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Espin S.,University of Murcia | Espin S.,University of Turku | Martinez-Lopez E.,University of Murcia | Jimenez P.,University of Murcia | And 3 more authors.
Environmental Research | Year: 2016

The main aim of the present study was to assess the concentration of metals (Pb, Cd, Hg, Cu and Zn) in blood, and elucidate their potential effects on oxidative stress biomarkers in red blood cells of Audouin's gull (Ichthyaetus audouinii) and Slender-billed gull (Chroicocephalus genei) chicks in Southeastern Spain. For this purpose, total glutathione (GSH) content, antioxidant enzymes activities (glutathione peroxidase, GPx; superoxide dismutase, SOD; catalase, CAT and glutathione-S-transferase, GST), and lipid peroxidation (TBARS) were analyzed. In general, metal exposure in both species can be considered low, except for Hg in Audouin's gull. Our findings show higher antioxidant levels in Audouin's gull than in Slender-billed gull; probably due to a combination of different basal antioxidant capacity between species, and to an up-regulation of the antioxidant system in Audouin's gull as a response to the higher Hg, Cu and Zn concentrations. This could reduce the production of TBARS keeping them at lower levels than those found in Slender-billed gull. In spite of this, the significantly higher Hg levels found in Audouin's gull (13.6 μg/dl wet weight) in comparison to Slender-billed gull (2.7 μg/dl), likely related to their different diet and the former consuming discarded fish, were able to produce lipid peroxidation in this species. The positive effect of Hg on SOD activity in Slender-billed gull, and of Pb on GSH levels in Audouin's gull, could reflect the necessity of the organism to upregulate these antioxidants to balance the increased oxidative stress caused by metals. The degree of metal exposure seems to be essential in the response of the antioxidant system, which may suffer up or down-regulations depending on metal concentrations. This study supports the interactive effects of metals on oxidative stress biomarkers, the complexity of the antioxidant system and the close cooperation between antioxidants, which requires the study of several metals and biomarkers to evaluate oxidative stress and damage in wild birds. © 2016 Elsevier Inc.

Espin S.,University of Murcia | Espin S.,University of Turku | Martinez-Lopez E.,University of Murcia | Jimenez P.,University of Murcia | And 3 more authors.
Environmental Research | Year: 2015

The purposes of this study were: (1) to determine the δALAD activity and δALAD ratio in blood of four free-living bird species (Griffon vulture, Eagle owl, Slender-billed gull and Audouin's gull); (2) and to investigate the correlations between δALAD activity/ratio and Pb concentrations in blood samples. A decrease was observed in δALAD activity in Griffon vultures and Eagle owls exposed to Pb. In addition, negative relationships were found between δALAD ratio or δALAD activity and Log blood Pb levels in Griffon vultures and Eagle owls, and these relationships were stronger in areas with the highest Pb exposure. We provide equations that may be helpful to estimate δALAD activity and δALAD ratio using blood Pb concentrations. Regarding gull species, δALAD activity found in the present study may be considered the normal activity in Slender-billed gull and Audouin's gull species, since very low blood Pb concentrations and no correlations were found in these species. Although both δALAD activity and δALAD ratio are sensitive biomarkers of Pb exposure and effect in birds, the use of δALAD ratio may improve the results. Besides, this study provides blood threshold concentrations at which Pb bears effects on δALAD enzyme (5. μg/dl in Eagle owl; 8. μg/dl in Griffon vulture; and probably >2. μg/dl in Slender-billed gull and Audouin's gull). Our findings show that Eagle owl seems to be more sensitive to δALAD enzymatic inhibition by Pb than Griffon vultures. Eagle owls and Griffon vultures exhibited up to 79% and 94% decrease in δALAD activity when blood Pb concentrations exceeded 19 and 30. μg/dl, respectively. Regarding the effects related with δALAD inhibition, significant negative correlations were found between δALAD activity and hematocrit in Eagle owls and Griffon vultures, which may be related to compensatory response associated with a decrease in δALAD activity. In addition, an effect on creatine kinase activity and total proteins in plasma was found in Griffon vultures. The significant negative correlations found between δALAD activity and tGSH in Griffon vulture, and between δALAD activity and Log CAT activity in Eagle owls, may be related to a protective response of antioxidant system against reactive oxygen species (ROS). The negative relationship found between δALAD activity and TBARS levels in Griffon vulture is probably related to an induction of lipid peroxidation by ROS that may be generated by δALA accumulation when δALAD activity is depressed. δALAD activity and δALAD ratio in blood are suggested as important nondestructive biomarkers for Pb exposure and effect for future biomonitoring studies in Griffon vulture and Eagle owl. Further studies are recommended to provide new data on Pb concentrations at which δALAD activity is affected in different wild bird species and to elucidate why different species tolerate Pb in different ways. © 2014 Elsevier Inc.

Espin S.,University of Murcia | Espin S.,University of Turku | Martinez-Lopez E.,University of Murcia | Jimenez P.,University of Murcia | And 3 more authors.
Environmental Research | Year: 2014

Metals are involved in the formation of reactive oxygen species (ROS) which may result in metal-related oxidative stress that can lead to oxidative damage to lipids, DNA and proteins. It is necessary to understand the mechanisms of metal toxicity in wild birds, and the concentrations that cause effects on oxidative stress biomarkers. The aim of this study is to assess the concentrations of lead (Pb), cadmium (Cd), mercury (Hg), copper (Cu) and zinc (Zn) with regards to oxidative stress in blood samples of 66 Griffon vultures (Gyps fulvus) from two areas of the Autonomous Community of Valencia (East of Spain). The two study areas (Alcoy n=36 and Cinctorres n=30) were selected as random locations of interest that had not yet been studied, and are feeding stations where supplementary food, mainly of pork origin, is provided for vultures. Given that the two study areas are not considered polluted sites, we expected to find low metal concentrations. However, there are no known threshold concentrations at which metals can affect antioxidant systems, and low metal levels may have an effect on antioxidant biomolecules. In this study, since sampling was done at the beginning of the hunting season, the low Pb levels found in most Griffon vultures from Alcoy and Cinctorres (median=12.37 and 16.26. μg/dl, respectively) are suggestive of background levels usually found in vultures that feed on pork carcasses all year round. The ingestion of game meat with bullet fragments in carcasses or with Pb shots embedded in the flesh could be the cause of the high blood Pb concentrations found in three vultures from Cinctorres (83, 290 and 362. μg/dl). Griffon vultures feeding in Cinctorres had enhanced CAT and GST activities and tGSH concentrations, which may be interpreted as protective response against the higher TBARS levels. This study provides threshold concentrations at which metals affect antioxidant system derived from 66 samples of Griffon vulture. Blood Cd concentrations greater than 0.05. μg/dl produced an induction of 33% in GPx and of 44% in CAT activity in erythrocytes of vultures from Alcoy. Hg concentrations in blood higher than 3. μg/dl produced an induction of 10% in SOD activity. Concentrations of Pb above 15. μg/dl in blood produced an inhibition of 12.5% in GPx and 11.3% in CAT activity, and a TBARS induction of 10.7% in erythrocytes of Griffon vultures. © 2014.

Martinez-Lopez E.,University of Murcia | Sousa A.R.,Abel Salazar Biomedical Sciences Institute | Maria-Mojica P.,University of Murcia | Maria-Mojica P.,Santa Faz Wildlife Recovery Center | And 3 more authors.
Ecotoxicology | Year: 2010

Mediterranean spur-thighed tortoise (Testudo graeca) is actually included in the IUCN as vulnerable species. Its main European population is located in southeastern Spain. Although a great deal of information has been acquired on the internal medicine and survey and even parasitological fauna on these animals, there are no references about contaminants levels in this species. The objectives of this study were to compare the levels of two metals (cadmium and lead) in the blood of spur-thighed tortoises from two different populations, one from Southeastern of Spain (n = 22) and the other from North of Africa (n = 39), kept in captivity at the Santa Faz Recuperation Centre (Alicante, Spain) and to investigate the relationship between their blood levels of lead and their blood δ-aminolevulinic acid dehydratase (δ-ALAD) activity. Blood lead and cadmium concentrations were higher in tortoises from African than in those from Spain. Moreover, a negative and significant correlation (P < 0.05) was found between δ-ALAD activity and blood lead levels, indicating the suitability of this enzyme as biomarker for lead in this species. © 2009 Springer Science+Business Media, LLC.

Gomez-Ramirez P.,University of Murcia | Martinez-Lopez E.,University of Murcia | Maria-Mojica P.,University of Murcia | Maria-Mojica P.,Santa Faz Wildlife Recovery Center | And 2 more authors.
Ecotoxicology | Year: 2011

In order to biomonitor lead contamination in Southeastern Spain, 218 blood samples from 28 to 30-day old Eurasian Eagle Owl chicks (Bubo bubo) born between 2003 and 2007 were analysed. In general, mean lead levels showed that chicks were exposed to background concentrations. However, mean levels in chicks born in an ancient and abandoned mining site ("Sierra Minera Cartagena-La Union") or in their surroundings (Geometric mean (GM) = 5.83 μg/dl, range 0.49-25.61 μg/dl), an area highly polluted by lead and other metals, were significantly higher (p < 0.001) than the rest of the population (GM = 1.66 μg/dl, range = Non detected-18.37 μg/dl). Because δ-ALAD activity is considered the best biomarker for lead exposure and effect in birds, the activity of this enzyme was also evaluated and correlated with lead levels in blood. In this study, low levels of blood lead inhibited δ-ALAD, even when lead concentrations were lower than the limits described by other authors in raptors. Adverse effects caused by this inhibition may occur when blood lead levels were above 15 μg/dl, although only eight chicks presented these concentrations in their blood. Sampling site also influenced enzymatic activity, since it decreased about 60% in the polluted area in relation to the rest. For all these reasons, further research regarding risk assessment for lead exposure in Eagle Owls nesting in the polluted area is advisable. Our results suggest that the Eurasian Eagle Owl can be considered a suitable sentinel animal for monitoring lead contamination and δ-ALAD activity can be used as a sensitive biomarker for lead exposure and effect in this species. © 2010 Springer Science+Business Media, LLC.

Espin S.,University of Murcia | Martinez-Lopez E.,University of Murcia | Maria-Mojica P.,University of Murcia | Maria-Mojica P.,Santa Faz Wildlife Recovery Center | Garcia-Fernandez A.J.,University of Murcia
Ecotoxicology | Year: 2012

The aim of this study was to explore the usefulness of feathers as a biomonitoring tool for organochlorine pesticides (OC) in a razorbill population (Alca torda). Fifteen OC were analyzed in feathers, including α-, β- and δ-hexachlorocyclohexane, lindane, aldrin, dieldrin, endrin, endosulfan I and II, endosulfan sulfate, p,p'-DDT, DDD, DDE, heptachlor and its epoxide. The geometric mean concentrations observed in this study were ∑DDT 67.40 ng/g, ∑HCH 62.88 ng/g, ∑Heptachlor 61.75 ng/g, ∑Endosulfan 19.70 ng/g, and ∑Drins 10.17 ng/g. The higher OC levels found in this study compared with other studies are probably affected by the razorbill diet and migration status. However, levels found in the feathers of the present study are related to concentrations in internal tissues below those which cause adverse reproductive and behavioral effects or other signs of organochlorine-pesticide poisoning in birds. Age does affect the concentration of OC pesticides in feathers. Thus, feathers would appear to be a promising tool for OC biomonitoring in seabirds, since it is possible to quantify OC compounds. © 2011 Springer Science+Business Media, LLC.

Espin S.,University of Murcia | Martinez-Lopez E.,University of Murcia | Gomez-Ramirez P.,University of Murcia | Maria-Mojica P.,University of Murcia | And 2 more authors.
Marine Pollution Bulletin | Year: 2012

Levels of mercury (Hg) were analyzed in the tissues of 50 Razorbills (Alca torda), from the Mediterranean area, which had drowned in fishing nets. The mercury distribution pattern in tissues was similar to those of other studies (liver > feather vane > kidney > muscle > brain > feather shaft), with mercury concentrations of 2.85 ± 0.90, 2.66 ± 1.60, 2.23 ± 0.87, 1.54 ± 0.54, 1.48 ± 0.54 and 1.30 ± 0.76. mg/kg (dry weight), respectively. It could be considered that Razorbills in the southwestern Mediterranean were chronically exposed to relatively low levels of MeHg, probably below 0.5. ppm, via dietary intake. We have proposed prediction equations for brain and kidney Hg concentrations using feather shafts as non-invasive samples. This work provides a solid understanding of Razorbill Hg exposure both in their wintering and breeding grounds, and shows that this species can be useful for assessing marine environmental health in the Mediterranean area. © 2012 Elsevier Ltd.

Espin S.,University of Murcia | Martinez-Lopez E.,University of Murcia | Gomez-Ramirez P.,University of Murcia | Maria-Mojica P.,University of Murcia | And 2 more authors.
Chemosphere | Year: 2010

Sixteen organochlorine pesticides (OC) were analyzed in several tissue types (abdominal and subcutaneous fat, liver and brain) from juvenile (n=14), immature (n=9), subadult (n=7) and adult (n=20) razorbill (Alca torda) collected from the southwestern Mediterranean coastline, in the East of Spain (La Marina, Elche, Alicante, Spain). These razorbills had drowned in fishing nets (most probably) while searching for food. The objective was to assess the exposure to organochlorine pesticide residues in this wintering population of marine birds. This paper presents, as far as we are aware, the first published data on OC concentrations in razorbills. The highest levels were found in abdominal fat followed by subcutaneous fat, liver and brain. A significant positive relationship was found between age and OC levels in tissues, and with the highest levels in adults. The group of ∑Drins had the highest concentrations, followed by ∑DDT, ∑Endosulfan, ∑HCH and ∑Heptachlor, with endrin aldehyde being the compound which reached the highest levels. The p,p'-DDE/p,p'-DDT ratio in fatty tissues suggests exposure to non-degraded DDT and thus is present in the environment despite its prohibition. The OC levels detected were higher than those found in other studies on Alcidae, which may be explained by the Mediterranean habitat in which the birds were found. However, these levels are below concentrations for which any observable effect has been described. © 2010 Elsevier Ltd.

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