Effects of age and sex on the content of heavy metals in the hair, liver and the longissimus lumborum muscle of roe deer Capreolus capreolus L

Direct and Indirect Linkages Between Trace Element Status and Health Indicators - a Multi-tissue Case-Study of Two Deer Species in Denmark

Measuring trace element concentrations in tissue can be a valuable approach to monitor animal health status. Temporal variation in the absorption, transport, and storage of elements between different tissues can, however, complicate the assessment of element-health relationships. Here, we measured concentrations of selected essential (copper (Cu), zinc (Zn), selenium (Se)) and non-essential (arsenic (As), cadmium (Cd), lead (Pb)) trace elements within blood, liver, kidney, and hair of fallow deer (Dama dama; N=20) and red deer (Cervus elaphus; N=21). Using multivariate regression and structural equation models, we estimated direct and indirect linkages between tissue-specific trace element profiles and long- (body condition) and short-term (serum protein biomarkers for acute inflammation, infection, and malnutrition) health indicators. Trace element concentrations varied markedly and were weakly correlated among tissues, with the exception of Se. After accounting for sex- and site-differences in trace element concentrations, body condition of red deer was directly, and positively, associated to trace element status in liver and hair, but not in kidney. For both deer species, trace element status in blood was directly linked to serum protein status with an indirect positive association to deer body condition. For fallow deer, no direct association between trace element status and body condition was detected in any of the tissues, possibly because of elemental homeostasis, and because all individuals were in good clinical health. This study shows that hair can serve as an effective, non-invasive, biomarker in deer health assessments, yet, to fully uncover trace element-health relationships a variety of sample matrices is preferred.

Influence of Area, Age and Sex on Per- and Polyfluorinated Alkyl Substances Detected in Roe Deer Muscle and Liver from Selected Areas of Northern Italy

Due to their physicochemical properties, per- and polyfluorinated alkyl substances (PFASs) persist and bioaccumulate in living organisms, causing adverse health effects. Since exposure to xenobiotics is influenced by factors related to both the living organism and the considered compounds, biomonitoring PFASs' presence in the environment is of crucial importance. This study aimed to detect and quantify 15 PFASs in the muscle and liver of 40 roe deer from a specific area in Northern Italy by UPLC-HRMS. In the roe deer, liver PFAS concentrations were higher than those seen in muscle (p < 0.05). Although PFAS content in animals from urbanized areas was higher than those found in deer from rural areas, this difference was not statistically significant. In female roe deer, the concentration was higher than in males (p < 0.05); moreover, older animals showed higher concentrations of PFASs in the liver than younger animals (p < 0.05). In conclusion, the amount of PFASs was higher in tissues from roe deer belonging to urbanized areas, showing that this species might serve as a good bioindicator due to its territorial behavior. PFAS content was significantly higher in female roe deer, although the reason is not fully known. Finally, PFAS concentration was higher in the liver of older animals, probably due to compromised hepatic function.

High-Resolution Mass Spectrometry Non-Targeted Detection of Per- and Polyfluoroalkyl Substances in Roe Deer (Capreolus capreolus)

Among wildlife species, roe deer stands out as a valuable indicator of environmental pollution due to its ecological significance and role as a game animal. The assessment of poly- and perfluoro substances (PFASs) bioaccumulation is of the utmost importance, relying on the liver and muscles as the main organs of interest. The study concerned the identification of 60 PFAS through a non-target workflow analysis based on HPLC Q-Exactive Orbitrap High-Resolution Mass Spectrometry in a homogeneous group of 18 female roe deer species. The developed strategy allowed us to individuate the 60 PFAS compounds with different levels of confirmation. Apart from seven PFASs identified via analytical standards, the remaining fifty-three features were identified with CL 2 or 3. Moreover, by applying a differential statistic approach, it was possible to distinguish the bioaccumulation patterns in the liver and muscle, identifying 12 PFAS upregulated in the muscle and 20 in the liver. The analysis reveals that specific PFAS compounds present exclusively in either the muscle or in the liver. The study emphasises the specificity of the liver and muscle as significant bioaccumulation sites for PFAS, raising questions about the underlying mechanisms of this process. In conclusion, the presented non-targeted PFAS analysis workflow evidenced promising and reliable results, successfully demonstrating its feasibility in the field of environmental research.

Roe Deer (Capreolus capreolus) Hair as a Bioindicator for the Environmental Presence of Toxic and Trace Elements

The return to pasture use as an alternative to intensive livestock farming implies some risks with the lack or the excessive presence of potentially toxic elements; in this regard, wild animals have been used as bioindicators for decades. Thus, the purpose of this study is quantifying Cu, Cr, Mn, Zn, Se, As, Cd, Ni, Pb, Al, Fe, and Mg in fur from roe deer and understanding if it is a valid bioindicator tool. Hair was collected from 39 hunted roe deer and divided by age (<36 months old/≥36 months old), sex (male/female), and area of origin (urbanized/rural area). The mean concentrations of Fe, Mg, Mn, Al, Cr, and Pb were higher (p < 0.05) in the urbanized group; the mean levels of Mg and Cr were higher (p < 0.05) in older animals; and Cu, Fe, Mg, Cd, and Cr showed a higher accumulation in females. Our findings showed an age-related variation of elements, with higher concentrations in adult animals and females. In conclusion, our findings prove that hair is a valid matrix for this type of survey, and wild animals are good bioindicators for monitoring the presence of trace elements in pastures.

Concentration of Selected Essential and Toxic Trace Elements in Horse Hair as an Important Tool for the Monitoring of Animal Exposure and Health

The main purpose of the study was to analyse the concentrations of selected essential and toxic trace elements in the hair of sports and recreational riding horses from studs located in central Poland and thus test the usefulness of this matrix for monitoring the exposure of these animals. We also measured the concentration of heavy metals in oats used as a basic component of the equine diet to investigate the interactions between these elements in the feed and hair. The basic chemical composition of oats was analysed. Elemental analysis was performed using an EcaFlow 150 GLP electrochemical analyser with an E-104L electrode and reference to a calibration curve. The chemical composition of oats was investigated by near infrared transmission (NIR) spectroscopy calibrated for an artificial neural network (ANN) using a Foss InfraXact spectrometer. Among all elements, the coefficient of variation was highest for Pb and lowest for Cd, regardless of the study group. The content of elements in horse hair was in the range of 153.56 to 185.79 mg·kg^-1 for Zn, 6.10 to 11.99 mg·kg^-1 for Cu, 0.578 to 0.813 mg·kg^-1 for Pb and 0.011 to 0.015 mg·kg^-1 for Cd (in kg of d.w.). For hair, we found a significant negative correlation for Zn-Cu (r_xy = -0.539) and Cd-Cu (r_xy = -0.676) at p ≤ 0.05. For feed, there was a highly significant positive correlation for Cu-Pb (r_xy = 0.723) and Zn-Cd (r_xy = 0.714) at p ≤ 0.01. We found significant negative oats-hair interactions for Cu-Zn, Pb-Cu, Cd-Cu and Zn-Pb, and a positive oats-hair interaction for Cu-Cu.