freeze at a height of 4.5 or 7.5cm from liquid nitrogen for 10min and thawed for 1min at 5ºC. To obtain fertilization ratios equivalent to those obtained with fresh sperm, in vitro fertilization should be performed with a concentration of 5x105 cryopreserved sperm cells per egg. DMSO did not affect the eggs in the tested conditions during the contact time of 4 hours.
- Perfil e recrutamento dos cuidadores de idosos institucionalizados na região do AlgarvePublication . Manuel, Soraia Cristina Gonçalves; Gonçalves, Gabriela; Braz, NídiaNas últimas décadas temos assistido a um progressivo aumento da esperança média de vida. É certo que essa evolução não é igual em todos os países, mas o aumento é constante. Esta alteração traz consigo diversas mudanças sociais, políticas, demográficas, às quais a sociedade tem de se adaptar. Com o aumento do índice de envelhecimento, existem mais idosos, muitos terão autonomia para fazer as suas atividades diárias e outros, devido às vicissitudes da vida e às alterações biológicas e físicas não terão. Como tal, é necessário criar-se estruturas que apoiem as famílias, como por exemplo, lares, serviços de apoio domiciliário e centros de dia. Nestes locais trabalham diversos profissionais, nomeadamente os cuidadores formais de idosos, que foram o alvo deste estudo e, sobre os quais analisamos o perfil de competências valorizadas pelos responsáveis das instituições com base nos processos de recrutamento e seleção e desenvolvimento de competências. Analisando as entrevistas feitas a 18 instituições da região do Algarve, 95% dos cuidadores formais são do género feminino e 5% do género masculino, a média de idades é 45.8 anos, 67% é natural da região sul de Portugal, 52% é casado/a ou vive em união de facto, 33% tem dois filhos, 38% tem o 3.º ciclo do ensino básico e 14% possui experiência na função. As principais conclusões que se retiram do estudo são que, apesar da baixa validade preditiva da entrevista, este é o instrumento mais utilizado pelos responsáveis das instituições nos processos de recrutamento e seleção; apenas 44 cuidadores possuíam experiência na função antes de iniciar funções na instituição; a formação é vista como importante mas centra-se em aspetos técnicos e relacionados com a função e descura um pouco as competências necessárias de um cuidador formal de idos