Multi-Omics Approaches for Freshness Estimation and Detection of Illicit Conservation Treatments in Sea Bass (Dicentrarchus Labrax): Data Fusion Applications.

Fish freshness consists of complex endogenous and exogenous processes; therefore, the use of a few parameters to unravel illicit practices could be insufficient. Moreover, the development of strategies for the identification of such practices based on additives known to prevent and/or delay fish spoilage is still limited. The paper deals with the identification of the effect played by a Cafodos solution on the conservation state of sea bass at both short-term (3 h) and long-term (24 h). Controls and treated samples were characterized by a multi-omic approach involving proteomics, lipidomics, metabolomics, and metagenomics. Different parts of the fish samples were studied (muscle, skin, eye, and gills) and sampled through a non-invasive procedure based on EVA strips functionalized by ionic exchange resins. Data fusion methods were then applied to build models able to discriminate between controls and treated samples and identify the possible markers of the applied treatment. The approach was effective in the identification of the effect played by Cafodos that proved to be different in the short- and long-term and complex, involving proteins, lipids, and small molecules to a different extent.

Effects of astaxanthin and canthaxanthin on oxidative stress biomarkers in rainbow trout.

Farmed trout are commonly fed carotenoid-enriched diets during the finishing period to acquire typical red-to-pink flesh color in salmonid muscle. The aim of this study was to examine the effects of two xanthophylls, astaxanthin (Ax) or canthaxanthin (Cx), administered individually or in combination, on oxidative stress biomarkers in kidney and liver of rainbow trout. Specimens were fed Ax (75 mg/kg) or Cx (25 mg/kg) individually or in combination in the diets for 8 weeks. Changes in concentration of oxidative stress biomarkers, including total glutathione, superoxide dismutase, glutathione peroxidase, glutathione reductase, and glutathione S-transferase, were recorded in Ax- and Cx-dosed trout. These two carotenoids, predominantly Cx, initiated enzymatic responses in rainbow trout. It is noteworthy that lipid peroxidation processes were not apparent in all Ax or Cx-dosed trout. Further, both combined xanthophylls did not exert significant synergistic effects in liver and kidney. Biomarker responses were generally altered in both tissues through the 4 and 8 weeks suggesting that different time-dependent mechanisms led to enhanced antioxidant defense in Ax and/or Cx-fed trout. Data demonstrated that these two xanthophylls did not exert detrimental effects on rainbow trout.

A comparative study on subacute toxicity of arsenic trioxide and dimethylarsinic acid on antioxidant status in Crandell Rees feline kidney (CRFK), human hepatocellular carcinoma (PLC/PRF/5), and epithelioma papulosum cyprini (EPC) cell lines.

Arsenic (As) is a global contaminant of terrestrial and aquatic environments posing concern for environmental and human health. The effects of subacute concentrations of arsenic trioxide (AsIII) and dimethylarsinic acid (DMAV) were examined using Crandell Rees feline kidney (CRFK), human hepatocellular carcinoma (PLC/PRF/5), and epithelioma papulosum cyprini (EPC). Whole monolayer with suffering cells (confluence 100%, pyknosis and refractive cells; value scale = 2) led to identification of subacute As concentrations for the three cell lines. The selected AsIII concentrations were 1.33 µM for CRFK and 33.37 µM for PLC/PRF/5 and EPC, at 48 hr time point. The selected DMAV concentrations were 0.67 mM for PLC/PRF/5, 1.33 mM for CRFK, and 2.67 mM for EPC for 48 hr. Unlike the AsIII test, the three cell lines did not exhibit marked susceptibility to DMAV-mediated toxicity. Several oxidative stress biomarker levels, directly or indirectly associated with reactive oxygen species (ROS) elimination including superoxide dismutase, catalase, glutathione peroxidases, glutathione reductase, glutathione S-transferase, glyoxalase I, glyoxalase II, and total glutathione, were determined in the three cell lines at 24 and 48 hr. Antioxidant responses in metal-treated cells were significantly altered compared to controls, suggesting a perturbation of redox state. The weakening of antioxidant pathway in either healthy or tumoral cells was greater using AsIII than DMAV. Differences in level of several oxidative stress biomarkers suggest that the oxidative stress mechanism induced by AsIII is distinctly different from DMAV. Multifaceted mechanisms of action underlying ROS generation in tumor and nontumor cells versus AsIII and DMAV exposure are thus involved. Since As-mediated toxicity is quite complex, more data regarding both oxidant-enhancement and oxidant-lowering strategies may be useful to improve knowledge regarding the influence of As on human and animal cells.

Sex- and age-related variation in metal content of penguin feathers.

The presence of xenobiotics, such as metals, in ecosystems is concerning due to their durability and they pose a threat to the health and life of organisms. Moreover, mercury can biomagnify in many marine food chains and, therefore, organisms at higher trophic levels can be adversely impacted. Although feathers have been used extensively as a bio-monitoring tool, only a few studies have addressed the effect of both age and sex on metal accumulation. In this study, the concentrations of trace elements were determined in the feathers of all members of a captive colony of African Penguins (Spheniscus demersus) housed in a zoological facility in Italy. Tests were performed by inductively coupled plasma-mass spectrometry to detect aluminum, arsenic, cadmium, cobalt, chromium, copper, iron, manganese, nickel, lead, selenium, tin, vanadium, and zinc. Mercury was detected by a direct mercury analyzer. Sexing was performed by a molecular approach based on analyzing the chromo-helicase-DNA-binding1 gene, located on the sex chromosomes. Sex- and age-related differences were studied in order to investigate the different patterns of metal bioaccumulation between male and female individuals and between adults and juveniles. Juvenile females had significantly higher arsenic levels than males, while selenium levels increased significantly with age in both sexes. Penguins kept in controlled environments-given that diet and habitat are under strict control-represent a unique opportunity to determine if and how metal bioaccumulation is related to sex and age.

Blood metal levels and related antioxidant enzyme activities in patients with ataxia telangiectasia.

Transition metals are cofactors for a wide range of vital enzymes and are directly or indirectly involved in the response against reactive oxygen species (ROS), which can damage cellular components. Their altered homeostasis has been studied in neurodegenerative disorders such as Alzheimer's disease (AD), Parkinson's disease (PD) and amyotrophic lateral sclerosis (ALS), but no data are available on rarer conditions. We aimed at studying the role of essential trace elements in ataxia telangiectasia (A-T), a rare form of pediatric autosomal recessive cerebellar ataxia with altered antioxidant response. We found an increased level of copper (Cu, p=0.0002) and a reduced level of zinc (Zn, p=0.0002) in the blood of patients (n. 16) compared to controls, using inductively coupled plasma mass spectrometry (ICP-MS). Other trace elements involved in the oxidative stress response, such as manganese (Mn) and selenium (Se), were unaltered. Cu/Zn-dependent superoxide dismutase (SOD1) was shown to have a 30% reduction in gene expression and 40% reduction in enzyme activity upon analysis of lymphoblastoid cell lines of patients (Student's t-test, p=0.0075). We also found a 30% reduction of Mn-SOD (SOD2; Student's t-test, p=0.02), probably due to a feedback regulatory loop between the two enzymes. The expression of antioxidant enzymes, such as erythrocyte glutathione peroxidase (GPX1), and SOD2 was unaltered, whereas catalase (CAT) was increased in A-T cells, both at the mRNA level and in terms of enzyme activity (~25%). Enhanced CAT expression can be attributed to the high ROS status, which induces CAT transcription. These results suggest that alterations in essential trace elements and their related enzymes may play a role in the pathogenesis of A-T, although we cannot conclude if altered homeostasis is a direct effect of A-T mutated genes (ATM). Altered homeostasis of trace elements may be more prevalent in neurodegenerative diseases than previously thought, and it may represent both a biomarker and a generic therapeutic target for different disorders with the common theme of altered antioxidant enzyme responses associated with an unbalance of metals.

Antioxidant responses and renal crystal formation in rainbow trout treated with melamine administered individually or in combination with cyanuric acid.

In 2007 and 2008, renal stone formation and kidney damage in human infants were linked to consumption of melamine (MEL)-contaminated infant formula, as well as renal failure and death in pets due to pet food containing both MEL and cyanuric acid (CYA). The aim of this study was to examine the effects of MEL and CYA administered individually or in combination on concentrations of certain metabolites and enzyme activities that serve as markers for oxidative stress in kidney and liver of rainbow trout. In addition, the levels of muscle MEL and renal crystal formation were determined. Trout were fed MEL and/or CYA for 8 wk at 250, 500, or 1000 mg of each compound/kg in feed. Fish muscle residues of MEL exhibited a dose-response relationship. Coexposure of trout to MEL and CYA at the highest dose led to lower MEL residue concentrations in muscle compared to exposure to MEL alone. Renal MEL-CYA complexes were found in kidneys of fish treated with combined MEL and CYA. A dose response was evident with respect to both (1) number of trout displaying renal crystals and (2) number of crystals per fish. Changes in concentration of antioxidant parameters, such as glutathione, superoxide dismutase, catalase, glutathione peroxidase, and glutathione S-transferase, were recorded in both tissues of MEL- and CYA-dosed trout. Lipid peroxidation was more pronounced in kidney than liver. Therefore, feed contaminated with both MEL and CYA could be problematic for fish, as MEL administered to trout, individually or in combination with CYA, may facilitate the onset of oxidative damage in trout.

Identification of Illicit Conservation Treatments in Fresh Fish by Micro-Raman Spectroscopy and Chemometric Methods.

In the field of food control for fresh products, the identification of foods subjected to illicit conservation treatments to extend their shelf life is fundamental. Fresh fish products are particularly subjected to this type of fraud due to their high commercial value and the fact that they often have to be transported over a long distance, keeping their organoleptic characteristics unaltered. Treatments of this type involve, e.g., the bleaching of the meat and/or the momentary abatement of the microbial load, while the degradation process continues. It is therefore important to find rapid methods that allow the identification of illicit treatments. The study presented here was performed on 24 sea bass samples divided into four groups: 12 controls (stored on ice in the fridge for 3 or 24 h), and 12 treated with a Cafodos-like solution for 3 or 24 h. Muscle and skin samples were then characterized using micro-Raman spectroscopy. The data were pre-processed by smoothing and taking the first derivative and then PLS-DA models were built to identify short- and long- term effects on the fish's muscle and skin. All the models provided the perfect classification of the samples both in fitting and cross-validation and an analysis of the bands responsible for the effects was also reported. To the best of the authors' knowledge, this is the first time Raman spectroscopy has been applied for the identification of a Cafodos-like illicit treatment, focusing on both fish muscle and skin evaluation. The procedure could pave the way for a future application directly on the market through the use of a portable device.

Fit-for-purpose in veterinary drug residue analysis: development and validation of an LC-MS/MS method for the screening of thirty illicit drugs in bovine urine.

A selective and sensitive method for screening 31 analytes (nine corticosteroids, eight ß-agonists, seven anabolic steroids, six promazines and zeranol) in bovine urine was validated according to 2002/657/EC guidelines. Upon optimization of sample treatment conditions, the extraction was performed by diethylether at pH 9, after deconjugation. Extraction yields (R%) proved higher than 70% for 19 analytes, 50

Microplastics as vectors of metals contamination in Mediterranean Sea.

Microplastics are contaminants of great concern all over the world. Microplastics constitute pollutants themselves; moreover, other contaminants such as metals are easily absorbed on their plastic surface, becoming bioavailable to marine biota such as zooplankton.We collected marine zooplankton from Mediterranean Sea to investigate trace elements associated with microplastics. Samples were subjected to visual sorting by a stereomicroscope, collected with sterile tweezers, pooled and subjected to sonication, filtration, and drying before being subjected to acid extraction. An ICP-MS was utilized for multi-elemental determination.Aluminum, iron, chromium, zinc, nickel, molybdenum, manganese, lead cobalt, and copper were found at concentrations of mg/kg while arsenic, vanadium, rubidium, and cadmium at level of µg kg-1. Other elements such as silver, beryllium, bismuth, selenium, tin, and thallium were under the limit of quantitation. Lower levels of iron and manganese in samples from Italy were found in comparison to England and Brazil, while aluminum, copper, and zinc registered comparable values. The presence of metals in marine waters is strictly related to sediment lithology and anthropogenic inputs, but plastic plays a key role as vectors for metal ions in the marine system, being able to concentrate metals several order of magnitude higher than in surrounding waters and exerting potential toxicity for living beings after chronic exposure.

Aluminium occurrence in plant feed from Northwestern Italy.

BACKGROUND: Aluminium (Al) is widespread in nature, but the main route of exposure for humans and animals is through food. Cereals and vegetables give and important contribute to dietary intake. This investigation focused on the occurrence aluminium in raw materials intended for animal consumption. In fact, Al is not included in the official monitoring programs, and little or no data are still available about its presence in feed or plant material. METHODS: Rice, wheat, corn, barley, rye, triticale, oats, and soy samples were collected in Northwestern Italy in an area characterized by clayey soil rich in aluminium silicates. Samples were subjected to homogenization and microwave acid digestion and Al was quantified by Inductively Coupled Plasma-Mass Spectrometer (ICP-MS). RESULTS: Different aluminium concentrations were found in the analyzed raw materials: soy (89 mg kg-1) > rye > rice > oat > triticale > barley > wheat > corn (2.9 mg kg-1). In this study, Al concentrations were found higher than those reported for same matrices in other UE and non-EU countries, especially in rice and soy. CONCLUSIONS: Al concentrations were related to the soil geological feature and to the physiological characteristics of the plant species. These two factors must be carefully considered for a reliable evaluation of aluminium exposure through feed and food.

First Insights Into Trace Element Accumulation by Philoscia affinis (Crustacea, Isopoda): a Novel Tracer to Assess Soil Contamination in Lowland Plains?

Isopods are terrestrial invertebrates that accumulate trace elements in large quantities, thus providing information on levels of soil contamination. However, the accumulation pattern seems to be species dependent. For this study, specimens of Philoscia affinis (Isopoda, Oniscidea) and soil samples were collected from both a protected area (site 1) and urban roadside (site 2) in the low plain of Friuli-Venezia Giulia (northeast Italy) to determine whether P. affinis could serve as a potential candidate for monitoring soil contamination. To do this, the following objectives were achieved: a) the level of trace elements (Al, Cd, Cu, Fe, Hg, Mn, Pb, Zn) were detected in soils and isopods; 2) the difference in trace elements accumulation was compared in the two sampling sites; 3) the bioaccumulation factor (BAF) was calculated for each element. With some exceptions, trace element concentrations were higher in both isopods and soil samples from the urban roadside compared to the protected area. Furthermore, except for Cd, Cu, and Zn, trace element levels were higher in the soil than in the isopod samples. The higher mean BAF values were recorded for Cd (6.169 and 6.974 for site 1 and 2, respectively), Cu (10.324 and 11.452 for site 1 and 2, respectively), and Zn (1.836 and 2: 1.943 for site 1 and 2, respectively), whereas BAF values <1 were recorded for the other elements. Philoscia affinis was found to be a potential candidate to monitor soil contamination as a macro-concentrator of Cu and Cd and a micro-concentrator of Zn.

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.

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.

Trace elements profile in the blood of Huntington' disease patients.

Huntington' disease (HD) is an autosomal dominant neurodegenerative disease characterized by progressive motor, psychiatric, and cognitive deterioration. HD is, together with spinocerebellar ataxias, spinobulbar muscular atrophy and dentatorubral-pallido- luysian atrophy, one of the nine disorders caused by an expansion of glutamine residues in the causative protein where the polyglutamine expansion cause aberrant protein folding. Since an excessive metal's accumulation in organs may induce protein misfolding and oxidative stress, we have studied the blood concentration of essential (Cr, Co, Cu, Fe, Mn, Mo, Ni, Se, Zn) and nonessential (As, Cd, Sb, Sn, V) trace elements in HD patients. We found increased levels of the essential elements iron, chromium, selenium and zinc and of the nonessential element arsenic in the blood of HD patients. Since alteration in metals homeostasis may contribute to the pathogenesis of neurodegenerative disease and could eventually constitute a target for therapy, we may suggest the utilize of the blood metal profile as a further in vivo tool to study and characterize Huntington disease.

Distribution and bioaccumulation of trace elements and lanthanides in apples from Northwestern Italy.

BACKGROUND: Transfer of metals from soil to plant is a possible route of contamination for the food chain. This investigation focused on the occurrence of 40 elements in the "Red Apple of Cuneo", an Italian excellence and a Protected Geographical Indication (P.G.I.). Four cultivars were considered: Red Delicious (Jeromine) and Gala (Bukeye, Brookfield, Schniga). METHODS: Trace elements and rare earth elements (REEs) detection was performed by an Inductively Coupled Plasma-Mass Spectrometer (ICP-MS) previous homogenization of samples and microwave acid digestion. One-way analysis of variance (ANOVA) with Bonferroni correction was employed to for statistical analysis. RESULTS: Concentrations of metals in the four apples cultivars were quite comparable, Al and Rb were the most represented nonessential elements while Fe, Cu and Zn between the essential; REEs were found at negligible concentrations. Bioaccumulation factors demonstrated an extremely low capacity of bioaccumulation from soil to fruit. CONCLUSIONS: The analysis performed on the "Red Apple of Cuneo" has shown that this product is safe for human consumption since metals were recovered at concentrations of no concern and lower than those registered in apples from other countries. Since each production area is characterized by a typical elemental pattern the multielemental profile based on the analysis of 40 elements could be useful to relate products to their region of origin. Differences between the four apple cultivars were instead not significant to discriminate between them.

Trace and rare earth elements in monofloral and multifloral honeys from Northwestern Italy; A first attempt of characterization by a multi-elemental profile.

BACKGROUND: Metals are a minor constituent in honey, but they have been suggested to be a potential tool to characterize honeys according to their botanical or geographical origin. METHODS: A total of 40 metals were analyzed by Inductively Coupled Plasma-Mass Spectrometry in monofloral and multifloral honeys from Northwestern Italy. PCA and ANOVA were used to discriminate honeys according to the various floral types. RESULTS: The highest levels of trace elements and rare earth elements (REEs) were found in chestnut honey, while the lowest concentrations were recorded in acacia and rhododendron honeys. Rubidium and aluminum were the most represented nonessential elements, while manganese, iron, zinc and copper had the highest values of the essential elements. Potentially toxic elements arsenic, cadmium and lead were close to or below the limit of quantification. CONCLUSIONS: The present study showed significant differences in metal concentrations according to honey floral type, reflecting the strong influence of botanical origin on the chemical composition of this particular food.

Trace elements and rare earth elements in honeys from the Balkans, Kazakhstan, Italy, South America, and Tanzania.

Honey is a very unusual food - a natural substance produced by bees from the nectar or secretion of plants and elaborated by the bees themselves. Differences in trace elements and rare earth elements (REEs) are related to botanical and geographical origin, and, as such, honey could be a suitable indicator for metal occurrence in the environment within the bee forage area. A total of 40 metals were analyzed by inductively coupled plasma-mass spectrometry in multi-floral honey samples from different geographical areas. The highest levels of trace elements and REEs were found in honey from Tanzania, while lower concentrations were recorded in Italian, Kazakhstan, the Balkans, and South American honeys. Tanzanian honey is of interest due to its different content of metals, related to the peculiar lithology and the mineral resources of this country. Rubidium and aluminum were the most represented nonessential elements, while manganese, iron, zinc, and copper registered the highest values of the essential elements. Very low concentrations were found for the toxic elements lead, cadmium, and arsenic. The present study showed differences in metal concentrations in multi-floral honey from different countries, confirming the strong influence of the area of origin on the chemical composition of honeys.

Macrobenthic invertebrates as bioindicators of trace elements in high-mountain lakes.

Alpine lakes are extreme ecosystems located in remote areas and populated by few but well-adapted species. Because of their remote location, they are often considered pristine, unpolluted ecosystems. Since the 1980s, however, they have been affected by global anthropogenic impacts. Macrobenthic invertebrates play a pivotal role in these ecosystems and can be used as bioindicators also for monitoring the accumulation of trace elements. We characterized the macrobenthic invertebrates community of Balma Lake (Cottian Alps, Northwest Italy) and Dimon Lake (Carnic Alps, Northeast Italy) in summer and autumn and measured the levels of nine trace elements (As, Cd, Cr, Cu, Fe, Ni, Pb, Se, Zn) in the most abundant taxa (Chironomidae and Oligochaeta in both lakes and Hirudinea in Dimon Lake) in both seasons. The highest levels of trace elements were recorded for Fe, Cu, and Zn according to their environmental availability and their function as essential elements. The total amount of trace elements was highest for the Chironomidae from both lakes compared to the other two taxa. As, Cd, Pb, and Zn were measured in sediment to calculate bioaccumulation factor (BAF) values. The amount of elements in sediment and macrobenthic invertebrates was higher for Dimon Lake, suggesting a greater flux via precipitation of contaminants from the lowland. The BAF values were decreased with increasing trace elements concentration in sediment, indicating mechanisms of elements excretion in biota where the environment is contaminated. This study is the first to report on the use of macrobenthic invertebrates to monitor trace elements in Alpine lakes.

Differential Bioaccumulation of Trace Elements and Rare Earth Elements in the Muscle, Kidneys, and Liver of the Invasive Indo-Pacific Lionfish (Pterois spp.) from Cuba.

The Indo-Pacific lionfish is a saltwater fish that inhabits the Red Sea waters and the Indian and Pacific oceans; it is an invasive species in the western Atlantic and was recently introduced into the local diet in the USA, Central and South America, and the Caribbean with the aim of controlling the invasion of this species. Due to its predatory nature, it tends to bioaccumulate metals and other contaminants via the marine food web and could thus constitute a suitable species for monitoring aquatic ecosystems. The presence and distribution of 23 trace elements and 16 rare earth elements (REEs) were investigated by inductively coupled plasma-mass spectrometry (ICP-MS) in the muscle, liver, and kidneys of lionfish from Cuba. Significant differences in metal concentrations were found in the different fish organs. The liver and kidneys registered the highest concentrations for most trace elements and for ΣREE, thus demonstrating that they are effective bioindicators of possible pollution on the environment in which fish live, and assuming great importance in the choice of early biomonitoring. Trace element concentrations in the muscle are instead of crucial interest for consumer safety. The limits set by EU regulations and Cuban guidelines for Cd and Pb in fish muscle were never exceeded, suggesting that lionfish from Cuba could therefore represent a good source of minerals and proteins for the local population. Graphical abstract.

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.