Changes in hematological parameters of Cichlasoma dimerus (Teleostei, Perciformes) exposed to sublethal concentrations of 4-tert-octylphenol

Hematological changes, redox imbalance, and changes in Na+/K+-ATPase activity caused by bisphenol-A and the integrated biomarker responses in Labeo rohita (Hamilton, 1822)

Bisphenol-A (BPA) is a plasticizer commonly used in the plastics industry to manufacture plastic materials. It is abundant in aquatic ecosystems, resulting in increased contamination and lower concentrations that may represent a significant threat to the aquatic system. Hence in the present study, an Indian major carp, Labeo rohita, was exposed to two different BPA concentrations (1 and 10 μg/L) for 30 days. Compared to control, the chronic effects resulted in significant alterations in red blood cell (RBC) and white blood cells (WBC) count. The exposure to BPA caused significant changes in antioxidant activity in gill, liver, and kidney tissues (inferred by catalase, glutathione peroxidase, and glutathione S-transferase activity) in L. rohita. Regarding lipid peroxidation (LPO), we observed an increase in liver and kidney alteration, while LPO was noted in gill tissue compared to the control. Furthermore, increased Na+/K+-ATPase activity was observed in gills at the end of the 10th day and a gradual decrease at the end of the 30th day. These results indicated that exposure to BPA alters the RBC and WBC levels, antioxidant enzyme activity (gills, liver, and kidney), and Na+/K+-ATPase activity in the gill of L. rohita exposed to BPA (at 1 and 10 μg/L). Therefore, our findings will help us gain better insight into the toxicity of BPA in freshwater ichthyofauna.

Blood biomarkers as diagnostic tools: An overview of climate-driven stress responses in fish

Global climate change due to anthropogenic activities affects the dynamics of aquatic communities by altering the adaptive capacities of their inhabitants. Analysis of blood provides valuable insights in the form of a comprehensive representation of the physiological and functional status of fish under various environmental and treatment conditions. This review synthesizes currently available information about blood biomarkers used in climate change induced stress responses in fish. Alterations in informative blood-based indicators are used to monitor the physiological fitness of individual fishes or entire populations. Specific characteristics of fish blood, such as serum and plasma metabolites, cell composition, cellular abnormalities, cellular and antioxidant enzymes necessitate adapted protocols, as well as careful attention to experimental designs and meticulous interpretation of patterns of data. Moreover, the sampling technique, transportation, type of culture system, acclimation procedure, and water quality must all be considered for valid interpretation of hemato-biochemical parameters. Besides, blood collection, handling, and storage time of blood samples can all have significant impacts on the results of a hematological analysis, so it is optimal to perform hemato-biochemical evaluations immediately after blood collection because long-term storage can alter the results of the analyses, at least in part as a result of storage-related degenerative changes that may occur. However, the scarcity of high-throughput sophisticated approaches makes fish blood examination studies promising for climate-driven stress responses in fish.

Influence of the Linear Alkylbenzene Sulfonate (LAS) on hematological and biochemical parameters of Nile Tilapia, Oreochromis niloticus

The acute toxicity of household detergent (Ariel) on blood parameters and histology of Oreochromis niloticus was investigated using static bioassay for 96 h. Linear alkylbenzenesulfonate (LAS) is an anionic surfactant widely used in detergents and cleaners, both in industrial and household applications. LAS contaminating aquatic ecosystems as a potential toxic pollutant, was investigated in the present study for acute toxicity. The fish samples were divided into six groups, including 20 fish in each group. Normal feed was given to control group without detergents treatment. Hematological parameters (RBC count, Hb, Ht and platelets) were significantly declined, while WBC count showed a highly significant increase. Compared with the control group, significant elevation of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) was recorded in fish treated with different concentrations of detergent. Catalase (CAT), Superoxide dismutase (SOD) activities and Reduced Glutathione (GSH) concentration showed a highly significant reduction. Total proteins showed significant decrease, while total lipids, cholesterol and triglycerides significantly increased. The mean lethal concentration (LC₅₀) for 96 h of Ariel was at concentration 10 mg/L. Relative percentage of detergent residues in fish muscles was increased with higher detergent concentrations. In conclusion, exposure to detergents resulted in great alterations in the histological structure of liver and gills.

Ivermectin: A multilevel approach to evaluate effects in Prochilodus lineatus (Valenciennes, 1836) (Characiformes, Prochilodontidae), an inland fishery species

Ivermectin (IVM) is one of the most widely used antiparasitics worldwide. It is a potent and effective drug for treatment and prevention of internal and external parasitic infections of livestock and humans. IVM is excreted unchanged in manure of treated animals. Thus, residues of IVM may reach aquatic systems, affecting non-target organisms such as fish. Although the presence of IVM in aquatic environments has been reported, a multilevel approach (from cellular to behavioral responses) is necessary to determine the health of exposed organisms and the environmental risks associated. The aim of the present study was to investigate the response of the Neotropical fish Prochilodus lineatus, one of the main target species of South American freshwater fisheries, exposed to environmental concentrations of IVM: low (0.5 μg L^-1) and high (1.5 μg L^-1). Behavioral responses were assessed in juvenile fish and included water column use, routine swimming, total distance travelled, total activity time and Maximum swimming speed achieved during the escape response. Biochemical/oxidative stress responses assessed included brain acetylcholinesterase (AChE), catalase (CAT) and glutathione S-transferase (GST) activities; total antioxidant competence against peroxyl radicals (ACAP) and lipid oxidative damage (TBARs). Hematological biomarker responses included blood glucose levels, hematocrit, hemoglobin concentration, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, and mean corpuscular volume. Condition factor and hepatosomatic index were also calculated. The lowest IVM concentration caused a significant decrease in GST activity and maximum swimming speed during the escape response. Multivariate analysis with biochemical/stress and behavioral data revealed overall effects of IVM treatments. This multilevel analysis shows detrimental effects related to swimming behavior and predator avoidance which could affect population size and size-structure of P. lineatus. To our knowledge this is the first attempt to assess the effects of IVM on Neotropical fishes using an integrative approach based on biomarkers from different levels of biological organization.

Chlorpyrifos levels within permitted limits induce nuclear abnormalities and DNA damage in the erythrocytes of the common carp

The organophosphate pesticide chlorpyrifos (CPF) is defined as a priority pollutant in surface freshwaters according to Directive 2013/39/EU of the European Parliament. The focus of this study was to assess the potential cytotoxic and genotoxic effects of permissible CPF levels on juvenile forms of the common carp. We found that low-level CPF exposure did not induce elevated levels of micronuclei, but significantly increased the frequency of total nuclear abnormalities (NAs) proportional to dose and time; notched, blebbed, lobed and eight-shaped nuclei, nuclear buds, nuclear bridges and binucleated cells were all detected. Decreased frequencies of polychromatic erythrocytes (PCEs) and DNA damage detected by comet assay were also observed, confirming the cytotoxic and genotoxic effects of CPF. Altogether, these data (1) demonstrate that CPF is toxic even at permissible levels, possessing considerable genotoxic and cytotoxic potential in peripheral erythrocytes of exposed fish and (2) validate the assessment of NAs, PCEs and comet assay performance as sensitive biomarkers for the early detection of CPF pollution. These findings can be applied to guide environmental risk assessment and biomonitoring programs.

Environmental Water Pollution, Endocrine Interference and Ecotoxicity of 4-tert-Octylphenol: A Review

4-tert-Octylphenol is a degradation product of non-ionic surfactants alkylphenol polyethoxylates as well as raw material for a number of industrial applications. It is a multimedia compound having been detected in all environmental compartments such as indoor air and surface waters. The pollutant is biodegradable, but certain degradation products are more toxic than the parent compound. Newer removal techniques from environmental waters have been presented, but they still require development for large-scale applications. Wastewater treatment by plant enzymes such as peroxidases offers promise in total removal of 4-tert-octylphenol leaving less toxic degradation products. The pollutant's endocrine interference has been well reported but more in oestrogens than in any other signalling pathways through which it is believed to exert toxicity on human and wildlife. In this paper we carried out a review of the activities of this pollutant in environmental waters, endocrine interference and relevance to its toxicities and concluded that inadequate knowledge of its endocrine activities impedes understanding of its toxicity which may frustrate current efforts at ridding the compound from the environment.

Multidisciplinary haematology as prognostic device in environmental and xenobiotic stress-induced response in fish

The variations of haematological parameters hematocrit, hemoglobin concentration, leukocyte and erythrocyte count have been used as pollution and physiological indicators of organic dysfunction in both environmental and aquaculture studies. These parameters are commonly applied as prognostic and diagnostic tools in fish health status. However, there are both extrinsic and intrinsic factors to consider when performing a blood test, because a major limitation for field researchers is that the "rules" for animal or human haematology do not always apply to wildlife. The main objective of this review is to show how some environmental and xenobiotic factors are capable to modulating the haematic cells. Visualizing the strengths and limitations of a haematological analysis in the health assessment of wild and culture fish. Finally, we point out the importance of the use of mitochondrial activities as part of haematological evaluations associated to environment or aquaculture stress.

Fertaric Acid Protects from Octylphenol-Related Hepatotoxicity in Rats: Biochemical, Molecular, and Histopathological Studies

The endocrine-disrupting chemical 4-tert-octylphenol (OP) can mimic estrogen and testosterone hormones and threaten health; fertaric acid (FA) is a hydroxycinnamic acid found in grapefruit. This study aimed to investigate whether FA has a protective effect on 4-tert-octylphenol-related hepatotoxicity. Thirty male albino rats were divided into 5 equal groups of 6 rats each as follows: control group-administrated orally with 1 ml saline 3 days/week for 4 weeks; corn oil group-administrated orally with 1 ml corn oil 3 days/week for 4 weeks; FA-treated group-administrated orally with FA (45 mg /kg body weight) dissolved in saline 3 days/week for 4 weeks; OP-treated group-administrated orally with OP (40 mg /kg body weight) dissolved in corn oil 3 days/week for 4 weeks; FA + OP-treated group-administrated orally with FA (45 mg /kg body weight) dissolved in saline 3 days/week for 4 weeks then administrated orally with OP (40 mg/kg body weight) dissolved in corn oil 3 days/week for another 4 weeks. The results obtained showed that OP-exposed rats had significant increase in serum aspartate aminotransferase, alanine aminotransferase, γ-glutamyl transferase, lactate dehydrogenase, bilirubin, serum and liver tumor necrosis factor-α, interleukin-1β and malondialdehyde, serum interleukin-6 and interleukin-10 and significant decrease in serum alkaline phosphatase, acid phosphatase, serum and liver superoxide dismutase, glutathione peroxidase, and catalase. OP caused an inhibitory action on the gene expression of liver proteins. Rats treated with FA before OP exposure had near-normal values. In addition, FA prevented the degradation of liver deoxyribonucleic acid (DNA), and DNA reformation occurred. In conclusion, FA protects from dangerous OP-related hepatic effects, and these results were supported by molecular and histological investigations.

The Role of Chlorogenic Acid Supplementation in Anemia and Mineral Disturbances Induced by 4-Tert-Octylphenol Toxicity

4-tert-octylphenol (OP) is an endocrine-disrupting chemical that causes harmful effects to human health. Chlorogenic acid is the major dietary polyphenol present in various foods and beverages. The aim of the present study was to evaluate the protective role of chlorogenic acid in anemia and mineral disturbance occurring in OP toxicity in rats. Thirty-two male albino rats were divided into four equal groups (8 rats/group) as follows. The first (control) group was treated daily with an oral dose of 1 ml saline for two weeks. The second group was treated daily with an oral dose of 60 mg chlorogenic acid/kg body weight for two weeks. The third and fourth groups received daily intraperitoneal (ip) injections with 100 mg OP/kg body weight for two weeks; the fourth group was treated daily with an oral dose of 60 mg chlorogenic acid/kg body weight for three weeks starting one week before OP injections. The results revealed that OP induced significant decreases in hemoglobin, hematocrit, red blood cells, mean cell volume, mean cell hemoglobin, mean cell hemoglobin concentration, platelet count, white blood cells, lymphocyte and neutrophil percent, transferrin receptor, serum calcium, phosphorous, sodium, potassium, chloride, glutathione-S-transferase, glutathione peroxidase, catalase, glutathione reductase, and superoxide dismutase. Moreover, significant increases in serum hepcidin, ferritin, transferrin, erythropoietin, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, urea, creatinine, selenium, zinc, manganese, copper, iron, malondialdehyde, and protein carbonyl levels were found in OP groups. OP exposure also induced cell apoptosis. Chlorogenic acid pretreatment in OP-treated groups restored all the mentioned parameters to approach the normal values. In conclusion, chlorogenic acid protects from anemia and mineral disturbances in 4-tert-octylphenol toxicity by ameliorating oxidative stress and apoptosis.

Characterization of the chemicals used in hydraulic fracturing fluids for wells located in the Marcellus Shale Play

Hydraulic fracturing, coupled with the advances in horizontal drilling, has been used for recovering oil and natural gas from shale formations and has aided in increasing the production of these energy resources. The large volumes of hydraulic fracturing fluids used in this technology contain chemical additives, which may be toxic organics or produce toxic degradation byproducts. This paper investigated the chemicals introduced into the hydraulic fracturing fluids for completed wells located in Pennsylvania and West Virginia from data provided by the well operators. The results showed a total of 5071 wells, with average water volumes of 5,383,743 ± 2,789,077 gal (mean ± standard deviation). A total of 517 chemicals was introduced into the formulated hydraulic fracturing fluids. Of the 517 chemicals listed by the operators, 96 were inorganic compounds, 358 chemicals were organic species, and the remaining 63 cannot be identified. Many toxic organics were used in the hydraulic fracturing fluids. Some of them are carcinogenic, including formaldehyde, naphthalene, and acrylamide. The degradation of alkylphenol ethoxylates would produce more toxic, persistent, and estrogenic intermediates. Acrylamide monomer as a primary degradation intermediate of polyacrylamides is carcinogenic. Most of the chemicals appearing in the hydraulic fracturing fluids can be removed when adopting the appropriate treatments.

Effects of waterborne exposure to 17β-estradiol and 4-tert-octylphenol on early life stages of the South American cichlid fish Cichlasoma dimerus

Estrogenic chemicals are often detected in the aquatic environment and can negatively affect animal development and reproduction. In teleost fishes, the hormonal regulation during a critical period of larval development has a strong influence on gonadal sex differentiation; thus this process may be affected by the exposure to environmental estrogens. In this study, we first assessed the lethal acute toxicity of the natural estrogen 17β-estradiol (E2) and the weaker estrogen mimics 4-tert-octylphenol (OP) and 4-nonylphenol (NP) on larval stages of the South American cichlid fish Cichlasoma dimerus. In a further experiment, we analyzed the effects of chronic waterborne exposure to E2 and OP on gonad development and sex differentiation. Exposure to high concentrations of E2 had a pronounced feminizing effect directing sex differentiation towards ovarian development, while testis development was inhibited at a lower, environmentally relevant concentration. Among OP-exposed fish, 15-38.5% of the males exhibited testicular oocytes (TOs), a commonly reported biomarker of estrogenic exposure. However, since TOs were also recorded in control males and the proportion of males with TOs was not significantly higher in OP treatments, their occurrence could not be attributed to OP exposure. In addition, TOs did not seem to impair male gonad development and functionality since normal spermatogenesis was observed in testes of OP-treated fish. These results indicate that E2 occurring in the South American aquatic environment may affect male reproductive development and pose a risk for wild C. dimerus, especially under prolonged exposure, while the effects of weaker xenoestrogens such as OP would be negligible for gonad development in this species. As illustrated by this study, the natural occurrence of TOs indicates that conclusions concerning the causes of this phenomenon must be drawn with care.

Nonmonotonic response of vitellogenin and estrogen receptor α gene expression after octylphenol exposure of Cichlasoma dimerus (Perciformes, Cichlidae)

In oviparous vertebrates, vitellogenin (VTG) is mainly produced by the liver in response to estrogen (E2) and its synthesis is traditionally coupled to estrogen receptor alpha induction. Even though VTG is a female-specific protein, chemicals that mimic natural estrogens, known as xenoestrogens, can activate its expression in males causing endocrine disruption to wildlife and humans. Alkylphenols such as nonylphenol (NP) and octylphenol (OP) are industrial additives used in the manufacture of a wide variety of plastics and detergents, and can disrupt endocrine functions in exposed animals. For more than a decade, the freshwater cichlid fish Cichlasoma dimerus has been used for ecotoxicological studies in our laboratory. We recently found an up-regulation of VTG gene expression in livers of male fish exposed to OP, from a silent state to values similar to those of E2-induced fish. To better understand the underlying mechanisms behind the action of xenoestrogens, the aim of this study was to analyze the dose-response relationship of C. dimerus VTG and estrogen receptors (ERs) gene expression after waterborne exposure to 0.15, 1.5, 15, and 150μg/L OP for up to 1 month (0, 1, 3, 7, 14, 21, and 28 days). At the end of the experiment, histological features of exposed fish included active hepatocytes with basophilic cytoplasm and high eosinophilic content in their vascular system due to augmented expression of VTG. In testis, high preponderance of sperm was found in fish exposed to 150μg/L OP. A classic dose-response down-regulation of the expression of Na(+)/K(+)-ATPase, a "non-gender specific gene" used for comparison, was found with increasing OP concentrations. No VTG and very low levels of ERα were detected in control male livers, but an up-regulation of both genes was found in males exposed to 0.15 or 150μg/L OP. Moreover, VTG transcripts were significant as early as day 3 or day 1 of exposure to these OP concentrations, respectively. Nearly no response was detected in 1.5 and 15μg/L OP exposed-fish. Data was curve-fitted evidencing a nonmonotonic dose-response curve. Interestingly, ERβ2 mRNA expression was augmented above baseline levels only when males were exposed to the lowest OP concentration. We speculate that genomic control of vitellogenesis is under control of multiple steroid receptors with different affinities for ligands. ERβ isoform, only up-regulated with very low concentrations of ligand, would act as a sensors of OP (or E2) to induce ERα and VTG. With high OP concentrations, the expression of ERα isoform is promptly augmented, with the concomitant VTG transactivation.