Browsing by Author "Pousao-Ferreira, Pedro"
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- Does consistent individual variability in pelagic fish larval behaviour affect recruitment in nursery habitats?Publication . Baptista, Vânia; Costa, Eudriano; Carere, Claudio; Morais, Pedro; Cruz, Joana; Cerveira, Inês; Castanho, Sara; Ribeiro, Laura; Pousao-Ferreira, Pedro; Leitão, Francisco; Teodosio, MariaIndividual animals across all taxa differ consistently in behaviour, i.e. they show personality traits. This inter-individual variability has significant ecological and evolutionary consequences, since it affects a range of population-level processes. Here, we focus on the selection and recruitment of nursery habitats in temperate fish larvae. The "Sense Acuity and Behavioural Hypothesis" has proposed that fish larvae could detect and follow environmental cues to actively choose suitable nursery habitats. We empirically tested this hypothesis questioning if this non-random active process occurs and if it could be linked to consistency in individual behaviours. Individual larvae of the white seabream Diplodus sargus (Linnaeus, 1758) were tested repeatedly at different ages in a two-channel choice-chamber apparatus exposing them to a flow with different stimuli, as nursery habitats (lagoon, coastal), different temperatures or salinities and recording exploratory activity and preference in the different conditions. Most larvae changed behaviour during ontogeny, but they were also significantly consistent in their behaviour, revealing strong individuality; yet, no significant preference for the presented stimuli emerged, nor it was related to individuality. Exploratory activity was higher when larvae showed unresponsive or inconclusive behaviours, meaning that the larvae tried to find a different stimulus from the one that we were offering or had random habitat selection. Individual behavioural consistency could influence the process of searching for suitable nursery habitats and, consequently, dispersion and connectivity of white seabream population. Characterizing the behaviour of temperate pelagic marine fish larvae may shed light on fish recruitment variability, help refining larval dispersion models and possibly help understanding effects of climate change on population distribution and connectivity. Significance statement A Chinese idiom says that "It is easier to change mountains and rivers than to alter one's character." What about fish? Well, fish can exhibit individuality traits that control autoecological and demecological processes. For example, shy fish have lower fitness while the rate of invasion progress is faster in populations with bolder individuals. Individuality studies rarely focused on fish larvae, except for coral fish. So, we tested if temperate fish larvae display consistent behaviour throughout ontogeny. This goal delves into the Sense Acuity And Behavioural Hypothesis which incorporated behaviour into the hypotheses deeming to explain fish recruitment variability. We found that temperate fish larvae display consistent individual behavioural differences in exploratory activity since early in ontogeny. This confirms the deterministic role of pelagic fish larvae behaviour on population connectivity processes, namely to control their dispersion and choose a nursery habitat.
- Effects of different slipping methods on the mortality of sardine, Sardina pilchardus, after purse-seine capture off the Portuguese Southern coast (Algarve)Publication . Marçalo, Ana; Guerreiro, Pedro; Bentes, Luis; Rangel, Mafalda; Monteiro, Pedro; Oliveira, Frederico; Afonso, Carlos; Pousao-Ferreira, Pedro; Benoit, Hugues P.; Breen, Mike; Erzini, Karim; Gonçalves, Jorge Manuel SantosThe effects of two different slipping methods on the survival, physical and physiological response of sardines, Sardina pilchardus, captured in a purse-seine fishery were investigated in southern Portugal. Sardines were collected and transferred into holding tanks onboard a commercial fishing vessel after being captured, crowded and deliberately released using two slipping procedures: standard and modified. The standard slipping procedure aggregated fish at high densities and made them "roll over" the floatline, while the modified procedure aggregated the fish at moderate densities and enabled them to escape through an opening created by adding weights to the floatline. Both slipping methods were compared with minimally harmed non-slipped sardines (sardines collected from the loose pocket of the purse seine). Survival rates were monitored in captivity over 28 days using three replicates for each treatment. The estimated survival of sardines was 43.6% for the non-slipped fish, 44.7% for the modified slipping and 11.7% for the standard slipping treatments. Scale loss indicated the level of physical impact experienced, with dead fish from the non-slipped and modified slipping technique showing significantly lower scale loss than those fish from the standard slipping treatment within the same period. Of the physiological indicators of stress measured, cortisol, glucose, lactate and osmolality attained peak values during slipping and up to the first hours after introduction to captivity. This work indicates that although delayed mortality after release may be substantial, appropriately modified slipping techniques significantly enhance survival of slipped sardines.
- Fatty acid profiles of the main lipid classes of green seaweeds from fish pond aquaculturePublication . Cardoso, Carlos; Ripol, Andrea; Afonso, Claudia; Freire, Margarida; Varela, João; Quental-Ferreira, Hugo; Pousao-Ferreira, Pedro; Bandarra, NarcisaThe lipid composition of five species of green seaweeds (Chaetomorpha linum, Rhizoclonium riparium, Ulva intestinalis, Ulva lactuca, and Ulva prolifera) grown in fish pond aquaculture systems was studied. In particular, the overall fatty acid (FA) profile and the FA profile of each main lipid class found in these seaweed species were thoroughly analyzed. It was found that every seaweed had a specific FA profile, whose specificities were rendered more obvious with the study of the FA profile per lipid class. However, between U.lactuca and U.intestinalis, there were only minor differences. Nonetheless, it was possible to identify significant differences between the palmitic acid content in the phospholipid (PL) and glycolipid (GL) classes of each seaweed. A clear distinction between the FA profiles of R.riparium and C.linum, which belong to the Cladophorales order, and those of Ulva genus, Ulvales order, was also determined. Moreover, there were also differences among lipid classes, yielding large contrasts between PLs+GLs and triacylglycerols (TAGs) as well as between monoacylglycerols (MAGs) and free fatty acids (FFAs). This study also found evidence supporting the location of particular FAs in specific TAG positions. FA profiles have the potential to be used as a chemotaxonomic tool in green seaweeds, providing a simple method to check authenticity of seaweed used as food.
- Reduction of skeletal anomalies in meagre (Argyrosomus regius, Asso, 1801) through early introduction of inert dietPublication . Martins, Gil; Ribeiro, Laura; Candeias-Mendes, Ana; Diogo, Patricia; Gamboa, Margarida; Barata, Marisa; Leonor Cancela, M.; Pousao-Ferreira, Pedro; J. Gavaia, PauloThe consolidation of meagre (Argyrosomus regius) in aquaculture requires an understanding and optimization of larval rearing and nutritional conditions. The aim of this study was to analyse the effects of an early introduction of inert diets during larval rearing, on growth performance, digestive enzymes activity and development of skeletal anomalies. This study evaluated the effects of three different timings for the introduction of inert diet during larval rearing: a control group (CTRL) where inert diet was initiated at 14 days after hatching (DAH) and two treatment groups that had an earlier introduction of inert diet at 8 DAH (T1) and 11 DAH (T2). Meagre larvae exhibited similar pancreatic and intestinal enzymatic activities among the different dietary treatments. No differences in the overall prevalence of anomalies were observed between treatments at 25 or 50 DAH, however, a significant reduction was observed in all groups with the transition from larval to juvenile stage. The precocious introduction of inert diet shifted the distribution of vertebral anomalies to a more anterior vertebral column region. Altogether, this study shows that earlier introduction of inert diets in meagre hatcheries can be beneficial for meagre production in aquaculture.
- Taurine modulates protein turnover in several tissues of meagre juvenilesPublication . Matias, Ana Catarina; Dias, Jorge; Barata, Marisa; Araujo, Ravi Luna; Bragança, José; Pousao-Ferreira, PedroThis study aimed to evaluate the modulatory effect of dietary taurine supplementation on protein turnover of meagre juveniles fed semi-purified plant-based diets. For that purpose, fish (3.2 +/- 0.2 g) were fed with five isoproteic (61.2%), isolipidic (16.6%) and isoenergetic (21.9 kJ g(-1)) experimental diets supplemented with 0.5% (Tau0.5), 1% (Tau1), 1.5% (Tau1.5) and 2% (Tau2) taurine or not (Tau0) for 38 days. the resulting growth parameters, protein expression levels and the activity of several proteolytic markers involved in the two major degradation pathways in vertebrates (autophagy-lysosomal and ubiquitin-proteasome) were assessed in the liver, intestine and white muscle of meagre. Increasing dietary taurine concentrations promoted fish growth, feed utilization and whole-body protein, lipid and energy contents. Dietary taurine seemed to modulate the activity of cathepsins D and B in white muscle and cathepsin L in the liver. Although, no significant effects were observed on proteasome activity, 1% dietary taurine supplementation decreased the expression of the Psmb4 proteasome subunit in the liver of fish when compared to lower taurine concentrations. No taurine effects were detected on the proteolytic markers analysed in the intestine of meagre. Hsp70 expression levels were also not affected by any of the experimental dietary taurine concentrations. Overall, experimental diet Tau2 promoted the highest growth rate which can be explained by a significant decrease in protein degradation in the liver and white muscle preferentially via the autophagy-lysosomal pathway (cathepsins) over the ubiquitin-proteasome route.
- The irrigation salinity and harvesting affect the growth, chemical profile and biological activities of Polygonum maritimum L.Publication . Rodrigues, Maria Joao; Monteiro, Ivo; Placines, Chloé; Castañeda-Loaiza, Viana; Slusarczyk, Sylwester; Matkowski, Adam; Pereira, Catarina; Pousao-Ferreira, Pedro; Custódio, LuísaPreviously, our group identified the halophyte Polygonum maritimum L. (sea knotgrass) as a promising source of ingredients for the cosmetic, food, pharmaceutical and veterinarian industries. To further explore this species, and to guarantee the supply of biomass for commercial purposes, it is necessary to ensure its sustainable production while assuring the preservation of its chemical and biological properties. In this context, this work aimed to cultivate this species in greenhouse conditions and to determine the influence of specific agronomic conditions, namely irrigation salinity and harvest, on the plant's growth performance and biological properties of obtained biomass. For that purpose, plants were grown in a greenhouse and irrigated with water with different salinities (0, 100, 200, 300 and 600 mM of sodium chloride - NaCl). After six weeks of irrigation, plants were cut 7 cm above soil level and submitted to an additional two harvests with a six-week interval. Plant growth performance was evaluated in terms of plant height, leaf number and surface area, moisture, and productivity. Acetone extracts were prepared from aboveground organs and evaluated for chemical composition (by spectrophotometric methods, and by ultra-high-resolution mass spectrometry - UHRMS), and for in vitro antioxidant properties [radical-scavenging activity (RSA) on DPPH and ABTS, ferric reducing antioxidant power (FRAP) and metal chelating activity on iron (ICA) and copper (CCA)]. Extracts were also appraised for in vitro anti-inflammatory activity on lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. Increased salinity and multiple harvests reduced plant growth and yields; the highest productivity was obtained in plants irrigated with freshwater at 2nd harvest (346 g/m(2) of dried biomass). The extracts maintained the in vitro biological properties and interesting chemical profile, however, these depended on the irrigation salinity and harvest regime. The highest antioxidant activities were obtained in extracts from plants irrigated with freshwater at the 3rd harvest (DPPH: 96.2%; ABTS: 89.1%; CCA: 61.6%; FRAP: 136%). The extracts from biomass obtained in 1st the harvest of freshwater-irrigated plants, and from those treated with 100 and 200 mM of NaCl, had significant anti-inflammatory properties. The main compounds detected were mostly flavonols (myricetin and quercetin glycosides), which varied according to both irrigation salinity and harvest. Our results indicate that sea knotgrass can be cultivated in greenhouse conditions aiming industrial commercial applications, irrigated with freshwater or with irrigation solutions with moderate salinity. Moreover, produced biomass maintain the biological and chemical properties previously detected in plants collected from the wild.