Lake Magadi, Kenya, is one of the most extreme aquatic environments on Earth (pH~10, anoxic to hy... more Lake Magadi, Kenya, is one of the most extreme aquatic environments on Earth (pH~10, anoxic to hyperoxic, high temperatures). Recently, increased water demand and siltation have threatened the viable hot springs near the margins of the lake where Alcolapia grahami, the only fish surviving in the lake, live. These Lake Magadi tilapia largely depend on nitrogen-rich cyanobacteria for food and are 100% ureotelic. Their exceptionally high aerobic metabolic rate, together with their emaciated appearance, suggests that they are energy-limited. Therefore, we hypothesized that during food deprivation, Magadi tilapia would economize their energy expenditure and reduce metabolic rate, aerobic performance and urea-N excretion. Surprisingly, during a 5-day fasting period, routine metabolic rates increased and swimming performance (critical swimming speed) was not affected. Urea-N excretion remained stable despite the lack of their N-rich food source. Their nitrogen use switched to endogenous so...
The individual toxicity and bioaccumulation of cadmium (Cd), copper (Cu) and zinc (Zn) towards co... more The individual toxicity and bioaccumulation of cadmium (Cd), copper (Cu) and zinc (Zn) towards common carp juveniles was evaluated in a direct comparison in two experimental setups. First, the fish were exposed for 10 days to different metal concentrations. Accumulated metals were quantified and showed a positive dose dependent uptake for cadmium and copper, but not for zinc. Toxicity was in the order Cd>Cu>Zn with 96h LC50 values (concentration where 50% of the animals dies within 96h) for Cd at 0.20±0.16 μM, Cu at 0.77±0.03 μM, and Zn at 29.89±9.03 μM respectively, and incipient lethal levels (concentration where 50% of the animals survives indefinitely) at 0.16 μM, 0.77 μM and 28.33 μM respectively. Subsequently, a subacute exposure experiment was conducted, where carp juveniles were exposed to 2 equitoxic concentrations (10% and 50% of LC50 96 h) of the three metals. The gill metal content was quantified after 1, 3 and 7 days, and was correlated to electrolyte levels and s...
Although aquatic organisms are increasingly exposed to pollutants and abnormally high temperature... more Although aquatic organisms are increasingly exposed to pollutants and abnormally high temperatures as a consequence of climate change, interactive effects between those stressors remain poorly assessed. Especially in ectotherms, such as fish, increases in ambient temperature are expected to affect fitness-related traits and physiology. We used the turquoise killifish Nothobranchius furzeri to study the effects of a range of 3,4-dichloroaniline concentrations (0, 50, 100 μg/L) in combination with two temperature conditions (control and control +4 °C) during four months of exposure. As part of an integrated multi-level approach, we quantified effects on classic life history traits (size, maturation time, body mass, fecundity), critical thermal maximum and physiology (energy reserves and stress-associated enzymatic activity). While no interactive effects of 3,4-DCA exposure and increased temperature emerged, our results do show a negative effect of 3,4-DCA on thermal tolerance. This finding is of particular relevance in light of increasing temperatures under climate change. Due to increases in pest species and faster degradation of 3,4-DCA under higher temperatures, increased use of the pesticide is expected under climate change which, in turn, could result in a decreased tolerance of aquatic organisms to high temperatures.
In this era of global climate change, ocean acidification is becoming a serious threat to the mar... more In this era of global climate change, ocean acidification is becoming a serious threat to the marine ecosystem. Despite this, it remains almost unknown how fish will respond to the co-occurrence of ocean acidification with other conventional environmental perturbations typically salinity fluctuation and high ammonia threat. Therefore, the present work evaluated the interactive effects of elevated pCO2, salinity reduction and high environmental ammonia (HEA) on the ecophysiological performance of European sea bass (Dicentrarchus labrax). Fish were progressively acclimated to seawater (32 ppt), to brackish water (10 ppt) and to hyposaline water (2.5 ppt). Following acclimation to different salinities for at least two weeks, fish were exposed to CO2-induced water acidification representing present-day (control pCO2, 400 μatm, LoCO2) and future (high pCO2, 1000 μatm, HiCO2) sea-surface CO2 level for 3, 7 and 21 days. At the end of each exposure period, fish were challenged with HEA for 6 h (1.18 mM representing 50% of 96 h LC50). Results show that, in response to the individual HiCO2 exposure, fish within each salinity compensated for blood acidosis. Fish subjected to HiCO2 were able to maintain ammonia excretion rate (Jamm) within control levels, suggesting that HiCO2 exposure alone had no impact on Jamm at any of the salinities. For 32 and 10 ppt fish, up-regulated expression of Na+/K+-ATPase was evident in all exposure groups (HEA, HiCO2 and HEA/HiCO2 co-exposed), whereas Na+/K+/2Cl- co-transporter was up-regulated mainly in HiCO2 group. Plasma glucose and lactate content were augmented in all exposure conditions for all salinity regimes. During HEA and HEA/HiCO2, Jamm was inhibited at different time points for all salinities, which resulted in a significant build-up of ammonia in plasma and muscle. Branchial expressions of Rhesus glycoproteins (Rhcg isoforms and Rhbg) were upregulated in response to HiCO2 as well as HEA at 10 ppt, with a more moderate response in 32 ppt groups. Overall, our findings denote that the adverse effect of single exposures of ocean acidification or HEA is exacerbated when present together, and suggests that fish are more vulnerable to these environmental threats at low salinities.
Ecotoxicology and environmental safety, Jan 6, 2017
Nothobranchius furzeri is a promising model for ecotoxicological research due to the species'... more Nothobranchius furzeri is a promising model for ecotoxicological research due to the species' short life cycle and the production of drought-resistant eggs. Although the species is an emerging vertebrate fish model for several fundamental as well as applied research domains, its potential for ecotoxicological research has not yet been tested. The aim of this study was to characterise the acute and chronic sensitivity of this species to copper as compared to other model organisms. Effects of both acute and chronic copper exposure were tested on survival, life history and physiological traits. We report a 24h-LC50 of 53.93µg Cu/L, which is situated within the sensitivity range of other model species such as Brook Trout, Fathead Minnow and Rainbow Trout. Moreover, in the full life cycle exposure, we show that an exposure concentration of 10.27µg/L did not cause acute adverse effects (96h), but did cause mortality after prolonged exposure (3-4 weeks). Also chronic, sublethal effects...
Insect larvae are reported to be a major component of the simple but highly productive trophic we... more Insect larvae are reported to be a major component of the simple but highly productive trophic web found in Lake Magadi (Kenya, Africa), which is considered to be one of the most extreme aquatic environments on Earth. Previous studies show that fish must display biochemical and physiological adjustments to thrive under the extreme conditions of the lake. However, information for invertebrates is lacking. In the present study, the occurrence of the larval chironomid Tanytarsus minutipalpus is reported in Lake Magadi for the first time. Additionally, changes in larval metabolism and antioxidant defense correlated with diel variations in the extremely hostile environmental conditions of the lake are described. Wide variations in water temperature (20.2-29.3(o)C) and dissolved oxygen content (3.2-18.6 mg O2 L(-1)) were observed at different times of day, without significant change in water pH (10.0±0.03). Temperature and dissolved oxygen were higher at 1:00 pm (29.3±0.4(o)C and 18.6±1.0...
We tested whether exposing fish to low ammonia concentrations induced acclimation processes and h... more We tested whether exposing fish to low ammonia concentrations induced acclimation processes and helped fish to tolerate subsequent (sub)lethal ammonia exposure by activating ammonia excretory pathways. Common carp (Cyprinus carpio) were pre-exposed to 0.27mM ammonia (∼10% 96h LC50) for 3, 7 and 14days. Thereafter, each of these pre-exposed and parallel naïve groups were exposed to 1.35mM high environmental ammonia (HEA, ∼50% 96h LC50) for 12h and 48h to assess the occurrence of ammonia acclimation based on sub-lethal end-points, and to lethal ammonia concentrations (2.7mM, 96h LC50) in order to assess improved survival time. Results show that fish pre-exposed to ammonia for 3 and 7days had a longer survival time than the ammonia naïve fish. However, this effect disappeared after prolonged (14days) pre-exposure. Ammonia excretion rate (Jamm) was strongly inhibited (or even reversed) in the unacclimated groups during HEA. On the contrary, after 3days the pre-exposure fish maintained Jamm while after 7days these pre-acclimated fish were able to increase Jamm efficiently. Again, this effect disappeared after 14days of pre-acclimation. The efficient ammonia efflux in pre-acclimated fish was associated with the up-regulation of branchial mRNA expression of ammonia transporters and exchangers. Pre-exposure with ammonia for 3-7days stimulated an increment in the transcript level of gill Rhcg-a and Rhcg-b mRNA relative to the naïve control group and the up-regulation of these two Rhcg homologs was reinforced during subsequent HEA exposure. No effect of pre-exposure was noted for Rhbg. Relative to unacclimated fish, the transcript level of Na(+)/H(+) exchangers (NHE-3) was raised in 3-7days pre-acclimated fish and remained higher during the subsequent HEA exposure while gill H(+)-ATPase activities and mRNA levels were not affected by pre-acclimation episodes. Likewise, ammonia pre-acclimated fish with or without HEA exposure displayed pronounced up-regulation in Na(+)/K(+)-ATPase activity and mRNA expression relative to the corresponding ammonia naïve groups. Overall, these data suggest that ammonia acclimation was evident for both lethal and the sub-lethal endpoints through priming mechanisms in ammonia excretory transcriptional processes, but these acclimation effects were transient and disappeared after prolonged pre-exposure.
The state of the art of research on the environmental physiology of marine fishes is reviewed fro... more The state of the art of research on the environmental physiology of marine fishes is reviewed from the perspective of how it can contribute to conservation of biodiversity and fishery resources. A major constraint to application of physiological knowledge for conservation of marine fishes is the limited knowledge base; international collaboration is needed to study the environmental physiology of a wider range of species. Multifactorial field and laboratory studies on biomarkers hold promise to relate ecophysiology directly to habitat quality and population status. The 'Fry paradigm' could have broad applications for conservation physiology research if it provides a universal mechanism to link physiological function with ecological performance and population dynamics of fishes, through effects of abiotic conditions on aerobic metabolic scope. The available data indicate, however, that the paradigm is not universal, so further research is required on a wide diversity of speci...
Archives of Environmental Contamination and Toxicology, 2016
To assess stress level induced by multiple stressors in aquatic organism, biomarkers have been ad... more To assess stress level induced by multiple stressors in aquatic organism, biomarkers have been adopted as early warning indicator due to their high accuracy, rapidity, and sensitivity. We investigated the effects of ectoparasitic isopod infection on heavy metal bioaccumulation (Fe, Cu, Zn, and Cd) in the fish Nemipterus furcosus and profiled the expression of metallothionein (MT) and heat shock proteins 70 (HSP70) genes of the fish host. Sixty individuals (parasitized and nonparasitized with Cymothoa truncata) were collected from three sites differing in the levels of anthropogenic activities off the South China Sea. Our results revealed no significant difference in heavy metal concentrations between infected and nonparasitized fish. We observed a positive correlation between heavy metal bioaccumulation in the fish host and anthropogenic activities. Accordingly, expression analysis of MT genes in fish liver showed significant differences in expression level between sampling sites, with lowest level in the least exploited site (Batu Rakit). A reverse pattern in HSP70 gene expression was demonstrated in fish muscle, showing the highest expression at Batu Rakit. While cymothoid infection in N. furcosus had no significant impact on fish MT gene expression, it resulted in a reduction of HSP70 level in liver of parasitized fish. These findings highlight the putative roles of MT in heavy metal assessment. Future studies should determine the kinetics of cymothoid infection and other potential stressors in characterizing the HSP70 gene expression profile.
Comparative biochemistry and physiology. Toxicology & pharmacology : CBP, Jan 10, 2016
In the present study, the effect of copper was examined in the common goldfish (Carassius auratus... more In the present study, the effect of copper was examined in the common goldfish (Carassius auratus auratus). Fish were fasted and exposed to either a high (0.84μM), a low (0.34μM) or a control copper concentration (0.05μM) for 1 and 7days. Swimming performance was not affected by either fasting or copper exposure. Food deprivation alone had no effect on ionoregulation, but low plasma osmolality levels and plasma Na(+) were noticed in fasted fish exposed to Cu for 7days. Both gill Na(+)/K(+)-ATPase and H(+)-ATPase activities were undisturbed, while both kidney ATPase activities were up-regulated when challenged with the high Cu levels. Up-regulated kidney ATPase activities likely acted as compensatory strategy to enhance Na(+) reabsorption. However, this up-regulation was not sufficient to restore Na(+) to control levels in the highest exposure group.
This study investigates the trophic interactions and As and Cd transfer along seven marine ecosys... more This study investigates the trophic interactions and As and Cd transfer along seven marine ecosystems in Peru. Five of these ecosystems are driven by aquaculture of the Peruvian scallop Argopecten purpuratus. A southward increased gradient of δ15N was observed among the three examined regions along the Peruvian coast. The stable isotope analysis in R (SIAR)-stable isotope mixing models helped to clarify the feeding ecology of A. purpuratus and its important predators (e.g., Bursa ventricosa, Romaleon setosum). The food items of A. purpuratus can be ranked in decreasing order of importance: seston > sediment > particulate organic matter (POM) > brackish-and-fresh water POM input, while A. purpuratus itself was found to be the main prey item for predators. The highest trophic magnification factors (TMFs) were 1.46 and 1.07 for As and Cd, respectively, and were both found at the location in front of the Illescas Reserve Zone (northern Peru). Metal biomagnification and non-biom...
Many species from several different families of fishes perform mouthbrooding, where one of the se... more Many species from several different families of fishes perform mouthbrooding, where one of the sexes protects and ventilates the eggs inside the mouth cavity. This ventilation behaviour differs from gill ventilation outside the brooding period, as the normal, small-amplitude suction-pump respiration cycles are alternated with actions including near-simultaneous closed-mouth protrusions and high-amplitude depressions of the hyoid. The latter is called churning, referring to its hypothetical function in moving around and repositioning the eggs by a presumed hydrodynamic effect of the marked shifts in volume along the mouth cavity. We tested the hypothesis that churning causes the eggs located posteriorly in the mouth cavity to move anteriorly away from the gill entrance. This would prevent or clear accumulations of brood at the branchial basket, which would otherwise hinder breathing by the parent. Dual-view videos of female Nile tilapias (Oreochromis niloticus) during mouthbrooding s...
The two morphotypes (leiurus and trachurus) of the three-spined stickleback Gasterosteus aculeatu... more The two morphotypes (leiurus and trachurus) of the three-spined stickleback Gasterosteus aculeatus, caught at the same location and time in the River Scheldt (Belgium), were investigated for physiological differences in swimming capacity and energetics associated with ...
Lake Magadi, Kenya, is one of the most extreme aquatic environments on Earth (pH~10, anoxic to hy... more Lake Magadi, Kenya, is one of the most extreme aquatic environments on Earth (pH~10, anoxic to hyperoxic, high temperatures). Recently, increased water demand and siltation have threatened the viable hot springs near the margins of the lake where Alcolapia grahami, the only fish surviving in the lake, live. These Lake Magadi tilapia largely depend on nitrogen-rich cyanobacteria for food and are 100% ureotelic. Their exceptionally high aerobic metabolic rate, together with their emaciated appearance, suggests that they are energy-limited. Therefore, we hypothesized that during food deprivation, Magadi tilapia would economize their energy expenditure and reduce metabolic rate, aerobic performance and urea-N excretion. Surprisingly, during a 5-day fasting period, routine metabolic rates increased and swimming performance (critical swimming speed) was not affected. Urea-N excretion remained stable despite the lack of their N-rich food source. Their nitrogen use switched to endogenous so...
The individual toxicity and bioaccumulation of cadmium (Cd), copper (Cu) and zinc (Zn) towards co... more The individual toxicity and bioaccumulation of cadmium (Cd), copper (Cu) and zinc (Zn) towards common carp juveniles was evaluated in a direct comparison in two experimental setups. First, the fish were exposed for 10 days to different metal concentrations. Accumulated metals were quantified and showed a positive dose dependent uptake for cadmium and copper, but not for zinc. Toxicity was in the order Cd>Cu>Zn with 96h LC50 values (concentration where 50% of the animals dies within 96h) for Cd at 0.20±0.16 μM, Cu at 0.77±0.03 μM, and Zn at 29.89±9.03 μM respectively, and incipient lethal levels (concentration where 50% of the animals survives indefinitely) at 0.16 μM, 0.77 μM and 28.33 μM respectively. Subsequently, a subacute exposure experiment was conducted, where carp juveniles were exposed to 2 equitoxic concentrations (10% and 50% of LC50 96 h) of the three metals. The gill metal content was quantified after 1, 3 and 7 days, and was correlated to electrolyte levels and s...
Although aquatic organisms are increasingly exposed to pollutants and abnormally high temperature... more Although aquatic organisms are increasingly exposed to pollutants and abnormally high temperatures as a consequence of climate change, interactive effects between those stressors remain poorly assessed. Especially in ectotherms, such as fish, increases in ambient temperature are expected to affect fitness-related traits and physiology. We used the turquoise killifish Nothobranchius furzeri to study the effects of a range of 3,4-dichloroaniline concentrations (0, 50, 100 μg/L) in combination with two temperature conditions (control and control +4 °C) during four months of exposure. As part of an integrated multi-level approach, we quantified effects on classic life history traits (size, maturation time, body mass, fecundity), critical thermal maximum and physiology (energy reserves and stress-associated enzymatic activity). While no interactive effects of 3,4-DCA exposure and increased temperature emerged, our results do show a negative effect of 3,4-DCA on thermal tolerance. This finding is of particular relevance in light of increasing temperatures under climate change. Due to increases in pest species and faster degradation of 3,4-DCA under higher temperatures, increased use of the pesticide is expected under climate change which, in turn, could result in a decreased tolerance of aquatic organisms to high temperatures.
In this era of global climate change, ocean acidification is becoming a serious threat to the mar... more In this era of global climate change, ocean acidification is becoming a serious threat to the marine ecosystem. Despite this, it remains almost unknown how fish will respond to the co-occurrence of ocean acidification with other conventional environmental perturbations typically salinity fluctuation and high ammonia threat. Therefore, the present work evaluated the interactive effects of elevated pCO2, salinity reduction and high environmental ammonia (HEA) on the ecophysiological performance of European sea bass (Dicentrarchus labrax). Fish were progressively acclimated to seawater (32 ppt), to brackish water (10 ppt) and to hyposaline water (2.5 ppt). Following acclimation to different salinities for at least two weeks, fish were exposed to CO2-induced water acidification representing present-day (control pCO2, 400 μatm, LoCO2) and future (high pCO2, 1000 μatm, HiCO2) sea-surface CO2 level for 3, 7 and 21 days. At the end of each exposure period, fish were challenged with HEA for 6 h (1.18 mM representing 50% of 96 h LC50). Results show that, in response to the individual HiCO2 exposure, fish within each salinity compensated for blood acidosis. Fish subjected to HiCO2 were able to maintain ammonia excretion rate (Jamm) within control levels, suggesting that HiCO2 exposure alone had no impact on Jamm at any of the salinities. For 32 and 10 ppt fish, up-regulated expression of Na+/K+-ATPase was evident in all exposure groups (HEA, HiCO2 and HEA/HiCO2 co-exposed), whereas Na+/K+/2Cl- co-transporter was up-regulated mainly in HiCO2 group. Plasma glucose and lactate content were augmented in all exposure conditions for all salinity regimes. During HEA and HEA/HiCO2, Jamm was inhibited at different time points for all salinities, which resulted in a significant build-up of ammonia in plasma and muscle. Branchial expressions of Rhesus glycoproteins (Rhcg isoforms and Rhbg) were upregulated in response to HiCO2 as well as HEA at 10 ppt, with a more moderate response in 32 ppt groups. Overall, our findings denote that the adverse effect of single exposures of ocean acidification or HEA is exacerbated when present together, and suggests that fish are more vulnerable to these environmental threats at low salinities.
Ecotoxicology and environmental safety, Jan 6, 2017
Nothobranchius furzeri is a promising model for ecotoxicological research due to the species'... more Nothobranchius furzeri is a promising model for ecotoxicological research due to the species' short life cycle and the production of drought-resistant eggs. Although the species is an emerging vertebrate fish model for several fundamental as well as applied research domains, its potential for ecotoxicological research has not yet been tested. The aim of this study was to characterise the acute and chronic sensitivity of this species to copper as compared to other model organisms. Effects of both acute and chronic copper exposure were tested on survival, life history and physiological traits. We report a 24h-LC50 of 53.93µg Cu/L, which is situated within the sensitivity range of other model species such as Brook Trout, Fathead Minnow and Rainbow Trout. Moreover, in the full life cycle exposure, we show that an exposure concentration of 10.27µg/L did not cause acute adverse effects (96h), but did cause mortality after prolonged exposure (3-4 weeks). Also chronic, sublethal effects...
Insect larvae are reported to be a major component of the simple but highly productive trophic we... more Insect larvae are reported to be a major component of the simple but highly productive trophic web found in Lake Magadi (Kenya, Africa), which is considered to be one of the most extreme aquatic environments on Earth. Previous studies show that fish must display biochemical and physiological adjustments to thrive under the extreme conditions of the lake. However, information for invertebrates is lacking. In the present study, the occurrence of the larval chironomid Tanytarsus minutipalpus is reported in Lake Magadi for the first time. Additionally, changes in larval metabolism and antioxidant defense correlated with diel variations in the extremely hostile environmental conditions of the lake are described. Wide variations in water temperature (20.2-29.3(o)C) and dissolved oxygen content (3.2-18.6 mg O2 L(-1)) were observed at different times of day, without significant change in water pH (10.0±0.03). Temperature and dissolved oxygen were higher at 1:00 pm (29.3±0.4(o)C and 18.6±1.0...
We tested whether exposing fish to low ammonia concentrations induced acclimation processes and h... more We tested whether exposing fish to low ammonia concentrations induced acclimation processes and helped fish to tolerate subsequent (sub)lethal ammonia exposure by activating ammonia excretory pathways. Common carp (Cyprinus carpio) were pre-exposed to 0.27mM ammonia (∼10% 96h LC50) for 3, 7 and 14days. Thereafter, each of these pre-exposed and parallel naïve groups were exposed to 1.35mM high environmental ammonia (HEA, ∼50% 96h LC50) for 12h and 48h to assess the occurrence of ammonia acclimation based on sub-lethal end-points, and to lethal ammonia concentrations (2.7mM, 96h LC50) in order to assess improved survival time. Results show that fish pre-exposed to ammonia for 3 and 7days had a longer survival time than the ammonia naïve fish. However, this effect disappeared after prolonged (14days) pre-exposure. Ammonia excretion rate (Jamm) was strongly inhibited (or even reversed) in the unacclimated groups during HEA. On the contrary, after 3days the pre-exposure fish maintained Jamm while after 7days these pre-acclimated fish were able to increase Jamm efficiently. Again, this effect disappeared after 14days of pre-acclimation. The efficient ammonia efflux in pre-acclimated fish was associated with the up-regulation of branchial mRNA expression of ammonia transporters and exchangers. Pre-exposure with ammonia for 3-7days stimulated an increment in the transcript level of gill Rhcg-a and Rhcg-b mRNA relative to the naïve control group and the up-regulation of these two Rhcg homologs was reinforced during subsequent HEA exposure. No effect of pre-exposure was noted for Rhbg. Relative to unacclimated fish, the transcript level of Na(+)/H(+) exchangers (NHE-3) was raised in 3-7days pre-acclimated fish and remained higher during the subsequent HEA exposure while gill H(+)-ATPase activities and mRNA levels were not affected by pre-acclimation episodes. Likewise, ammonia pre-acclimated fish with or without HEA exposure displayed pronounced up-regulation in Na(+)/K(+)-ATPase activity and mRNA expression relative to the corresponding ammonia naïve groups. Overall, these data suggest that ammonia acclimation was evident for both lethal and the sub-lethal endpoints through priming mechanisms in ammonia excretory transcriptional processes, but these acclimation effects were transient and disappeared after prolonged pre-exposure.
The state of the art of research on the environmental physiology of marine fishes is reviewed fro... more The state of the art of research on the environmental physiology of marine fishes is reviewed from the perspective of how it can contribute to conservation of biodiversity and fishery resources. A major constraint to application of physiological knowledge for conservation of marine fishes is the limited knowledge base; international collaboration is needed to study the environmental physiology of a wider range of species. Multifactorial field and laboratory studies on biomarkers hold promise to relate ecophysiology directly to habitat quality and population status. The 'Fry paradigm' could have broad applications for conservation physiology research if it provides a universal mechanism to link physiological function with ecological performance and population dynamics of fishes, through effects of abiotic conditions on aerobic metabolic scope. The available data indicate, however, that the paradigm is not universal, so further research is required on a wide diversity of speci...
Archives of Environmental Contamination and Toxicology, 2016
To assess stress level induced by multiple stressors in aquatic organism, biomarkers have been ad... more To assess stress level induced by multiple stressors in aquatic organism, biomarkers have been adopted as early warning indicator due to their high accuracy, rapidity, and sensitivity. We investigated the effects of ectoparasitic isopod infection on heavy metal bioaccumulation (Fe, Cu, Zn, and Cd) in the fish Nemipterus furcosus and profiled the expression of metallothionein (MT) and heat shock proteins 70 (HSP70) genes of the fish host. Sixty individuals (parasitized and nonparasitized with Cymothoa truncata) were collected from three sites differing in the levels of anthropogenic activities off the South China Sea. Our results revealed no significant difference in heavy metal concentrations between infected and nonparasitized fish. We observed a positive correlation between heavy metal bioaccumulation in the fish host and anthropogenic activities. Accordingly, expression analysis of MT genes in fish liver showed significant differences in expression level between sampling sites, with lowest level in the least exploited site (Batu Rakit). A reverse pattern in HSP70 gene expression was demonstrated in fish muscle, showing the highest expression at Batu Rakit. While cymothoid infection in N. furcosus had no significant impact on fish MT gene expression, it resulted in a reduction of HSP70 level in liver of parasitized fish. These findings highlight the putative roles of MT in heavy metal assessment. Future studies should determine the kinetics of cymothoid infection and other potential stressors in characterizing the HSP70 gene expression profile.
Comparative biochemistry and physiology. Toxicology & pharmacology : CBP, Jan 10, 2016
In the present study, the effect of copper was examined in the common goldfish (Carassius auratus... more In the present study, the effect of copper was examined in the common goldfish (Carassius auratus auratus). Fish were fasted and exposed to either a high (0.84μM), a low (0.34μM) or a control copper concentration (0.05μM) for 1 and 7days. Swimming performance was not affected by either fasting or copper exposure. Food deprivation alone had no effect on ionoregulation, but low plasma osmolality levels and plasma Na(+) were noticed in fasted fish exposed to Cu for 7days. Both gill Na(+)/K(+)-ATPase and H(+)-ATPase activities were undisturbed, while both kidney ATPase activities were up-regulated when challenged with the high Cu levels. Up-regulated kidney ATPase activities likely acted as compensatory strategy to enhance Na(+) reabsorption. However, this up-regulation was not sufficient to restore Na(+) to control levels in the highest exposure group.
This study investigates the trophic interactions and As and Cd transfer along seven marine ecosys... more This study investigates the trophic interactions and As and Cd transfer along seven marine ecosystems in Peru. Five of these ecosystems are driven by aquaculture of the Peruvian scallop Argopecten purpuratus. A southward increased gradient of δ15N was observed among the three examined regions along the Peruvian coast. The stable isotope analysis in R (SIAR)-stable isotope mixing models helped to clarify the feeding ecology of A. purpuratus and its important predators (e.g., Bursa ventricosa, Romaleon setosum). The food items of A. purpuratus can be ranked in decreasing order of importance: seston > sediment > particulate organic matter (POM) > brackish-and-fresh water POM input, while A. purpuratus itself was found to be the main prey item for predators. The highest trophic magnification factors (TMFs) were 1.46 and 1.07 for As and Cd, respectively, and were both found at the location in front of the Illescas Reserve Zone (northern Peru). Metal biomagnification and non-biom...
Many species from several different families of fishes perform mouthbrooding, where one of the se... more Many species from several different families of fishes perform mouthbrooding, where one of the sexes protects and ventilates the eggs inside the mouth cavity. This ventilation behaviour differs from gill ventilation outside the brooding period, as the normal, small-amplitude suction-pump respiration cycles are alternated with actions including near-simultaneous closed-mouth protrusions and high-amplitude depressions of the hyoid. The latter is called churning, referring to its hypothetical function in moving around and repositioning the eggs by a presumed hydrodynamic effect of the marked shifts in volume along the mouth cavity. We tested the hypothesis that churning causes the eggs located posteriorly in the mouth cavity to move anteriorly away from the gill entrance. This would prevent or clear accumulations of brood at the branchial basket, which would otherwise hinder breathing by the parent. Dual-view videos of female Nile tilapias (Oreochromis niloticus) during mouthbrooding s...
The two morphotypes (leiurus and trachurus) of the three-spined stickleback Gasterosteus aculeatu... more The two morphotypes (leiurus and trachurus) of the three-spined stickleback Gasterosteus aculeatus, caught at the same location and time in the River Scheldt (Belgium), were investigated for physiological differences in swimming capacity and energetics associated with ...
XV Congreso Latinoamericano de Ciencias del Mar – COLACMAR. Oral presentation: Bioaccumulation of... more XV Congreso Latinoamericano de Ciencias del Mar – COLACMAR. Oral presentation: Bioaccumulation of cadmium and copper in juvenile European sea bass “Dicentrarchus labrax” following acute and chronic exposure
IV Congreso de Ciencias del Mar del Perú – CONCIMAR. Oral presentation: Influencia de la Salinida... more IV Congreso de Ciencias del Mar del Perú – CONCIMAR. Oral presentation: Influencia de la Salinidad en la Bioacumulación y Toxicidad de Metales Pesados en Pez Lubina “Dicentrarchus Labrax”
European sea bass Dicentrarchus labrax was acutely exposed to Cd concentrations of 17.79, 142.33 ... more European sea bass Dicentrarchus labrax was acutely exposed to Cd concentrations of 17.79, 142.33 and 177.92 μM and Cu concentration of 31.47, 75.54 and 80.26 μM over a 10-day period, and to chronically Cd concentration of 14.46 μM and a Cu concentration of 10.76 μM (according to 10% of 96h-LC50 obtained values at 20‰) for a short exposure period (SEP) of 10 days and long period (LEP) of 28 days, both experiments were conducted at 20‰. Survival time in relation to the tissue Cu does not show a clear relationship between tissue Cu and time to death, tissue concentrations in dead fish was in the same range as concentrations in the survivors. However for Cd, a significant difference were observed in tissue Cd, the dead individuals exhibited accumulated Cd about of 5 to 18-fold more in liver, 10-31-fold in kidney, 12-31-fold in gill and 1.5-29-fold in intestine than in surviving individuals, this seems to explain partially the cause of death. Among dead and surviving individuals, a clear difference in speed of accumulation (μmol/g dwt /day) was apparent, accumulation rates were extremely high in dead fish, such as 2.417 ± 1.774 and 10.076 ± 11.097 in kidney compared to lower values than 0.035 and 0.026 of exposed survivors to Cd and Cu respectively. All examined tissues (liver, kidney, gill and intestine) showed significantly higher Cd accumulation rates at the two highest acute exposures compared to chronic exposed fish (with the exception of kidney at 177. 92 μM), whereas for Cu, intestine and gill showed the same pattern for all acute exposures, and kidney and liver only over 80.26 and 75.54 μM exposure respectively. Among the different exposure periods, liver, gill and intestine Cd were significantly higher over the LEP, while kidney does not show variations. For Cu, liver and intestine from the LEP also exhibited significantly higher concentrations compared to those at SEP. Kidney and gill showed the opposite response but not statistically different (SEP > LEP in Cu concentrations).
Uploads