The dissertation work was carried out in the laboratory of toxicological monitoring of the NSC "IECVM", in accordance with the task 38.02.01.01 F "To study the spread of toxic contaminants of feed (pesticides, micromycetes, mycotoxins, inorganic elements, etc.) and their impact on the animal body, quality and safety of livestock products, taking into account the requirements of the European Union" (state registration number 0116U000220), 2015-2020.
The dissertation addressed scientific and applied issues related to ensuring the quality and safety of poultry products (eggs and meat) when exposed to varying doses of bromine (sodium bromide), namely monitoring the bromine content in chicken eggs, feed and water from different poultry farms in Ukraine; identifying markers of acute and chronic exposure to sodium bromide in laboratory animals (white rats); studying the effect of sodium bromide on the body of laying hens in a subchronic toxicological experiment; and assessing the quality and safety of the resulting poultry products (meat and eggs). A subacute toxicological experiment was conducted to study the effect of poultry products (meat and eggs) with high bromine content on the bodies of white male rats.
The scientific novelty of the results obtained is that for the first time in Ukraine, monitoring studies of bromine content in feed, water and poultry products (chicken eggs) were conducted, and a positive correlation (r=0, 96) of bromine content in feed with the number of bromine-containing pesticides registered and authorized for use in Ukraine, and that bromine ingestion in poultry products occurs mainly due to excessive intake of bromine with alimentary environmental factors (feed and water). The knowledge base on markers of acute and chronic bromine toxicity in laboratory animals (white rats) has been supplemented. New data were obtained on the toxicodynamics and toxicokinetics of bromine in the body of laying hens, and it was found that excessive bromine intake leads to inhibition of the protein synthesizing function of the liver with hepatotoxic effects, but almost does not affect the quality of the products obtained, but a significant amount of bromine is excreted from the body of the bird with the egg protein, increasing the danger of such products. For the first time, it has been proven that poultry products (meat and eggs) with a high bromine content contribute to a decrease in the concentration of thyroid hormones (total thyroxine and triiodothyronine) in the blood serum of rats in a subacute experiment. Based on the data obtained, for the first time in Ukraine, we developed a "Method for in vivo diagnosis of bromine poisoning in poultry" (utility model patent of Ukraine No. 143071), which allows us to determine the degree of bromine poisoning depending on the amount of bromine in egg whites.
The practical significance of the results is that, based on the research, scientific and methodological recommendations "Diagnosis and Prevention of Bromine Poisoning in Poultry" were developed (approved by the Scientific and Methodological Council of the State Service of Ukraine for Food Safety and Consumer Protection: Protocol No. 1 of May 12, 2021), which are aimed at improving the diagnostic and preventive work of the laboratories of the State Service of Ukraine for Food Safety and Consumer Protection that conduct research on feed and livestock products.
Main results of the work. New knowledge on residual amounts of bromine in water, feed and eggs in Ukraine was obtained as a result of systematic monitoring studies conducted during 2016-2020. The acute toxicity parameters of bromine (sodium bromide) for white male rats were established, which classifies it by the level of toxicity as a Class IV substance (low-toxic) and as a moderately hazardous substance (III hazard class).
When sodium bromide was administered at a dose of 250.0 mg/kg of feed on day 18-28 of the experiment, the element content in egg white exceeded the control value by 26.9 times and remained 3.5 times higher than the control 14 days after the end of the administration, which potentially increased the hazard of such products. Sub chronic administration of sodium bromide to laying hens with feed reduces the quality of "white" meat, and "red" meat. In addition, bromine accumulates in both types of muscles during the administration period and is not completely excreted from them 14 days after the end of sodium bromide administration. When consuming products (eggs and meat) with a high bromine content, the main target organs of toxic effects in rats of the first experimental group (eggs), especially in the early stages of the study, were the liver, and the second (meat) - the liver and lungs, respectively.Studies of toxicokinetics of bromine in poultry products have shown that the element accumulated most in rats that consumed eggs with high bromine content.
