Abstract
Simple summaryProtocols were adjusted and established for biomarker assessment in two blood fractions: plasma and the post-mitochondrial fraction (S9). Basal biomarker values were determined in white stork (Ciconia ciconia) nestlings from Croatia, and biomarker responses in two different types of blood samples were compared. Novel fluorescence-based glutathione and reactive oxygen species detection was established providing the potential usage of blood for assessment of environmental impact at the molecular level.White stork (Ciconia ciconia) nestlings can provide quantitative information on the quality of the surrounding environment by indicating the presence of pollutants, as they depend on locally foraged food. This study represents the first comparison of biomarkers in two fractions of white stork nestling blood: plasma and S9 (the post-mitochondrial fraction). The aim of this study was to evaluate acetylcholinesterase (AChE), carboxylesterase (CES), glutathione S-transferase (GST), and glutathione reductase (GR), as well as to establish a novel fluorescence-based method for glutathione (GSH) and reactive oxygen species (ROS) detection in plasma and S9. Considering the enzymatic biomarkers, lower variability in plasma was detected only for AChE, as CES, GST, and GR had lower variability in S9. Enzyme activity was higher in plasma for AChE, CES, and GST, while GR had higher activity in S9. Regarding the fluorescence-based method, lower variability was detected in plasma for GSH and ROS, although higher GSH detection was reported in S9, and higher ROS was detected in plasma. The present study indicated valuable differences by successfully establishing protocols for biomarker measurement in plasma and S9 based on variability, enzyme activity, and fluorescence. For a better understanding of the environmental effects on nestlings’ physiological condition, biomarkers can be measured in plasma and S9.
Highlights
IntroductionThe white stork (Ciconia ciconia) is a large migratory bird species breeding in Europe and wintering in Africa, associated with open wet grasslands and agriculture habitats [1]
As an apex bird species with opportunistic feeding habits, their diet mostly comprises of various invertebrates, amphibians, fish, snakes, lizards, small mammals, and, occasionally, trash from landfills [4,5,6,7,8,9]
Sex was determined from S9 using the CHD gene
Summary
The white stork (Ciconia ciconia) is a large migratory bird species breeding in Europe and wintering in Africa, associated with open wet grasslands and agriculture habitats [1]. In recent years, studies show that a high percentage of white storks stay in south-western Europe during winter [2,3]. White stork nestlings are fed on local food sources, foraged by their parents, making them suitable bioindicators and sentinels of contaminants in a local environment [10,11]. A decline in the breeding population of storks is related to decreasing availability of grasslands and wetlands and increase in anthropogenic activities, especially intensive agriculture [12]
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