Sapientia
Repositório Científico da UAlg
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Sperm characterization of endangered leuciscids endemic from the iberian peninsula: gamete storage as a tool for helping ex-situ breeding programs
Publication . Hernandez, Ana; Sousa-Santos, Carla; Gil, Fátima; Guerreiro, Pedro Miguel; Cabrita, Elsa; Gallego, Victor
Populations of freshwater fish species endemic to the Iberian Peninsula have been declining since the mid-20th century, and several types of actions (from in situ to ex situ measurements) have been applied over the past decades for preserving these species. However, limited knowledge about their reproductive biology makes it necessary to investigate different aspects of the reproductive cycle for improving breeding programs. The main objectives of this work were to advance knowledge concerning sperm kinetics and spermatozoa morphology and to develop protocols for the short- and long- term storage of gametes. Populations of different endangered leuciscid species (Anaecypris hispanica, Iberochondrostoma lusitanicum, Achondrostoma occidentale, and Squalius aradensis) were sampled during the spring of 2022 both in captive populations kept at Aquário Vasco da Gama (AVG) and in wild populations from different Portuguese rivers. Sperm samples were collected and sperm motion parameters were assessed, for the first time, for these four species. Sperm kinetics differed between species in motility and velocity traits, also showing a different number of sperm subpopulations. The longevity of sperm (swimming period) was also different among species: the shortest period was obtained for the wild population of S. aradensis (values close to zero at 40 s), and the longest swimming period for the captive population of I. lusitanicum (values close to zero at 120 s). Furthermore, different storage trials were carried out diluting the sperm in a extender solution (75 mM NaC1, 70 mM KC1, 2 mM CaC12, 1 mM, MgSO4, l0 mM Hepes, pH 8) at a ratio 1:20 (sperm:extender). Sperm quality (>40% of motile cells) was kept for a maximum of four days of storage, depending on the species. In addition, new cryopreservation protocols (using DMSO, Methanol and/or egg yolk) were tested for cryobanking the sperm of these threatened species. Cryopreserved samples showed significantly lower motility when compared with fresh samples, and the best results were obtained for I. lusitanicum, reaching 20% of motile cells after thawing using 10% of DMSO supplemented with 10% of egg yolk. This study is the first of its kind to successfully achieve gamete cryopreservation of Iberian endemic and endangered freshwater fish species, developing new and useful tools to complement the management and conservation programs.
Inclusive tourism: assessing the accessibility of Lisbon as a tourist destination
Publication . Rebelo, Sandra; Patuleia, Mafalda; Dias, Álvaro
Full accessibility to people with reduced mobility, applied to tourism, is difficult to achieve and should not be seen in an absolute way, but as a concern to make tourism services more accessible and focused on the specific and individual needs of people as tourists. National and regional entities should adopt good practices to build a tourism of all, for all. The Delphi method was used in order to verify the accessibility and attractiveness of the city of Lisbon as a tourist destination by addressing the following objectives: to analyse the competitiveness of a destination for people with reduced mobility, to analyse if Lisbon is attractive and inclusive, considering its infrastructures, services, hospitality, tourist attractions and accessibility. The results obtained in the study show that Lisbon’s factors and resources are increasingly accessible to people with reduced mobility. Our findings reveal that entertainment, general and tourism infrastructures, accommodation, the various activities and cultural resources and the quality of services present greater accessibility for people with reduced mobility. The factors with less importance were: marketing of a destination, accessibilities, and natural resources.
Public leadership challenges in a complex context
Publication . Fialho, Elisabete; Sousa, Maria José; Moreira, Ana Sofia
The objectives of this study are to identify the importance of teleworking during the COVID-19 pandemic and, evaluate the future development of this working form, characterize the process, identify its benefits and challenges, and present some solutions to deal with telework. To this end, the following research questions were formulated: (1) What areas of telework had the most significant impact during the COVID-19 pandemic? (2) What is the impact of telework on productivity? (3) What are the positive and negative aspects of teleworking? (4) What solutions do leaders propose for telework to intensify in the future? The sample for this study consists of 159 participants holding managerial positions. The data analyses were completed and allowed us to study the challenges of leadership in teleworking in direct public administrations. The results indicate that productivity is maintained, although productivity has decreased in the education sector. The positive aspects found were flexibility, better time management, that communication became simpler, and greater motivation. As negative aspects, we found changes in leadership, communication, and lack of material. To minimise the negative aspects of teleworking, the leaders essentially mentioned mixed-work (face-to-face and teleworking), distribution of appropriate material, training, teleworking regulation, and productivity control.
Effects of environmental enrichment on the welfare of gilthead seabream broodstock
Publication . Oliveira, Ana Rita; Cabrera-Álvarez, María J.; Soares, Florbela; Candeias-Mendes, Ana; Arechavala-Lopez, Pablo; Saraiva, João
The intensification of aquaculture practices in the last decade has led to the reduction in welfare of farmed fish. Recently, one of the tools that has been considered important to guarantee or improve the welfare of captive fish is the application of environmental enrichment (EE). The physiological state and behaviour of fish can be used as indicators of the welfare of the animal, as well as of the positive impact of the EE in their well-being. In this study, behavioural and physiological indicators were measured to assess the effects of structural environmental enrichment on the welfare of gilthead seabream broodstock. Over the course of 5 months, 60 adult seabreams were distributed in six 3000 L cylindrical tanks. Three of the tanks were enriched with nine hanging organic ropes on 1 m2 floating structures, while the other three tanks had no enrichment. Fish were filmed regularly
before, during, and after feeding, cleaning, and sampling procedures. Operational welfare indicators (OWIs) recently developed for farmed seabream were used and adapted to build an ethogram for the broodstock behaviour analysis. According to our results, fish reared in enriched tanks hardly schooled and presented a more independent swimming activity compared to fish from non-enriched tanks. Moreover, structural enrichment seemed to increase the spatial use of the bottom of the tank, and promoted seabream natural behaviour (hierarchical competitions, foraging, etc.). In addition, fish in enriched tanks presented a higher growth rate, and further studies will determine if such
enrichment structures also affect reproductive potential of seabream broodstocks as well as epigenetic effects on offspring.
Evaluating repetitive mucus extraction effects on mucus biomarkers, mucus cells and skin-barrier status in a marine fish model
Publication . Sanahuja, Ignasi; Guerreiro, Pedro Miguel; Girons, Albert; Fernández-Alacid, Laura; Ibarz, Antoni
Among all the mucosal barriers, the skin and its surrounding mucus are possibly the main defensive tools used by fish against the environment. Due to its less-invasive extraction, the study of its production and functions has gained high interest in the last years. However, there are still many gaps in research, such as the possible alteration of mucus composition or the skin integrity resulting from the sampling process. In the current study, skin mucus extraction impacts were determined by comparing the effects of one-single extraction (SEG; single extraction group) and three successive extractions (REG; repetitive extractions group, separated by 4 days) on mucus properties and on skin epithelial integrity. In terms of analytical evaluation, plasma biomarkers and plasma antibacterial capacity were also determined. With regard skin histology and skin barrier properties, both SEG and REG did not evidence differences with respect to intact skin (ØEG). Interestingly, the repetitive mucus extraction protocol seemed to activate skin mucus turnover, significantly increasing the number of low-size mucus cells (cell area < 100 µm2 ) and reducing the number of high-size mucus cells (cell area > 150 µm2 ). Repetitive extraction of skin mucus diminished the amounts of soluble protein and glucose in mucus with regard to one-single extraction and increased cortisol exudation. These metabolites remained unaltered in plasma, indicating the different response among both sampling targets. Despite mucus biomarkers modification, the antibacterial capacity against the pathogenic bacterial (P. anguilliseptica and V. anguillarum) was maintained in both plasma and mucus irrespective of the number of mucus extractions. Overall, the mucus sampling protocol scarcely affected skin integrity and mucus antibacterial properties and only modified metabolites exudation, evidencing a feasible and minimally invasive method for studying fish health and welfare as an alternative or as a complement to plasma. The knolwdege provided here highlighted that this methodology is putatively transferable to farm culture conditions and showed that it is very useful for the study of threatened species aimed at preserving fish welfare.