Cadmium and copper reduce hematopoietic potential in common carp (Cyprinus carpio L.) head kidney

The effects of cadmium and copper on activity of common carp head kidney hematopoietic tissue were evaluated. The fish were subjected to short-term (3 h, Cd-s and Cu-s) or long-term (4 weeks, Cd-l and Cu-l) exposures to 100 % 96hLC₅₀ or 10 % 96hLC₅₀, respectively. Head kidneys were isolated weekly from 5 fish of each group for 4 weeks (post-short-term exposure and during long-term exposure). Percentage of early blast cells among the hematopoietic precursors was calculated. Proliferative and apoptotic activity were evaluated using immunocytochemical staining for proliferating cell nuclear antigen (PCNA) and caspase 3, respectively. Hematopoietic activity was calculated as the ratio of proliferating to apoptotic cells. All metal exposures induced an increase in frequency of early blast cells. The frequency of proliferating (PCNA-positive) cells also significantly increased. A considerable and significant increase in the frequency of apoptotic cells was the most pronounced effect of metal exposures. Both short-term and long-term treatments caused similar effects, but in case of Cd exposures, the reaction was more pronounced. All metal exposures reduced hematopoietic potential of fish measured as the ratio of proliferating to apoptotic precursor cell frequency. However, in all cases, hematopoietic activity was higher than 1 showing that the rate of repair of hematopoietic tissue prevailed over destruction.     

Effects of calcium and copper exposure on lipogenic metabolism, metal element compositions and histology in Synechogobius hasta

The present study was conducted to evaluate the effects of calcium (Ca) and copper (Cu) exposure on growth performance, metal element composition, enzymatic activities and histology in Synechogobius hasta and tested the hypothesis that Ca could protect against Cu-induced toxicity in the fish species. Three hundred sixty S. hasta (initial mean weight 22.6 ± 0.2 g, mean ± SEM) were stocked in 18 circular fiberglass tanks (water volume: 300 l), 9 of which were pre-exposed to Ca at a rate of 600 mg Ca/l for 10 days and then exposed to concentrations of 0, 77 and 154 μg Cu/l for 30 days. Another 9 tanks were cultured in natural seawater (no extra Ca addition) for 10 days and then exposed to concentrations of 0, 77 and 154 μg Cu/l for 30 days. Both Ca exposure and then waterborne Cu exposure influenced the accumulation of metal elements (Cu, iron, zinc and manganese) in several tissues (muscle, intestine, gill, liver and spleen), changed hepatic lipogenic metabolism and induced histological alterations in liver, gill and spleen. In general, Ca exposure seemed to mitigate the severity of Cu-induced mortality and histopathological injuries, indicating that Ca exposure had the capacity to decrease Cu toxicity in S. hasta. To our knowledge, it is the first study involved in the effects of Ca and Cu exposure on hepatic lipogenic metabolism and metal element compositions in a wide range of tissues and organs in fish, which provides new insight into the protective effect of Ca on toxic metal elements in fish.     

两种多糖对齐口裂腹鱼生长、血清抗氧化指标及组织镉积累量的影响

为研究0.40%硫酸软骨素(CS)和酸解氧化魔芋葡甘露聚糖(AOKGM)对齐口裂腹鱼生长、抗氧化及镉胁迫之后抗氧化性能和组织中(肝脏、肾脏和鳃)镉积累量的影响,实验选取450尾初始体质量为(98.00±8.54) g的齐口裂腹鱼分为3组(对照组、AOKGM组和CS组),进行为期8周的养殖实验,然后每个实验组选取120尾齐口裂腹鱼暴露在镉环境中,进行15 d的镉胁迫实验(镉浓度分别为0、0.10、0.25和1.00 mg/L),分别对2种多糖在齐口裂腹鱼生长及抗氧化性能方面进行相关研究,以及分析镉胁迫后2种多糖的抗氧化性能和组织中镉的积累量。结果显示,与对照组相比,2种多糖显著提高了齐口裂腹鱼的特定生长率、脾体指数和头肾指数;粗脂肪、灰分和粗蛋白质相对于对照组也有显著影响。CS和AOKGM均显著提高血清超氧化物歧化酶(SOD)活性、总蛋白(TP)和一氧化氮(NO)含量,降低葡萄糖(GLU)含量;CS能显著提高血清谷胱甘肽过氧化物酶(GSH-Px)活性和胆固醇(TC)含量,降低丙二醛(MDA)含量。结果显示,与镉浓度0 mg/L相比,MDA含量在镉浓度为1.00 mg/L时最高,SOD活性在镉浓度为1.00 mg/L时最低,GSH-Px活性在镉浓度为0.25和1.00 mg/L时显著降低,NO含量在镉浓度为0.25和1.00 mg/L时显著升高。镉胁迫实验中,与对照组相比,2种多糖组的SOD活性显著提高,MDA含量降低;NO含量在镉浓度0.10～1.00 mg/L胁迫时显著降低;CS显著提高镉浓度0.10、0.25 mg/L胁迫下的GSH-Px活性,AOKGM组GSH-Px活性在镉浓度为0.25、1.00 mg/L时显著高于对照组。与无镉组对比,齐口裂腹鱼肝脏、肾脏和鳃镉的积累量在各镉浓度下显著增加;而CS和AOKGM均能够降低机体组织镉含量。研究表明,在饲料中添加0.40%的2种多糖均能提高齐口裂腹鱼生长、抗氧化性能,降低镉胁迫下鱼体肝脏、肾脏和鳃中镉的积累量,缓解镉对齐口裂腹鱼造成的氧化损伤,为齐口裂腹鱼饲料的开发提供新的理论依据。     

Trace metal levels in eels grown in power station cooling water

Measurements have been made of heavy metal concentrations in eels grown in condenser discharge water and cooling-tower pond water to ascertain if abnormal metal accumulation occurs under these conditions. Eels from other locations were also analysed to provide comparative data. Cadmium, copper, iron, nickel and zinc concentrations were measured in liver and muscle tissue. Comparison of the metal concentrations in the eels maintained in the three experimental regimes with those from other sites does not indicate any abnormal accumulation in those fish kept at an elevated temperature. The fastest growing eels in condenser water appear to develop new tissues more rapidly than they accumulate metals, thus reducing the specific metal concentration.There is considerable variation in metal concentrations in eels, with particularly high liver cadmium concentrations being observed in eels collected from polluted areas of the Bristol Channel. Muscle cadmium levels, however, are generally low and constant and would not appear to constitute a human health risk from food consumption.     

Response of ATPases in the osmoregulatory tissues of freshwater fish Oreochromis niloticus exposed to copper in increased salinity

An increase in salinity of freshwater can affect the physiology and metal uptake in fish. In the present study, Nile tilapia Oreochromis niloticus were exposed to copper (1.0 mg/l) in increased salinities (2, 4, and 8 ppt) for 0, 1, 3, 7, and 14 days. Following the exposures, the activities of Na⁺/K⁺-ATPase, Mg²⁺-ATPase, and Ca²⁺-ATPase were measured in the gill, kidney, and intestine to evaluate the changes in osmoregulation of fish. Results showed that increases in salinity and Cu exposure of fish significantly altered the ATPase activities depending on the tissue type, salinity increase, and exposure durations. Salinity-alone exposures increased Na⁺/K⁺-ATPase activity and decreased Ca²⁺-ATPase activity. Na⁺/K⁺-ATPase activity decreased following Cu exposure in 2 and 4 ppt salinities, though the activity increased in 8 ppt salinity. Ca²⁺-ATPase activity decreased in the gill and intestine in all salinities, while the activity mostly increased in the kidney. However, there were great variations in Mg²⁺-ATPase activity following exposure to salinity alone and salinity+Cu combination. Cu accumulated in the gill and intestine following 14 days exposure and accumulation was negatively correlated with salinity increase. Data indicated that ATPases were highly sensitive to increases in salinity and Cu and might be a useful biomarker in ecotoxicological studies. However, data from salinity increased freshwaters should carefully be handled to see a clear picture on the effects of metals, as salinity affects both metal speciation and fish osmoregulation.     

重金属对鱼类毒性的综合研究

鱼体重金属蓄积量的研究，同时取相应组织块进行病变的内在联系及重金属对鱼胚和鱼苗的毒性作用的研究，证实了温州市水产养殖场遭受到附近一家铅锌冶炼厂废水、废渣的污染。     

Assessment of tissue-specific effect of cadmium on antioxidant defense system and lipid peroxidation in freshwater murrel, Channa punctatus

The effects of different concentrations of cadmium chloride on the extent of lipid peroxidation (LPO) and alterations in the antioxidant enzyme activities were studied in liver, kidney and gill tissues of freshwater murrel, Channa punctatus. The fish specimens were exposed to 6.7, 13.4 and 20.1 mg l⁻¹ sublethal concentrations of cadmium chloride and the oxidative stress was assessed after 24, 48, 72 and 96 h post-exposure. The biomarkers selected for the study were thiobarbituric acid reactive substances for assessing the extent of lipid peroxidation and antioxidant defense system such as reduced glutathione (GSH), glutathione reductase (GR), glutathione peroxidase (GP_X), glutathione-S-transferase (GST), catalase (CAT) and superoxide dismutase (SOD) activities. In general, the cadmium exposure elevated the LPO in subject tissues of treated group and modulated the activities of GPx, GST, SOD, CAT, GR and level of GSH after given exposure as compared to the control. All enzymes activities, except CAT (in kidney and gills), and amount of LPO elevated significantly (P < 0.05) in treated group with respect to control in all tissues, while significant difference was not observed between the exposed concentrations and within exposure duration. The results indicated that increase in LPO level and the fluctuation in antioxidant defense system in fish could be due to cadmium-induced increase in the production of reactive oxygen species (ROS). The potential role of these parameters as biomarkers of heavy metal pollution in aquatic system is discussed.     

Acute exposure to copper induces variable intensity of oxidative stress in goldfish tissues

Copper is an essential element, but at high concentrations, it is toxic for living organisms. The present study investigated the responses of goldfish, Carassius auratus, to 96 h exposure to 30, 300, or 700 μg L^?1 of copper II chloride (Cu²⁺). The content of protein carbonyls was higher in kidney (by 158%) after exposure to 700 mg L^?1 copper, whereas in gills, liver, and brain, we observed lower content of protein carbonyls after exposure to copper compared with control values. Exposure to copper resulted in increased levels of lipid peroxides in gills (76%) and liver (95–110%) after exposure to 300 and 700 μg L^?1 Cu²⁺. Low molecular mass thiols were depleted by 23–40% in liver and by 29–67% in kidney in response to copper treatment and can be used as biomarkers toxicity of copper. The activities of primary antioxidant enzymes, superoxide dismutase and catalase, were increased in liver as a result of Cu²⁺ exposure, whereas in kidney catalase activity was decreased. The activities of glutathione-related enzymes, glutathione peroxidase, glutathione-S-transferase, and glutathione reductase were decreased as a result of copper exposure, but glutathione reductase activity increased by 25–40% in liver. Taken together, these data show that exposure of fish to Cu²⁺ ions results in the development of low/high intensity oxidative stress reflected in enhanced activities of antioxidant and associated enzymes in different goldfish tissues.     

Mercury and methyl mercury concentration in sediment,benthic, Barbus Grypus and pelagic,Barbus esocinus fish species,from Musa estuary,Iran

The concentrations of mercury (Hg) and methyl mercury (MeHg) in sediment and tissues of Barbus grypus and Barbus esocinus fish species from Musa estuary, north part of the Persian Gulf, were measured. The order of Hg and MeHg concentrations in the sediment and tissues of the fish species was as follows: liver > gill > muscle > sediment. In the tissues of two fish species, the Hg and MeHg concentrations were highest in liver whereas lowest in the muscle. In the sediment, mean concentrations of Hg and MeHg were 0.83 and 0.437 µg g^?1. Mean concentrations of Hg and MeHg in B. grypus were 1.2–0.624 µg g^?1 and in all tissues of B. esocinus were 0.75 and 0.421 µg g^?1. Significant correlation between heavy metal concentration in sediment and fish may be related to high variability of heavy metal in the sediment.     

Effects of fish size on the response of antioxidant systems of Oreochromis niloticus following metal exposures

The size of a fish is an important factor in its physiology, and metal uptake is affected by animal physiology. In this study, small and large tilapias (Oreochromis niloticus) differing approximately twofold in length and fivefold in weight were compared for their antioxidant response. Both groups were exposed to Cu or Cr (1.0 μg/mL) in a freshwater (?80 mg CaCO₃/L, conductivity 1.77 mS/cm) using 2 exposure protocols (20 μM for 48 h and 10 μM for 6 days). Following the exposures, the antioxidant enzyme activities (superoxide dismutase, SOD; catalase, CAT; glutathione peroxidase, GPX; glutathione reductase, GR and glutathione S-transferase, GST) and glutathione (GSH) levels were measured in the liver of fish. Results showed that small fish was affected from exposure conditions much more than large ones as their antioxidant parameters significantly decreased even in controls. Metal exposures of small fish caused significant increases in SOD and CAT activity in acute Cu or Cr exposures. Subchronic Cr exposure of small fish also caused significant increases in CAT, GPx and GST activities, while there was no significant change in Cu-exposed ones. Large fish, however, showed different antioxidant responses as their levels mostly decreased. This study demonstrated that the response of antioxidant system in the liver of tilapia varied in relation to fish sizes and emphasized using different size groups in environmental monitoring and also in evaluation of fish biomarkers.     

Effect of taurine supplementation on hepatic metabolism and alleviation of cadmium toxicity and bioaccumulation in a marine teleost,red sea bream, <Emphasis Type="Italic">Pagrus major</Emphasis>

This study was performed to unravel the mechanism of the beneficial action of taurine on marine teleost fish, red sea bream (Pagrus major), by analyzing the hepatic metabolism. Moreover, the ameliorative effects of the nutrient against cadmium toxicity and bioaccumulation were further evaluated. The fish were fed a diet containing 0 % (TAU0 %), 0.5 % (TAU0.5 %), or 5.0 % (TAU5.0 %) taurine for 40–55 days (d) and subjected to cadmium acute toxicity and bioaccumulation tests. Taurine deficiency in feed severely affected growth and the hepatic metabolic profiles of the fish, including a remarkable increase in myo-inositol, aspartate, and ß-alanine in the TAU0 % group, which indicates a complementary physiological response to taurine deficiency. For the acute toxicity test, fish were fed the test diets for 55 d and were then exposed to different dose of cadmium ranging from 0 to 5.6 mg/L for 96 h. Fish fed taurine had a higher tolerance to cadmium than those not fed taurine. For the bioaccumulation test, fish were fed the test diets for 40 d and then were chronically exposed to 0.2 mg/L of cadmium for 28 d followed by depuration for 21 d. Cadmium concentrations in the liver and muscle of fish fed TAU5.0 % were significantly lower than those of fish fed TAU0 % for the first 7 d of exposure and the first 7 d of elimination. Our findings suggest a possible mechanism for the beneficial role played by taurine and that the inclusion of taurine in fish aquaculture feed may reduce cadmium contamination of fish intended for human consumption.     

Alteration in certain enzymological parameters of an Indian major carp, Cirrhinus mrigala exposed to short- and long-term exposure of clofibric acid and diclofenac

The extensive use of pharmaceuticals in human and veterinary medicine may enter the aquatic environment and pose a serious threat to non-target aquatic organisms like fish. In this study, Indian major carp Cirrhinus mrigala was exposed to different concentrations (1, 10 and 100 μg L^?l) of most commonly used pharmaceutical drugs clofibric acid (CA) and diclofenac (DCF) to evaluate its impacts on certain enzymological parameters during short- and long-term exposures. During short-term (96 h) exposure period, plasma glutamate oxaloacetate transaminase (GOT), glutamate pyruvate transaminase (GPT) and gill Na⁺/K⁺-ATPase activity were significantly altered at all concentrations of both the CA- and DCF-treated fish. In long-term exposure (35 days), gill Na⁺/K⁺-ATPase activity was found to be significantly increased at all concentration of CA and DCF exposures throughout the study period (except at the end of 7th day in 10 and 100 µg L-1) . However, a biphasic trend was observed in plasma GOT and GPT activity when compared to the control groups. In both short- and long-term exposure, a significant (P < 0.01 and P < 0.05) changes were observed in all enzymological parameters of fish C. mrigala exposed to different concentrations of CA and DCF. The alterations of these enzymological parameters can be effectively used as potential biomarkers in monitoring of pharmaceutical toxicity in aquatic environment and organisms.     

Induction of metallothionein synthesis in rainbow trout,Salmo gairdneri,during long-term exposure to waterborne cadmium

Rainbow trout were exposed to 200 g cadmium/l in the water during four months at 6–10°C. The liver, kidney and gills were analyzed for cadmium, copper, zinc, metallothionein and metallothionein mRNA. Cadmium accumulated in all three organs and reached the highest concentration in the kidney. The tissue zine and copper concentrations showed no major alterations during the experiment. The cytosolic distribution of cadmium, copper and zinc was followed during four months of exposure by Sephadex G-75 chromatography. It was found that cadmium was predominantly associated with proteins of an apparent molecular vieght of 10,000 daltons. These proteins were further identified as metallothioneins after fast protein liquid chromatography on a Mono-Q column. The metallothionein concentration was significantly higher in liver of exposed fish than in control fish after only one month. The kidneys reached significantly elevated levels of metallothionein in the exposed group after three months. In the gills, elevated metallothionein concentrations were observed after four months of exposure. After four months of exposure, the metallothionein mRNA content of liver and kidney was analyzed using a rainbow trout anti-sense RNA probe. Elevated MT mRNA levels were observed in both kidney and liver. These results demonstrate thatde novo synthesis of metallothionein is induced by cadmium in rainbow trout after exposure to the metalvia water.     

Copper and lead accumulation in common carp females during long‐term dietary exposure to these metals in pond conditions

The aim of the research was to observe the process of copper and lead accumulation in tissues of adult females of the common carp, during a long‐time (3 years) dietary exposure to these metals in pond conditions. The fish were divided into 3 groups, which were fed with control pellets (control group) and pellets contaminated with lead (group Pb, 68.4 mg Pb kg^?1dry weight) or copper (group Cu, 153.1 mg Cu kg^?1) for three exposure periods: the first, the second and the third vegetation seasons. Quite a different profile of tissue metal accumulation was observed for copper and for lead in female carps. Copper accumulates mainly in the liver (205.4 ± 35.2 mg kg^?1), reaching values 70 times higher than in control, and 300 times higher than in some other tissues, while lead accumulated mainly in the kidney (1.7 ± 0.25 mg kg^?1) and intestine (2.2 ± 0.2 mg kg^?1). Even when exposed to Cu or Pb for three consecutive seasons, the carps studied did not accumulate these metals in the muscles at the level dangerous for human health in case of ingestion.     

Toxicity evaluation of copper oxide bulk and nanoparticles in Nile tilapia, <Emphasis Type="Italic">Oreochromis niloticus</Emphasis>, using hematological,bioaccumulation and histological biomarkers

The increased industrial applications of nanoparticles (NPs) augment the possibility of their deposition into aquatic ecosystems and threatening the aquatic life. So, this study aimed to provide a comparable toxicological effects of nano-CuO and bulk CuO on a common freshwater fish, Oreochromis niloticus. Fish were exposed to two selected doses (1/10 and 1/20 of the LC₅₀/96 h) of both nano-/bulk CuO for 30 days. Based on the studied hematological parameters (RBCs count, hemoglobin content and hematocrit%), the two selected concentrations of CuO in their nano- and bulk sizes were found to induce significant decrease in all studied parameters. But, nano-CuO-treated fish showed the maximum decrease in all recorded parameters among the all studied groups especially at the low concentration of 1/20 LC₅₀/96 h. Hematological status was also confirmed using the calculated blood indices (MCV, MHC and MCHC). In case of bulk CuO-treated groups, the significant decrease in the studied hematological parameters was not followed by any change in MCV and MCH (normocytic anemia), while fish that exposed to NPs showed a significant increase in all calculated blood parameters reflecting erythrocytes swelling which is related to the intracellular osmotic disorders (macrocytic anemia). Regarding metal bioaccumulation factor, the results showed that CuO NPs had more efficiency to internalize fish tissues (liver, kidneys, gills, skin and muscle). The accumulation pattern of Cu metal was ensured by histopathological investigation of liver, kidneys and gills. The histopathological analysis revealed various alterations that varied between adaptation responses and permanent tissue damage.     

Metamorphosis to Postlarvae of Penaeus chinensis Osbeck by Removal of Heavy Metals from Rearing Systems with Polymeric Absorbent

The effect of removing heavy metal ions (copper, zinc, lead, and cadmium) with a polymeric heavy metal absorbent (PHMA) on metamorphosis of Penueus chinensis Osbeck was investigated. There was a significant ( P < 0.05) reduction in metamorphosis of protozoea to mysis at concentrations more than 31.0 μg/L copper, 38.3 μg/L zinc, 32.5 μg/L lead, and 30.3 μg/L cadmium, in the absence of PHMA. At concentrations more than 61.0 μg /L copper, 68.3 μg/L zinc, 62.5 μg/L lead, and 60.3 μg/L cadmium there was a significant ( P < 0.01) interaction between the absence and the presence of PHMA for metamorphosis of mysis to postlarvae. At concentrations of 12.3 μg/L copper, 45.8 μg/L zinc, 106.2 μg/L lead, and 200.2 μg/L cadmium, the metamorphosis of protozoea to mysis was blocked, but it was 51.4% in the presence of PHMA. At concentrations of 252.3 μg/L copper, 335.8 μ/L zinc, 806.2 μg/L lead and 300.2 μg/L cadmium, the metamorphosis of mysis to postlarvae was stopped, but it was 51.0% in the presence of PHMA. The toxicity of copper, zinc, lead, and cadmium to P. chinensis was reduced with PHMA.     

Specific accumulation of heavy metals in squid collected from offshore Korean waters: preliminary results for offshore biomonitoring and food safety assessment

ABSTRACT:   Japanese common squid Todarodes pacificus collected from the East Sea/Sea of Japan were analyzed for cadmium, zinc and copper to elucidate the specific accumulation of heavy metals in various organs of squid of varying size and sex. There was no relationship between the size and sex of squid and the concentrations of heavy metals in various organs. Amongst organs, the liver contained the highest concentrations of all metals and the mantle had the lowest concentrations. In the liver and gills, concentrations of copper were higher than the other metals because of the existence of copper in hemocyanin in the blood. Cadmium showed the highest ratios (L/M) of the concentrations in the liver and in the mantle, even though cadmium in liver had lower concentrations than copper and zinc. This indicates that cephalopods constitute an important source of cadmium for cephalopod predators. The results show that the Japanese common squid is a useful bioindicator of metal pollution in offshore Korean waters.     

Availability of squid viscera meal with cadmium removal treatment as a feed ingredient for fingerling black rockfish Sebastes schlegeli

Two 12-week feeding experiments were conducted to evaluate the nutritional value of squid viscera meal with cadmium removal treatment (dCSVM), which contained 1.5–2.0 mg/kg cadmium, as an alternative protein source to sardine meal in diets for fingerling black rockfish Sebastes schlegeli. Initial mean body weights in experiments 1 and 2 were 23.0 and 6.4 g, and the replacement rates of sardine meal with dCSVM in the test diets were 20–80 % and 30–60 %, respectively. In experiment 1, inclusion of dCSVM at 40 % and higher replacement rates of sardine meal retarded the growth of fish due partly to inferior dCSVM protein digestibility. The cadmium (Cd) concentrations in fish muscle of all treatment groups were below the detection limit (<0.1 mg/dry matter). In experiment 2 using dCSVM containing Cd at a lower level and having a higher protein digestibility than in experiment 1, no significant differences were observed in the growth between the control and 60 % replacement groups, although feed efficiency gradually decreased with the increase of dCSVM inclusion. These results show that dCSVM is safe and useful as an alternative protein source and could replace up to 60 % of sardine meal in fingerling black rockfish diets.     

栉孔扇贝对铜、铅、镉的累积效应

试验结果表明:当常规理化指标一致时,随着Cu、Pb、Cd质量浓度的升高,栉孔扇贝各组织的蓄积量明显升高;Cu、Cd在扇贝组织中蓄积量是内脏团>鳃>肌肉,Pb在扇贝组织中的蓄积量是鳃>内脏团>肌肉;当Cu、Pb、Cd质量浓度(0.1 mg/L)相同时,其鳃、内脏团、肌肉中重金属蓄积量的上升速率是Cu>Cd>Pb。