The effects of diphenyl diselenide on oxidative stress biomarkers in Cyprinus carpio exposed to herbicide quinclorac (Facet®)

A review of the impact of herbicides and insecticides on the microbial communities

Enhancing crop yield to accommodate the ever-increasing world population has become critical, and diminishing arable land has pressured current agricultural practices. Intensive farming methods have been using more pesticides and insecticides (biocides), culminating in soil deposition, negatively impacting the microbiome. Hence, a deeper understanding of the interaction and impact of pesticides and insecticides on microbial communities is required for the scientific community. This review highlights the recent findings concerning the possible impacts of biocides on various soil microorganisms and their diversity. This review's bibliometric analysis emphasised the recent developments' statistics based on the Scopus document search. Pesticides and insecticides are reported to degrade microbes' structure, cellular processes, and distinct biochemical reactions at cellular and biochemical levels. Several biocides disrupt the relationship between plants and their microbial symbionts, hindering beneficial biological activities that are widely discussed. Most microbial target sites of or receptors are biomolecules, and biocides bind with the receptor through a ligand-based mechanism. The biomarker action mechanism in response to biocides relies on activating the receptor site by specific biochemical interactions. The production of electrophilic or nucleophilic species, free radicals, and redox-reactive agents are the significant factors of biocide's metabolic reaction. Most studies considered for the review reported the negative impact of biocides on the soil microbial community; hence, technological development is required regarding eco-friendly pesticide and insecticide, which has less or no impact on the soil microbial community.

Effect of Prepartum Maternal Supplementation with Diphenyl Diselenide on Biochemical, Immunological, and Oxidative Parameters of the Offspring

This study aimed to assess the impact of prepartum maternal diphenyl diselenide (PhSe)2 supplementation on the development, biochemical, immune, and antioxidant parameters of calves. Eighteen Holstein breed calves were used, born to females who were or were not subjected to supplementation, at 42, 28, and 14 days prior to calving. The (PhSe)2 group (DDG) was administered 3 μmol/kg of (PhSe)2 in 4 mL of dimethyl sulfoxide (DMSO), while the DMSO and NaCl groups were administered 4 mL of DMSO and 0.9% NaCl, subcutaneously. The calves were evaluated based on their weight, withers height, body condition score 24 h post-birth (0), as well on days 14, 28, 42, 56, 70. Blood samples were also taken to determine serum variables. Calves on the DDG showed higher average levels of total protein, albumin, and globulins on day 0, and the immunoglobulin G level was significantly higher than the other groups on days 0, 14, 56, 70. Maternal supplementation showed immunomodulatory effect on calves, evidenced by the exceptional rates of passive immunity transfer, as well as the enhancement of humoral immunity. Our research offers fresh insights into the immunomodulatory potential of (PhSe)2, making it a viable alternative in facing this challenging phase, rearing dairy calves.

Impact of commercial formulations of herbicides alone and in mixtures on the antioxidant system and body condition parameters in tadpoles of Rhinella icterica (Spix 1824)

Pesticide usage has increased over the last decades, leading to concerns regarding its effects on non-target organisms, especially amphibians. Tadpoles of Rhinella icterica were collected in a pesticide-free place, acclimated in the laboratory (21 days) and exposed (7 days) to three herbicides (20µg/L atrazine (A); 250µg/L glyphosate (G); 20µg/L quinclorac (Q)) and their mixtures. Only 2% mortality was observed over the 28 days of the study. Despite this, significant variations were observed for markers of oxidative balance and body condition when comparing all experimental groups. K and Kn factor showed the lowest values in the group A+G+Q, as well as the activity levels of GST and SOD. In contrast to this, the CAT activity was higher in the same group (A+G+Q). The mixture of the three herbicides proved to be more harmful, which points to the need for more restrictive laws for the use of mixed herbicides.

Neuro-hepatopathological changes in juvenile Oreochromis niloticus exposed to sublethal concentrations of commercial herbicides

The current study estimates the impact of different common herbicides on antioxidant defenses and histological structure of liver and spinal cord of juvenile tilapia. Eighty-four fish were divided into seven groups: group 1 fish acted as controls and the remaining fish were exposed to sublethal concentrations of acetochlor, bispyribac-sodium, bentazon, bensulfuron-methyl, halosulfuron-methyl, or quinclorac at sublethal concentrations 2.625, 0.800, 36.00, 2.50, 1.275, and 11.250 mg/l, respectively, for 96 h. Antioxidant parameters changed in response to some test herbicides and the greatest effects were caused by exposure to acetochlor and quinelorac for all antioxidant measurements. Prominent histological changes in liver tissue included loss of liver architecture and the appearance of fatty liver cells, necrotic areas, foci of leukocytic infiltration and many apoptotic cells. The most obvious changes in the spinal cord in all treated fish were degradation of myelinated white matter fibers with the emergence of empty spaces, large aggregation of pyknotic neuroglial nuclei, and damaged areas in the dorsal horn of gray matter. Collectively, the harmful effect of tested herbicides on antioxidant capacity and significant alterations in histological structures of liver and spinal cord of Oreochromis niloticus.

Biochemical and body condition markers in Rhinella icterica tadpoles exposed to atrazine, glyphosate, and quinclorac based herbicides in ecologically relevant concentrations

Amphibians have suffered population decline due to several factors, including exposure to pesticides. In the south of Brazil, rice cultivations use herbicides based on atrazine, glyphosate and quinclorac as the commercial formulations Primoleo®, Roundup® and Facet®, respectively. Rhinella icterica was chosen to evaluate oxidative balance markers and body condition after exposure to three concentrations of herbicides (10, 20 and 40 µg/L of atrazine and quinclorac; 100, 250 and 500 µg/L of glyphosate). These xenobiotics, regardless of the concentrations used, accelerated the development process of animals and seemed to act as modulators of development. We observed no significant variations for any of the oxidative balance markers studied (superoxide dismutase, catalase, TBARS and carbonylated proteins); however, we cannot rule out that other antioxidant system components prevent oxidative stress. In general, atrazine and glyphosate accelerated the development of tadpoles, and quinclorac retards this process, which could impact the survival of these animals.

Is the Synthetic Fungicide Fosetyl-Al Safe for the Ecotoxicological Models Danio rerio and Enchytraeus crypticus?

Worldwide, pesticides have contaminated the environment, affecting non-target species. The aim of this work was to evaluate the effects of fosetyl-Al (FOS) on model organisms. Based on the 3 Rs for animal research and described guidelines, the OECD 236 and 220 were applied with some modifications. The FOS test concentrations were 0.02–0.2–2–20–200 mg/L for Danio rerio and 250–500–750–1000–1250 mg/kg for Enchytraeus crypticus. Besides the standard endpoints, additional endpoints were evaluated (D. rerio: behavior and biochemical responses; E. crypticus: extension of exposure duration (28 d (days) + 28 d) and organisms’ sizes). For D. rerio, after 96 h (h), hatching was inhibited (200 mg/L), proteins’ content increased (2 and 20 mg/L), lipids’ content decreased (2 mg/L), glutathione S-transferase activity increased (2 mg/L), and, after 120 h, larvae distance swam increased (20 mg/L). For E. crypticus, after 28 d, almost all the tested concentrations enlarged the organisms’ sizes and, after 56 d, 1250 mg/kg decreased the reproduction. In general, alterations in the organisms’ biochemical responses, behavior, and growth occurred at lower concentrations than the effects observed at the standard endpoints. This ecotoxicological assessment showed that FOS may not be considered safe for the tested species, only at higher concentrations than the predicted environmental concentrations (PECs). This research highlighted the importance of a multi-endpoint approach to assess the (eco)toxic effects of the contaminants.

Toxicology and pharmacology of synthetic organoselenium compounds: an update

Here, we addressed the pharmacology and toxicology of synthetic organoselenium compounds and some naturally occurring organoselenium amino acids. The use of selenium as a tool in organic synthesis and as a pharmacological agent goes back to the middle of the nineteenth and the beginning of the twentieth centuries. The rediscovery of ebselen and its investigation in clinical trials have motivated the search for new organoselenium molecules with pharmacological properties. Although ebselen and diselenides have some overlapping pharmacological properties, their molecular targets are not identical. However, they have similar anti-inflammatory and antioxidant activities, possibly, via activation of transcription factors, regulating the expression of antioxidant genes. In short, our knowledge about the pharmacological properties of simple organoselenium compounds is still elusive. However, contrary to our early expectations that they could imitate selenoproteins, organoselenium compounds seem to have non-specific modulatory activation of antioxidant pathways and specific inhibitory effects in some thiol-containing proteins. The thiol-oxidizing properties of organoselenium compounds are considered the molecular basis of their chronic toxicity; however, the acute use of organoselenium compounds as inhibitors of specific thiol-containing enzymes can be of therapeutic significance. In summary, the outcomes of the clinical trials of ebselen as a mimetic of lithium or as an inhibitor of SARS-CoV-2 proteases will be important to the field of organoselenium synthesis. The development of computational techniques that could predict rational modifications in the structure of organoselenium compounds to increase their specificity is required to construct a library of thiol-modifying agents with selectivity toward specific target proteins.

Ecological impacts of pesticides on Astyanax jacuhiensis (Characiformes: Characidae) from the Uruguay river, Brazil

Brazilian freshwater ecosystems are continuously exposed to pesticides and domestic sewage. The Uruguay River was chosen for this study because of its international importance, as it flows through Brazil, Argentina, and Uruguay. It receives contaminants such as pesticides and domestic residues. Thus, the aim of this study to assess the accumulation of pesticides in muscle of the fish Astyanax jacuhiensis, its biochemical responses, and the presence of pesticides in water. In total, seven pesticides were registered in water from both river sites. Eight pesticides were detected in fish muscle. The biochemical responses showed that brain lipid peroxidation (LPO) and protein carbonyl (PC) in A. jacuhiensis were higher in the summer. Muscle showed the highest LPO levels in the spring and the highest PC in the summer. Liver LPO and PC levels were higher in the spring and summer. In the gills, the PC was higher in the spring and the LPO in the spring and winter. In the brain and in the gills, glutathione-S-transferase activity was high in the summer and autumn. Catalase activity was lower during the winter and spring. Non-protein thiol (NPSH) levels were lower in the brain in the winter and spring. Muscle tissue showed lower NPSH in the winter (site 1). Liver NPSH showed increased levels in liver in the spring and winter (site 2). The biochemical results clearly is related to pesticides and/or to the presence of other contaminants in the water such as metals or domestic sewage. The accumulation of pesticides in fish muscle added evidence that pesticides have been used in the area surrounding the Uruguay River. In conclusion, the biomarkers assayed in the present study could be used in future investigations considering other sampling sites along Uruguay River.

Modulation of redox and insulin signaling underlie the anti-hyperglycemic and antioxidant effects of diphenyl diselenide in zebrafish

The organic selenium compound diphenyl diselenide (DD) has been recognized as an antioxidant and neuroprotective agent, exerting an anti-hyperglycemic effect in experimental models of diabetes. However, the precise mechanisms involved in the protection are unclear. Using the zebrafish (Danio rerio) as a model organism, here we investigated biomarkers underlying the protective effects of DD against hyperglycemia, targeting in a transcriptional approach the redox and insulin-signaling pathway. Fish were fed on a diet containing DD (3 mg/kg) for 74 days. In the last 14 days, they were exposed to a 111 mM glucose solution to induce a hyperglycemic state. DD reduced blood glucose levels as well as normalized the brain mRNA transcription of four insulin receptors-coding genes (Insra1, Insra2, Insrb1, Insrb2), which were down-regulated by glucose. DD alone caused an up-regulation of relative mRNA transcription in both Insra receptors and glucose transporter 3 genes. DD counteracted hyperglycemia-induced lipid peroxidation, protein and thiol depletion. Along with the decreased activity of antioxidant enzymes SOD and GPx, the brain of hyperglycemic fish presented a reduction in mRNA transcription of FoxO3A, FoxO3B, Nrf2, GPx3A, SOD1, and SOD2 genes. Besides normalizing the transcriptional levels, DD caused an up-regulation of relative mRNAs that encode Nrf2, FoxO1A, FOXO3A, GPx4A, PTP1B, AKT and SelP. Collectively, our findings suggest that the antioxidant and anti-hyperglycemic actions of DD in a zebrafish diabetes model are likely associated with the regulation of the oxidative stress resistance and the insulin-signaling pathway and that could be related to the modulation at mRNA level of two important transcription factors, Nrf2 and FoxO.

Diphenyl diselenide dietary supplementation protects against fumonisin B1-induced oxidative stress in brains of the silver catfish Rhamdia quelen

The trend toward using plant-based ingredients in aquafeeds has raised important concerns for aquaculture owing to the negative impacts of mycotoxins on fish health; with emphasis for contamination by fumonisin B₁ (FB₁). The brain is an important target of FB₁; however, study of the pathways linked to brain damage is limited to an analysis of histopathological alterations. Reports have demonstrated the protective effects of dietary supplementation with diphenyl diselenide (Ph₂Se₂) in the brains of fish subjected to several environmental insults; nevertheless, its neuroprotective effects in fish fed with diets contaminated with FB₁ remain unknown. Therefore, the aim of this study was to evaluate whether oxidative damage may be a pathway associated with FB₁-induced neurotoxicity, as well as to evaluate whether dietary supplementation with Ph₂Se₂ prevents or reduces FB₁-mediated brain oxidative damage in silver catfish. Brain reactive oxygen species (ROS), lipid peroxidation (LOOH) and protein carbonylation increased on day 30 post-feeding in animals that received FB₁-contaminated diets compared to the control group, while brain antioxidant capacity against peroxyl radicals (ACAP) levels and catalase (CAT), glutathione peroxidase (GPx) and glutathione S-transferase (GST) activities were lower. Diphenyl diselenide dietary supplementation avoid increases in brain ROS levels, as well minimizing the augmentation of LOOH levels. Furthermore, Ph₂Se₂ prevented impairment of brain ACAP levels, as well as GPx and GST activities elicited by FB₁-contaminated diets. These data suggest that dietary supplementation with 3 mg/kg Ph₂Se₂ prevented FB₁-induced brain damage in silver catfish, and this protective effect occurred through avoided of excessive ROS production, as well as via prevention of brain lipid damage. Furthermore, Ph₂Se₂ exerted its neuroprotective effects via ameliorative effects on the enzymatic and non-enzymatic antioxidant defense systems, and may be an approach to prevent FB₁-induced brain oxidative stress; however, is not an alternative to prevent the impairment on performance caused by FB₁.

Diphenyl diselenide dietary supplementation alleviates behavior impairment and brain damage in grass carp (Ctenopharyngodon idella) exposed to methylmercury chloride

Mercury (Hg) induces neurobehavioral disorders through reactive oxygen species (ROS) elevation and impairment of brain key enzyme activities. Nevertheless, the therapeutic and toxic selenium concentrations for fish are very close; diphenyl diselenide (Ph₂Se₂), an organoselenium compound with neuroprotective effects, may be an alternative to elemental Se. Therefore, the aim of this study was to determine whether dietary supplementation with Ph₂Se₂ prevented or reduced the neurobehavioral alterations and oxidative damage elicited by CH₃HgCl in grass carp Ctenopharyngodon idella. Fish exposed to CH₃HgCl exhibited significantly reduced distance travelled and swimming speed compared to the control group, as well as augmented cortisol and ROS levels and xanthine oxidase (XO) activities. CH₃HgCl exposure significantly increased lipid peroxidation (LOOH) and protein carbonylation (PC) levels compared to those of the control group, while acetylcholinesterase (AChE) and sodium-potassium pump (Na⁺, K⁺-ATPase) activities were inhibited. Dietary supplementation with 3 mg/kg Ph₂Se₂ ameliorated locomotor activity impairment and prevented the augmented brain cortisol and ROS levels as well as XO activity. The supplement reduced lipid and protein damage elicited by CH₃HgCl and exerted protective effects on brain AChE and Na⁺, K⁺-ATPase activities. Exposure to an environmental concentration of CH₃HgCl elicited neurobehavioral alterations linked to reduced locomotor activity, a finding that can be explained by oxidative damage and reduced activity of AChE and Na⁺, K⁺-ATPase in telencephalon and mesencephalon structures. Dietary supplementation with Ph₂Se₂ prevented CH₃HgCl-induced locomotor impairment. This effect appeared to be mediated by antioxidant action. Ph₂Se₂ may be a viable approach to prevention or reduction CH₃HgCl-mediated neurotoxic effects.

Effects of Multi-Component Mixtures from Sewage Treatment Plant Effluent on Common Carp (Cyprinus carpio) under Fully Realistic Condition

This study characterized changes in biomarker responses in common carp (Cyprinus carpio) upon exposure to effluent water discharged from a sewage treatment plant (STP) under real conditions. Fish were exposed to contamination in Cezarka pond, which receives all of its water input from the STP in the town of Vodnany, Czech Republic. Five sampling events were performed at day 0, 30, 90, 180, and 360 starting in April 2015. In total, 62 pharmaceutical and personal care products (PPCPs) were detected in the polar organic chemical integrative sampler. Compared to a control pond, the total concentration of PPCPs was 45, 16, 7, and 7 times higher in Cezarka pond at day 30, 90, 180, and 360, respectively. The result of oxidative stress and antioxidant enzyme biomarkers indicated alterations in the liver and intestine tissues of fish from Cezarka pond at day 30 and 360, respectively. High plasma vitellogenin levels were observed in both exposed females (180 and 360 days) and males (360 days) compared with their respective controls. However, only exposed female fish had higher vitellogenin mRNA expression than the control fish in these periods. Exposed female fish showed irregular structure of the ovary with scattered oocytes, which further developed to a vitellogenic stage at day 360. Low white blood cell levels were indicated in all exposed fish. Despite numerous alterations in exposed fish, favorable ecological conditions including high availability of food resulted in a better overall condition of the exposed fish after 1 year of exposure compared to the controls.

Integrated biomarkers response confirm the antioxidant role of diphenyl diselenide against atrazine

Atrazine (ATZ) is a herbicide worldwide used. That can cause oxidative damage in non-target organisms, such as fish. Furthermore, the threat of exposure to pesticides together with poor nutrition is hazardous to the normal development of fish, and supplementation of the fish diet with antioxidants compounds is an alternative approach to prevent the hazardous effects of pesticide exposure. Here we aimed to investigate the capacity of diphenyl diselenide (PhSe)₂ diet supplementation to improve the antioxidant defense of Cyprinus carpio (carp) exposed to environmental concentrations of ATZ. To prove the efficiency of (PhSe)₂, we used the Integrated Biomarkers Response (IBR) methodology. Therefore, carp were fed for 8 weeks diets either with or without (PhSe)₂ and exposed to 2 or 10µg/L of ATZ for 96h, euthanized, and their liver, gills, and muscle tissues were removed for biochemical assays. ATZ was able to cause oxidative damage from reactive species production in all tissues of carp, as observed by the increase of lipid peroxidation and protein damage. The activity of some antioxidant enzymes was inhibited in carp exposed to ATZ. However, (PhSe)₂ supplementation was able to prevent this ATZ-induced damage by improving the activities of antioxidant enzymes and through antioxidant competence of (PhSe)₂per se. Furthermore, IBR was shown to be a useful tool to compare treatments, even at different concentrations, and identify the efficiently antioxidant behavior of the organoselenium compound.

Oxidative effects of the acute exposure to a pesticide mixture of cypermethrin and chlorpyrifos on carp and zebrafish - A comparative study

The use of commercial pesticides combinations increases the risk of intoxication in non-target aquatic organisms. Here, we investigate the potential of a commercial pesticide formulation containing (CYP) plus chlorpyrifos (CPF) to induce oxidative damage on two fish species (common carp and zebrafish). Carp and zebrafish were exposed for 96 h under laboratory conditions. Fish were divided in three different groups: CTL, 0.3 μg L^-1 or 0.6 μg L^-1 of CYP and 0.5 or 1 μg L^-1 of CPF in commercial formulation. Both carp and zebrafish showed an increase in lipid peroxidation (LPO) and glutathione-S-transferase (GST) activity when compared to control group. Other oxidative parameters responded differently to exposure in carp and zebrafish. There were an increase in ascorbic acid (ASA) levels and decrease in catalase (CAT) activity and non-protein thiols (NPSH) levels in treated groups of carps. In the other hand, zebrafish showed significant decrease in ASA and increase in CAT activity and NPSH levels. Overall, we demonstrate noxious effects on redox parameters in two fish experimental models and different effects were observe in each fish species exposed to commercial pesticide formulation. This difference responses observed can be related with specific mechanisms of detoxification and antioxidant defense system of each species.

Effect of diphenyl diselenide diet supplementation on oxidative stress biomarkers in two species of freshwater fish exposed to the insecticide fipronil

The ability of diphenyl diselenide [(PhSe)2] to attenuate oxidative damage was evaluated in the liver, gills, brain, and muscle of carp (Cyprinus carpio) and silver catfish (Rhamdia quelen) experimentally exposed to fipronil (FPN). Initially, the fish were fed a diet without (PhSe)2 or a diet containing 3.0 mg/kg of (PhSe)2 for 60 days. After the 60-day period, the fish were exposed to 0.65 µg/L of FPN for 192 h. The results showed that carp exposed to FPN and not fed with (PhSe)2 exhibited acetylcholinesterase (AChE) inhibition in brain and muscle, and increased thiobarbituric acid-reactive substance (TBARS) in liver, gills, and brain. Furthermore, FPN decreased nonprotein thiols (NPSH) and δ-aminolevulinate dehydratase (δ-ALA-D) in carp liver and gills, and increased plasma glucose and protein levels. In silver catfish, FPN inhibited AChE and increased TBARS levels in muscle. In addition, glutathione S-transferase (GST) decreased in liver and muscle, and plasma glucose was increased. (PhSe)2 reversed some of these effects. It prevented the increase in TBARS levels in liver, gills, and brain in carp and in silver catfish muscle, and reversed the increase in plasma glucose levels in both species. Additionally, (PhSe)2 increased the NPSH levels in carp and silver catfish that had decreased in response to FPN exposure. However, (PhSe)2 was not effective in reversing the AChE inhibition in brain and muscle or the δ-ALA-D decrease in carp liver. Thus, (PhSe)2 protects tissues of both species of fish, mainly by preventing or counteracting the effects of FPN, on TBARS levels, antioxidants, and present anti-hyperglycemic property.

Effects of diphenyl diselenide on growth, oxidative damage, and antioxidant response in silver catfish

The aim of this study was to evaluate the effects of dietary diphenyl diselenide [(PhSe)2] at different concentrations (1.5, 3.0, and 5.0 mg/kg) on growth, oxidative damage and antioxidant parameters in silver catfish after 30 and 60 days. Fish fed with 5.0 mg/kg of (PhSe)2 experienced a significant decrease in weight, length, and condition factor after 30 days and these parameters increased after 60 days. Thiobarbituric acid reactive substances (TBARS) and protein carbonyl (PC) decreased in the liver of silver catfish supplemented with (PhSe)2 after 30 days at all concentrations, while after 60 days these parameters decreased in liver, gills, brain, and muscle. Supplementation with (PhSe)2 induced a decrease in catalase (CAT) activity from liver only after 60 days of feeding. Superoxide dismutase (SOD) decreased at 5.0 mg/kg after 30 and 60 days and glutathione peroxidase (GPx) was enhanced at 1.5 and 3.0 mg/kg after 30 and 60 days. Silver catfish supplemented for 30 days showed a significant increase in liver glutathione S-transferase (GST) at 3.0 mg/kg, while after 60 days GST activity increased in liver at 1.5, 3.0, and 5.0 mg/kg and in gills at 3.0 and 5.0 mg/kg of (PhSe)2. After 30 days, non-protein thiols (NPSH) did not change, while after 60 days NPSH increased in liver, gills, brain, and muscle. In addition, ascorbic acid (AA) levels after 30 days increased in liver at three concentrations and in gills and muscle at 1.5 mg/kg, while after 60 days, AA increased at all concentrations in all and tissues tested. Thus, diet supplemented with (PhSe)2 for 60 days could be more effective for silver catfish. Although the concentration of 5.0 mg/kg showed decreased growth parameters, concentrations of 1.5 and 3.0 mg/kg, in general, decreased oxidative damage and increased antioxidant defenses.

Spatial and temporal biomarkers responses of Astyanax jacuhiensis (Cope, 1894)(Characiformes: Characidae) from the middle rio Uruguai, Brazil

Due to intense agricultural activity in the rio Uruguai (South Brazil), there is the potential for aquatic contamination by agrochemicals. In this region, there are many reservoirs to meet the water demand for rice fields, forming lentic environments. In line with this information, the aim of this study was to show a comparative analysis of some biomarkers, such as lipid peroxidation (TBARS), gluthatione S-transferase (GST), non-protein thiols (NPSH), amino acids (AA) and piscine micronucleus tests (MNE) in Astyanax jacuhiensis from lentic and lotic environments in the middle rio Uruguai region, comparing warm and cold seasons. Eight pesticides were found in water samples, with propoxur having the highest concentration found in both environments and seasons. Fish from the warm season showed higher levels of biochemical biomarkers, and fish from the cold season showed higher levels of MNE and AA. TBARS and AA presented higher levels in fish from the river, while GST, NPSH, MNE and AA presented higher levels in fish from dams. These environments have different characteristics in terms of redox potential, aeration, sedimentation, trophic structure, agrochemicals input and others, which may affect the physiological and biochemical responses of fish in against adverse situations.

Diet with diphenyl diselenide mitigates quinclorac toxicity in silver catfish (Rhamdia quelen)

In this study, the protective effects of diphenyl diselenide [(PhSe)2] on quinclorac- induced toxicity were investigated in silver catfish (Rhamdia quelen). The fish were fed for 60 days with a diet in the absence or in the presence of 3.0 mg/Kg (PhSe)2. Animals were further exposed to 1 mg/L quinclorac for 8 days. At the end of experimental period, fish were euthanized and biopsies from liver and gills, as well as blood samples, were collected. The cortisol and metabolic parameters were determined in plasma, and those enzyme activities related to osmoregulation were assayed in the gills. In liver, some important enzyme activities of the intermediary metabolism and oxidative stress-related parameters, such as thiobarbituric acid-reactive substance (TBARS), protein carbonyl, catalase (CAT), superoxide dismutase (SOD), glutathione S-transferase (GST), nonprotein thiols (NPSH) and ascorbic acid contents were also evaluated. Compared to the control group, quinclorac exposure significantly decreased hepatosomatic index and increased cortisol and lactate values in plasma. Moreover, the activities of fructose biphosphatase (FBPase), glucose-6-phosphate dehydrogenase (G6Pase), glycogen phosphorilase (GPase) and aspartate aminotransferase (AST) were significantly increased in liver. Quinclorac also induced lipid peroxidation while the activity of SOD, NPSH and ascorbic acid levels decreased in the liver. However, dietary (PhSe)2 reduced the herbicide-induced effects on the studied parameters. In conclusion, (PhSe)2 has beneficial properties based on its ability to attenuate toxicity induced by quinclorac by regulating energy metabolism and oxidative stress-related parameters.

Effect of atrazine, glyphosate and quinclorac on biochemical parameters, lipid peroxidation and survival in bullfrog tadpoles (Lithobates catesbeianus)

Increased use of pesticides worldwide has led to damage not only to natural ecosystems but also to nontarget species. This study assessed the effects of different concentrations of the herbicides atrazine, glyphosate, and quinclorac on biochemical parameters, lipid peroxidation, and survival in tadpoles of Lithobates catesbeianus (bullfrog). Two hundred eighty-eight tadpoles were acquired from a frog farm in the south of Brazil. All animals were kept in aquariums under controlled laboratory conditions for 7 days and exposed to commercial formulations of atrazine (5, 10, and 20 μg/L), glyphosate (36, 72, and 144 μg/L), and quinclorac (0.05, 0.10, and 0.20 μg/L) for 7 days thereafter. The concentrations used in this study are similar to the levels of these herbicides found in natural water bodies. After exposure, gill, liver, and muscle samples were removed from each animal for quantitation of glycogen, total lipids, triglycerides, cholesterol, total proteins, and lipid peroxidation. Atrazine, glyphosate, and quinclorac exposure induced a significant decrease in levels of glycogen and total lipids in gill, liver, and muscle. Triglycerides levels in the gill increased after exposure to glyphosate, and decreased after exposure to atrazine and quinclorac; their levels in liver and muscle decreased on exposure to all herbicides. Cholesterol and total protein levels decreased in liver and muscle for all three herbicides. All tissues exhibited increased lipid peroxidation after exposure to all herbicides. In conclusion, exposure to the herbicides tested in this study induced significant changes in biochemical parameters and increased lipid peroxidation levels in tadpoles of L. catesbeianus.

Evaluation of the effects induced by dietary diphenyl diselenide on common carp Cyprinus carpio

Several diets employed in aquaculture are enriched with selenium (Se), as it is a fundamental element to aquatic vertebrates. Diphenyl diselenide [(PhSe)₂], which is a synthetic organoselenium compound, has been considered a potential antioxidant agent in different experimental models. Thus, the aim of this study was to evaluate the effects of dietary diphenyl diselenide at concentrations of 1.5, 3.0, and 5.0 mg/kg for 60 days and to determine its optimal supplemental level for carp, Cyprinus carpio. Neither growth retardation nor hepatoxicity was induced by the inclusion of diphenyl diselenide at concentrations ranging from 1.5 to 5.0 mg/kg. In addition, the inclusion of 3.0 mg/kg of diphenyl diselenide stimulated the weight and length of the carp. The supplementation with 1.5 and 3.0 mg/kg of diphenyl diselenide did not produce oxidative damage in the tissues, verified by peroxidation lipid and protein carbonyl assays. However, at 5.0 mg/kg, it caused an increase of the lipid peroxidation in the liver, brain, and muscle, and inhibited the cerebral acetylcholinesterase activity. An increase of the hepatic superoxide dismutase activity and non-protein thiols content in all tissues and ascorbic acid in the liver, gills, and brain was verified in carp fed with the diet containing 3.0 mg/kg of diphenyl diselenide. This diet had advantageous effects for the fish used in experiments. Therefore, this compound could be considered a beneficial dietary supplement for carp nutrition.

Comparative study on effects of dietary with diphenyl diselenide on oxidative stress in carp (Cyprinus carpio) and silver catfish (Rhamdia sp.) exposed to herbicide clomazone

The study investigated the capacity of diphenyl diselenide [(PhSe)2] (3.0mg/kg), on reduce the oxidative damage in liver, gills and muscle of carp and silver catfish exposed to clomazone (192h). Silver catfish exposed to clomazone showed increased thiobarbituric acid-reactive substance (TBARS) in liver and muscle and protein carbonyl in liver and gills. Furthermore, clomazone in silver catfish decrease non-protein thiols (NPSH) in liver and gills and glutathione peroxidase and ascorbic acid in liver. (PhSe)2 reversed the effects caused by clomazone in silver catfish, preventing increases in TBARS and protein carbonyl. Moreover, NPSH and ascorbic acid were increased by values near control. The results suggest that (PhSe)2 attenuated the oxidative damage induced by clomazone in silver catfish. The clomazone no caused an apparent situation of oxidative stress in carp, showing that this species is more resistant to this toxicant. Altogether, the containing (PhSe)2 diet helps fish to increase antioxidants defenses.

Oxidative stress in carp exposed to quinclorac herbicide under rice field condition

This study evaluated parameters of oxidative stress and antioxidant profile in fish after herbicide exposure. Cyprinus carpio were exposed to quinclorac (initial concentration 344.60μg/L) for 7, 30, and 90 days under rice field condition. Thiobarbituric acid-reactive substances (TBARS) were evaluated in brain, liver and muscle tissues, and protein carbonyl in liver. Enzymatic parameters such as catalase (CAT) and gluthatione S-transferase (GST) activities also were studied in liver. TBARS levels fluctuated in the brain showing increase in 7 days and decrease in 30 days, while in liver it was observed increase in 7 and 30 days, as well as in muscle after 30 and 90 days. The protein carbonyl was also increased after 30 and 90 days of herbicide exposure. CAT and GST activities were decreased after 30 and 90 days, respectively. The alterations observed suggest that a commercial formulation containing quinclorac causes oxidative damage in different tissues of carp after a long time of exposure. This study pointed out the importance of quinclorac toxicity considering the concentration used in rice fields.