This study aimed to assess the effects of low and high water hardness in interaction with differe... more This study aimed to assess the effects of low and high water hardness in interaction with different water pH in pacu (Piaractus mesopotamicus). Pacu juveniles were subjected to low (50 mg CaCO3 L-1 - LWH) or high water hardness (120 mg CaCO3 L-1 - HWH) at water pH of 5.5 (acidic), 7.5 (circumneutral) or 9.0 (alkaline) for 15 days. Gills and kidneys were collected (days 1, 5 and 15). Gill Na+/K+-ATPase (NKA) and vacuolar-type H+-ATPase (V-ATPase) activities were higher in alkaline pH with HWH on day 1. Gill and kidney NKA and V-ATPase activities were higher in acidic pH with LWH on day 15. Gill NKA activity of pacus under alkaline pH with LWH was higher than those exposed to HWH. Reduced antioxidant capacity in the gills and kidney and enhanced thiobarbituric acid reactive substances (TBARS) levels were demonstrated in fish exposed to acidic or alkaline pH, mainly with LWH. HWH increased glutathione-S-transferase (GST) activity and reduced TBARS levels in the gills and kidney. On day...
This study analyzed the relationship between several water quality parameters (pH, hardness, alka... more This study analyzed the relationship between several water quality parameters (pH, hardness, alkalinity, turbidity, iron and manganese) levels measured over a 16 year period with fish distribution and aquaculture in the state of Rio Grande do Sul, Southern Brazil. The mean pH values were within a neutral range (6.5-7.5), but the maximum and minimum values reached inappropriate levels for fish farming in some cities. Alkalinity levels were very low (except in the southwest region of the state), which may have contributed to pH variation. Hardness, turbidity, iron (except the region near Caçapava do Sul City) and manganese were within safe ranges for fish farming; however, turbidity levels occasionally increased to levels outside the safe range. In conclusion, the water quality in the Rio Grande do Sul, in general, can be considered adequate for aquaculture, but the fish farmers must be aware of the methods to reduce turbidity, such as the use of calcium sulfate.
Marine and Freshwater Behaviour and Physiology, 2015
The White Shrimp (Litopenaeus vannamei) is reared in several types of systems. Changes in pH in s... more The White Shrimp (Litopenaeus vannamei) is reared in several types of systems. Changes in pH in some can produce sub-lethal effects that result in poor growth and survival. The aim of the present study was to determine the acidic and basic pH 50% lethal limits after 96 h exposure (pH50–96 h) and to evaluate the sub-lethal effects of pH on oxidative stress parameters in juvenile L. vannamei. The experimental design comprised nine treatments with three replications of each. The nine treatments consisted of pH 10.5, 10.0, 9.5, 9.0, 7.0, 5.0, 4.5, 4.0 and 3.5. The treatment at 7.0 was used as the control. The sub-lethal pH tests were: basic pH 9.5, neutral pH 7.0 (control) and acidic pH 4.5. For each experimental pH and sampling point, the hemolymph of six shrimp was collected to determine catalase and glutathione S-transferase’s activities and total antioxidant capacity. The values of lethal pH50 at 24, 48, 72 and 96 h for juvenile L. vannamei had basic pH values equal to 9.82, 9.62, 9.59 and 9.58 and acidic pH values of 3.86, 3.92, 3.94 and 4.04, respectively. The shrimp exposed to basic and acidic pH levels showed antioxidant responses with changes in antioxidant activity.
The aim of this study was to determine oxidative stress parameters in the liver and gill of Brazi... more The aim of this study was to determine oxidative stress parameters in the liver and gill of Brazilian flounder juveniles (307.0 ± 16.0 g and 30.0 ± 4.0 cm) submitted to different water temperature (17.1, 23.0 and 28.8ºC) for 72 h and maintained at salinity 25‰. After the acclimation of 7 days, in 23ºC, fish were transferred to 200 L tanks containing seawater (salinity 25‰) at 28.8ºC (heat shock), 17.1ºC (cold shock) or 23.0ºC (control), five replicates (five fish tank-1). The sampled collection occurred in 0 (pre-challenge), 3, 24, 48 and 72 h after temperature shock. Flounder exposed to 17.1ºC and 28.8ºC showed significantly higher TBARS levels and GST activity in the liver post-exposition (PE) in relation to the control (23ºC). CAT activity in liver present a significantly increase at 17.1ºC, in first 48 h, and subsequently decrease in 72 h PE in relation to 28.8ºC. The gills of flounder showed significantly higher TBARS levels, GST and CAT activity when submitted at 17.1 and 28.8...
Ionic contents (Na+, K+ and Cl-) of plasma and gallbladder bile (GB) of juveniles silver catfish,... more Ionic contents (Na+, K+ and Cl-) of plasma and gallbladder bile (GB) of juveniles silver catfish, Rhamdia quelen (156.1±0.2g, 28.2±0.3cm), were determined in three different times (0, 6 and 24h) after exposure to: a) control or high dissolved oxygen (DO = 6.5mg L-1) + low NH3 (0.03mg L-1); b) low DO (3.5mg L-1) + low NH3; c) high DO + high NH3 (0.1mg L-1); and d) low DO + high NH3. High waterborne NH3 or low DO levels increased plasma and GB ion levels. These parameters might have followed different mechanisms to affect osmoregulation since a synergic effect of these variables was detected.
The present study compared some morphometric parameters of the digestive tract of four teleosts w... more The present study compared some morphometric parameters of the digestive tract of four teleosts with different feeding habits: traira (Hoplias malabaricus, carnivore), silver catfish (Rhamdia quelen, omnivore), hassar (Hoplosternum littorale, omnivore), and grass carp (Ctenopharyngodon idella, herbivore). The digestive tract was removed from fish collected from nature and fixed for some morphometric analyses, such as: intestinal quotient, intestinal area quotient, vilosity height, digestive somatic index, and hepatosomatic index. Grass carp showed the highest values of intestinal quotient and height vilosity. On the other hand, the intestinal area quotient was higher in traira than in the other species. The intestinal quotient can be used to estimate the feeding habit, and the intestinal area quotient, vilosity height and the relationships between digestive tract length and fish weight or digestive tract weight can provide important additional information to analyze the feeding habits.
The effects of various levels of oxygen saturation and ammonia concentration on NTPDase (ecto-nuc... more The effects of various levels of oxygen saturation and ammonia concentration on NTPDase (ecto-nucleoside triphosphate diphosphohydrolase, E.C. 3.6.1.5) and acetylcholinesterase (AChE, E.C. 3.1.1.7) activities in whole brain of teleost fish (Rhamdia quelen) were investigated. The fish were exposed to one of two different dissolved oxygen levels, including high oxygen (6.5 mg.L-1) or low oxygen (3.5 mg.L-1), and one of two different ammonia levels, including high ammonia (0.1 mg.L-1) or low ammonia (0.03 mg.L-1) levels. The four experimental groups included the following (A) control, or high dissolved oxygen plus low NH3; (B) low dissolved oxygen plus low NH3; (C) high dissolved oxygen plus high NH3; (D) low dissolved oxygen plus high NH3. We found that enzyme activities were altered after 24 h exposure in groups C and D. ATP and ADP hydrolysis in whole brain of fish was enhanced in group D after 24 h exposure by 100% and 119%, respectively, compared to the control group. After 24 h e...
The purpose of this study was to investigate Na+, Cl-, K+, Ca2+, and Mg2+ levels in the plasma of... more The purpose of this study was to investigate Na+, Cl-, K+, Ca2+, and Mg2+ levels in the plasma of freshwater and marine/estuarine teleosts collected at different salinities (0 to 34) from the estuarine and freshwater portions of the São Gonçalo channel in Southern Brazil. Any relationship between plasma ion levels and salinity and the capacity of ionic regulation of teleosts found at three or more different salinities (Genidens barbus and Micropogonias furnieri) was also investigated. Results showed no relationship between plasma ion levels and salinity when considering all species together, but the two species collected from three or more different salinities showed a significant positive relationship between plasma ion levels and salinity, indicating that G. barbus and M. furnieri have a high capacity to regulate plasma ion levels at both low and high salinities.
The objective this study was to evaluate the effects of dietary protein levels in pirapitinga, Pi... more The objective this study was to evaluate the effects of dietary protein levels in pirapitinga, Piaractus brachypomus, submited to extremely acidic or alkaline pH. Juveniles were fed for 20 days with three diets with different crude protein (CP) levels (25.3, 32.4 and 40.0%) and then separated in five groups (n=10, three replicates each) which were kept in 60 L aquaria and exposed to pH 3.0, 3.5, 7.0, 10, or 10.5. Fish were removed from aquaria when they showed loss of swimming balance, and then blood was collected and plasma separated for measurement of Na+, Cl- and K+ levels. The increase of dietary protein levels (up to 40.0% CP) provided some protection for pirapitinga at pH 3.5 or 10.0 because the time to lose equilibrium increased after acute exposure, but was not effective for compensating ion loss at very acidic (Na+ and Cl-) and alkaline (Cl-) pH.
This study aimed to assess the effects of low and high water hardness in interaction with differe... more This study aimed to assess the effects of low and high water hardness in interaction with different water pH in pacu (Piaractus mesopotamicus). Pacu juveniles were subjected to low (50 mg CaCO3 L-1 - LWH) or high water hardness (120 mg CaCO3 L-1 - HWH) at water pH of 5.5 (acidic), 7.5 (circumneutral) or 9.0 (alkaline) for 15 days. Gills and kidneys were collected (days 1, 5 and 15). Gill Na+/K+-ATPase (NKA) and vacuolar-type H+-ATPase (V-ATPase) activities were higher in alkaline pH with HWH on day 1. Gill and kidney NKA and V-ATPase activities were higher in acidic pH with LWH on day 15. Gill NKA activity of pacus under alkaline pH with LWH was higher than those exposed to HWH. Reduced antioxidant capacity in the gills and kidney and enhanced thiobarbituric acid reactive substances (TBARS) levels were demonstrated in fish exposed to acidic or alkaline pH, mainly with LWH. HWH increased glutathione-S-transferase (GST) activity and reduced TBARS levels in the gills and kidney. On day...
This study analyzed the relationship between several water quality parameters (pH, hardness, alka... more This study analyzed the relationship between several water quality parameters (pH, hardness, alkalinity, turbidity, iron and manganese) levels measured over a 16 year period with fish distribution and aquaculture in the state of Rio Grande do Sul, Southern Brazil. The mean pH values were within a neutral range (6.5-7.5), but the maximum and minimum values reached inappropriate levels for fish farming in some cities. Alkalinity levels were very low (except in the southwest region of the state), which may have contributed to pH variation. Hardness, turbidity, iron (except the region near Caçapava do Sul City) and manganese were within safe ranges for fish farming; however, turbidity levels occasionally increased to levels outside the safe range. In conclusion, the water quality in the Rio Grande do Sul, in general, can be considered adequate for aquaculture, but the fish farmers must be aware of the methods to reduce turbidity, such as the use of calcium sulfate.
Marine and Freshwater Behaviour and Physiology, 2015
The White Shrimp (Litopenaeus vannamei) is reared in several types of systems. Changes in pH in s... more The White Shrimp (Litopenaeus vannamei) is reared in several types of systems. Changes in pH in some can produce sub-lethal effects that result in poor growth and survival. The aim of the present study was to determine the acidic and basic pH 50% lethal limits after 96 h exposure (pH50–96 h) and to evaluate the sub-lethal effects of pH on oxidative stress parameters in juvenile L. vannamei. The experimental design comprised nine treatments with three replications of each. The nine treatments consisted of pH 10.5, 10.0, 9.5, 9.0, 7.0, 5.0, 4.5, 4.0 and 3.5. The treatment at 7.0 was used as the control. The sub-lethal pH tests were: basic pH 9.5, neutral pH 7.0 (control) and acidic pH 4.5. For each experimental pH and sampling point, the hemolymph of six shrimp was collected to determine catalase and glutathione S-transferase’s activities and total antioxidant capacity. The values of lethal pH50 at 24, 48, 72 and 96 h for juvenile L. vannamei had basic pH values equal to 9.82, 9.62, 9.59 and 9.58 and acidic pH values of 3.86, 3.92, 3.94 and 4.04, respectively. The shrimp exposed to basic and acidic pH levels showed antioxidant responses with changes in antioxidant activity.
The aim of this study was to determine oxidative stress parameters in the liver and gill of Brazi... more The aim of this study was to determine oxidative stress parameters in the liver and gill of Brazilian flounder juveniles (307.0 ± 16.0 g and 30.0 ± 4.0 cm) submitted to different water temperature (17.1, 23.0 and 28.8ºC) for 72 h and maintained at salinity 25‰. After the acclimation of 7 days, in 23ºC, fish were transferred to 200 L tanks containing seawater (salinity 25‰) at 28.8ºC (heat shock), 17.1ºC (cold shock) or 23.0ºC (control), five replicates (five fish tank-1). The sampled collection occurred in 0 (pre-challenge), 3, 24, 48 and 72 h after temperature shock. Flounder exposed to 17.1ºC and 28.8ºC showed significantly higher TBARS levels and GST activity in the liver post-exposition (PE) in relation to the control (23ºC). CAT activity in liver present a significantly increase at 17.1ºC, in first 48 h, and subsequently decrease in 72 h PE in relation to 28.8ºC. The gills of flounder showed significantly higher TBARS levels, GST and CAT activity when submitted at 17.1 and 28.8...
Ionic contents (Na+, K+ and Cl-) of plasma and gallbladder bile (GB) of juveniles silver catfish,... more Ionic contents (Na+, K+ and Cl-) of plasma and gallbladder bile (GB) of juveniles silver catfish, Rhamdia quelen (156.1±0.2g, 28.2±0.3cm), were determined in three different times (0, 6 and 24h) after exposure to: a) control or high dissolved oxygen (DO = 6.5mg L-1) + low NH3 (0.03mg L-1); b) low DO (3.5mg L-1) + low NH3; c) high DO + high NH3 (0.1mg L-1); and d) low DO + high NH3. High waterborne NH3 or low DO levels increased plasma and GB ion levels. These parameters might have followed different mechanisms to affect osmoregulation since a synergic effect of these variables was detected.
The present study compared some morphometric parameters of the digestive tract of four teleosts w... more The present study compared some morphometric parameters of the digestive tract of four teleosts with different feeding habits: traira (Hoplias malabaricus, carnivore), silver catfish (Rhamdia quelen, omnivore), hassar (Hoplosternum littorale, omnivore), and grass carp (Ctenopharyngodon idella, herbivore). The digestive tract was removed from fish collected from nature and fixed for some morphometric analyses, such as: intestinal quotient, intestinal area quotient, vilosity height, digestive somatic index, and hepatosomatic index. Grass carp showed the highest values of intestinal quotient and height vilosity. On the other hand, the intestinal area quotient was higher in traira than in the other species. The intestinal quotient can be used to estimate the feeding habit, and the intestinal area quotient, vilosity height and the relationships between digestive tract length and fish weight or digestive tract weight can provide important additional information to analyze the feeding habits.
The effects of various levels of oxygen saturation and ammonia concentration on NTPDase (ecto-nuc... more The effects of various levels of oxygen saturation and ammonia concentration on NTPDase (ecto-nucleoside triphosphate diphosphohydrolase, E.C. 3.6.1.5) and acetylcholinesterase (AChE, E.C. 3.1.1.7) activities in whole brain of teleost fish (Rhamdia quelen) were investigated. The fish were exposed to one of two different dissolved oxygen levels, including high oxygen (6.5 mg.L-1) or low oxygen (3.5 mg.L-1), and one of two different ammonia levels, including high ammonia (0.1 mg.L-1) or low ammonia (0.03 mg.L-1) levels. The four experimental groups included the following (A) control, or high dissolved oxygen plus low NH3; (B) low dissolved oxygen plus low NH3; (C) high dissolved oxygen plus high NH3; (D) low dissolved oxygen plus high NH3. We found that enzyme activities were altered after 24 h exposure in groups C and D. ATP and ADP hydrolysis in whole brain of fish was enhanced in group D after 24 h exposure by 100% and 119%, respectively, compared to the control group. After 24 h e...
The purpose of this study was to investigate Na+, Cl-, K+, Ca2+, and Mg2+ levels in the plasma of... more The purpose of this study was to investigate Na+, Cl-, K+, Ca2+, and Mg2+ levels in the plasma of freshwater and marine/estuarine teleosts collected at different salinities (0 to 34) from the estuarine and freshwater portions of the São Gonçalo channel in Southern Brazil. Any relationship between plasma ion levels and salinity and the capacity of ionic regulation of teleosts found at three or more different salinities (Genidens barbus and Micropogonias furnieri) was also investigated. Results showed no relationship between plasma ion levels and salinity when considering all species together, but the two species collected from three or more different salinities showed a significant positive relationship between plasma ion levels and salinity, indicating that G. barbus and M. furnieri have a high capacity to regulate plasma ion levels at both low and high salinities.
The objective this study was to evaluate the effects of dietary protein levels in pirapitinga, Pi... more The objective this study was to evaluate the effects of dietary protein levels in pirapitinga, Piaractus brachypomus, submited to extremely acidic or alkaline pH. Juveniles were fed for 20 days with three diets with different crude protein (CP) levels (25.3, 32.4 and 40.0%) and then separated in five groups (n=10, three replicates each) which were kept in 60 L aquaria and exposed to pH 3.0, 3.5, 7.0, 10, or 10.5. Fish were removed from aquaria when they showed loss of swimming balance, and then blood was collected and plasma separated for measurement of Na+, Cl- and K+ levels. The increase of dietary protein levels (up to 40.0% CP) provided some protection for pirapitinga at pH 3.5 or 10.0 because the time to lose equilibrium increased after acute exposure, but was not effective for compensating ion loss at very acidic (Na+ and Cl-) and alkaline (Cl-) pH.
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Papers by Luciano De O. Garcia