Gill Injuries Research Articles

The toxicity, ways of exposure and effects of Cu nanoparticles and Cu bulk salts on different organisms

Nanotoxicology is projected as an emerging branch of toxicology to address the gaps in knowledge and adverse health effects likely to be caused by nanomaterials. This branch of nanotoxicology would make an important contribution to the development of a sustainable nanotechnology and covers the physicochemical factors, routes of exposure, biodistribution, molecular factors, genotoxicity and regulatory aspects. It is also involved in proposing reliable, healthy, and safe test protocols for nanomaterials in human and environmental risk assessment. Some nanoparticles such as copper is harmful to aquatic life, a small fraction of its nanoparticles can dissolve in water and produce toxic impacts on fish and other aquatic life. Copper nanoparticles are widely used as antimicrobial (antiviral, antibacterial, antifouling, antifungal), antibiotic treatment alternatives, nanocomposite coating, catalyst, lubricants, inks, for filtration of air and liquid. Fish are vulnerable to copper nanoparticles because it can induce gill injury and acute lethality. They are also emitted as particulates from smelters, metal foundries, and as pollutant from asphalt and rubber tires. Their long-term biological consequences on aquatic species are still unclear so it is pertinent to assess the toxicity of Cu nanoparticles and Cu salt in aquatic life. In view of these facts the following review article presents the toxicity, ways of exposure and effects of Cu nanoparticles on different organisms in vivo and vitro.

Gill histopathological characteristics of Caspian roach (Rutilus rutilus caspicus) fingerlings treated with potassium permanganate and formalin

The aim of this study was to determine the gill histopathological characteristics of Caspian roach (Rutilus rutilus caspicus) fingerlings exposed to different concentrations of potassium permanganate (PM) and formalin (FO). The fish were exposed to different PM and FO concentrations over different periods: 1 ppm PM for 24 h (1-P24), 2 ppm PM for 24 h (2-P24), 5 ppm PM for 0.5 h (5-P0.5), 10 ppm PM for 0.5 h (10-P0.5), 10 ppm FO for 24 h (10-F24), 20 ppm FO for 24 h (20-F24), 40 ppm FO for 0.5 h (40-F0.5) and 80 ppm FO for 0.5 h (80-F0.5). After exposure, gill samples were collected for histological examination. The most frequent gill histopathological symptoms were hyperplasia and epithelial lifting. The order of the gill injury index (Ig.i) among the treatments was as follow: 1-P24, 2-P24 < 5-P0.5, 40-F0.5 < 10-F24 < 10-P0.5, 20-F24, 80-F0.5. Comparing the two agents, it is concluded that there is no significant difference in the gill damages between the agents during the short-bath treatments. However, PM causes less pathological symptoms than FO during the long-bath treatments. Comparing the bath durations, the agents showed different behaviours. PM-treated fish showed significantly lower gill damage during the long-bath compared to the short-bath treatment; whereas, pathological symptoms of FO-treated fish was dose-dependent for each exposure period, separately. Overall, exposure of Caspian roach to PM, at the concentrations recommended for long bath, resulted in milder gill damages compared to FO.

Minimal effects of waterborne exposure to single-walled carbon nanotubes on behaviour and physiology of juvenile rainbow trout (Oncorhynchus mykiss)

Fish behaviours are often considered to be sensitive endpoints of waterborne contaminants, but little attention has been given to engineered nanomaterials. The present study aimed to determine the locomotor and social behaviours of rainbow trout (Oncorhynchus mykiss) during waterborne exposure to single-walled carbon nanotubes (SWCNTs), and to ascertain the physiological basis for any observed effects. Dispersed stock suspensions of SWCNTs were prepared by stirring in sodium dodecyl sulphate (SDS), an anionic surfactant, on an equal w/w basis. Trout were exposed to control (no SWCNT or SDS), 0.25mgL−1 SDS (dispersant control), or 0.25mgL−1 of SWCNT for 10 days. Video tracking analysis of spontaneous locomotion of individual fish revealed no significant effects of SWCNT on mean velocity when active, total distance moved, or the distribution of swimming speeds. Hepatic glycogen levels were also unaffected. Fish exposed to SWCNTs retained competitive fitness when compelled to compete in energetically costly aggressive interactions with fish from both control groups. Assessment of the respiratory physiology of the fish revealed no significant changes in ventilation rate or gill injuries. Haematocrit and haemoglobin concentrations in the blood were unaffected by SWCNT exposure; and the absence of changes in the red and white pulp of the spleen excluded a compensatory haematopoietic response to protect the circulation. Despite some minor histological changes in the kidneys of fish exposed to SWCNT compared to controls, plasma ion concentrations and tissue electrolytes were largely unaffected. Direct neurotoxicity of SWCNT was unlikely with the brains showing mostly normal histology, and with no effects on acetylcholinesterase or Na+/K+-ATPase activities in whole brain homogenates. The minimal effects of waterborne exposure to SWCNT observed in this study are in contrast to our previous report of SWCNT toxicity in trout, suggesting that details of the dispersion method and co-exposure concentration of the dispersing agent may alter toxicity.

Histopathological effects of 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) in the gills, intestine and liver of turbot (Psetta maxima)

Polybrominated diphenyl ethers (PBDEs) have become ubiquitous environmental pollutants because of their widespread use as flame retardants in various consumer products (plastics, textiles, electronic appliances and building materials) and their long half-life. BDE-47 (2,2′,4,4′-tetrabromodiphenyl ether) is the major PBDE congener detected in the environment and in animal tissues. In the present study, the histopathological effects are examined of BDE-47 on the gills, intestine and liver tissues of juvenile turbot (Psetta maxima).The specimens were exposed to two concentrations of BDE-47 (0.03 and 0.3µg/L) for a period of 15 days. The histological changes were detected microscopically and evaluated with quantitative or semi-quantitative analyses. At the doses of BDE-47 assayed, the most common gill injuries were lamellar fusion, blood congestion and hyperplasia and hypertrophy of the epithelial and mucous cells. In the intestine of fish exposed to BDE-47, the alterations detected were hyperplasia and hypertrophy of mucous cells. Hepatic lesions in the liver of fish exposed to BDE-47 were characterized by circulatory disturbances, irregular morphology of hepatocytes, cellular and nuclear hypertrophy, and nuclear vacuolation and pyknosis. As BDE-47 is present in food and other material related to aquaculture systems, our results indicate that exposure to this pollutant could have serious consequences on health in turbot and other cultured fish.

Can fish gill anomalies be used to assess water quality in freshwater Neotropical systems?

Gill anomalies in two fish species (Geophagus brasiliensis and Astyanax bimaculatus) were compared among three freshwater systems with different water quality: one eutrophic river, one eutrophic reservoir, and one oligotrophic reservoir. The raised hypotheses are that reservoirs with low water quality (eutrophic) have fish with more gills anomalies compared with reservoirs with high water quality (oligotrophic), and that the more stable environmental conditions of eutrophic rivers have fish with better healthy conditions than eutrophic reservoirs that have lesser stable environmental conditions. Gills of 36 adult individuals of G. brasiliensis and 23 of A. bimaculatus collected during the winter 2008 and winter 2009 were examined, and the proportions of occurrence of nine histological alterations were compared for the two species among the three systems using a binomial t test for independent samples. Histological changes in fish gills that are reversible and unspecific, such as epithelial lifting, interstitial edema, leukocyte infiltration, hyperplasia of the epithelial cells, lamellar fusion, and vasodilatation were common in both fish species in the three systems. However, lamellar aneurism, which is a more serious and often irreversible anomaly, and lamellar blood congestion occurred only in fish from the two reservoirs. Alternatively, necrosis occurred more in fish from the river. Fish gill anomalies in both species did not differ between the two reservoirs, despite having different water quality. We rejected the hypothesis that reservoirs with lower water quality have fish with more gill injuries compared with high water quality reservoirs. Moreover, the eutrophic river seems to affect differently the healthy condition of fish species, compared with the eutrophic reservoir.

Estimating post-release survival and the influential factors for recreationally caught Black bream ( Acanthopagrus butcheri) in the Glenelg River, south eastern Australia

Black bream ( Acanthopagrus butcheri) is the main target species amongst the estuarine recreational fisheries of Victoria, Australia. The A. butcheri fishery is managed through legal-minimum length and daily bag limits. The success of this management strategy requires that the survival rate for released fish is high. This study used the most common angling practices to estimate post-release survival and identify influential factors for undersized A. butcheri in Victoria. In total 1557 and 923 A. butcheri were caught and monitored for initial (≤1 h) and delayed (72 h) survival, respectively. Fish were caught across 3 years, with each year separated into cold and warm water periods with 8 fishing trial days in total. Only 1 of the 266 controls used to assess confinement effects died. Total survival was 95% (S.E. ± 0.8%) for shallow- and 74% (S.E. ± 3%) for deep-hooked fish and decreased as fish length increased. A post-mortem (PM) procedure was developed and showed that throat and gill injuries were the most frequent cause of deep-hooking death. It revealed that 97% of hooks left in fish remained there after 72 h and identified hooking location inaccuracies recorded at the time of capture. Total survival for deep-hooked fish was 20% higher when hooks were left in the fish. Deep-hooked fish were more likely to bleed when hooks were removed and total survival was lower for fish that bleed (58%) than fish that did not bleed (80%). Shallow-hooking rates decreased as fish length increased and were higher during warm water compared to cold water trials. The high shallow-hooking and survival rates observed suggest that A. butcheri survival in the fishery would be high, but deep-hooking has the potential to undermine the management strategy. Determining the shallow-hooking rate in the fishery would help clarify the impact of these findings at the fishery level.

Exposure to Copper Nanoparticles Causes Gill Injury and Acute Lethality in Zebrafish (Danio rerio)

Increasing use of metallic nanomaterials is likely to result in release of these particles into aqueous environments; however, it is unclear if these materials present a hazard to aquatic organisms. Because some dissolution of metal particles will occur, it is important to distinguish effects of nanoparticulates from dissolved metals. To address this issue, acute toxicity of soluble copper and 80 nm copper nanoparticle suspensions were examined in zebrafish. The results demonstrate that nanocopper is acutely toxic to zebrafish, with a 48 h LC50 concentration of 1.5 mg/L. Rapid aggregation of copper nanoparticles occurred after suspension in water, resulting in 50-60% of added mass leaving the water column. While dissolution of particulate copper occurred, it was insufficient to explain the mortality in nanocopper exposures. Histological and biochemical analysis revealed that the gill was the primary target organ for nanocopper. To further investigate the effects of nanocopper on the gill, zebrafish were exposed to 100 microg/L of nanocopper or to the concentration of soluble copper matching that present due to dissolution of the particles. Under these conditions, nanocopper produced different morphological effects and global gene expression patterns in the gill than soluble copper, clearly demonstrating that the effects of nanocopper on gill are not mediated solely by dissolution.

Toxicity of titanium dioxide nanoparticles to rainbow trout ( Oncorhynchus mykiss): Gill injury, oxidative stress, and other physiological effects

Mammalian and in vitro studies have raised concerns about the toxicity of titanium dioxide nanoparticles (TiO 2 NPs), but there are very limited data on ecotoxicity to aquatic life. This paper is an observational study where we aim to describe the toxicity of TiO 2 NPs to the main body systems of rainbow trout. Stock solutions of dispersed TiO 2 NPs were prepared by sonication without using solvents. A semi-static test system was used to expose rainbow trout to either a freshwater control, 0.1, 0.5, or 1.0 mg l −1 TiO 2 NPs for up to 14 days. Exposure to TiO 2 NPs caused some gill pathologies including oedema and thickening of the lamellae. No major haematological or blood disturbances were observed in terms of red and white blood cell counts, haematocrit values, whole blood haemoglobin, and plasma Na + or K + concentrations. Tissue metal levels (Na +, K +, Ca 2+ and Mn) were generally unaffected. However, some exposure concentration-dependent changes in tissue Cu and Zn levels were observed, especially in the brain. Exposure to TiO 2 NPs caused statistically significant decreases in Na +K +-ATPase activity (ANOVA, P < 0.05) in the gills and intestine, and a trend of decreasing enzyme activity in the brain (the latter was not statistically significant). Thiobarbituric acid reactive substances (TBARS) showed exposure concentration-dependent and statistically significant (ANOVA or Kruskal–Wallis test, P < 0.05) increases (two-fold or more) in the gill, intestine and brain, but not the liver during exposure to TiO 2 NPs compared to controls. TiO 2 NP exposure caused statistically significant (ANOVA, P < 0.05) increases in the total glutathione levels in the gills, but depletion of hepatic glutathione compared to controls. Total glutathione levels in the brain and intestine were unaffected. Liver cells exposed to TiO 2 NPs showed minor fatty change and lipidosis, and some hepatocytes showed condensed nuclear bodies (apoptotic bodies). Fish probably ingested water containing TiO 2 NPs during exposure (stress-induced drinking) which may have resulted in some areas of erosion on the intestinal epithelium. Overall we conclude that titanium dioxide nanoparticles are not a major ionoregulatory toxicant, or haemolytic, at the concentration and exposure times used. Respiratory distress is a concern and sub-lethal toxicity involves oxidative stress, organ pathologies, and the induction of anti-oxidant defences, such as glutathione.

Short-term hooking mortality of tailor ( Pomatomus saltatrix) in Western Australia and the impact on yield per recruit

Recreational catches of tailor ( Pomatomus saltatrix) in Western Australia are regulated by a size and daily catch limit. Short-term mortality rates of angler-caught tailor were investigated to determine the effectiveness of these management strategies in coastal and estuarine waters around Perth, WA. A total of 1155 tailor were caught using five hook types. The overall mortality rate during a 2 h holding period was 3.0%. Legal sized fish had a higher mortality rate than sublegal size fish. Treble hooks produced a significantly higher mortality rate than the other hook types. Although yield per recruit curves calculated using the sublegal fishing mortality estimate for each hook type were similar, yield per recruit calculated using the treble hook mortality was lowest. Ganged hooks with/without terminal trebles were most likely to cause jaw injury while barbed and barbless single hooks were more likely to cause gill injury. Gill injury was responsible for a significantly higher mortality rate than other injury positions. These results suggest current management strategies, including discouraging the use of treble hooks, may be effective in ensuring the survival of a high proportion of sublegal and over the daily catch limit caught and released tailor.

Acute defense mechanisms against hemorrhage from mechanical gill injury in rainbow trout.

By cutting gill filaments in anesthetized rainbow trout (Oncorhynchus mykiss), observing the bleeding through a stereomicroscope, and using blockers of various known endogenous filament artery vasoconstrictors, we have here attempted to characterize hemostatic mechanisms in gills. The immediate hemostatic response to a cut in a gill filament artery was a local vasoconstriction, stopping the hemorrhage within approximately 20 s. In heparinized fish, the hemorrhage recommenced after approximately 8 min, suggesting that the vasoconstriction soon subsides and blood clotting becomes responsible for the hemostasis. Antagonists of acetylcholine, adenosine, and serotonin receptors were unable to block the hemostatic vasoconstriction. Also, tetrodotoxin was without effect, indicating a nonnervous origin. By contrast, indomethacin significantly affected the measured bleeding times, suggesting that eicosanoids play a significant role in this process (possibly by stimulating vasoconstriction and/or by inducing local thrombocyte aggregation). By possessing several hundred virtually identical filaments with readily observable vasculature, the fish gill appears to be a good experimental model for studying hemostatic mechanisms.

Environment-induced gill disease of cultured rainbow trout ( Salmo gairdneri)

Rainbow trout from eight North German freshwater culture facilities were investigated for chronic health damage resulting from captivity. The fishes were raised under a wide variety of conditions in net cages, circulation tanks, raceways, and earthen ponds. The most obvious non-contagious health problem was gill injury. Hyperplasia of the gill filaments, leading to lamellar fusion or the development of apical caps, as well as necrotic or advanced degenerative processes were observed. In addition, the gill filaments were frequently shortened, significantly reducing the functional surface of the organ. The lesions occurred in almost the same form in all of the culture units. It is likely that they are part of a syndrome induced by the environmental conditions typical of freshwater aquaculture facilities. These are characterized by an accumulation of nitrogenous excretion and decomposition products, extreme diurnal fluctuations in the concentration of dissolved gases, and intensive feeding involving the sudden addition of large amounts of artificial products. Under such conditions even small quantities of un-ionized ammonia can be toxic for epithelial tissues and disturb the normal elimination of protein metabolites across the gills. The pathological processes may be accelerated by secondary bacterial infections.