Percorrer por autor "Marques, António"
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- Bioaccessibility of lipophilic and hydrophilic marine biotoxins in seafood: an in vitro digestion approachPublication . Alves, Ricardo N.; Rambla-Alegre, Maria; Braga, Ana Catarina; Maulvault, Ana L.; Barbosa, Vera; Campàs, Mònica; Reverté, Laia; Flores, Cintia; Caixach, Josep; Kilcoyne, Jane; Costa, Pedro Reis; Diogène, Jorge; Marques, AntónioThis study aimed to assess the bioaccessibility of different marine biotoxins in naturally contaminated shellfish and fish gonads using an in vitro digestion methodology. In general, hydrophilic toxins (domoic acid, paralytic shellfish poisoning toxins and tetrodotoxins) showed higher bioaccessibility than lipophilic ones (okadaic acid and azaspiracids). The bioaccessibility of toxins from the okadaic acid group ranged from 69% (raw European razor clams) to 74% (raw donax clams). Regarding azaspiracids, 47% of the initial content was bioaccessible in steamed blue mussel. As for hydrophilic toxins, 100% of the initial content was bioaccessible after digestion in raw shellfish and puffer fish gonads. The total tetrodotoxin bioaccessibility in puffer fish gonads decreased significantly after steaming. The profile of tetrodotoxins changed during the digestion process: TTX and 11-norTTX-6S-ol analogues decreased significantly after digestion, but the 5,6,11-trideoxy TTX analogue increased in both raw and steamed puffer fish gonads. These preliminary findings confirm the need to consider bioaccessibility data in future seafood risk assessment, as such information enables a more accurate and realistic estimation of potential seafood hazards, particularly in what concerns lipophilic toxins, therefore, constituting a crucial tool in the refinement of regulatory limits for the presence of biotoxins in seafood.
- Do toxic epiphytic microalgae compromise the consumption of edible macroalgae?Publication . Chainho, Tomás; Cereja, Rui; Barbosa, Miguel; Xavier, Maria João; Pereira, Alícia; Oliveira, Inês; Caria Mendes, Madalena; Marques, António; Reis Costa, PedroThe growing global demand for farmed macroalgae highlights the need to better understand potential contaminant loads, including toxins from harmful algal blooms, and their implications to human health. In this study, the green macroalga Ulva rigida was co-cultivated with the epiphytic dinoflagellate Prorocentrum lima to determine whether toxins produced by the toxic dinoflagellate accumulate in the macroalgae and assess the efficacy of post-harvest processing techniques to reduce or eliminate the risk of toxins contamination. Ulva rigida (60 g wet weight) was maintained under controlled laboratory conditions in sterile F/2 medium and in co-culture with P. lima. Macroalgae were divided into two treatments: a) no processing; b) processing. Samples were analysed by LC-MSMS to detect okadaic acid (OA) and dinophysistoxin-1 (DTX1). High toxins levels were detected after 7 days of exposure to P. lima. Contrastingly, the post-harvesting process of washing and scrubbing was efficient in reducing toxins loads, indicating that lipophilic toxins were surface bound and can be easily eliminated using efficient post-harvest processes. The results indicate that epiphytic toxic microalgae may jeopardize the consumption of macroalgae, particularly if appropriate post-harvest processes are not applied to ensure the safety of farmed macroalgae for consumers.
- Eco-innovative aquafeeds biofortified with asparagopsis taxiformis to improve the resilience of farmed white seabream (Diplodus sargus) to marine heatwave eventsPublication . Marmelo, Isa; Lourenço-Marques, Cátia; Silva, Iris A.L.; Soares, Florbela; Pousão-Ferreira, Pedro; Mata, Leonardo; Marques, António; Diniz, Mário Sousa; Maulvault, Ana LuísaExtreme weather events, like marine heatwaves (MHWs), are becoming more frequent and severe due to climate change, posing several challenges to marine ecosystems and their services. As disease outbreaks are often prompted by these acute phenomena, it is essential to develop ecoinnovative strategies that can efficiently improve farmed fish resilience, especially under suboptimal rearing conditions, thereby ensuring a sustainable aquaculture production. This study aimed to unveil farmed juvenile white seabream ( Diplodus sargus, , 28.50 +/- 1.10 g weight, n = 150) immune and antioxidant responses under a category II MHW in the Mediterranean Sea (+4 degrees C, 8 days of temperature increase plus 15 days of plateau at the peak temperature) and to investigate whether a 30 days period of prophylactic biofortification with Asparagopsis taxiformis (1.5 %, 3 % and 6 %) enhanced fish resilience to these extreme events. Several biomarkers from different organization levels (individual, cellular, biochemical and molecular) were assessed upon 30 days of biofortification (T30), exposure (after 8 days of temperature increase + 15 days at peak temperature, T53) and recovery (8 days of temperature decrease, T61) from the MHW. Results showed that MHW negatively affected the fish physiological status and overall wellbeing, decreasing specific growth rate (SGR) and haematocrit (Ht) and increasing erythrocyte nuclear abnormalities (ENAs) and lipid peroxidation (LPO). These adverse effects were alleviated through biofortification with A. taxiformis. . Seaweed inclusion at 1.5 % was the most effective dose to minimize the severity of MHW effects, significantly improving immune responses of D. sargus (i.e. increased levels of immunoglobulin M, peroxidase activity and lysozyme expression) and modulating antioxidant responses (i.e. decreased LPO, catalase and glutathione S-transferase activity). These findings confirm that A. taxiformis is a functional ingredient of added value to the aquaculture industry, as its inclusion in marine fish diets can beneficially modulate fish immunity and resilience under optimal and adverse rearing conditions.
- Farmed and wild macroalgae as a safe source of macro and trace elementsPublication . Chainho, Tomás; Cereja, Rui; Pereira, Alícia; Marques, Vera; Silva, João C.; Pessanha, Sofia; Reis Costa, Pedro; Marques, AntónioThe increasing popularity of macroalgae products highlights their potential as a safe source of essential macro and microelements for consumers. This study characterized wild and farmed macroalgae elemental composition and assessed the presence of biotoxins to identify potential health risks. Wild and farmed macroalgae samples were collected throughout 2024–2025, from three aquaculture production sites along the Portuguese coast (Ria de Aveiro, Matosinhos, and Olhão). Samples were freeze-dried, compressed and using a microXRF spectrometer, elemental composition was assessed. Macroalgae species factor was the strongest driver of elemental composition, explaining over 80% variation in macro and trace elements. Origin did not showcase statistical significance for elemental composition. Seasonal differences, though relatively small in extent, significantly impacted redox-sensitive elements in macroalgae, namely copper and manganese. All elements stayed below 30% of the recommended dietary recommendations, except iron (ranging from 0.5% to 111.8% of UL%) and Mn (ranging from 0.1% to 101% of UL%). All samples revealed the absence of regulated marine toxins. Only traces of the non-regulated cyclic-imine toxin SPX1 were detected in samples of Fucus vesiculosus. All quantified elements do not represent any risk for human health, strengthening the safety of macroalgae from the Portuguese coast.
- Hot and toxic: accumulation dynamics and ecotoxicological responses of mussel Mytilus galloprovincialis exposed to marine biotoxins during a marine heatwavePublication . Dias, Marta; Özkan, Busenur; Ramos, João; Marques, António; Rosa, Rui; Reis Costa, Pedro; Maulvault, Ana LuísaClimate change is increasing marine heatwaves (MHWs) frequency and severity worldwide. These extreme events often cause bivalves' mass mortality and facilitate the growth, proliferation and dispersion of toxinproducing microalgae blooms associated with threats to seafood safety. Yet, the interactive effects between MHW and uptake of marine biotoxins by biota are a novel topic still lacking thorough research, from both the ecotoxicological and seafood safety standpoints. This study assessed the effects of a MHW event on the accumulation/elimination dynamics of diarrhetic shellfish toxins in Mytilus galloprovincialis exposed to Prorocentrum lima and the ecotoxicological responses of mussels co-exposed to these two stressors. Results showed that acute exposure to +4 degrees C reduced toxins accumulation (-49 %) and elimination (-77 %) compared to control temperature. Moreover, exposure to MHW and toxins affected mussels' antioxidant activity, lipid and protein damage, and metabolism in a tissue-specific manner. These findings highlight that M. galloprovincialis can face higher vulnerability to toxins when MHW events strike.
- In vitro bioaccessibility of the marine biotoxin okadaic acid in shellfishPublication . Braga, Ana C.; Alves, Ricardo N.; Maulvault, Ana L.; Barbosa, Vera; Marques, António; Costa, Pedro R.Okadaic acid (OA) and their derivatives are marine toxins responsible for the human diarrhetic shellfish poisoning (DSP). To date the amount of toxins ingested in food has been considered equal to the amount of toxins available for uptake by the human body. In this study, the OA fraction released from the food matrix into the digestive fluids (bioaccessibility) was assessed using a static in vitro digestion model. Naturally contaminated mussels (Mytilus galloprovincialis) and donax clams (Donax sp.), collected from the Portuguese coast, containing OA and dinophysistoxin-3 (DTX3) were used in this study. Bioaccessibility of OA total content was 88% and 75% in mussels and donax clams, respectively. Conversion of DTX3 into its parent compound was verified during the simulated digestive process and no degradation of these toxins was found during the process. This is the first study assessing the bioaccessibility of OA group toxins in naturally contaminated seafood. This study provides relevant new data that can improve and lead to more accurate food safety risk assessment studies concerning these toxins. (C) 2016 Elsevier Ltd. All rights reserved.
- Paralytic shellfish toxins and ocean warming: bioaccumulation and ecotoxicological responses in jujvenile Gilthead Seabream (Sparus aurata)Publication . Barbosa, Vera; Santos, Marta; Anacleto, Patrícia; Maulvault, Ana Luísa; Pousão-Ferreira, Pedro; Reis Costa, Pedro; Marques, AntónioWarmer seawater temperatures are expected to increase harmful algal blooms (HABs) occurrence, intensity, and distribution. Yet, the potential interactions between abiotic stressors and HABs are still poorly understood from ecological and seafood safety perspectives. The present study aimed to investigate, for the first time, the bioaccumulation/depuration mechanisms and ecotoxicological responses of juvenile gilthead seabream (Sparus aurata) exposed to paralytic shellfish toxins (PST) under different temperatures (18, 21, 24 °C). PST were detected in fish at the peak of the exposure period (day five, 0.22 µg g-1 N-sulfocarbamoylGonyautoxin-1-2 (C1 and C2), 0.08 µg g-1 Decarbamoylsaxitoxin (dcSTX) and 0.18 µg g-1 Gonyautoxin-5 (B1)), being rapidly eliminated (within the first 24 h of depuration), regardless of exposure temperature. Increased temperatures led to significantly higher PST contamination (275 µg STX eq. kg-1). During the trial, fish antioxidant enzyme activities (superoxide dismutase, SOD; catalase, CAT; glutathione S-transferase, GST) in both muscle and viscera were affected by temperature, whereas a significant induction of heat shock proteins (HSP70), Ubiquitin (Ub) activity (viscera), and lipid peroxidation (LPO; muscle) was observed under the combination of warming and PST exposure. The differential bioaccumulation and biomarker responses observed highlight the need to further understand the interactive effects between PST and abiotic stressors, to better estimate climate change impacts on HABs events, and to develop mitigation strategies to overcome the potential risks associated with seafood consumption.
- The impact of climate Change on bivalve farming: combined effect of temperature and salinity on survival and feeding Behavior of clams Ruditapes decussatusPublication . Rato, Ana; Joaquim, Sandra; Matias, Ana Margarete; Roque, Cláudia; Marques, António; Matias, DomitíliaEuropean clam (Ruditapes decussatus) is one of the most relevant emergent bivalve species from the aquaculture sector in Europe with high economic value. Climate changes represent a potential limiting factor to this activity, directly interfering with the survival and behavior of bivalves. Severe fluctuations in temperature along with periods of heavy rainfall or periods of drought that significantly change the salinity can promote physiological stress in bivalves, resulting in changes in physiological and behavioral responses and, in extreme cases, leading to high mortalities. This study aimed to evaluate the combined effect of temperature and salinity on mortality and feeding behavior of R. decussatus. Juveniles and adults were exposed to combined ranges of temperature (5 degrees C-35 degrees C) and salinity (0-40). Mortality and feeding behavior were registered every 24 h of each 120-h trial. A control temperature range was set between 15 degrees C and 23 degrees C, where mortality and feeding behavior were considered as the normal scenario. Our data suggested salinity 15 as a "turning point," a point from which occurred distinct patterns in mortality and feeding behavior. The results evidently indicate that abrupt reductions in salinity and sharp increases in temperature will lead to high mortality of R. decussatus. Juveniles were revealed to be more sensitive to the increase of temperature in a less saline environment, to suffer greater and faster mortalities, and to be more resistant to extremely high temperatures under more saline conditions. The high temperatures and sporadic heavy rainfall that are predicted to occur in the south of Europe due to climate changes will contribute to compromise the recruitment of European clam, thus threatening the production of this species and consequently impacting the economic sector.