Applying Artificial Neural Networks to Oxidative Stress Biomarkers in Forager Honey Bees (Apis mellifera) for Ecological Assessment.

Insect pollinators provide an important ecosystem service that supports global biodiversity and environmental health. The study investigates the effects of the environmental matrix on six oxidative stress biomarkers in the honey bee Apis mellifera. Thirty-five apiaries located in urban, forested, and agricultural areas in Central Italy were sampled during the summer season. Enzyme activities in forager bees were analyzed using an artificial neural network, allowing the identification and representation of the apiary patterns in a Self-Organizing Map. The SOM nodes were correlated with the environmental parameters and tissue levels of eight heavy metals. The results indicated that the apiaries were not clustered according to their spatial distribution. Superoxide dismutase expressed a positive correlation with Cr and Mn concentrations; catalase with Zn, Mn, Fe, and daily maximum air temperature; glutathione S-transferase with Cr, Fe, and daily maximal air temperature; and glutathione reductase showed a negative correlation to Ni and Fe exposure. This study highlights the importance of exploring how environmental stressors affect these insects and the role of oxidative stress biomarkers. Artificial neural networks proved to be a powerful approach to untangle the complex relationships between the environment and oxidative stress biomarkers in honey bees. The application of SOM modeling offers a valuable means of assessing the potential effects of environmental pressures on honey bee populations.

Phylogenetic Diversity of the Red Swamp Crayfish Procambarus clarkii and Its Dispersal Pattern in Northern and Central Italy.

The red swamp crayfish Procambarus clarkii is one of the most threatening freshwater species in the world. The aim of this study is to provide a better understanding of the phylogeography and the invasion routes of P. clarkii populations in the Italian Peninsula through the analysis of mitochondrial phylogeny. Mitochondrial control region and cytochrome c oxidase subunit I (COI) sequences of 153 samples collected from six Italian basins were analyzed and compared to worldwide data. Except for the lakes Bolsena and Posta Fibreno, a high genetic variability was found in the other basins. The mitochondrial DNA pattern of P. clarkii from the lakes Candia and Massaciuccoli confirmed the hypothesis of double introduction events. Another entry point could be represented by Lake Trasimeno, which shows haplotypes originating from Louisiana and not shared with other Italian basins. Moreover, unique lineages were also found in the Stella River, thus enhancing the hypothesis that multiple introductions of P. clarkii occurred in northern and Central Italy and strengthening the idea that knowledge about the dispersion routes of this alien species can be useful to predict its invasiveness and elaborate control strategies to preserve biodiversity.

Sex and seasonal differences in metal accumulation of selected tissues in red swamp crayfish from Lake Trasimeno (Umbria, Italy).

Concentrations of essential metals (Cu, Co, Cr, Fe, Ni, Mn, and Zn) and non-essential and toxic metals (Ag, Cd, Hg, and Pb) were quantified in hepatopancreas and abdominal muscle for 73 specimens (37 males and 36 females) of Procambarus clarkii from Lake Trasimeno (Italy) in a year's campaign (July 2018 to June 2019). Elemental concentrations determined in crayfish differed in tissues, seasons, and gender. Both sexes showed lower concentrations in abdominal muscle than in hepatopancreas. Essential metals accumulated in higher concentrations in both tissues than non-essential elements, while associations between essential metals were stronger, especially for females; however, a strong correlation was also observed between Cu and Ag in both sexes. No significant differences in concentrations were recorded between sexes for all seasons; contrarily, significant differences among the total seasonal concentrations (males plus females) were observed only for essential metals and for Ag. Seasonal Toxic Contamination Index (TCI) for Cr, Ni, Cu, Zn, Cd, Pb, and Hg were calculated to assess the toxicity level of metals in the sediments. TCI higher than 1 was detected for Ni only in summer, confirming the close connection between the fluctuating hydrological levels of the shallow Lake Trasimeno, strongly dependent on precipitation, and the metal contamination levels of sediments.

Ecotoxicity of Copper(I) Chloride in Grooved Carpet Shell (Ruditapes decussatus).

Copper (Cu) is a ubiquitous trace element in the aquatic environment, and is usually found at low levels. Copper environmental concentrations can be altered as a result anthropogenic activities. Shellfish are useful bioindicators to ensure adequate environmental monitoring. Thus, the aim of the present study was as follows: (a) determine the LC50 of copper(I) chloride in grooved carpet shell (Ruditapes decussatus) collected in the Santa Gilla lagoon (Sardinia, Italy), and (b) analyze the antioxidant biomarkers in digestive gland and gills of same specimens exposed to different concentrations of the above-mentioned metal (0.045, 0.45, and 0.90 mg/L) for 96 h. A withdrawal period of 96 h was considered for the treated clam, carrying out the same biochemical analyses, superoxide dismutase (SOD), catalase (CAT), selenium-dependent glutathione peroxidase (Se-GPx), glutathione S-transferases (GSTs), and total glutathione (GSH+2GSSG) in the two tissues. Different time and dose responses of the antioxidant biomarkers were recorded in the digestive glands and gills. Oxidative stress biomarkers highlighted the ability of Cu to induce oxidative stress in R. decussatus. Clam, following the withdrawal period of 96 h, has not been able to achieve the control levels of all biochemical markers in the digestive gland and gills. R. decussatus can be a suitable model to assess the ecotoxicity of copper in aquatic ecosystems. These findings may advance knowledge on the role and the effects of copper on oxidative stress biomarkers in grooved carpet shell. The metal ecotoxicity response can be useful to perform accurate biomarker-based monitoring programs using this bivalve species.

Multi-Level System to Assess Toxicity in Water Distribution Plants.

The toxicity of water samples from water distribution plants needs to be investigated further. Indeed, studies on the pro-oxidant effects driven by tap water are very limited. In this study, the water quality, pro-oxidant effects, and potential health risks driven by exposure to groundwater samples from two water plants (sites A and B) located in Northwestern Italy were investigated in a multi-level system. Physicochemical parameters and the absence of pathogens, cyanotoxins, and endocrine active substances indicated a good water quality for both sites. The 25 metals analyzed were found under the limit of quantification or compliant with the maximum limits set by national legislation. Water samples were concentrated by the solid-phase extraction system in order to assess the aquatic toxicity on Epithelioma papulosum cyprini (EPC) cell line. Levels of superoxide dismutase, catalase, glutathione peroxidase, glutathione S-transferase, and glutathione reductase were evaluated through the Integrated Biomarkers Response (IBRv2) index. EPC cell line was found a sensible model for assessing the antioxidant responses driven by both water concentrates. A similar antioxidant response was shown by plots and IBRv2 suggesting a muted risk for the two sampling sites.

Modulation of Antioxidant Defense in Farmed Rainbow Trout (Oncorhynchus mykiss) Fed with a Diet Supplemented by the Waste Derived from the Supercritical Fluid Extraction of Basil (Ocimum basilicum).

Phytotherapy is based on the use of plants to prevent or treat human and animal diseases. Recently, the use of essential oils and polyphenol-enriched extracts is also rapidly increasing in the aquaculture sector as a means of greater industrial and environmental sustainability. Previous studies assessed the antibacterial and antiparasitic effects of these bioactive compounds on fish. However, studies on the modulation of oxidative stress biomarkers are still scant to date. Thus, in this study, the modulation of antioxidant defense against oxidative stress exerted by fish diets supplemented with a basil supercritical extract (F1-BEO) was assessed in rainbow trout Oncorhynchus mykiss. The F1-BEO extracted with supercritical fluid extraction was added to the commercial feed flour (0.5, 1, 2, 3% w/w) and mixed with fish oil to obtain a suitable compound for pellet preparation. Fish were fed for 30 days. The levels of stress biomarkers such as superoxide dismutase, catalase, glutathione peroxidase, glutathione S-transferase, glutathione reductase, glyoxalase I, glyoxalase II, lactate dehydrogenase, glutathione and malondialdehyde showed a boost in the antioxidant pathway in fish fed with a 0.5% F1-BEO-supplemented diet. Higher F1-BEO supplementation led to a failure of activity of several enzymes and the depletion of glutathione levels. Malondialdehyde concentration suggests a sufficient oxidative stress defense against lipid peroxidation in all experimental groups, except for a 3% F1-BEO-supplemented diet (liver 168.87 ± 38.79 nmol/mg prot; kidney 146.86 ± 23.28 nmol/mg prot), compared to control (liver 127.76 ± 18.15 nmol/mg prot; kidney 98.68 ± 15.65 nmol/mg prot). Our results suggest supplementing F1-BEO in fish diets up to 0.5% to avoid potential oxidative pressure in farmed trout.

Ecotoxicity in Hyriopsis bialatus of copper and zinc biocides used in metal-based antifouling paints.

Biofouling is a costly burden for the shipping industry. Metal-based antifouling paints are widely used to protect submerged surfaces, but the release of metals from coatings and the recoating of hulls can leach large amounts of copper and zinc into aquatic environments, posing a risk for aquatic ecosystems and biodiversity. With this study, we studied the time-course metal accumulation and oxidative stress in the digestive gland and the gills of Hyriopsis bialatus, an Asian freshwater mussel, exposed to sublethal concentrations of cuprous chloride (50 and 5 µg/L) and zinc sulfate (1000 and 100 µg/L). Time-dependent accumulation was observed after exposure to copper, but zinc uptake was negligible. Integrated biomarker response (IBRv2) and statistical analysis of individual biomarker levels showed a greater biomarker response in the digestive gland and the gills after exposure to the higher concentration of CuCl and ZnSO4. Both compounds elicited a biochemical response, especially in the digestive gland. Glutathione peroxidase activity was increased after exposure to both metals at both concentrations, suggesting a powerful defense against lipid peroxidation. The biological impact of zinc was less than that of copper, suggesting mitigated ecological pressure.

Lethal and Sublethal Responses of Hydropsyche pellucidula (Insecta, Trichoptera) to Commercial Polypropylene Microplastics after Different Preconditioning Treatments.

Microplastics (MPs) pose biological and chemical hazards in aquatic and terrestrial food webs across the globe. Research on microplastic contamination has long focused on marine ecosystems, whereas the toxicological impact on freshwater organisms is still little explored. In this study, the lethal and sublethal response of the freshwater macroinvertebrate Hydropsyche pellucidula exposed to polypropylene MPs after different pre-conditioning treatments was assessed. Field samples were collected in a riverine system (Vipacco river; northeast Italy) to assess the characteristics of the MPs in the aquatic environment Both water and sediment were contaminated by MPs (3.73 ± 2.11 items m-3 per min and 3.33 ± 4.16 items dm-3, respectively). The chemical MPs composition included polystyrene, polyethylene terephthalate, polyurethane, polyamide, polypropylene, and polyethylene. Polypropylene (PP), although not the most abundant polymer recorded in the study area, was preferred over the other types according to its abundance in freshwater and H. pellucidula feeding behavior. A housing test was performed to recreate the natural conditions of larvae sampled for a reliable response to the ecotoxicological tests. The microplastics underwent either preconditioning with Vipacco River water (PP-river) and surfactant Triton X-100 (PP-sf) or no pre-treatment (PP). Submersion of microplastics in 10 µg L-1 of surfactant solution for 24 h was sufficient to induce consistent spectral changes and modify the chemical profile of the plastic surface. Mortality rate differed according to treatment: PP and PP-river > positive control > PP-sf > negative control. Integrated biomarker response (IBRv2) and analysis of oxidative stress biomarker levels showed a greater response of superoxide dismutase and lipid peroxidation (malondialdehyde) in larvae treated with PP conditioned in surfactant. Our findings enhance knowledge on the toxicity of PP and conditioning phases on H. pellucidula larvae.

Population Ecology and Genetic Diversity of the Invasive Alien Species Procambarus clarkii in Lake Trasimeno (Italy).

The deliberate or accidental introduction of invasive alien species (IAS) causes negative ecological and economic impacts altering ecosystem processes, imperiling native species and causing damage to human endeavors. A monthly monitoring program was performed in Lake Trasimeno (Central Italy) from July 2018 to July 2019 in order to provide an upgrade of the population ecology of Procambarus clarkii and to assess the genetic diversity by analyzing the relationships among mitochondrial DNA diversity. Our results confirmed that P. clarkii is well acclimatized in the lake, revealing a stable population structure favored by the resources and conditions typical of this ecosystem, which seem to be optimal for the maintenance of the species. Four distinct mitochondrial haplotypes were detected, but one of them was clearly overrepresented (76%), suggesting that a single predominant introduction event may have occurred in this area, likely followed by secondary events. The identification of the typical genetic variants provides a better understanding of the evolutionary scenarios of P. clarkii in this biotope and it can be helpful in management plans concerning the expanding populations of this invasive alien species.

First insights into oxidative stress and theoretical environmental risk of Bronopol and Detarox® AP, two biocides claimed to be ecofriendly for a sustainable aquaculture.

Bronopol and Detarox® AP are broad spectrum antimicrobial biocides of growing interest for the aquaculture sector. While their effectiveness against aquatic pathogens has been demonstrated, toxicity data on wild or farmed species are still lacking, as is information on their potential environmental risk for aquatic ecosystems. With this study, we assessed the acute and sublethal toxicity of Bronopol and Detarox® AP in the freshwater bivalve Sinanodonta woodiana and their theoretical risk for aquatic ecosystem. The 96-h median lethal concentration (LC50) was determined using the acute toxicity test, while for the sublethal toxicity test the bivalves were exposed to two concentrations for 14 days of Bronopol (2.5 and 50 mg/L) and Detarox® AP (1.11 and 22.26 mg/L) followed by a 14-day withdrawal period. Biocide-mediated oxidative processes were investigated via a panel of oxidative stress biomarkers (malondialdehyde, superoxide dismutase, catalase, glutathione peroxidase, glutathione S-transferase). Theoretical environmental risk assessment of both biocides, with predicted concentration of no effect (PNEC), expected theoretical concentration (TEC) in the environment, and risk quotient (RQ) was performed. TEC was calculated using a model based on the size of the aquaculture facility and the receiving basin, the estimated quantity of biocide dissolved in water, and published data on biocide stability in water. Although the LC50 was higher for Bronopol (2440 mg/L) than for Detarox® AP (126 mg/L), fluctuations in oxidative stress biomarkers levels indicated that both biocides exert a slight oxidative pressure on S. woodiana. Theoretical environmental risk assessment suggested a muted risk with Detarox® AP and greater eco-sustainability compared to Bronopol.

Metal load and oxidative stress driven by organotin compounds on rainbow trout.

Tributyltin-based (TBT) antifouling paints, widely used for the treatment of flooded surfaces, have been banned in 2008 for their high environmental persistence and bioaccumulation in aquatic organisms. Although it is still present in aquatic ecosystems, oxidative stress driven by TBT has been still poorly investigated in fish. The aim of the study was to examine the time-course stress responses in liver of rainbow trout that received a single intraperitoneal injection of tributyltin chloride (TBTC) or tributyltin ethoxide (TBTE), both at a dose of 0.05 and 0.5 mg/kg. Levels of metallothioneins, total glutathione, malondialdehyde, superoxide dismutase, catalase, glutathione peroxidase and glutathione S-transferase were evaluated at 3 and 6 days post-injection. Tin load was measured in the muscle of the same fish. Differences were observed in the time-course accumulation of tin with a clear dose-response relationship. Although individual oxidative stress biomarkers varied, the biomarker profile indicated different stress mechanisms caused by both TBTC and TBTE. The weak induction of metal-trapping metallothioneins and the changes of oxidative stress biomarkers suggested a stress-pressure in both TBT-treated trout, advising for an ecotoxicological risk for freshwater ecosystems.

Ecology of oxidative stress in the Danube barbel (Barbus balcanicus) from a winegrowing district: Effects of water parameters, trace and rare earth elements on biochemical biomarkers.

Fish can be highly vulnerable to environmental pressures because they are exposed to oxidative stressors in the aquatic environment. Such stressors can affect the levels of antioxidant biomarkers against reactive oxygen species (ROS). With this study we investigated the oxidative stress ecology in Danube barbel (Barbus balcanicus) from the Barbucina creek (northeast Italy), a watercourse in the Collio winegrowing district. To do this, superoxide dismutase (SOD), catalase (CAT), and glutathione S-transferase (GST) activity was measured in gills, liver, and muscle, while metallothioneins (MT) and trace and rare earth elements (REEs) levels were determined in muscle. The effect of environmental factors (physicochemical parameters of water, trace elements and REEs) on oxidative stress biomarkers was thus assessed. High concentrations were determined for cerium (Ce), scandium (Sc), neodymium (Nd), lanthanum (La), yttrium (Y), and praseodymium (Pr) among the REEs. Among the trace elements, arsenic (As), copper (Cu), and mercury (Hg) levels were higher compared to published data, suggesting their role as stressors. The multiple linear regression (MLR) model showed a statistically significant association (R2 = 0.858; F = 10.07; p = 0.015) between As, Cu, Hg, and Pr and SOD activity in the gills, indicating a functional relationship between them. Differently, CAT activity was significantly higher in the liver, probably in response to long-term Cu contamination of the watercourse. This was confirmed by the MLR model that showed a significant association (R2 = 0.638; F = 8.152; p = 0.02) between the concentration of MT and of Cu. Our data show a biochemical defensive response by Danube barbel to the disturbances in the aquatic ecosystem of the Barbucina creek. These insights advance our understanding of the role and the effects of environmental factors as trace elements and REEs on oxidative stress in fish.

Reduction of oxidative stress and ornithine decarboxylase expression in a human prostate cancer cell line PC-3 by a combined treatment with α-tocopherol and naringenin.

Differentiation of a human aggressive PC-3 cancer cell line was obtained, in a previous investigation, by the synergic effect of α-tocopherol (α-TOC) and naringenin (NG). This combined treatment induced apoptosis and subsequent reduction of the PC-3 cell proliferation and invasion, by a pro-differentiating action. Since one of the peculiar characteristics of NG and α-TOC is their strong antioxidant activity, this study aimed to investigate their potential effect on the activity of the main enzymes involved in the antioxidant mechanism in prostate cancer cells. NG and α-TOC administered singularly or combined in the PC-3 cell line, affected the activity of several enzymes biomarkers of the cellular antioxidant activity, as well as the concentration of total glutathione (GSH + GSSG) and thiobarbituric acid reactive substances (TBARS). The combined treatment increased the TBARS levels and superoxide dismutase (SOD) activity, while decreased the glutathione S-transferase (GST), glutathione reductase (GR), and glyoxalase I (GI) activities. The results obtained indicate that a combined treatment with these natural compounds mitigated the oxidative stress in the human PC-3 cell line. In addition, a significant reduction of both ornithine decarboxylase (ODC) expression and intracellular levels of polyamines, both well-known positive regulators of cell proliferation, accompanied the reduction of oxidative stress observed in the combined α-TOC and NG treatment. Considering the established role of polyamines in cell differentiation, the synergism with NG makes α-TOC a potential drug for further study on the differentiation therapy in prostate cancer patients.

BFRs (PBDEs and HBCDs) in freshwater species from Lake Trasimeno (Italy): The singular case of HBCDs in red swamp crayfish.

Eighty-six samples belonging to five different species (crucian carp, Carassius carassius; European perch, Perca fluviatilis; tench, Tinca tinca; eel, Anguilla anguilla; red swamp crayfish, Procambarus clarkii) collected from Lake Trasimeno (Italy) were analyzed to assess polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs) contamination. The Trasimeno is the largest Italian peninsular lake located in Umbria (Central Italy), in a rural area with low anthropogenic impact. All the samples were analyzed by an in-house developed analytical procedure involving a single sample preparation with dual detection: Gas- and Liquid-Chromatography coupled to tandem Mass Spectrometry (GC-MS/MS for PBDEs and LC-MS/MS for HBCDs). BFRs levels in crucian carp, tench and European perch were negligible and mostly below quantification limits (LOQs). In eel, the species with the higher fat content, PBDE sum (15 congeners) ranged from 0.269 to 0.916 ng/g w.w. BDE-47, -100 and -154 accounted for roughly 57%, 16% and 11% of the PBDE sum, respectively, while BDE-99 (usually one of the most abundant congeners in biota), only for 3%. HBCDs (sum of α-, ß-, γ-isomers) were found between 0.157 and 1.14 ng/g w.w. with α- as predominant isomer (92% of the sum), followed by γ- (5%) and ß- (2%). Peculiar was the contamination in red swamp crayfish characterized by negligible PBDEs and very high HBCDs levels with a singular contamination pattern. In female pools (n = 9) the mean HBCDs sum was 0.150 ng/g w.w., while in males higher concentrations were measured (mean = 2.77 ng/g w.w.). A significant correlation seems to exist between the contamination level and the seasonal cycle only in male crayfish. Interestingly, among the HBCDs, the γ-isomer was the highest (67% of the total) while α- contributes only for 20%.

Functional Feeding Groups of Aquatic Insects Influence Trace Element Accumulation: Findings for Filterers, Scrapers and Predators from the Po Basin.

For this study, we measured the concentrations of 23 trace elements (Al, As, Ba, Bi, Cd, Cr, Co, Cu, Fe, Ga, Hg, In, Li, Mn, Mo, Ni, Pb, Se, Sr, Ti, Tl, V, and Zn) in the whole bodies of three functional feeding groups (FFG) (filterers-Hydropsychidae, scrapers-Heptageniidae, and predators-Odonata) of aquatic insects collected from two sites in the Po basin (Po Settimo and Malone Front, Northwest Italy) to determine: (a) how FFG influence trace element accumulations, (b) if scrapers accumulate higher elements compared to the other FFG, since they graze on periphyton, which represents one of the major sinks of metals, and (c) the potential use of macroinvertebrates to assess the bioavailability of trace elements in freshwater. The hierarchical clustering analysis generated three main groups based on trace element concentrations: the most abundant elements were Fe and Al, followed by Sr, In, Zn, V, Mo, and Cu. Tl was below the limit of detection (LOD) in all FFG. Ga was detected only in scrapers from both sites and Hg only in predators from Po Settimo. The principal component analysis showed that concentrations of Al, As, Bi, Cd, Co, Cr, Ga, Fe, In, Mn, Pb, Ni, and Sr were highest in scrapers, suggesting that trace elements accumulate from the ingestion of epilithic periphyton (biofilm). Odonata (predators) accumulate certain elements (Ba, Hg, Li, Se, V, Ti, and Zn) in higher concentrations by food ingestion composed of different aquatic organisms. Differently, Cu and Mo concentrations were the highest in filterers due to their bioavailability in the water column. Non-metric multidimensional scaling clearly differentiated the FFG based on their ability to accumulate trace elements. The findings from this study represent an important step toward the definition of an innovative approach based on trace element accumulation by macroinvertebrates.

Oxidative stress ecology on Pacific oyster Crassostrea gigas from lagoon and offshore Italian sites.

Crassostrea gigas is a sentinel species along the Italian coast. In mussels, the levels of oxidative stress biomarkers can be modulated by several environmental pollutants or pathogens and also fluctuate in response to reproductive stages and seasonal changes. In this study, adult Crassostrea gigas were sampled during summer and autumn from two lagoon and two offshore sites along the Adriatic coast of Italy in order to investigate the influence of seasonality on oxidative stress biomarkers. Trace elements load of Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Se and Zn suggests low contamination for lagoon and offshore sites. Levels of total glutathione, superoxide dismutase, catalase, glutathione peroxidases, glutathione reductase and glutathione S-transferase were analyzed in digestive gland and gills of the Pacific oysters in June, July, September and October. OsHV-1 and Vibrio aestuarianus were detected in lagoon sites, but both pathogens did not affect the biomarkers levels in both tissues. Although several biological responses were found different among the four sites in the same month, principal component analysis revealed similar trend in biomarkers levels between sites during the whole sampling period. On the other hand, a different biochemical pattern through the months emerged, suggesting that the level of oxidative stress biomarkers in both tissues may be related to seasonal progress and biological cycle of oysters sampled from the two lagoons and offshore sites along the Italian coasts of the Mediterranean Sea.

Accumulation of As, Cd, Pb, and Zn in sediment, chironomids and fish from a high-mountain lake: First insights from the Carnic Alps.

Though mountain lakes are generally much less influenced by human activities than other habitats, anthropogenic threats can still alter their natural condition. A major source of global environmental pollution in mountain ecosystems is trace element contamination. For this study we investigated for the first time the accumulation of As, Cd, Pb, and Zn in sediment, Diptera Chironomidae (prey), and bullhead Cottus gobio (predator) in a typical high-mountain lake (Dimon Lake) in the Carnic Alps. Significant differences in trace element levels were observed between sediment, Diptera Chironomidae, and C. gobio liver and muscle samples (Kruskal-Wallis test; p < .03 for all elements). As and Pb levels were highest in sediment, Cd and Zn levels were highest in Diptera Chironomidae, and the lowest values for all elements were measured in C. gobio muscle and liver. Bioaccumulation factor values were much higher in Diptera Chironomidae than fish muscle and liver, with the highest values recorded for Cd (5.16) and Zn (4.37). Trophic transfer factor values were very low for all elements in fish muscle and liver, suggesting a biodilution effect along the food chain. Further studies are needed to expand on these first findings that provide useful insights to inform environmental monitoring and policy in remote high-mountain lakes.

Effect of Feed Supplemented with Selenium-Enriched Olive Leaves on Plasma Oxidative Status, Mineral Profile, and Leukocyte DNA Damage in Growing Rabbits.

This study investigated the effect of a dietary combination of selenium and olive leaves on rabbit health status in order to evaluate the potential use of these combinations as functional ingredients in feed and food. Sixty weaning rabbits were fed with three diets: control feed (C), control feed + 10% normal olive leaves (OL), or olive leaves enriched in Se (2.17 mg Se/kg d.m.; SeOL). The plasma mineral profile, antioxidant status, and leukocyte DNA damage were determined. Inorganic Se was the most abundant form in the OL diet, while the organic one was higher in SeOL than C and OL. A similar trend was found in the plasma. Protein oxidation showed higher values in both supplemented groups; in addition, dietary Se led to a significant improvement (+ 40%) in ferric reducing ability of plasma (FRAP). A marked reduction in DNA damage (9-fold) was observed in the SeOL group compared to C. The combination of selenium and olive leaves in the diet of growing rabbits increased plasma SeMet and FRAP and reduced leukocyte DNA damage.

Oxidative stress ecology in brook trout (Salvelinus fontinalis) from a high-mountain lake (Cottian Alps).

High-mountain lakes are pristine ecosystems characterized by extreme environmental conditions. The atmospheric transport of pollutants from lowlands may add further stress to organisms inhabiting these environments. We investigated the environmental stress pressure on brook trout (Salvelinus fontinalis) from a high-mountain lake in the Cottian Alps (Piedmont, northwest Italy). To do this, males and females of brook trout were sampled from Balma Lake in summer (August) and autumn (October) 2017 in order to assess the influence of trace elements accumulation and environmental parameters (physicochemical parameters and nutrient characteristics of water) on oxidative stress biomarkers. Bioaccumulation of Al, As, Cd, Cr, Cu, Fe, Hg, Pb, Ni, Se, and Zn and metallothionein levels were measured in muscle tissue of males and females. Liver, gills, kidney, and spleen tissue samples were analyzed for superoxide dismutase, catalase, total glutathione peroxidase, selenium-dependent glutathione peroxidase, glutathione reductase, and glutathione S-transferase activity. Analysis of environmental parameters showed changes in biomarker levels with seasonal variations. Water temperature was significantly higher in summer than autumn (Wilcoxon test; p = .0078), while pH was significantly higher in autumn than in summer (Wilcoxon test; p = .0078). Sex-related differences in oxidative stress biomarkers in tissues were unremarkable, whereas seasonal variability of oxidative stress biomarkers was observed, with major differences occurred for liver in summer and for gills, kidney, spleen and muscle in autumn. Positive correlations between environmental parameters and biomarkers were noted. Major fluctuations in water temperature, pH, Cu, Pb and Hg produced changes in biomarker levels; however, increased food intake during the ice-free season was probably the main factor that influenced changes in oxidative stress biomarker levels in brook trout in this extreme ecosystem.

Could Dietary Black Soldier Fly Meal Inclusion Affect the Liver and Intestinal Histological Traits and the Oxidative Stress Biomarkers of Siberian Sturgeon (Acipenser baerii) Juveniles?

The trial investigates if a highly defatted Hermetia illucens larva meal (H) at two dietary inclusion levels and a vegetable protein based diet (VEG) influences the normal gut and liver histology and the oxidative stress biomarkers in liver and kidney of Siberian sturgeon juveniles. Fish were fed four diets: one control diet (H0) containing 70% of fishmeal (FM), two diets including 18.5% (H185) and 37.5% (H375) of highly defatted H in substitution for 25% and 50% of FM, and one vegetable protein based diet (VEG). At the end of a growth trial, 12 fish per treatment were sacrificed by over-anaesthesia to collect 12 liver and 5 distal intestine samples for histological analyses, as well as 12 liver and kidney samples for biochemical analyses. The H and VEG diets did not significantly affect the histology of liver and distal intestine, but alterations of the oxidative stress biomarkers were detected at the highest inclusion level of H (37.5%). In order to avoid unfavorable effects on the fish health, an inclusion level up to 18.5% of H is recommended for Siberian sturgeon juveniles.