Bioconcentration of alcohol ethoxylates in carp (Cyprinus carpio)

The uptake, distribution, and clearance of three labeled nonionic surfactants, 14C-labeled dodecyl tetra(oxyethylene) ether [14C-C12-AE(4)], 14C-labeled dodecyl octa(oxyethylene) ether [14C-C12-AE(8)], and 14C-labeled dodecyl hexadeca(oxyethylene) ether [14C-C12-AE(16)] were investigated in carp (Cyprinus carpio) exposed to concentrations of 0.2-0.6 mg X liter-1, using whole-body autoradiography and the liquid scintillation counting method. 14C radioactivity was rapidly absorbed into the fish body and distributed in skin, nasal and oral cavities, gills, brain, hepatopancreas, kidney, gall bladder, and intestinal content at comparatively high concentrations. The calculated wet weight whole-body bioconcentration factor at steady state in the fish exposed to 14C-C12-AE(4), 14C-C12-AE(8), or 14C-C12-AE(16) for 72 hr was 310, 220, or 4.3, respectively. Clearance of 14C radioactivity from the fish body was rapid, with half-lives of 30-80 hr. The metabolites of 14C-C12-AE(4) were also examined in gills, blood, kidney, hepatopancreas, or gall bladder by thin-layer chromatography.     

Effects of water-borne cadmium on the skin of the common carp (Cyprinus carpio)

The skin of carp, Cyprinus carpio, was studied at the ultrastructural level after exposure of the fish to low and high concentrations of cadmium in the water (22 and 560 g/L, respectively) for different periods. The effects of the low concentration of cadmium were similar to those of the high concentration, although they appeared later. The basal lamina and the skin surface became highly undulating. Chloride cells appeared between the pavement cells. Necrotic pavement cells were seen from the first day on, while apoptotic pavement cells appeared after several days. Filament cells contained many electron-transparent and electron-dense secretory vesicles. Mitotic cells were commonly seen, mainly in cells adjacent to club cells or close to the epidermal surface. Mucous cells differentiated close to the skin surface. They became elongated and synthesized highly electron-dense mucosomes. The epidermis became infiltrated by many leucocytes. As the experiment progressed, many leucocytes degenerated, and their remnants were found within macrophages and club cells. Fibroblasts displayed intense synthesis and, in fish from the low cadmium concentration, deposited a dense network of collagen fibers in the dermis. Melanosomes were located in the extensions of melanocytes. In these cells aggregation of melanosomes and apoptotic processes were common. Several of these changes were observed earlier under the impact of stressors other than cadmium. Some changes, such as the appearance of tumorlike bodies at the skin surface, the appearance of Merkel cells throughout the epidermis, and the coupling of leucocytes, may be specific for cadmium.     

Bioaccumulation of micropollutants and biomarker responses in caged carp (Cyprinus carpio)

At four different aquatic sites in Flanders (Belgium) with different types and degrees of contamination, juvenile carp (Cyprinus carpio) were exposed in cages for 4 weeks. After exposure, metals, polychlorinated biphenyls (PCBs), and selected organochlorine pesticides (OCPs) were analyzed in the tissues of the carp. Besides pollutant accumulation, several effects were measured as well. Condition measures such as changes in weight, condition factor (CF), and hepatosomatic index (HSI) were assessed. In addition, activity of acetylcholinesterase (AChE) and a set of blood biochemical parameters were measured. At all sites, accumulation of metals in the fish tissues was observed. Levels of cadmium and lead at some of the exposure sites were higher than the levels at the start and comparable to levels in fish from moderately metal-contaminated sites. For most organic pollutants, however, levels were not significantly higher than at the start. Only for two PCB congeners, levels had slightly increased but were still lower than levels in carp captured at noncontaminated sites. Although food limitation probably caused some of the observed effects, significant relationships were found between metal load in tissues and CF, AChE, plasma osmolality and HSI. This study shows that caged carp might be useful for the assessment of bioaccumulation and some effects of micropollutants in aquatic ecosystems.     

A comparison of trace element concentrations in cultured and wild carp (Cyprinus carpio) of Lake Kasumigaura,Japan

The concentrations of 13 elements were determined in the muscle, liver, intestine, kidney, and gonads of cultured and wild carp caught at two sites in Lake Kasumigaura, Japan, between September 1994 and September 1995. Despite having a reputation for being heavily polluted, the carp were not heavily burdened with metals. Our results suggest that despite their dietary differences, the wild and cultured fish were accumulating and distributing metals in the same manner and that aquaculture practices are not increasing metal concentrations in these fish. Metal concentrations were lowest in muscle, and did not exceed established quality standards for fish. The differences in metal concentrations between cultivated and wild carp are negligible and should pose no health problems for consumers of either type of fish.     

Effects of long-term exposure to simazine in real concentrations on common carp (Cyprinus carpio L.)

The effects of a 90 day simazine exposure at concentrations of 0.06 (reported concentration in Czech rivers), 1, 2, and 4 μg L?1 were assessed in one-year-old common carp (Cyprinus carpio L.). Its influence on biometric parameters, hematology, blood biochemistry, liver biomarkers, and histology was investigated. Biometric parameters of common carp exposed to simazine at 0.06 μg L?1 showed no differences from untreated fish. Simazine concentrations of 1, 2, and 4 μg L?1 caused significant (p<0.01) increase of hepatosomatic indices relative to controls. Hematological profiles showed significant (p<0.01) decrease in leukocyte count relative to controls at all concentrations. Biochemical profiles of common carp exposed to simazine at all concentrations showed significant (p<0.01) increase in activity of alkaline phosphatase. In addition, at concentrations of 1 and 2 μg L?1, there was a significant increase in alanine aminotransferase (p<0.05), and, at 4 μg L?1, a significant increase in total protein (p<0.05), albumins (p<0.05), and alanine aminotransferase (p<0.05) compared with controls. Renal histology revealed severe hyaline degeneration of the epithelial cells of caudal kidney tubules in fish at all exposure levels compared to controls. Chronic exposure of common carp to simazine caused significant shifts in hematological, biochemical, and biometric profiles, and histopathological changes. The results of this study indicate that chronic exposure of simazine has altered multiple physiological indices in fish hematology and biochemistry, which potentially may be a biomarker of simazine toxicity; however, before these parameters are used as special biomarkers for monitoring residual simazine in aquatic environment, more detailed experiments in laboratory need to be performed in the future.     

鲤、鲫鱼卵脂质和脂肪酸的构成分析

<正>鱼卵富含各种长链不饱和脂肪酸,可以防治心血管疾病,尤其是磷脂中较高的磷脂酰胆碱等,有改善学习能力等营养和生理功能[1-3]。淡水杂食性鱼如鲤(Cyprinus carpio,carp)、鲫(Car-assius auratus,crucian carp)的卵,繁殖季节最大可达体重10%～25.81%。而淡水鱼卵脂质和脂肪酸,特别是磷脂,研究较少。本研究旨在分析两种淡水鱼卵脂质和脂肪酸构成。     

Dietary accumulation and metabolism of polybrominated diphenyl ethers by juvenile carp (Cyprinus carpio)

Polybrominated diphenyl ethers (PBDEs) are hydrophobic organic contaminants with properties and nomenclature similar to polychlorinated biphenyls (PCBs). While much information is available on the bioaccumulation and pharamcokinetics of PCBs, little information is available on PBDEs. In this study, juvenile carp were exposed to a diet spiked with a cocktail of four BDE congeners (2,4,4'-tribromoDE [BDE 28], 2,2',4,4'-tetrabromoDE [BDE 47], 2,2',4,4',5-pentabromoDE [BDE 99], and 2,2',4,4',5,5'hexabromoDE [BDE 153]) for 60 d followed by a 40-d depuration period. As a positive control, three PCB congeners with similar log K(ow), values (2,2',5,5'-tetrachlorobiphenyl [PCB 52], 2,2',4,4', 5,5'-hexachlorobiphenyl [PCB 153], and 2,2',3,4,4',5,5'-heptachlorobiphenyl [PCB 180]) were included in the cocktail to compare their assimilation and fate with the model BDE congeners. Concentrations of BDEs and PCBs were monitored in whole-fish tissues and liver tissues over the duration of the experiment. In addition, blood serum samples were taken and pooled among replicates to determine if any phenolic metabolites of BDE and PCBs were formed. Rapid assimilation of BDE 47 was observed relative to all other BDE and PCB congeners, whereas apparently no accumulation of BDE 99 occurred over the course of the experiment. Assimilation efficiencies for BDE 47 suggest that approximately 100% of the BDE 47 exposure was absorbed by carp tissues after 60 d. However, based on the time course of BDE 47 assimilation, it is improbable that all BDE 47 was assimilated; more likely, production of BDE 47 in carp tissues occurred as a result of debromination of higher-brominated compounds, possibly BDE 99. The net assimilation efficiencies of BDE 28 and BDE 153 were also apparently low (20 and 4%, respectively) relative to the three PCBs (40% assimilated) examined in this study. The low assimilation efficiency and high depuration rates for BDEs suggest a higher potential for biotransformation. While all three PCB compounds displayed very similar assimilation and depuration rates, three of the four BDE compounds displayed significantly different assimilation rates among BDE congeners and relative to the PCBs. This study suggests that BDEs have significantly different fate dynamics relative to PCBs in wild carp and likely other species of fish.     

Copper speciation in the gill microenvironment of carp (Cyprinus carpio) at various levels of pH

The fish gill microenvironment of Cyprinus carpio under stress of copper exposure was investigated. pH and other parameters including free copper activity, alkalinity, and inorganic and organic carbons in the surrounding water (inspired water) and in the gill microenvironment (expired water) were measured or calculated at various levels of pH and varying total copper concentrations. The chemical equilibrium calculation (from MINEQA2) and complexation modeling (mucus-copper) were coupled to calculate both species distribution. The results indicate that the pH in the fish gill microenvironment was different from that in the surrounding water with a balance point around 6.9. The secretion of both CO(2) and mucus was affected in both linear and nonlinear ways when the fish were exposed to elevated concentrations of copper. The complexation capacity of the gill mucus was characterized by a conditional stability constant (logk(Cu-mucus)) of 5.37 along with a complexation equivalent concentration (L(Cu-mucus)) of 0.96 mmol Cu/mg C. For both the fish microenvironment and the surrounding water, the dominant copper species shifted from Cu(2+) to CuCO(3)(0) and to Cu(OH)(2)(0) when the pH of the surrounding water changed from 6.12 to 8.11. The change in copper speciation in the gill microenvironment is smaller than that in the surrounding water due to the pH buffering capacity of the fish gills.     

Dietary phosphatidylcholine affects postprandial plasma levels and digestibility of lipid in common carp (Cyprinus carpio)

This study examined the effect of purified soyabean phosphatidylcholine (SPC) on circulating plasma lipids and nutrient digestibility in juvenile common carp. The fish (100 (SD 15) g, 25 degrees C) were fed, for 4 weeks, a casein-based diet containing either 12 % soyabean oil (diet SBO) or 8 % SBO plus 4 % SPC (diet SPC). The lipid, protein and energy contents of the faeces were analysed for the determination of apparent digestibility. At the end of the trial, the fish were fasted for 48 h and fed a single meal. Plasma lipids were then analysed over the next 48 h. The growth (1.63 v. 1.26 % per d) and apparent lipid digestibility (96.3 v. 92.1 %) were higher in SPC- than in SBO-fed fish. The amplitude of the postprandial (8 h after the meal) TAG peak was identical in fish from both treatments, despite the 33 % lower amount of TAG in diet SPC. Both observations support the idea that SPC stimulates intestinal TAG uptakes. The lower TAG:phospholipid ratio of the secreted plasma lipids at the time of absorption suggests a larger number of smaller intestinal lipoproteins in SPC- than SBO-fed fish, possibly due to the recycling of absorbed lysophosphatidylcholine for chylomicron formation. In the 48 h unfed state, phospholipid levels remained approximately 20 % higher in SPC-fed than in SBO-fed fish, but we observed no hypocholesterolaemic effect of SPC. In summary, the present data support earlier histological indications of a positive role of dietary phosphatidylcholine in intestinal TAG uptakes in carp.     

The influence of mucus on copper speciation in the gill microenvironment of carp (Cyprinus carpio)

pH and mucus (as total organic carbon) in the gill microenvironment of carp, Cyprinus carpio, exposed to various concentrations of total copper were measured in an exposure experiment using Playle's apparatus. The activities of free copper ions in both inspired and expired waters were determined using a copper ion selective electrode. A trial-and-error procedure of coupling species distribution calculations (MINEQA2) with single-site complexation modeling (mucus-copper) was proposed for computation of both copper speciation and complexation capacity of gill mucus for copper in an interactive loop. The method was demonstrated to be valid in calculating the metal speciation in this study. It was found that pH and alkalinity in the gill microenvironment were slightly higher than in the surrounding water of pH 6.7. The rates of excretion of CO(2), HCO(-)(3), and mucus at the gills increased, either linearly or nonlinearly with increases in the total copper concentration in the surrounding water. The conditional complexation stability constant of the mucus was calculated as log k=5.32, while the complexation stability equivalent concentration of the mucus was derived as 0.95 mmolCu/mgC. As a consequence of changes in pH and alkalinity, in conjunction with occurrence of mucus, copper speciation in the gill microenvironment is significantly different from that in the surrounding water, with 3-20% of the copper complexed by the gill mucus. The sequence of species domination also shifted from CuCO(0)(3), Cu(2+), CuHCO(+)(3), and Cu(OH)(0)(2) in the surrounding water to CuCO(0)(3), Cu(2+), Cu(OH)(0)(2), CuHCO(+)(3), and mucus-Cu in the gill microenvironment.     

Differential metallothionein induction patterns in fed and starved carp (Cyprinus carpio) during waterborne copper exposure

Starved and fed carp (Cyprinus carpio) were exposed to sublethal waterborne copper exposure (1 microM) for 28 d in softened Antwerp, Belgium, city tap water. Copper accumulation in liver and gill tissues was determined, and changes in branchial Na+/K+-adenosine 5'-triphosphatase (ATPase) activity and metallothionein (MT) induction in gill and liver tissues were investigated following 28-d copper exposure. Gill Na+/K+-ATPase activity in exposed fish, both starved and fed, was at its lowest values after 3 d of exposure, after which it slowly recovered to preexposure values. No significant differences in branchial Na+/K+-ATPase activity were found between starved and fed fish. Copper accumulation in the liver and gills of the exposed starved carp was significantly higher than that in the exposed fed carp. The highest MT induction was found in liver tissues. Different patterns of MT induction were observed in the starved and fed carp during copper exposure. Before exposure, MT concentrations in the livers of the starved fish were significantly higher than those in the fed ones. Copper exposure significantly increased MT concentration in the liver of the fed fish, but no changes occurred in the starved fish. In contrast, copper exposure increased MT concentrations in the gills of the starved fish during the first week of exposure, whereas only a slight increase in MT concentration in the gills of the fed fish was observed. When taking into account the role of feeding status in MT induction, hepatic MT was a more relevant indicator for long-term monitoring of copper pollution in carp, but gill MT provided useful information regarding short-term copper toxicity.     

Vitellogenin induction and reduced serum testosterone concentrations in feral male carp (Cyprinus carpio) captured near a major metropolitan sewage treatment plant.

Endocrine disrupting chemicals can potentially alter the reproductive physiology of fishes. To test this hypothesis, serum was collected from common carp (Cyprinus carpio) at five riverine locations in Minnesota. Male fish collected from an effluent channel below the St. Paul metropolitan sewage treatment plant had significantly elevated serum egg protein (vitellogenin) concentrations and significantly decreased serum testosterone concentrations compared to male carp collected from the St. Croix River, classified as a National Wild and Scenic River. Carp collected from the Minnesota River, which receives significant agricultural runoff, also exhibited depressed serum testosterone concentrations, but no serum vitellogenin was apparent. These data suggest that North American rivers are receiving estrogenic chemicals that are biologically active, as has been reported in Great Britain.     

Toxicity of microcystins in the isolated hepatocytes of common carp (Cyprinus carpio L.)

The toxicity of hepatotoxic microcystins produced mainly by Microcystis aeruginosa in mammals and fishes was well studied in recent years. However, there were scarcely reports in toxic effects of microcystins on isolated hepatocytes of fishes, especially investigation of microcystin-induced apoptosis and/or necrosis in carp hepatocytes. In the present study, the isolated hepatocytes of common carp were exposed to various concentrations of microcystins (0.01, 0.1, 1, 10, 100, 1000 microg L(-1)) for 2, 4, 8, 16 and 24h, respectively, and cytotoxicity of microcystins in the toxin-treated cells was determined. Results of this study showed that cytotoxicity of microcystins on carp hepatocytes was time and dose-dependent, and the approximate LC(50) of microcystins in carp hepatocytes was 169.2 microg L(-1). The morphological changes typical of apoptosis, such as blebbing of cell membrane, condensation and fragmentation of cell nucleus were observed in the hepatocytes exposed to microcystins (1, 10 and 100 microg L(-1)) using fluorescence and differential interference contrast microscopy. Agarose gel electrophoresis of DNA demonstrated a typical apoptotic "ladder pattern" in microcystin-treated hepatocytes after 16 h of exposure. Results of the present study indicated that the form of cell death in microcystin-treated hepatocytes depend on the exposure dose of toxin. When lower concentration of microcystins (10 and 100 microg L(-1)) was used for exposure, carp hepatocytes died in apoptosis while, when higher one used (1000 microg L(-1)), they died in the form of necrosis.     

Reproductive toxicity in mink (Mustela vison) chronically exposed to environmentally relevant polychlorinated biphenyl concentrations

Female mink were exposed to a technical polychlorinated biphenyl (PCB) preparation (Clophen A50 [A50]; 0.1 or 0.3 mg/animal/d), one fraction of A50 containing the non- and mono-ortho-chlorinated congeners (0-1-ortho-chlorobiphenyls [CBs]), another fraction of A50 containing the congeners with two to four ortho-chlorines (2-4-ortho-CBs), or an organic extract from Baltic gray seal blubber. The animals were exposed for 18 months, including two reproduction seasons. Among the animals given the highest dose of A50, the whelping frequency was reduced in the second reproductive season, and all kits died within 24 h of birth. Reproduction was also impaired by the lower dose of A50. Daily exposure to the 0-1-ortho-CBs separated from 0.3 mg A50 severely reduced kit survival. Reproduction was not significantly impaired by daily exposure to the 2-4-ortho-CBs separated from 0.3 mg A50 or by exposure to the blubber extract. We conclude that the reproductive toxicity in chronically PCB-exposed mink is caused by the aryl hydrocarbon (Ah) receptor agonists. The lowest-observed-effect level for reproductive impairment was 2.4 ng 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalents (TEQs) per kilogram body weight and day (22 pg TEQs/g feed). Ethoxyresorufin-O-dealkylase (EROD) was strongly induced by the 0-1-ortho-CBs and pentoxyresorufin-O-dealkylase by the 2-4-ortho-CBs. High EROD activity was correlated with low kit production, and consequently EROD may serve as a marker for reproductive toxicity by Ah receptor agonists in mink.