Temporal trends (1953-2012) of toxic and essential elements in red deer antlers from northeastern Poland

Red deer antlers have a number of advantages that make them a unique material for monitoring trace elements. As antlers are shed and regrown every year, results of toxicological investigations can be applied to a particular region and time. We analyzed the content of four toxic (Pb, Cd, Hg, As) and three essential (Cu, Zn, Fe) trace elements in 254 red deer antler samples spanning between 1953 and 2012. Age of stags did not influence concentrations of analyzed elements in antlers, except for Zn whose level increased with age. The highest concentrations of toxic elements occurred at the beginning of the analyzed period. Levels of Pb, Hg and Zn in antlers decreased over the course of the study. Levels of Cd and As were low and presented a steady trend. Variations in the levels of the analyzed elements in red deer antlers are considered to reflect levels of exposure of animals in their habitat over the sixty-year study period. The range of essential element levels did not indicate any contamination. Environmental conditions in the Mazury Region during the last decades appeared to have improved significantly, as established by declining trends of toxic elements levels in deer antlers.

Total mercury levels in the muscle and liver of livestock and game animals in Poland, 2009-2018

The bioaccumulation of mercury (Hg) in the food chain may pose a threat to human health. The risk of dietary Hg intake is mostly caused by the consumption of fish and seafood, therefore the knowledge on the exposure from land animal products is limited. In our article, we summarized the results of analyses of Hg in muscle tissue and liver of different livestock and game animals obtained during ten years of official monitoring that was carried out in Poland from 2009 to 2018. The majority of the results in muscle tissue were below the limits of quantification (LOQs). The mean Hg concentrations in muscle tissue ranged from 0.6 to 5.6 μg kg^-1 of wet weight and the mean liver Hg concentrations were within the range of 0.8-16.4 μg kg^-1 of wet weight, with lowest levels in chickens and highest in wild boars. The results revealed decreasing trends in liver Hg in cattle and cervids over the years, which was congruous with decreasing emission of Hg in Europe. Our results showed that the consumption of meat and liver of livestock and game animals in Poland may be considered to be safe for human health, which was confirmed by the low number of noncompliant samples relative to the applicable legal limits, as well as by estimated dietary exposure.

Simultaneous Determination of Ten Illegal Azo Dyes in Feed by Ultra-high Performance Liquid Chromatography Tandem Mass Spectrometry

Introduction

The paper presents the method of simultaneous determination of 10 illegal azo dyes in feed by ultra-high performance liquid chromatography coupled with tandem mass spectrometry technique.

Material and Methods

The dyes were extracted with hexane, evaporated to dryness, and analysed. Separation was achieved in 7 min in a gradient elution using acetonitrile (A) and 0.1% formic acid (B) as a mobile phase.

Results

The validation results showed the repeatability of the method, which was evaluated at three levels (50, 500, and 5,000 µg/kg). All the matrix calibration curves for the working ranges were linear (R² 0.9904 to 1.0), the repeatability was between 2.1% and 24%, and recoveries ranged from 77.9% to 120%. The LOD and LOQ were at 1–2 and 5–10 µg/kg for different dyes, respectively. Furthermore, the method was applied in the homogeneity tests of the in-house prepared feed containing Sudan I at the levels of 0.5, 5, and 50 mg/kg.

Conclusions

A sensitive, selective, and fast multiresidue method was successfully developed and validated. Its robustness was confirmed by the analysis of an experimental feed containing Sudan I.

Can red deer antlers be used as an indicator of environmental and edible tissues' trace element contamination?

Venison is an attractive product for consumers concerned with healthy lifestyle; however, it can contain high levels of toxic elements, and therefore, it is a possible source of hazardous contaminants in human diet. Antlers are suitable bioindicators of environmental metal contamination, and herein, we assessed the ability of trace element levels in antlers to indicate levels in edible soft tissues. We determined the concentrations of lead (Pb), cadmium (Cd), mercury (Hg), arsenic (As), copper (Cu), zinc (Zn), and iron (Fe) in the liver, kidney, muscle, and antlers of 14 free-ranging red deer (Cervus elaphus) from northeastern Poland using atomic absorption spectrometry. We found the highest concentrations of Pb (0.321 ± 0.165 mg/kg), As (0.045 ± 0.074 mg/kg), Zn (105.31 ± 16.33 mg/kg), and Fe (220.92 ± 117.18 mg/kg) in antlers; of Cd (4.974 ± 1.90 mg/kg) and Hg (0.048 ± 0.102 mg/kg) in kidney; and of Cu (7.29 ± 7.02 mg/kg) in the liver. A positive relationship between concentrations in antlers and muscle was found only for Cu (p = 0.001), and it therefore appears that red deer antlers cannot be used as an index for element concentrations in soft tissues. While our results confirm that the Mazury region is little polluted, consumption of red deer offal from this area should be limited according to extant legal limits set for livestock consumption.

Expression of metallothionein in the liver and kidneys of the red deer (Cervus elaphus L.) from an industrial metal smelting area of Poland

The metallothionein 1 (MT1) coding sequence of red deer was identified and compared to orthologous sequences from other mammals. Over 90% identity was observed between red deer MT1 amino acid sequence and MT1 sequences of other ruminants. Liver and kidney samples of red deer were collected from the industrial zinc smelting site of Miasteczko Slaskie and from the Masuria Lake District serving as a pollution-free control site. The concentrations of cadmium (Cd), lead (Pb), copper (Cu) and zinc (Zn) were analyzed by the atomic absorption spectrometry technique (AAS). The levels of Cd in the liver of red deer from the metal smelting region was about 8 times higher than for the reference control site. Next, the expression of MT1 mRNA in the liver of red deer was quantified by the reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and the expression of MT1/2 protein in the liver and kidneys was analyzed by immunohistochemistry. Positive correlations were found between expression levels for MT1 mRNA and the concentrations of Cu and Zn in liver of red deer, and with the age of animals. Immunohistochemical staining demonstrated the nuclear and cytoplasmatic expression in both liver and kidney tissues, but with no obvious relationship shown for the expression of MT1/2 protein and tissue metal levels. Our results showed that the analysis of MT expression levels in the red deer could not be used independently as a biomarker for identifying exposure to Cd, but could be co-analyzed with tissue metal levels to give better prognosis for environmental exposure to metals.

Effect of doxycycline concentrations in chicken tissues as a consequence of permanent exposure to enrofloxacin traces in drinking water

Introduction: The main problem in poultry farming is the difficulty in producing food of animal origin without using antibacterial agents. Because most antibacterial compounds are dispensed in water, some water supply systems can be contaminated by antibiotics which are then administered to the animals unintentionally. This can lead to unexpected increases in antibiotic residues in food of animal origin. The aim of the present study was to determine whether the constant exposure of chicken broilers to enrofloxacin affects the withdrawal time of a therapeutic doxycycline that is intentionally administered to the chickens.

Material and Methods: The concentrations of doxycycline, enrofloxacin, and ciprofloxacin were determined by LC-MS/MS in muscles and liver of the chickens.

Results: Doxycycline residue concentrations in the chicken tissues from the group that received trace amounts of enrofloxacin were nearly 50% greater than those of the group that received only doxycycline.

Conclusion: These results indicated that constant exposure to enrofloxacin in trace amounts significantly influences the residual doxycycline concentration in chicken tissues.

Oestrogenic and (anti)androgenic activity of zearalenone and its metabolites in two in vitro yeast bioassays

Selected resorcylic acid lactones (RALs) – zearalenone (ZEA), α-zearalanol (α-ZAL), β-zearalanol (β-ZAL), α-zearalenol (α-ZOL) and β-zearalenol (β-ZOL) were investigated for their oestrogenic and (anti)androgenic activity using two in vitro RIKILT yeast Estrogen and Androgen bioAssays. Our results show that all tested compounds are able to induce hERα-dependent transcription and the rank of their potencies, based on EC50 values is as follows: α-ZOL > α-ZAL > ZEA > β-ZAL > β-ZOL. None of the tested compounds appeared to be androgenic when tested individually at concentrations ranging from 0.1 pM to 0.1 mM. However, all RALs inhibited 17β-testosterone-induced transcriptional activity. The highest antiandrogenic potential showed α-ZOL, β-ZAL and β-ZOL with the IC50 of 6.2 μM, 11.5 μM and 15.2 μM, respectively. When compared with flutamide, for which a relative antiandrogenic potency (RAAP) was assumed as 100%, the corresponding RAAPs for α-ZOL, β-ZAL and β-ZOL were 220, 119 and 89.8%, respectively. In summary, our study revealed that RALs possess not only oestrogenic, but also antiandrogenic activity. Further research is warranted to clarify the role of disruption of androgen receptor signalling in humans and animals.

Usefulness of immature golden hamster (Mesocricetus auratus) as a model for uterotrophic assay

The present study assessed the sensitivity of immature hamster uterotrophic assay to reference oestrogen agonists/antagonists in order to develop a sensitive model for evaluation of endocrine-active compounds in diets. After performing a baseline for control animals, the sensitivity of immature females (postnatal day 18) to reference compounds was evaluated in a three-day uterotrophic assay. The absolute and adjusted dry uterine weights, fold induction over control for absolute wet uterine weight, and wet uterine weight/body weight ratio (%) were used as endpoints. The significantly active doses for reference oestrogens were as follows: 0.6 μg/kg for 17α-ethinyloestradiol (s.c.); 1 μg/kg/day (s.c.) and 40 μg/kg (p.o.) for diethylstilboestrol; 40 mg/kg (s.c.) and 160 mg/kg (p.o.) for bisphenol A. Co-treatment with tamoxifen at a dose of 1 mg/kg significantly antagonised the uterotrophic effect induced by 1 μg/kg 17α-ethinyloestradiol, and showed the attenuated proliferative effect in histopathological examination. We found immature hamster uterotrophic assay as a sensitive model that could be a good alternative to the rat assay.

Application of the yeast-based reporter gene bioassay for the assessment of estrogenic activity in cow's milk from Poland

Milk contain compounds acting through the estrogen receptor signaling. The still open question whether such estrogens pose a risk for human health, encouraged us to measure the overall estrogenic activity of cow's milk in the in vitro yeast reporter bioassay. First, we assessed the ability of the bioassay to detect estrogens frequently detected in milk. The relative potencies of 16 compounds descended in the order: 17β-estradiol (17β-E2), 17α-ethinylestradiol, diethylstilbestrol, dienestrol, 17α-E2, estrone, zearalenone, estriol, equol, genistein, 17β-E2 glucuronide, bisphenol A, apigenin, daidzein. Flavone, 4-n-nonylphenol and 4-t-octylphenol shown no activity in the bioassay.The estrogenic activities of milk samples without hydrolysis were below the detection limit, whereas in 50% of the deconjugated samples they varied between 0.29 and 0.49 ng EEQ mL(-1). We also compared the estrogenic activity in raw cow's milk collected from rural and industrial locations in Poland. In our pilot study we did not observe statistically significant difference in estrogenic activities in milk collected from the two locations. We found that the daily intake of estrogens with milk may be higher than estrogen levels in human serum. Further studies are warranted to evaluate the significance of milk and dairy as a source of estrogens for humans.

The effect of selected environmental Fusarium mycotoxins on the ovaries in the female wild boar (Sus scrofa)

The contamination of agricultural crops with Fusarium mycotoxins poses one of the greatest problems in food production. Wild boars live in specific habitats and are physiologically sensitive to Fusarium mycotoxins, therefore, they are an interesting model for studies investigating the effects of the discussed toxin, in particular under low-dose exposure. The objective of this study was to determine potential effects of Fusarium mycotoxins ingested with naturally contaminated food on reproductive function based on the proliferation and apoptotic indices of ovarian follicles in female wild boars. The experiment was conducted on 40 wild boars inhabiting north-eastern Poland. The effect of seasonal variations in the quantity and quality of ingested food on the concentrations of Fusarium mycotoxins and their metabolites in the blood of wild boars was analyzed. The observed differences in toxin levels were accompanied by changes in proliferation and apoptotic indices. Proliferation processes were most intense in autumn-winter and were least advanced in winter-spring. The intensity of apoptotic processes was inversely correlated with proliferation.

Rapid method for the determination of metamizole residues in bovine muscle by LC-MS/MS

Metamizole is a pyrazolone non-steroidal anti-inflammatory drug allowed for use in food-producing animals. According to Council Directive 96/23, residues of this drug have to be monitored because of the potential risk to consumers' health. Metamizole is hydrolysed to its marker residue 4-methylaminoantypyrine.This compound is further metabolised to three main metabolites: 4-formylaminoantipyrine, 4-aminoantipyrine and 4-acetylaminoantipyrine. The MRL of 4-methylaminoantipyrine in animal tissues is 100 µg kg(-1). Considering the above points, a method for the detection of four metamizole metabolites in bovine muscles was developed. Analytes were extracted from muscle by a mixture of acetonitrile and sodium acetate buffer. After centrifugation, the supernatant was passed through alumina cartridges, diluted with mobile phase and analysed by using LC-MS/MS. Four metamizole metabolites were separated on a C8 column in 23 min with a gradient of methanol:acetonitrile:ammonium formate solution and analysed by using positive ionisation. Validation of the method indicated a within-laboratory reproducibility in the range of 7-30% and recovery in the range of 45-95%. The method fulfils the criteria for confirmatory methods and, thanks to its labour efficiency, may also be used for screening purposes.