IPMA Aquaculture Research Station

Olhão, Portugal

IPMA Aquaculture Research Station

Olhão, Portugal
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Pereira P.,University of Aveiro | Puga S.,University of Minho | Puga S.,ICVS 3Bs PT Government Associate Laboratory | Cardoso V.,University of Minho | And 9 more authors.
Aquatic Toxicology | Year: 2016

The current study contributes to fill the knowledge gap on the neurotoxicity of inorganic mercury (iHg) in fish through the implementation of a combined evaluation of brain morphometric alterations (volume and total number of neurons plus glial cells in specific regions of the brain) and swimming behavior (endpoints related with the motor activity and mood/anxiety-like status). White seabream (Diplodus sargus) was exposed to realistic levels of iHg in water (2μgL-1) during 7 (E7) and 14 days (E14). After that, fish were allowed to recover for 28 days (PE28) in order to evaluate brain regeneration and reversibility of behavioral syndromes. A significant reduction in the number of cells in hypothalamus, optic tectum and cerebellum was found at E7, accompanied by relevant changes on swimming behavior. Moreover, the decrease in the number of neurons and glia in the molecular layer of the cerebellum was followed by a contraction of its volume. This is the first time that a deficit on the number of cells is reported in fish brain after iHg exposure. Interestingly, a recovery of hypothalamus and cerebellum occurred at E14, as evidenced by the identical number of cells found in exposed and control fish, and volume of cerebellum, which might be associated with an adaptive phenomenon. After 28 days post-exposure, the optic tectum continued to show a decrease in the number of cells, pointing out a higher vulnerability of this region. These morphometric alterations coincided with numerous changes on swimming behavior, related both with fish motor function and mood/anxiety-like status. Overall, current data pointed out the iHg potential to induce brain morphometric alterations, emphasizing a long-lasting neurobehavioral hazard. © 2015 Elsevier B.V.


Puga S.,University of Minho | Puga S.,ICVS 3Bs PT Government Associate Laboratory | Pereira P.,University of Aveiro | Pinto-Ribeiro F.,University of Minho | And 9 more authors.
Aquatic Toxicology | Year: 2016

The current study aims to shed light on the neurotoxicity of MeHg in fish (white seabream – Diplodus sargus) by the combined assessment of: (i) MeHg toxicokinetics in the brain, (ii) brain morphometry (volume and number of neurons plus glial cells in specific brain regions) and (iii) fish swimming behavior (endpoints associated with the motor performance and the fear/anxiety-like status). Fish were surveyed for all the components after 7 (E7) and 14 (E14) days of dietary exposure to MeHg (8.7 μg g−1), as well as after a post-exposure period of 28 days (PE28). MeHg was accumulated in the brain of D. sargus after a short time (E7) and reached a maximum at the end of the exposure period (E14), suggesting an efficient transport of this toxicant into fish brain. Divalent inorganic Hg was also detected in fish brain along the experiment (indicating demethylation reactions), although levels were 100–200 times lower than MeHg, which pinpoints the organic counterpart as the great liable for the recorded effects. In this regard, a decreased number of cells in medial pallium and optic tectum, as well as an increased hypothalamic volume, occurred at E7. Such morphometric alterations were followed by an impairment of fish motor condition as evidenced by a decrease in the total swimming time, while the fear/anxiety-like status was not altered. Moreover, at E14 fish swam a greater distance, although no morphometric alterations were found in any of the brain areas, probably due to compensatory mechanisms. Additionally, although MeHg decreased almost two-fold in the brain during post-exposure, the levels were still high and led to a loss of cells in the optic tectum at PE28. This is an interesting result that highlights the optic tectum as particularly vulnerable to MeHg exposure in fish. Despite the morphometric alterations reported in the optic tectum at PE28, no significant changes were found in fish behavior. Globally, the effects of MeHg followed a multiphasic profile, where homeostatic mechanisms prevented circumstantially morphometric alterations in the brain and behavioral shifts. Although it has become clear the complexity of matching brain morphometric changes and behavioral shifts, motor-related alterations induced by MeHg seem to depend on a combination of disruptions in different brain regions. © 2016 Elsevier B.V.


Pereira P.,University of Aveiro | Raimundo J.,IPMA Portuguese Institute for the Sea and Atmosphere | Barata M.,IPMA Aquaculture Research Station | Araujo O.,IPMA Portuguese Institute for the Sea and Atmosphere | And 5 more authors.
Metallomics | Year: 2015

There are several aspects of inorganic mercury (iHg) toxicokinetics in fish that remain undeveloped despite its environmental ubiquity, bioaccumulation capacity and toxicity. Thus, this study presents new information on the uptake, distribution and accumulation of iHg following water contamination by adopting a novel set of body compartments (gills, eye wall, lens, blood, liver, brain and bile) of the white sea bream (Diplodus sargus) over 14 days of exposure. Realistic levels of iHg in water (2 μg L-1) were adopted in order to engender reliable conclusions in the assessment of fish health. A depuration phase of 28 days was also considered with the purpose of clarifying iHg elimination. It was found that iHg was accumulated faster in the gills (within 1 day), which also had the highest accumulated levels among all the target tissues/organs. Moreover, iHg increased gradually with exposure time in all the tissues/organs, except for the lens that showed relatively unaltered levels throughout the experiment. After 14 days of exposure, lower values of Hg were recorded in the brain/eye wall compared to the liver, which is probably related with the presence of blood-organ protection barriers, which limit iHg influx. iHg reached the brain earlier than the eye wall (3 and 7 days, respectively) and, hence, higher accumulated levels were recorded in the former. A depuration period of 28 days did not allow the total elimination of iHg in any of the tissues/organs. Despite this, iHg was substantially eliminated in the gills, blood and liver, whereas the brain and eye wall were not able to eliminate iHg within this timeframe. The brain and eye wall are more "refractory" structures with regard to iHg elimination, and this could represent a risk for wild fish populations. © 2015 The Royal Society of Chemistry.


PubMed | University of Lisbon, Acadia University, University of Minho, University of Aveiro and IPMA Aquaculture Research Station
Type: | Journal: Aquatic toxicology (Amsterdam, Netherlands) | Year: 2016

The current study aims to shed light on the neurotoxicity of MeHg in fish (white seabream - Diplodus sargus) by the combined assessment of: (i) MeHg toxicokinetics in the brain, (ii) brain morphometry (volume and number of neurons plus glial cells in specific brain regions) and (iii) fish swimming behavior (endpoints associated with the motor performance and the fear/anxiety-like status). Fish were surveyed for all the components after 7 (E7) and 14 (E14) days of dietary exposure to MeHg (8.7gg


PubMed | University of Minho, IPMA Portuguese Institute for the Sea and Atmosphere, University of Aveiro and IPMA Aquaculture Research Station
Type: | Journal: Aquatic toxicology (Amsterdam, Netherlands) | Year: 2016

The current study contributes to fill the knowledge gap on the neurotoxicity of inorganic mercury (iHg) in fish through the implementation of a combined evaluation of brain morphometric alterations (volume and total number of neurons plus glial cells in specific regions of the brain) and swimming behavior (endpoints related with the motor activity and mood/anxiety-like status). White seabream (Diplodus sargus) was exposed to realistic levels of iHg in water (2gL(-1)) during 7 (E7) and 14 days (E14). After that, fish were allowed to recover for 28 days (PE28) in order to evaluate brain regeneration and reversibility of behavioral syndromes. A significant reduction in the number of cells in hypothalamus, optic tectum and cerebellum was found at E7, accompanied by relevant changes on swimming behavior. Moreover, the decrease in the number of neurons and glia in the molecular layer of the cerebellum was followed by a contraction of its volume. This is the first time that a deficit on the number of cells is reported in fish brain after iHg exposure. Interestingly, a recovery of hypothalamus and cerebellum occurred at E14, as evidenced by the identical number of cells found in exposed and control fish, and volume of cerebellum, which might be associated with an adaptive phenomenon. After 28 days post-exposure, the optic tectum continued to show a decrease in the number of cells, pointing out a higher vulnerability of this region. These morphometric alterations coincided with numerous changes on swimming behavior, related both with fish motor function and mood/anxiety-like status. Overall, current data pointed out the iHg potential to induce brain morphometric alterations, emphasizing a long-lasting neurobehavioral hazard.


Saavedra M.,Portuguese Institute for the Ocean and Atmosphere IPMA | Pereira T.G.,Portuguese Institute for the Ocean and Atmosphere IPMA | Grade A.,Portuguese Institute for the Ocean and Atmosphere IPMA | Barbeiro M.,Portuguese Institute for the Ocean and Atmosphere IPMA | And 5 more authors.
International Journal of Food Science and Technology | Year: 2015

Larger meagre are more common in the market but, recently, smaller fish have started to be commercialised as well. This study aims to evaluate flesh quality and muscle cellularity of meagre of three different sizes: 800, 1500 and 2500 g. Results showed a higher fat content in larger fish (2.9% compared to 1.3% in small fish), and that texture was not affected by fish size. In terms of muscle cellularity, a higher frequency of smaller fibres was observed in 800 and 1500 g (33% compared to 18% in 2500 g) meagre, whereas in 2500 g meagre, there was a higher frequency of larger fibres. Muscle fibre density was reduced with fish weight (431 and 297 fibres mm-2 for 800 and 2500 g meagre, respectively). In conclusion, this study shows that meagre of different weights are different in terms of fat content and muscle cellularity and that 800 g meagre seems to have a good potential for being commercialised. © 2015 Institute of Food Science and Technology.


Saavedra M.,Portuguese Institute for the Ocean and Atmosphere IPMA | Candeias-Mendes A.,IPMA Aquaculture Research Station | Castanho S.,IPMA Aquaculture Research Station | Teixeira B.,Portuguese Institute for the Ocean and Atmosphere IPMA | And 2 more authors.
Aquaculture | Year: 2015

The indispensable amino acid (AA) profile of fish carcass has been commonly used to estimate the AA requirements of fish. In this study the AA composition of whole body tissue of meagre, Argyrosomus regius, was determined at 0, 3, 6, 8, 12, 17, 20, 24, 30 and 39days after hatching (DAH). Several differences were observed during meagre larval ontogeny with the AA profile at 0DAH being different from the remaining larval ages and with a change occurring around 12 and 17DAH which was reflected in some AA such as arginine, valine and tyrosine. Meagre and diet AA profiles were compared and several AAs were found to be in apparent deficiency in the diets. In rotifers a lower number of AA were apparently in deficiency but the correlation between larval and diet AA profiles was low (R2 lower than 0.7). Although a higher number of AA were apparently in deficiency in Artemia and dry feed, the correlations obtained were high (R2 above 0.75). Histidine appeared to be the limiting AA in all diets. These results suggest that the higher nutritional imbalances in meagre larval ontogeny occur during the first 10days of feeding when larvae are fed on rotifers. To solve these apparent nutritional imbalances, an alternative to rotifers should be found or at least a reduction of the period when larvae are fed on rotifers alone. Given the potential of meagre to aquaculture, the use of suitable diets for this species should be formulated. The results obtained in this study can be used to formulate AA balanced diets which are expected to increase growth and decrease larval mortality. © 2015 Elsevier B.V.

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