The purpose of these studies was to analyse and compare the content of bromine in samples of chicken eggs, feed, and water from different regions of Ukraine in the dynamics of 2016 – 2020: with an increased risk of bromine in products (Kharkiv, Poltava, Dnipropetrovsk and Mykolaiv regions) and outside the risk zone (Volyn, Vinnytsia and Zaporizhzhia). Studies of bromine content in eggs, feed, and water were performed in the laboratory of toxicological monitoring of the National Scientific Center "Institute of Experimental and Clinical Veterinary Medicine" (Kharkiv) using X-ray fluorescence analysis. As a result of the conducted researches, the increase of the bromine content in chicken eggs in the dynamics of 2016 – 2020 was established: the bromine content increased regardless of the region of the poultry farm location. The highest bromine concentration in chicken eggs was found in Kharkiv, Dnipropetrovsk, Mykolaiv, and Zaporizhia regions. Bromine source in poultry products is the excessive intake of bromine in the poultry body with alimentary environmental factors (feed and water). Bromine content in feed for chickens increased in the research dynamics (from 35.1% in the Poltava region to 2.5 times in the Zaporizhzhia region). It exceeded the established EFSA (4.4% of the total) and the average in Ukraine (51.2% of the total number of samples). In addition, the average bromine content in feed from poultry farms of the studied regions of Ukraine correlated with the number of registered and approved bromine-containing pesticides. The average bromine concentration in water sources in the studied regions of Ukraine had no significant differences compared to the beginning of the study but exceeded the maximum allowable concentration by 21.7% in 2016, 34.8% in 2018 and 39.1% in 2020. The maximum bromine concentration was in water sources in Mykolayiv, Kharkiv, and Dnipropetrovsk regions.

Bromine content in fodder and water for laying chickens in Ukraine gradually increasing, thereby accumulating in the poultry production (eggs and meat): according to the data, intake of bromine with chicken eggs in 2020 has almost doubled, compared with 2016. Taking into account the ability of bromine to accumulate and the scales of consumption of poultry products, it is relevant to study the effects of high bromine concentration on the level of thyroid hormones and clinical-biochemical parameters of blood of white rats. At the laboratory of Toxicological Monitoring of the National Scientific Center the Institute of Experimental and Clinical Veterinary Medicine and the Department of Experimental Pharmacology and Toxicology of the State Institution V.Y. Danylevskyi Institute of Problems of Endocrine Pathology of the National Academy of Medical Sciences of Ukraine, we carried out studies on white outbred male rats (n = 144). The diet of experimental groups was supplemented with eggs and meat containing high bromine concentration. We determined increase in the coefficients of liver weight and decrease in the coefficients of lung weight in the experimental rats. Moreover, we determined changes in the biochemical blood profile, in particular: after egg consumption, there occurred 20.0–22.0% decrease in the enzymatic activity of alanine aminotransferase, 23.0–48.4% in the activity of aspartate aminotransferase, and on average 21.3% decrease in alkaline phosphatase, compared with the control; after meat consumption, the level of total proteins decreased by 8.6%, glucose by 12.2–14.5%, also there were 13.8–18.5% decrease in the activity of alanine aminotransferase and 12.1–83.0% increase in the activity of aspartate aminotransferase on the 28th day, and 23.2–35.3% decrease in the activity of alkaline phosphatase. After the intake of both poultry products, the blood serum of animals was observed to have decrease in the level of overall thyroxine and overall triiodothyronine (1.3 times on average, depending on the period of study). The results of the studies can help in prediction and timely alleviation of the negative impact of poultry products with high bromine content on the human organism.

The prohibition of using antibiotics with growth-stimulating properties in the European Union led to the search for new, safer, more effective, and cheaper feed additives. One of these substances was rare earth elements (REE, atomic numbers 57–71) due to their low toxicity and protective and antioxidant properties. At the same time, higher efficiency of organic forms of REE was noted. Thanks to this, it is possible to assume their even more pronounced effect in nano-sized form as feed additives and the need to conduct research in this direction. Therefore, this work aims to study the metabolic parameters of the blood in rats under long-term oral administration of nanoparticles of one of the representatives of rare earth elements – gadolinium orthovanadate (NP GdVO4:Eu3+) under food stress. Experimental samples of gadolinium orthovanadate nanoparticles activated by Europium (spindle-shaped geometry; size 8×25 nm; initial concentration 1.0 g/dm3) were used in work. Experimental studies on rats were carried out based on the vivarium of the NSC “IEKVM”. The object of research was 140 mature male Wistar rats with an initial weight of 180–200 g. Four groups of animals, 35 rats each, were formed according to the principle of analogs. During the experiment, animals of the control group received drinking water without additives; rats of the І experimental group were given a solution of NP GdVO4:Eu3+ at a dose of 0.2 mg/dm3 (≈ 0.03 mg/kg of body weight); II research group – at a dose of 1.0 mg/dm3 (≈ 0.15 mg/kg of body weight) and rats of III research group – at a dose of 2.0 mg/dm3 (≈ 0.30 mg/kg of body weight). Drinking was carried out for 56 days, then it was completed, and the rats were observed for another 14 days. A nutritionally unbalanced diet was used as a stress factor. Taking into account the results of biochemical studies, the adaptogenic effect of NP GdVO4:Eu3+ in the range of doses of 0.2–1.0 mg/dm3 of drinking water (≈ 0.03–0.15 mg/kg of body weight) on the body of white rats was established under conditions of food stress with optimal duration of action – 28–42 days. Under the conditions of administration at a dose of 2.0 mg/dm3 of drinking water (≈ 0.30 mg/kg of body weight), a hepatic(cyto-)toxic effect of nanoparticles was detected, which was accompanied by an irreversible decrease in the structural indicators of lipid metabolism, the consumption of antioxidant resources and the induction of intensity processes of lipid peroxidation against the background of alanine aminotransferase hyperenzymemia.

The aim of the scientific work was to study the toxicokinetics of Bromine in the body of laying hens under conditions of subchronic administration of sodium bromide diet. The subject of the study was the content of bromine in the organs and tissues of laying hens under conditions of subchronic administration of sodium bromide diet. The experiment was on laying hens. Three experimental and one control groups of animals were formed (n=15). The background indicator of the Bromine content in the compound feed was 2.0 mg/kg of feed. An aqueous solution of sodium bromide was added daily to the feed of the experimental groups for 28 days, and the observation of the poultry was continued for the next 14 days. The poultry of the experimental groups received bromine with feed at a dose of 10.0 mg/kg, II – 50.0 mg/kg, III – 250.0 mg/kg of feed. The selection of organs was under conditions of euthanasia of the poultry, by total exsanguination, during inhalation chloroform anesthesia on days 14, 28 and 42 of the experiment, 5 animals per group. The following research methods were used in the work: clinical (daily examination of the poultry), pathological (dissection and sampling of organs for research), toxicological (determination of Bromine content using X-ray fluorescence analysis), statistical (processing of the results was carried out by methods of variation statistics using the Statistica 6.0 software ( StatSoft Inc., USA)). It was found that bromine is absorbed most intensively in the small intestine: on the 28th day of the experiment, its content exceeded the control in group I by 6.5 times, in group II – 22 times, in III – 201.1 times. The study of the content of bromine in the liver, spleen, heart, and brain of three experimental groups testifies to the "material" accumulation of the element. In addition to the digestive tract, the excretion of bromine from the body of laying hens occurred through the kidneys, and possibly with exhaled air. In group III, on the 28th day, its content in the kidneys was 23.1 times higher than the control indicator, and on the 14th day in the lungs, the excess of the control indicator was 27.4 times. The excess of the element was not excreted from the body within 14 days after the cessation of the intake of sodium bromide with food. Key words: Bromine, subchronic intake, laying hens, bromine content in organs, toxicokinetics, sodium bromide.

The purpose of this study was to determine the quality and safety of eggs obtained from laying hens after their experimental poisoning with sodium bromide. According to the principle of analogues, three experimental and one control group of laying hens (n = 15) were formed. The background bromine content of the compound feed was 2.0 mg/kg. An aqueous solution of sodium bromide was added daily to the feed of the chickens of the experimental groups for 28 days, followed by the observation of the birds for 14 days without its addition. Chickens of the 1st experimental group received bromine with feed at a dose of 10.0 mg/kg, 2nd — 50.0 mg/kg, 3rd — 250.0 mg/kg of feed. During the experiment, eggs were collected daily, their quality was determined according to the requirements of DSTU 5028:2008 ‘Hen’s Eggs for Human Consumption. Specifications’ and the rules for the veterinary and sanitary examination of poultry eggs. In addition, the bromine content was determined separately in egg white, yolk, and shell. Bromine content was determined by X-ray fluorescence analysis. Statistical processing of research results was conducted. Under the conditions of the chronic experiment, clinical manifestations of poisoning in chickens were not observed. No significant deviation from the control group was observed in productivity, egg mass, white to yolk mass ratios, and pH values of yolk and white. However, an uneven distribution of the eggs by category was established. Starting from the 2nd day of the experiment, bromine was excreted in laying hens with egg whites. The maximum value was observed on the 18th–28th days of the experiment: in the 1st experimental group a reliable excess 2.5 times of bromine content relative to the control was observed; in 2nd — 7.2 times, and in 3rd — 26.9 times. Thus, eggs from chickens of all groups conformed to DSTU 5028:2008 and the rules for the veterinary and sanitary examination of poultry eggs. However, the bromine content in the eggs of all experimental groups reliably exceeded the reference value for 28 days when sodium bromide was received with feed. Even 14 days after the experiment, the content of the element reliably exceeded the control value in the eggs of chickens from the 2nd and 3rd experimental groups, which may indicate the ability of bromine to cumulate