Belgorod Region is one of the main agro-industrial regions of Russia. The volume of production in the livestock sector in 2022 amounted to 203 billion rubles. Most often, livestock farms are located near agricultural land with plant crops, which increases the risk of contamination of the latter with various toxicants. The purpose of this work was to study and assess the contamination with heavy metal ions and toxic chemicals of the soils of agricultural lands and nearby reservoirs in the Prokhorovsky district of the Belgorod region. Watercress (Lepidium sativum) and crustaceans (Daphnia magna Straus) are bioindicators.

Finding alternatives to antimicrobials in poultry farming is crucial to ensuring biosafety and food quality for humans. The purpose of this article was to provide a comprehensive description of thymus development in chicks of a hybrid egg-laying breed in the early postnatal period and to evaluate the effect of probiotics and antibiotics on this process. Materials and methods. The research focused on Hisex Brown cockerels (n = 100) from day 1 to day 20 of life fed on 4 different diets: standard diet (control), diet with a probiotic, diet with an antibiotic (enrofloxacin) and diet with their combination. Chicks’ thymus was studied using macroscopic morphometry and light microscopy. Results. The research demonstrated a significant increase in thymus weight in all the experimental groups compared to the control. In animals treated with a probiotic microorganism, by day 20 the histoarchitectonics in the thymus had become more complicated, with a clear delineation of the regions, formation of Hassal’s corpuscles, and developed vascularization of the medulla as well as a significant increase in the relative area of the medulla (up to 43.40 %). The group that was given enrofloxacin showed less pronounced changes: the relative area of the medulla on day 20 was 40.76 %, which was virtually the same as in the control group (40.73 %). In the group that received enrofloxacin and a probiotic, by day 20 the relative area of the medulla had increased statistically significantly and reached 46.5 %. The dynamics of the relative areas of the cortex and medulla in the thymus of Hisex Brown chicks demonstrates a strong influence of the diet on the development of this organ. In the control group, we observed a stable but low development of the medulla, with the predominance of the cortex, which may indicate insufficient stimulation of the immune function on a standard diet. The groups that received a probiotic microorganism demonstrated a significant increase in the relative area of the medulla and a decrease in the area of the cortex. This emphasizes the positive effect of the diets with probiotics on the development of the thymus, which may improve the functional activity of this organ and the body’s immune response.

High metabolic rate of broiler chickens during the early postnatal period requires significant attention from poultry farmers. During this period, physiological functions are formed under significant stress. Furthermore, high risks of infectious diseases can lead to significant economic losses in poultry farming. Enrofloxacin, which is used during the early stages of poultry development, has found wide application in modern broiler poultry farming. The use of bacilli-based probiotics is of particular interest due to their ability to optimize the microbiome and stimulate natural defense mechanisms. The aim of this study was to compare the dynamics of blood biochemical parameters in broiler chickens treated with the antibiotic enrofloxacin, the probiotic strain Bacillus subtilis BKM B-3728D (KE) and their combination. The experiment was conducted on 100 Ross-308 broiler chickens divided into four groups: a control group and experimental groups treated with probiotic, antibiotic enrofloxacin and their combination. Blood biochemical parameters and animal growth were assessed over time, with statistical data processing using the Mann-Whitney test. The probiotic was found to optimize metabolic processes, resulting in a significant reduction in glucose levels by 9-15% and activation of protein metabolism. In contrast, antibiotic therapy caused liver dysfunction (a 32% decrease in bilirubin and 35% decrease in ALT) and a significant disruption of lipid metabolism (a 104% increase in triglycerides). Combined use of the drugs did not demonstrate a synergistic effect and was accompanied by signs of metabolic stress. The obtained results confirm the potential of using Bacillus subtilis strain BKM B-3728D for optimizing the metabolic status of broilers. However, complete replacement of antibiotics with probiotics requires additional research to select compatible strains and develop effective administration regimens.

исследованы структурные и сорбционные характеристики бактериальной целлюлозы (БЦ), синтезированной симбиотической культурой чайного гриба Medusomyces gisevii на питательных средах с различными источниками углерода (3% сахароза, 6% сахароза, 6% меласса). Установлено, что максимальный удельный выход биомассы БЦ наблюдается при использовании 6% мелассы (11.807 г/г), в то время как наибольшее содержание чистой целлюлозы зафиксировано в среде с 6% сахарозой (3.81%). Методами сканирующей электронной микроскопии и газоадсорбционного анализа показано, что лиофилизированные образцы БЦ обладают развитой макропористой структурой. Изучена сорбционная способность материалов в отношении катионного красителя метиленового голубого. Установлено, что лиофилизированная БЦ обладает значительно более высокой сорбционной емкостью (22.809 мг/г) по сравнению с нативной пленкой, высушенной конвективным способом (11.689 мг/г). Показана перспективность использования бактериальной целлюлозы в качестве основы для сорбционных материалов и функциональных носителей. Цели: исследование влияния условий культивирования и методов сушки на структурно-морфологические и адсорбционные характеристики бактериальной целлюлозы. Методы. Для культивирования использовали питательные среды с вариацией источника углерода. Структуру образцов изучали с помощью сканирующего электронного микроскопа Nova NanoSem 450 (FEI Company, США) и газоадсорбционного анализатора TriStar II 3020 (Micromeritics, США). Сорбционную емкость определяли с использованием спектрофотометра Nabi (MicroDigital Co., Республика Корея) по поглощению метиленового голубого из водного раствора. Результаты. Установлены оптимальные условия культивирования для максимального выхода биомассы и содержания целлюлозы. Выявлено, что метод лиофильной сушки позволяет получить материал с высокой удельной поверхностью и развитой пористой структурой, что обуславливает его повышенную сорбционную активность. Выводы. Бактериальная целлюлоза, в особенности её лиофилизированная форма, демонстрирует высокий потенциал в качестве эффективного и биосовместимого сорбента, а также перспективного носителя активных веществ и медицинских препаратов. he structural and sorption characteristics of bacterial cellulose (BC) synthesized by the symbiotic culture of Kombucha Medusomyces gisevii in nutrient media with different carbon sources (3% sucrose, 6% sucrose, 6% molasses) were studied. It was found that the maximum specific yield of BC biomass was observed when using 6% molasses (11.807 g/g), while the highest content of pure cellulose was recorded in a medium with 6% sucrose (3.81%). Scanning electron microscopy and gas adsorption analysis showed that lyophilized BC samples have a developed macroporous structure. The sorption capacity of the materials with respect to the cationic dye methylene blue was studied. It was found that lyophilized BC possesses a significantly higher sorption capacity (22.809 mg/g) compared to the native film dried by convection (11.689 mg/g). The potential of using bacterial cellulose as a basis for sorption materials and functional carriers is demonstrated. Objectives: study of the influence of cultivation conditions and drying methods on the structural, morphological and adsorption characteristics of bacterial cellulose. Methods. Nutrient media with varying carbon sources were used for cultivation. Sample structure was examined using a Nova NanoSem 450 scanning electron microscope (FEI Company, USA) and a TriStar II 3020 gas adsorption analyzer (Micromeritics, USA). Sorption capacity was determined using a Nabi spectrophotometer (MicroDigital Co., Republic of Korea) based on the absorption of methylene blue from an aqueous solution. Results. Optimal cultivation conditions for maximum biomass yield and cellulose content were determined. It was found that freeze-drying produces a material with a high specific surface area and a developed porous structure, resulting in increased sorption activity. Conclusions. Bacterial cellulose, especially its lyophilized form, demonstrates high potential as an effective and biocompatible sorbent, as well as a promising carrier of active substances and medicinal preparations.

The widespread use of antimicrobial drugs, such as enrofloxacin, in poultry farming is associated with risks of residue accumulation in the products and the development of antimicrobial resistance, posing a serious threat to consumer health. Probiotics, particularly those based on Bacillus subtilis, are considered a safe alternative capable of not only maintaining bird health but also improving the nutritional characteristics of the products. The purpose of this article was to conduct a comparative assessment of the effects of enrofloxacin, probiotic B. subtilis, and their combination on the haematological and biochemical blood parameters in egg-laying hybrid chickens as key indicators of the metabolic and immune status. Materials and methods. The research was conducted on Hisex Brown cockerels from one day to three weeks old (n = 100). Four groups of chickens were formed: a control group, a group that received the probiotic B. subtilis, a group that was given enrofloxacin, and a group that received a combination of the two. Blood sampling for biochemical and haematological analysis was performed on days 1, 5, 10 and 20 of the experiment. Results. The group that received enrofloxacin demonstrated a significant decrease in total protein and bilirubin levels on day 5, indicating liver dysfunction. In the groups that were given the probiotic, an increase in total protein by day 20 and a positive dynamic in lipid metabolism were observed. On day 10, these groups showed a significant decrease in pseudo-eosinophil concentration and an increase in lymphocyte levels, indicating stimulation of specific immunity. The combined use of the probiotic with the antibiotic mitigated some of the negative effects of the latter. The use of B. subtilis helped stabilize the biochemical status, optimize lipid metabolism and activate the specific immune response in chickens, in contrast to the negative impact of enrofloxacin. The obtained data confirm the potential for using probiotics to optimize poultry farming in order to enhance product safety and quality.

The specific enzymatic activity of bacterial cultures illustrates the key applications of a studied strain of bacteria and the biological products based on it. The proteolytic activity of extracellular enzymes in the temperature range 20–45 and the activity of β-1,4-glucanase were studied, and the influence of pH and temperature on the activity and stability of the enzyme was revealed. The optimal cultivation conditions for the Lysobacter strain were selected for the highest production of β-1,4-glucanase: glucose, 1% by weight; yeast extract, 0.2% by weight; CMC, 0.75% by weight; pH 7; amount of inoculum, 3.5% by volume; optimal temperature for incubation, 30 °C. Enzyme stability results showed that the enzyme retained 90% of its activity after minimal preincubation at pH 5.5 and more than 60% of its maximum activity at pH 4–10, demonstrating stability over a wide pH range. More than 60% of β-1,4-glucanase’s enzymatic activity is observed in the range of 20–45 °C. Consequently, biocompositions based on Lysobacter sp. can be used in a wide range of temperatures and pH, which represents its promising use as a probiotic drug.