Search

Aerial insectivores through their insect diet can contribute to biotransfer of elements across habitats. We investigate the relationship between dietary composition as expressed by the contributions of six functional invertebrate prey groups (primarily of agriculturally subsidised invertebrates characteristic of agricultural areas in temperate regions of Europe) and concentrations of essential (Na, K, Ca, Mg, Fe, Cu, Zn, Mn, Co) and non-essential (As, Cd, Pb) elements of environmental concern in the faeces of nestlings of three species of avian aerial insectivores - Common Swift Apus apus, Barn Swallow Hirundo rustica and House Martin Delichon urbicum - which breed sympatrically and use apparently similar resources of flying insect prey. There were significant differences between the species for 7 of the 12 elements (Ca, Zn, Cu, Co, As, Pb, Cd); these differences were attributable to the variable dietary composition, even though the concentrations of the elements varied enormously between the faecal samples from the individual species. Partial correlation analysis between the biomass (expressed in mg dry weight) of the six functional prey groups and faecal concentrations of elements showed the highest number of significant relationships for toxic metals (As, Pb and Cd). The results of the General Regression Model explaining faecal element concentrations revealed the different explanatory power of the effects of PCA (of six functional prey groups) dietary scores. A significant fit of GRM was obtained for 7 elements (Na, Mg, Fe, Mn, As, Pb, Cd) for Barn Swallows, 2 elements (Cu, As) for House Martins and 1 element (Mn) for Common Swifts. Overall, the results confirmed our predictions that the biomass of consumed coprophilous taxa and insects from crop habitats was positively correlated with the faecal concentrations of toxic elements. Unexpectedly, however, the faecal samples (primarily those of Common Swifts) that contained many oil-seed rape insect pests had lower Ca, Pb and Cd levels and a higher As level. Our study implies that the cross-boundary transfer of contaminants, primarily non-essential elements, by aerially foraging birds through the considerable accumulation of their faeces has potential consequences for the local biogeochemical cycle and environmental quality., (Copyright © 2015 Elsevier B.V. All rights reserved.)

The aim of this work was to determine interrelationships among macroelements Na, K, Ca, Mg, and Fe, microelements Zn, Cu, Mn, and Co, and toxic heavy metals Pb and Cd in the blood of white stork Ciconia ciconia, during postnatal development, in different Polish environments, and their impact on the activity of antioxidant enzymes. We considered the content of thiobarbituric acid-reactive substances (TBARSs), i.e., malondialdehyde (MDA), and activity of superoxide dismutase (SOD), catalase (CAT), ceruloplasmine (CP), glutathione peroxidase (GPx), and glutathione reductase (GR). Blood samples were collected from storks developing at Odra meadows (Kłopot; southwestern Poland). They were compared with blood of chicks from several suburban sites located 20 km away from Zielona Góra (0.1 million inhabitants; southwestern Poland) and near Głogów, where a copper smelter is situated. We also conducted research in the Pomeranian region (Cecenowo; northern Poland). We collected blood samples via venipuncture of the brachial vein of chicks in 2005-2007. They were retrieved from the nest and placed in individual ventilated cotton sacks. The blood was collected using a 5-ml syringe washed with ethylenediaminetetraacetic acid (EDTA). We found significant interactions between macro- and microelements and enzymatic activity and TBARS products. We noticed the predominance of Cd and Pb participation in element-enzyme interactions. Simultaneously, we found interrelationships between cadmium and Na, K, Ca, Mg, and Fe and the activity of antioxidant enzymes SOD, CAT, CP, GR, and TBARS products in the blood of white stork chicks. In the case of lead these relationships were not numerous and they were significant for Ca, Mg, Cu, Mn, and Co. Correlations with enzymes were significant for Pb-CAT and Pb-TBARS. We noted that activities of most enzymes (SOD, CAT, CP, GR) and TBARS products are determined by their interactions with physiological elements Na, Ca, Mg, Fe, and Zn and toxic heavy metals. White stork chicks ranged in age from 17 to 59 days. Concentrations of elements in the blood were age related. Among enzymes, only SOD, CAT, and GPx were age related. Young storks differed in the case of element concentration (except for Ca, Zn, and Cd) and enzymatic activity. We found that significant element-element interaction/enzyme activity predominated in the case of physiological elements and toxic metals, which we explain by the intensive and prevailing access of toxic metals in redox reactions. This causes changes in the priority of these metals, reflected by their influence on the enzymatic activity of antioxidant enzymes. The content of Cd and Pb in blood of young storks from different regions tends to affect the lipid peroxidation process negatively. However, in many cases we observed an increase in enzymatic activity with an increase in heavy metals. This indicates the changes in oxidative stress intensity in chicks in response to environmental differentiation. The increase in lipoperoxidation modifies antioxidant enzyme activity and causes changes in SOD, CAT, CP, GPx, and GR activity in chicks from various regions, principally increases in enzyme activity in chicks from polluted environments and suburbs. We suggest that the source of heavy metals in chicks' blood might be used as a biological test system of adaptation to oxidative stress. We also report that a high level of heavy metals is accompanied by increased lipid peroxidation. Thus young storks are probably significantly susceptible to environmental conditions. They demonstrated initiation of lipoperoxidation and oxidative modification of proteins that coincide with chemical elements, as a possible antioxidant defense system.

The aim of this study was to investigate the activity of antioxidant enzymes in the blood of White Stork Ciconia ciconia chicks (aged 19-54 days) in Poland in 2006. We took under consideration superoxide dismutase (SOD), catalase (CAT), ceruloplasmine (CP), glutathione peroxidase (GPx), glutathione reductase (GR) and the content of thiobarbituric acid-reactive substances (malondialdehyde) in polluted (copper manufacture), suburban areas, at the Odra meadows, and at swamps near Baltic Sea in the Pomeranian region. We examined the levels of Na, K, Ca, Mg, Fe, Zn, Cu, Mn, Co, Cd, and Pb and compared ecophysiological determinations for developing storks. Blood samples of wing venous were collected from 91 chicks from 33 nests. The degree of activity of antioxidant enzymes studied has been different in White Stork chicks' blood from Poland regions, as a rule. We have stated a relatively high level of CAT, GPx, SOD, and GR activity and malondialdehyde (MDA) content in chicks from polluted areas. However, relative value for GR in storks from Odra meadows was considerably higher (about 112 nmol NADPH(2)/min ml) than those in chicks from other environments (56-84 nmol on average). Relatively high levels of CAT, CP, and GPx (2.7 mkM/min l, 22.2 mg/l, and 3.8 nmol GSH/min ml, respectively) were also stated in chicks nested in swamps near Baltic Sea. Simultaneously, we have stated differences (p<0.02-p<0.001) in the level of elements (besides Ca) in blood of young storks from the studied areas. We found a high level of toxic metals, e.g. Cd, either from swamps near Baltic Sea (2.7 mg/kg) or from Głogów smelter (2.2mg/kg), whilst Pb concentration was high in chicks from Głogów (7.2 mg/kg). Cd and Pb levels in blood of chicks were different in individuals from each region (p<0.001). Birds from a smelter have the highest level of these elements, whereas the lowest one was stated in chicks from Odra meadows (Cd: 1.45, Pb: 0.84 mg/kg). Thus, Cd could be a useful marker of response for polluted stress. We also observed a relatively high level of Mg in chicks from both Pomeranian (7000 mg/kg) and polluted (about 6000 mg/kg) areas. Potassium, zinc, and cobalt levels were highest in chicks from suburbs (4.65, 10.1, and 2.7 mg/kg, respectively) and polluted regions (3.8, 9.7, and 5.6 mg/kg, respectively), whilst Cu and Mn were highest in those from polluted (10.9 and 47.6 mg/kg, respectively) and Pomeranian regions (11 and 42.2 mg/kg, respectively). Concentrations of Na, K, and Ca in chicks from Głogów smelter (143.2, 3.8, and 115.9 mg/kg, respectively) were often similar to those from Odra meadows (147.8, 3.6, and 112.5 mg/kg, respectively). This was probably due to a similar degree of homeostatic regulations of an organism. The levels of Mg, Fe, Zn, and Cu were often different (p<0.02-p<0.001) in the blood of White Stork chicks from the studied areas. Co, Pb, and Cd levels were higher (p<0.001) in chicks from Głogów smelter than in those from Odra meadows. It is evidence for importance of anthropopression, which influenced the course of biogeochemical processes and the bioaccumulation of toxic metals locally. This takes place also in chicks from swamps near Baltic Sea, in which the level of Cd was high (2.7 mg/kg); so we can state the high intensity of intoxication in this region. We can conclude that the use of hematological research assesses the condition of birds and might give a positive association with miscellaneous environmental loads. The high concentration of toxic heavy metals involved greater intensity of antioxidant enzymes' activity. Environmental intoxication causes an increase of lipoperoxidation intensity in growing chicks and changes the response of their immunological system.