The main criteria for evaluating vaccines are their immunogenicity, specific activity, and safety. The aim of this work was to develop real-time PCR for the detection and quantification of viral nucleic acids in order to standardize the production conditions for an intranasal vaccine against respiratory diseases in newborn calves. Combinations of primers and probes (for each pathogen individually) were designed to identify a 97 bp region of glycoprotein G of the respiratory syncytial virus (RSV) located in the range from 4849 to 4945 bp; a 130 bp region of the PI-3 pathogen P-gene in the range from 2856 to 2985 bp; a 171 bp locus. In the region from 8271 to 8341 bp, a PKO was created and synthesized, which is a double-stranded DNA molecule (5618 bp) closed in a ring, containing a nucleotide sequence consisting of engineered primers and probes for the indication of IRT, PI-3 and IBR viruses. Using PCO, the optimal conditions for quantitative PCR-RV and the composition of the reaction mixture were determined. The minimum concentration of plasmid DNA at which successful amplification was observed was 5 pg/μL, which corresponded to a dilution of 10-10, with 826 plasmid DNA molecules per mL of solution. According to the results of amplification of the viruscontaining material, the following concentrations of pathogens were established: IBR – 0.7-1.5 million copies of DNA/ml, PI-3 – 0.1 -0.5 million copies of RNA/ml, and RSV – 20-80 thousand copies of RNA/ml. The developed method for determining the quantitative content of viral nucleic acids based on RT-PCR is a promising approach for the production of vaccines for the prevention of respiratory infections in young animals, as it ensures compliance with quality standards.

Maintaining the stable well-being of the country's livestock industry with respect to infectious disease epizootics is a crucial task for veterinary science and practice. It is of paramount importance in protecting the health and lives of animals and humans, providing the population with environmentally safe food products, and providing industry with high-quality raw materials. Antiepidemic measures should be developed taking into account the epizootic situation, obtained through the analysis of long-term data on the development of the epizootic process for each infectious disease in a specific area. We conducted a retrospective analysis of infectious pathologies in animals and birds based on an assessment of the epizootic situation and the scope of preventive measures in the region. Statistical processing of the data was carried out in accordance with generally accepted methods. To measure the epizootic manifestations of individual nosological forms and the nosological profile, we determined the population boundaries of the epizootic process and determined the incidence rate (the ratio of the number of sick animals to the total number of susceptible animals of the corresponding species, %; for birds, 0/0000). The study subjects were cattle, small ruminants, horses, pigs, and poultry. The volume of analyzed data on the diagnostics of infectious diseases of animals and birds for 2015-2023 amounted to 11,736,393 studies (cattle – 8,731,847, small ruminants – 597,365, horses – 639,947, pigs – 288,400, and poultry – 1,478,834). The structure of infectious diseases of animals was established, the leading nosological entities were: leukemia in cattle (1.49±0.25%, r=-0.943; p≤0.01), listeriosis in small ruminants, leptospirosis in horses and pigs (0.16±0.052%, r=0.14, p≤0.01 and 0.01±0.004%, r=0.09, respectively). In birds, the most common are Newcastle disease and Marek's disease.

This study presents a comprehensive analysis of the epizootic situation concerning anthrax and necrobacillosis in the Republic of Sakha (Yakutia) over an extended period from 1890 to 2014. The research incorporates data from long-term veterinary monitoring, archival materials, and field studies, encompassing disease dynamics, geographical distribution, and factors influencing the circulation of these dangerous pathogens. The results demonstrate the persistent endemicity of anthrax in the region, particularly among reindeer populations. During the study period, major disease outbreaks were recorded, with the most significant occurring in 1969, 1980, and 1993. Of particular epidemiological concern are unaccounted animal burial sites - of 285 registered anthrax burial grounds, only 75 have precisely identified locations. Spatial distribution analysis reveals distinct zonal patterns of epizootic activity, with highest risk in forest-tundra and mountainous areas. Parallel investigation of necrobacillosis epidemiology shows this disease causes substantial economic losses to reindeer husbandry. Over the last five years of observation, 48,138 cases were recorded with a 19.8% mortality rate. A clear seasonal pattern was established, with peak incidence in July-August correlating with activity periods of blood-sucking insects as potential disease vectors. The study demonstrates that systematic vaccination using modern preparations significantly reduces disease incidence. However, challenges persist regarding hard-to-reach areas and insufficient vaccination coverage of wild animal populations. These findings have important practical implications for developing sciencebased control measures against zoonotic infections in Arctic regions.

The intestinal microbiota of vertebrates is a complex biological system that plays a key role in metabolism and the formation of immune defense. Microbial communities decompose complex organic compounds, synthesize vitamins and ensure the stability of the internal environment of the body, closely interacting with its physiological processes. Thus, the intestinal microbiota directly affects the health of the host organism. The study of evolutionary relationships in the intestinal microbiota of broad whitefish (Coregonus nasus) by amplicon sequencing of the 16S rRNA gene contributes to an understanding of their trophic and competitive interactions in the host organism. The following methods were used in the study: NGS sequencing of the 16S rRNA gene in the V3-V4 and V4-V5 regions on the Illumina MiSeq platform in PE mode, as well as processing the obtained data using Trimmomatic v0.39, VSEARCH v2.21.1, MAFFT v7.505, FastTree v2.1.11 software. All analyses were performed on Python 3.10.6 using scipy, statsmodels, and biopython packages. The resulting phylogenetic trees demonstrate a high level of taxonomic differentiation, reflecting both recent evolutionary divergences (characterized by short branches and high node support) and ancient divergences supported by significant branch lengths in certain clades. Such organization indicates multiple radiations within bacterial taxa due to adaptation to different ecological niches, which indicates the complexity and interconnectedness of microbial communities in the studied samples. The high phylogenetic diversity of the detected taxa, including the presence of OTUs classified as Candidatus or belonging to poorly studied groups, highlights the insufficient study of the freshwater fish microbiota in existing databases.

With the rapid growth rate of the turkey breeding industry and the emergence of new viral diseases, we have to face the problem of the lack of diagnostic kits and methods of specific prevention of these diseases in Russia. The most common and economically dangerous immunosuppressive disease is hemorrhagic enteritis of turkeys. There are no kits available for the diagnosis of the GEI virus in Russia, which is why the purpose of our work was to develop a serological diagnostic method using the latex agglutination reaction as an example. 4 groups were created with the difference that different buffer solutions were used for diluting and washing latex, different types of latex, their size, as well as the type of purification of the globulin fraction (the first method using PEG 6000, and the second by precipitation of the globulin fraction with ammonium sulfate followed by dialysis). After deposition of the globulin fraction on latex microspheres, according to the method described in the article, checks were carried out in the following way: latex diagnosticum in a volume of 50 ml was dripped onto plastic and a supernatant of homogenate of turkeys infected with the GEI virus was added to it, and 50 ml of latex diagnosticum was dripped with the addition of a supernatant of homogenate of spleens of uninfected turkeys. The ingredients were mixed using a wooden stick and waited 10 minutes to account for the reaction. After taking into account the reaction, it was concluded that the best modification of latex is carboxylated with a diameter of 200-400 nm, the best buffer is tris-salt, and the best dilution of the globulin fraction is 1:2-1:16.

Goose parvovirus (PG) remains a global problem in poultry farming. For this reason, it is necessary to develop a new diagnostic approach that will be simpler and faster than traditional tests, while revealing the breed and age predisposition. We conducted a serological study among geese of different ages of the "Linda" and "Large Gray" breeds for the presence of specific antibodies to the pathogen virus PH after immunization with a live strain of the LIV-22 vaccine. The method of enzyme immunoassay (ELISA) was used to assess the intensity of humoral immunity. Today, ELISA has advantages such as simplicity and speed of work, and also allows you to examine a large number of samples at the same time. However, the method we used has so far been used to determine the level of antibodies in samples without making a relationship between the breed and the age of the bird. Based on the latter, this study has wide practical significance, as it allows for a more detailed study of the nature of the spread of the virus. A series of studies have proven a direct link between the level of antibodies and the age and breed characteristics of the geese. It was found that the older bird shows higher indices of the arithmetic mean titer of antibodies in comparison with the young. The latter allows us to conclude that it is advisable to take a differentiated approach to preventive measures and vaccination, taking into account the characteristics of each specific group of birds, based on their breed and age. The results obtained are the basis for the development of the most optimal vaccination schemes and recommendations for improving the sanitary and hygienic conditions of poultry keeping, contributing to reducing the risk of outbreaks of viral enteritis in geese.

In the conditions of intensive development of turkey farming, the range of relevant infectious diseases is also expanding, timely diagnostics and prevention of which prevents significant economic losses of poultry farms. Hemorrhagic enteritis of turkeys is an acute highly contagious viral disease of turkeys and pheasants, characterized by gastrointestinal bleeding, necrosis of the spleen, diarrhea and sudden death. The virus of hemorrhagic enteritis of turkeys, in addition, causes immunodepression, which increases the susceptibility of turkeys to bacterial (Escherichia coli, Ornithobacterium rhinotracheale) and viral infections, which also leads to economic damage. Literary sources were reviewed in Russian and international citation databases using keywords related to hemorrhagic enteritis in turkeys, marbled spleen disease, and adenovirus splenomegaly in chickens. The review included research published between 1993 and 2020, as well as information from a 1937 article that first reported data on hemorrhagic enteritis in turkeys. In the Russian Federation, hemorrhagic enteritis of turkeys and related infections are poorly studied, and specific preventive measures have not been developed. Information on the biological properties of pathogens, epizootological features of the course of hemorrhagic enteritis in turkeys and related infections, diagnostic methods and specific prevention methods will help veterinary specialists in ensuring epizootological well-being for these infections. The effectiveness of measures when the disease occurs depends on timely diagnosis. The correctness of sampling pathological material that must be sent to the laboratory for isolation and identification of the pathogen directly affects the speed of research and their reliability. The purpose of this article was to present modern information on hemorrhagic enteritis in turkeys and related infections, such as marbled spleen disease in pheasants and adenovirus splenomegaly in chickens.

The article presents the results of the study of enterobiocenosis, biochemical parameters of blood serum and immune response of chickens under the influence of the symbiotic drug Biosib© PRO in experimental colibacillosis. Four groups of chickens were formed with 10 heads in each: Group I (positive control group), Group II (negative control), kept on a basic diet, Group III (experimental symbiotic) and Group IV (using an antibiotic). At the age of 16 days, experimental infection with E. coli O78 culture was carried out. To study the dynamics of enterobiocenosis, bacteriological and proteomic (MALDI-TOF) research methods were used, hematological, biochemical and immunobiological tests were carried out according to generally accepted methods. The studies showed that the use of the symbiotic in the experimental group of chickens contributed to the cessation of clinical signs of the disease on the 4th day, while in the group where the antibiotic was used, they continued for 5 days. When studying the parietal enteromicrobiocenosis in broiler chickens of experimental groups after infection with the E. coli O78 culture, the original culture was detected in 72.4% of cases in groups I and IV, while in birds of group III, E. coli O78 was detected in 30% of cases. In broiler chickens of experimental groups, I and IV after oral administration of E. coli, the frequency of detection of bifidobacterial and lactobacilli significantly decreased. In group III, the species and quantitative composition of other representatives of the microbial community of the small intestine did not change significantly. Against the background of the use of the symbiotic, an increase in the total number of erythrocytes, hemoglobin, in the blood serum - an increase in the total amount of protein, albumin, bactericidal, lysozyme and phagocytic activity, as well as an increase in live weight compared to birds that did not receive the drug were noted in experimental chickens.

The aim of the work was to study the features of cultivation and determination of the infectious activity of the respiratory syncytial virus strain "RB23" for the further creation of a live attenuated importsubstituting vaccine against IRT, PG-3 and RSV for nasal immunization of newborn calves. The quality of replication on cell lines was carried out by assessing infectious titers by the direct cytopathic effect of the virus on mammalian cells, and also using the stained foci method. The degree of RSV replication on the LEC cell culture depending on the cultivation time was determined by the quantitative PCR method. It was shown that LEC and T-1 cells are permissive for RSV. Moreover, the sensitivity of LEC cells exceeded the sensitivity of T-1 cells by 1.96, 1.88 and 7.69%, respectively, in three consecutive passages. Changing the MEM medium with the addition of glutamine during RSV cultivation on the 4th day contributed to an increase in replicative activity by 8.6% compared to flasks in which the medium was not changed. It was also noted that the optimal period for RSV cultivation is seven days, further cultivation leads to the degradation of extracellular viral particles, which reduces the concentration of virions by 26.5-40.0%. The RSV biomass "RB23" has been produced for further development of a live attenuated import-substituting vaccine against IRT, PG-3 and RSV for nasal immunization of newborn calves with an infectious RSV titer of 4.75±0.18 lg TCID ₅₀/cm³, a FFU titer of 1.5x10⁶ FFU/cm³ and a virion count in a virus-containing suspension of at least 4.5±0.20 million  copies/ml.

Infectious bursal disease and infectious anemia of chickens are significant and pressing problems in the modern poultry industry. The infectious bursal disease virus (IBDV) and chicken infectious anemia virus (CIAV) are highly prevalent, causing severe damage to lymphoid organs and tissues. This results in significant immunosuppression, increasing poultry susceptibility to secondary infections, reducing production performance, diminishing the efficacy of preventive measures, and raising economic losses. Currently, these diseases primarily occur in subclinical forms, against a vaccine-induced immunity background, and in co-infections. They are often accompanied by secondary infections and lack distinctive clinical signs, complicating diagnosis. We developed a multiplex real-time PCR assay for simultaneous detection of both viruses in a single sample. The assay employs primers targeting highly conserved overlapping regions of the IBDV and CIAV genomes, with TaqMan probes for detection. Analytical sensitivity testing using 10-fold serial dilutions confirmed high coefficients of determination and amplification efficiency. The assay demonstrates high specificity, with no cross-reactivity or nonspecific amplification. Its performance metrics (determination coefficients, reaction efficiency, and low intra- and inter-assay variability) are comparable to single-assays for IBDV and CIAV. The multiplex format significantly reduces processing time, minimizes contamination risks, and maintains high sensitivity and specificity. This PCR assay is expected to enable rapid and accurate identification of IBDV and CIAV, greatly improving diagnostic efficiency.

In the Republic of Karakalpakstan, the epizootic situation regarding blood-parasitic diseases in cattle has not yet been adequately studied. Blood-parasitic diseases in cattle are seasonal and coincide with the period of tick activity, that is, the warm season. According to A.G. Gafurov (2002), a high prevalence of ixodid ticks has been observed in all municipal districts of the republic in recent years. This article investigates the epizootiological status of theileriosis in cattle in the northern regions of the Republic of Karakalpakstan. The study examines the carrier state of blood-parasitic disease pathogens in cattle, as well as the fauna of ticks that serve as vectors of these diseases. Blood smear samples were collected from infected animals and analyzed. The results of the study revealed that Boophilus calcaratus ticks were not found in the surveyed areas, whereas Hyalomma anatolicum — the main vector of cattle theileriosis — was identified with a prevalence of up to 61%, and Hyalomma detritum up to 39%. Among 567 head of cattle examined in farms located in the Khodjeyli, Buzatov, and Nukus districts, 67 animals (11.8%) were diagnosed with theileriosis. Parasitological analysis of blood smears from cattle in the "Islambek-Zaynab" farm (Khodjeyli district), among rural residents of the Nukus district, and in the "Shakhamanly Asadbek" farm (Buzatov district) showed the presence of theileria pathogens in 22.2% of the animals. It was also established that the first recorded outbreak of theileriosis in the northern regions of the republic occurred at the end of May (3.3%), with the peak incidence observed in July (7.6%).

The article presents an analysis of the epizootiological situation regarding parasitic infections in goats across four family farms and one personal subsidiary farm in several districts of Leningrad Oblast (Luga, Sestroretsk, Gatchina) and Pskov District in Pskov Oblast. A total of 127 goats of various age groups and breeds (Alpine dairy, Saanen, Czech brown, Russian brown, Nubian) were examined. Using the Darling flotation method with a universal flotation solution and the Berman-Orlov helmintholarscopic method, no helminth or protozoan infestations were detected in the goats from the family farms in the Luga district and the personal subsidiary farm in the Sestroretsk district of Leningrad Oblast. Regular deworming and the establishment of a proper management and feeding system for the animals in these farms have achieved stable and effective control of infestations. In two farms in the Gatchina district of Leningrad Oblast and in the family farm in Pskov district of Pskov Oblast, infestations of goats with helminths and protozoa of the genus Eimeria were found. In the family farm in Gatchina district, the Eimeria infection rate varied from 73.3% to 100%. For goats aged up to two years, the infection intensity reached up to 1710 oocysts per gram of feces. The identified oocysts varied in size and shape, indicating an infestation by several species of this genus of coccidia. Using the Berman-Orlov method, larvae and eggs from the genera Strongyloides and Mullerius were detected, as well as in one of the farms, lung strongyles of the genus Dictyocaulus. In the family farm in Pskov district, the extent and intensity of Eimeria infestation in goats were lower than in the farms of Leningrad Oblast (extent 26%, intensity up to 342 oocysts per gram of feces); however, all animals were infested with nematodes. In the fecal samples from goats, free-living nematode larvae from the genus Strongyloides were found, as well as eggs and larvae of gastrointestinal strongyles. To develop scientifically grounded measures to combat parasitic diseases in private farms, it is essential to regularly conduct an analysis of the parasitic situation, which includes studying the qualitative and quantitative composition of the parasite fauna, their distribution patterns in biocenoses.

Cases of D. renale infection have been reported in Russia, but they are relatively rare. The species D. renale reaches a length of up to 1 meter in females and affects, as a rule, the right kidney of carnivorous, wild and domestic mammals. The disease is characterized by damage to the kidneys, renal pelvis and general intoxication of the body. This article describes a clinical case of diagnosis of dioctophimosis and treatment of a 3-year-old dog brought from the Republic of Kazakhstan to Moscow. The dog was admitted to a veterinary clinic in December 2024 with signs of urinary retention and the presence of blood in it. To clarify the diagnosis, laboratory tests were performed, which included a general urinalysis, general and biochemical blood tests, as well as an ultrasound examination of the kidneys. The results of the blood test showed impaired kidney function. Urine analysis revealed hematuria, as well as eggs of D. renale helminths. An ultrasound examination of the kidneys was performed, which confirmed the presence of helminths in the renal pelvis. The diagnosis of dioctophimosis is confirmed by the results of a lifetime laboratory diagnosis – photographs of characteristic eggs of the parasite. The patient was prescribed fenbendazole and ivermectin as anthelmintic drugs. The only treatment for dogs with dioctophimosis is surgery and removal of the dioctophyma from the affected organ (kidney). The ultrasound data, which confirmed the presence of sexually mature D. renale worms in the right kidney, served as the basis for unilateral nephrectomy. The operated patient's condition is satisfactory, and the prognosis after surgery is favorable.

The aim of this study is to identify the current species composition of helminths in carnivorous mammals in Uzbekistan, the pathways of parasite community formation, and the ecological characteristics of epizootologically significant species. This study also aims to substantiate the ecological and epizootological foundations for the prevention of parasitic diseases in animals. The material for this study was parasitofaunal collections from domestic and wild Carnivora carnivores from various regions of Uzbekistan. The trophic and ecological relationships between helminths and their carnivorous mammal hosts Canidae, Mustelidae, and Felidae of Uzbekistan were studied. The species diversity of helminths in domestic and wild carnivores has been established. The faunal composition of helminths in the studied carnivorous mammals is represented by four main taxonomic groups: Cestoda, Trematoda, Acanthocephala, and Nematoda, comprising a total of 70 species. Taxonomic analysis revealed a clear gradation based on the degree of host infestation: the highest species richness of helminths is characteristic of the Canidae family, with 51 species, followed by the Felidae family with 40 species, while the Mustelidae family exhibits the least diversity, with 35 species. Within families, the highest parasite species diversity was recorded in the fox (Vulpes vulpes) with 42 species and the domestic dog (Canis lupus familiaris) with 32 species. In contrast, the lowest values were observed in the weasel (Mustela nivalis) and otter (Lutra lutra). Based on their biological cycle, the helminths we recorded are classified as homoxenous (10 species) and heteroxenous (60 species). Oligochaete species, mollusks, crustaceans, and insects have been identified as intermediate hosts for carnivorous helminths. Helminth species of epizootological and epidemiological significance have been identified.

The fight against obstetric and gynecological diseases in cattle, in particular endometritis, is an important link in the system of measures for the improvement of livestock. At the same time, the development of effective complex means and methods of treatment and prevention of endometritis is an urgent task of veterinary medicine. The study of animal tolerance of the target species and the identification of a set of morphological and functional disorders in the use of newly created drugs is an integral part of the preclinical study of drugs and allows us to conclude that further laboratory and industrial tests can be performed. This article presents results of studying the tolerability of the original drug «Endoseptam» for the treatment and prevention of obstetric and gynecological diseases in cattle experiments. The studies included conventional clinical, hematological, and microbiological methods. To conduct the experiments, three groups of healthy lactating cows were formed, with 6 animals in each: the first served as a control, the cows of the second group were intrauterinely injected with the drug "Endoseptam" in a therapeutic dose (100 ml four times with an interval of 24 hours), the animals of the groups were injected with the drug in a dose of 300 ml four times with an interval of 24 hours. It was found that when using the drug «Endoseptam» at a therapeutic dose and three times its maximum, there was no negative effect on the body, in particular morphological and functional disorders, thus «Endoseptam» has no general toxic effect, is safe and well tolerated by animals of the target species.

Over the past decade, research has been directed to reduce the development of microbial resistance. However, even with strict regulation of the use of antimicrobial drugs, the problem of resistance remains. The problem of the emergence of resistant strains that can be transmitted to humans is also increasing, especially with consuming animal products. The above facts are becoming a problem in the fight against such a disease as mastitis, the treatment of which is based on the use of antimicrobial drugs. As a result, research aimed at studying the sensitivity of mastitis pathogens in cows to antibacterial drugs and the development of approaches to prevent antibiotic resistance spread is relevant. The work was carried out in the period 2023-2024 in the Sverdlovsk region. For microorganism identification a cultural method and MALDI-TOF (mass spectrometry) were used, and sensitivity to antibacterial drugs and disinfectants was also determined using the disk diffusion method in accordance with EUCAST recommendations. For detection of microorganism’s DNA and resistance genes to antimicrobial drugs PCR diagnostics were used. The studies revealed the dominant causative agents of mastitis in cows were S. aureus (100%), E. coli (70-75%), E. faecalis/faecium (60%). The main resistance genes were determined in E. coli isolates – blaCTX-M, blaOXA-10 responsible for resistance to fluoroquinolones, ampicillins; S. aureus – mecA associated with resistance to β-lactams; Streptococcus spp. and Staphylococcus spp. ErmB – resistance to macrolides; P. аeruginosa blaVIM/blaNDM – resistance to carbapenems. Based on the data obtained, recommendations were given for the implementation of preventive measures on hygiene and disinfection, control of resistance of identified bacterial isolates, herd management, milking optimization, and environmental control on farms.

Phytobiotic feed additives have promising potential in the feeding of farm animals, providing improved health and productivity. These compounds have a variety of effects, including antioxidant, anti-inflammatory, antibacterial, and anti-QS. Thus, phytobiotics may represent a potential tool for the treatment and prevention of infectious diseases of farm animals. However, hepatotoxicity is a significant side effect of some of them, so more detailed studies are needed to safely use these compounds as feed additives, including dose, bioavailability, metabolic interactions, and risks associated with long-term exposure. The purpose of this research was to evaluate the toxicity of two phytobiotic compounds, 7,8-dihydroxy-4-methylcoumarin and vanillic acid, using a recombinant luminescent strain of Escherichia coli K12 MG1655 pXen7 and a representative ciliated protozoon, Stylonychia mytilus. These two test organisms are commonly used to assess the overall toxicity of feeds. The results of the study showed differences in the toxicity levels of the two compounds when tested using both organisms. Vanillic acid exhibited higher toxicity than 7,8-dihydroxy-4-methylcoumarin. For the bacterial biosensor, complete suppression of luminescence was observed at maximum concentrations (0,0125 and 0,125 M). For Stylonychia, instant cell lysis was observed across the entire concentration range after one hour of exposure. In contrast, 7,8-dihydroxy-4-methylcoumarin showed a lower toxic effect, with the toxic effect only manifesting itself at high doses and disappearing with a decrease in concentration. However, after three hours of exposure for Stylonychia mytilus, a toxic effect was still recorded at all remaining experimental sites. These results emphasize the need for careful monitoring of phytobiotic use in animal feed and highlight the importance of further research on these feed additives.

Deltamethrin is widely used in agriculture and veterinary medicine. In recent years, data have begun to appear in the scientific literature on the effect of deltamethrin and other synthetic pyrethroids on the reproductive system and, in particular, on the quality of seminal fluid. However, the mechanisms of development of these disorders are not fully understood. The purpose of this work is to determine the triggers of oxidative stress in reproductive organs of rats exposed to deltamethrin. The study was conducted on 48 male laboratory rats with a body weight of 230-250 g. Metabolic changes in the testes after a single administration of deltamethrin at a dose of 17.4 mg/kg body weight (1/5 LD50) were assessed after 1 and 3 days. The evaluation criteria were the content of pyruvic, lactic and uric acids, inorganic phosphate (Pi), glutathione, malondialdehyde (MDA), the activity of glutathione peroxidase (GPx) and glutathione reductase (GR) in the organs of the reproductive system. The obtained results were subjected to statistical processing. Administration of deltamethrin to laboratory rats at a dose of 1/5 LD 50 causes changes in metabolism in the reproductive organs: testicles, epididymis, prostate gland and seminal vesicles. After 1-3 days, an increase in the content of lactate, pyruvate, urate, Pi, and MDA in the rats' organs was noted. This indicates a violation of energy metabolism and increased lipoperoxidation processes, which leads to a decrease in glutathione levels. Glutathione deficiency is aggravated by the increased activity of antioxidant enzymes (GPx and GR). The trigger mechanism for the development of oxidative stress in the organs of the reproductive system is the disruption of energy metabolism caused by the deep catabolism of purines to uric acid. This process is accompanied by increased generation of free radicals and depletion of the pool of non -enzymatic antioxidants. A decrease in the function of the antioxidant system against the background of MDA accumulation in the organs of the reproductive system indicates the development of oxidative stress.

The high demand for animal feed protein stimulates research into technologies that allow obtaining alternative high-quality protein substrates that are highly nutritious and meet safety requirements. The most promising objects for protein production are black soldier flies (Hermetia illucens L.), for the cultivation of which it is effective to use livestock and poultry waste. The aim of the study was to investigate the subchronic toxicity of protein-lipid meal obtained by processing biological waste of poultry farms using black soldier flies on laboratory animals. The studies were conducted on white laboratory mice, which were fed 1000 mg/kg, 200 mg/kg and 100 mg/kg of proteinlipid meal for ninety days. It was found that with free oral administration (with palatability control) of protein-lipid meal obtained as a result of processing biological waste of poultry farms using H. illucens in all tested doses, no changes in the general and clinical condition of laboratory animals were noted. By the ninetieth day of the experiment, an increase in the body weight of the experimental animals by 5.8-26.9% of the initial was recorded. Death of animals was recorded in all experimental groups. Over the entire observation period, 18,6% of animals from the experimental groups dropped out of the experiment, of which 85,7% died for reasons related to feeding due to acute intestinal dilation and necrotic nephrosis. After the completion of the experiment, 12.5% of the mice were found to have leukocyte infiltration of the glandular part of the stomach. No dependence on an increase in the dose of the obtained product was established. Pathomorphological changes associated with feeding were recorded in 13.6% of mice receiving protein-lipid flour at a dose of 1000 mg/kg, in 15,0% of mice receiving 200 mg/kg and in 31.0% receiving the product at a dose of 100 mg/kg.

Chitosan and its derivatives are also used in pharmaceuticals as an excipient, a carrier of a drug or a therapeutic agent. The study was conducted on the basis of the Department of Biochemistry and Physiology of the St. Petersburg State University of Veterinary Medicine. A systematic review of the literature on toxicological studies of chitosan (in vitro and in vivo) was performed. The aim of this study was to test the safety of a feed additive containing chitosan using bioassay methods for general toxicity. An experimental sample of a feed additive was developed based on burnt diatomite (0.3-0.7 mm) and a concentrate of water-soluble chitosan. Toxicity during repeated administration in vivo. The general toxicity and acute toxicity of Danio rerio were determined in accordance with GOST 31674-2012 "Feed, compound feed, and feed raw materials. Methods for determining general toxicity." The infusoria were kept in a Lozin-Lozinsky medium prepared according to GOST 31674 -2012. The effect of the aqueous extract on the test system was evaluated in microaquaria using immunological plates. Survival control was performed using a light microscope at a magnification of 100x. Observations were made in both the control solution and the aqueous extract 30 minutes, 1 hour, 2 hours, and 3 hours after the start of the experiment. The biotesting was performed with double repetition for each sample. The survival rate of ciliates after 3 hours in an aqueous extract of the undiluted sample is 83%; the survival rate of ciliates after 3 hours in an aqueous extract of the diluted sample is 83%. The results of the studies showed that the presented sample of a feed additive containing chitosan and diatomite is non-toxic (harmless). The article also discusses possible mechanisms of the toxic effect of chitosan and recommendations for safe use in veterinary medicine.

Hepatotoxicants are chemical compounds capable of selectively damaging the liver, which can lead to impairment of its metabolic, detoxifying, and excretory functions. Currently, the search for reliable biomarkers for the early diagnosis of hepatotoxic conditions, especially latent ones, is a pressing issue. The aim of this study was to evaluate the effects of various modern hepatotoxicants on sorbitol elimination in laboratory rats. Representatives of different chemical classes were used as model hepatotoxicants: carbon tetrachloride (CCl₄) as a classic hepatotoxicant, paracetamol (acetaminophen) at a hepatotoxic dose, and the industrial toxicant Nnitrosodimethylamine (NDMA). Experiments were conducted on sexually mature male and female Wistar rats (n=48). Hepatotoxicity was induced by a single administration of toxicants at established doses. Twenty-four hours after intoxication, animals were administered sorbitol intraperitoneally at a dose of 500 mg/kg. Blood samples were collected to determine plasma sorbitol concentrations at 0, 30, 60, 120, 240, 360, and 480 minutes after administration. The results showed that all studied hepatotoxicants significantly delayed sorbitol elimination compared to the control group, but with different pharmacokinetic profiles. The most pronounced inhibition of sorbitol clearance was observed with CCl₄ intoxication, characterized by a prolonged half-life (T₁/₂) and a high area under the concentration-time curve (AUC). Paracetamol intoxication resulted in a moderate delay in elimination, while NDMA caused a biphasic change in plasma sorbitol levels with a period of initial slow elimination followed by a secondary rise in concentration, probably related to impaired enterohepatic circulation.

The aim of this study was to conduct a comparative correlation analysis of the pharmacokinetic parameters of exogenous sorbitol in clinically healthy laboratory rats and cattle to assess the degree of similarity or difference in its elimination and distribution, which forms the basis for substantiating (or refuting) the possibility of creating cross-species diagnostic models. Correlation analysis is a key method in veterinary pharmacology, allowing for the evaluation of relationships between pharmacokinetic parameters and organ function in animals. This study examined the correlations between the pharmacokinetic parameters of exogenous sorbitol in clinically healthy laboratory rats and farm animals (cattle). Sorbitol plasma concentration, total plasma clearance, mean residence time, and volume of distribution were analyzed. Parametric (Pearson correlation coefficient) and nonparametric (Spearman rank correlation coefficient) methods were used for statistical analysis. The results showed no consistent correlations between species or between males and females, indicating significant interspecies and individual differences in sorbitol metabolism. These data highlight the need to consider species-specific characteristics when using sorbitol as a marker for assessing hepatobiliary function. Further research across a wider range of animal species is required to develop universal diagnostic models. Thus, this study makes a significant contribution to understanding the principles of species-specific pharmacokinetics and serves as an important caution against the simplistic cross-species transfer of diagnostic methods. Its findings provide the basis for a more balanced, differentiated, and, consequently, more effective approach to assessing hepatobiliary function in animals of various species in clinical and scientific veterinary practice.

The article presents the results of determining the protein, fat, and water content in the muscle tissue of caged fur–bearing animals – ferrets and minks - in the context of their potential use as raw materials for the production of such feed products as protein hydrolysate. The aim of the work was to compare the chemical composition and determine the possibility of using a nondestructive express method of infrared spectrometry in the near range to predict the mass fraction of protein, mass fraction of fat and mass fraction of water in the meat of furbearing animals. Chemical analysis of muscle tissue samples of fur-bearing animals was carried out according to generally accepted methods. Significant interspecific differences in the mass fractions of water, protein, and fat have been established. The largest mass fraction of protein was recorded in ferret meat (21.5±0.8%), while mink meat was characterized by the maximum mass fraction of fat (12.8±1.2%). Based on chemical analysis data using a diffuse reflection NIRS spectrometer, calibration models were developed to quickly determine these indicators. Validation of the models showed a high accuracy of the forecast: the coefficient of determination for the mass fraction of protein was 0.98, for the mass fraction of fat – 0.99, for the mass fraction of water – 0.97. The data obtained indicate the high nutritional value and promising use of products from the slaughter of fur-bearing animals in the feed industry for the production of protein hydrolysates. The method of infrared spectrometry in the near range is recommended for implementation in the system of operational quality control of raw materials at enterprises producing feed products.

The bactericidal properties of copper have been known for a long time. The general trend of displacing antibiotics from industrial livestock farming prompted us to search for and create new additives with bactericidal properties. We have developed and patented the feed additive adsorbent of mycotoxins of double action "Cu-Active". Our goal was to conduct a comparative analysis of various copper-containing feed additives according to the declared copper level indicators, as well as their effect on the sensitivity of opportunistic and pathogenic microorganisms. Samples of various additives with an essential microelement were purchased in the retail network, and therefore available to consumers. To avoid advertising and anti-advertising, the article specifies only the tested form of copper and the country of manufacture, the manufacturer is not specified. When performing in vitro work, we were guided by approved standard methods. We studied the comparative effect of 5 copper-containing additives in various concentrations and forms of application. All tested additives showed a high degree of copper concentration as an active substance. The standard deviation did not exceed the standard values and fluctuated within the range of 0.67-3.93%. The additive we created, “Cu-Active”, had the highest concentration of the microelement and showed 1.7-5.9 times better results compared to other additives. We have reliably established that chelated forms of copper have virtually no effect on the zone of growth inhibition of microorganisms, while sulfate forms of copper-containing compositions, especially in dry form, have a medium and high degree of sensitivity to growth inhibition of various test microorganisms (Salmonella enterica, Klebsiella pneumoniae, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa). It has been proven that the dualaction mycotoxin adsorbent additive we created is not inferior to imported analogues in terms of the range of results obtained and has a high competitive advantage.

The functional load and stress during transportation of animals for slaughter is accompanied by an increase in the energy needs of the body, which can eventually lead to a deterioration in the condition of the animal and a decrease in the quality of meat obtained from it. In this study, to assess the clinical and functional state of the animal before slaughter, the indicators of pig energy exchange were determined under the influence of the functional transport load, which was a metered irritant (damaging factor). The study was conducted under production conditions on 90 healthy Latvian White pigs, aged 6-9 months and weighing 80-100 kg. During the study, the animals were exposed to damaging factors prior to slaughter to determine their ability to withstand physical and stressful conditions during transport and at the slaughterhouse. The results obtained made it possible to evaluate the dynamics of changes in energy exchange indicators before transportation, after delivery to the slaughterhouse and 1 hour before slaughter, to conduct a comparative analysis of glucose levels, lactic acid concentrations in the blood, and changes in the level of buffer base deficiency in the blood under the influence of functional load of varying severity during transportation to the slaughter site. The time allowed for the experimental animals to rest did not fully restore the energy exchange indicators after the load to the initial level. The study established a tendency to decrease aerobic energy production in animal muscles as the transport load increases before slaughter, which reduces the content of acids and glycogen in muscle tissue. As a result, conditions are created that promote the development of microorganisms in meat, which negatively affects its safety. At the same time, the nutritional value of meat raw materials is deteriorating, which is characterized as DFD (dark, firm, dry) meat.

Fusarium fungi are widely distributed in nature and produce the most toxic mycotoxins: T-2 toxin, diacetoxyscirpenol, nivalenol, deoxynivalenol, zearalenone, fumonisins, and moniliformin. Although fusariotoxins are commonly present in food and feed, their combined effects are still poorly understood. However, their possible interactions can potentially lead to antagonistic, additive, or synergistic effects. The purpose of this study was to evaluate the biochemical parameters of the blood serum of white rats under the combined effect of fumagillin (T-2 toxin, deoxynivalenol, zearalenone, fumonisin B1). The experiment was conducted on 60 white rats (weighing 119-125 g at the beginning of the experiment), divided into 10 groups based on the principle of analogues. The first group was a biological control, the second received a feed containing T–2 toxin at a dose of 0.1 mg/kg (at the MPC level), the third received a feed containing fumonisin B1 at a dose of 5.0 mg/kg (at the MPC level), the fourth received a feed containing deoxynivalenol at a dose of 1.0 mg/kg (at the MPC level), the fifth group is a feed containing zearalenone at a dose of 1 mg/kg (at the MPC level), the sixth is a feed containing a mixture of mycotoxins two times lower than the MPC), the seventh is a feed containing a mixture of mycotoxins 25% lower than the MPC), the eighth is a feed containing a mixture of mycotoxins in within the maximum permissible concentration), the ninth is a feed containing a mixture of mycotoxins 25% higher than the maximum permissible concentration), the tenth is a feed containing a mixture of mycotoxins 50% higher than the maximum permissible concentration). The combination of deoxynivalenol, T-2 toxin, zearalenone, and fumonisin B1 reduces the content of protein, triglycerides, and glucose, and increases the content of bilirubin, the activity of aminotransferases, alkaline phosphatase, and gammaglutamyltransferase.

In industrial broiler farming, biologically active preparations are increasingly being used to increase the growth and development rates of poultry. The article presents the results of studies on the dynamics of the histological structures of the cervical part of the esophagus in Ross-308 broiler chickens during the period from the beginning of the rearing process to the technological slaughter period, using domestic feed additives (Kovelos-Sorb enterosorbent and Ecostimul-2 bioflavonoid) in addition to the main feeding regimen. Chicks in groups 1, 2, and 3 received Kovelos-Sorb at doses of 0.1-gram, 0.14 gram, and 0.18 gram per 1 kg of live weight per day, and Ecostimul-2 at a dose of 1 milligram per 1 kg of live weight per day. The experiment was conducted at the Department of Normal and Pathological Morphology and Physiology of Animals at the Bryansk State Agrarian University. The research method included the preparation of thin histological sections and the micrometry of the mucous, muscular, and adventitious layers, as well as the submucosal base of the cervical region. Dynamic changes were recorded every 10 days. The results of the micrometry were statistically processed and analyzed. As a result of the experiment, we noted that the bioadditives introduced into the main broiler diet had a positive effect on the histometric indicators of the thickness of the esophagus wall, both in general and in its layers, especially the submucosal base, as well as on the number and diameter of the glands of the submucosal base, in the direction of increase. The prevalence of micrometric structures was recorded in the birds of the experimental groups, especially the third group, in comparison with the control group, which indicates the stimulating effect of the applied additives on the development of the cervical part of the esophagus. An increase in the number of glands in the microscope field of view and the diameter of the submucosal glands in the experimental groups of broilers indicates a more active process of mucus secretion and its interaction with the feed than in the control group.

The purpose of the study is to examine the morphofunctional indicators of blood and the dynamics of weight-growth indices of chickens when using the Ergamin amino acid complex. Two groups of day-old roosters of the Highsex-Brown cross were formed: a control group and an experimental group. The birds in the control group received a balanced main diet. For the chickens in the experimental group, the Ergamin amino acid complex was added to the main diet at a dose of 10 g/l for the first ten days of life. Blood samples were collected on the first, third, fifth, seventh, and ninth days after the feed additive was discontinued. The chicks were weighed and their body length was measured every two days until they reached 25 days of age. The results were used to calculate weight and growth indices, including absolute body weight gain, relative body weight gain, specific body weight growth rate, and body mass index. The analysis of hematological blood parameters indicates that the feed additive does not have a negative effect on the physiological state of the chicks when administered at a dose of 10 g/L during the first ten days of life. There is no inhibitory effect on the respiratory function of the blood, and there is a slight increase in the levels of hemoglobin and red blood cells in the blood. The studied white blood cell parameters indicate that the amino acid complex does not have a negative impact on the immune system of the chicks. The use of the feed additive does not lead to intoxication or inflammation in the experimental group of animals. By the end of the experiment, the weight of the chickens that received Ergamin was higher than the control values, on average, by 2.8%.

Guinea pigs are prone to connective tissue pathologies, the most common are: geriatric arthrosis of the pelvic extremities, nutritional deficiency of calcium, osteodystrophy caused by hyperparathyroidism. Also, pigs with shiny fur, possessing the "satin" gene, are predisposed to pathologies of connective tissue. The presence of this gene, by the end of the first year of life, causes pathologies of dense fibrous connective tissue in guinea pigs, as well as osteodystrophy, the combination of the above pathologies in guinea pigs with the satin gene was called satin pig syndrome. The aim of the study was to establish the structural features of the pelvic limb and determine the values of the acetabular angle in clinically healthy guinea pigs and in pigs with suspected connective tissue pathology (chondro- and osteodystrophy). Guinea pigs of different ages served as the material for the study, the average weight was 700-800 grams. Research methods: fine anatomical dissection, radiography, computed tomography. The acetabular angle was determined in the RadiAnt program. An analysis of the data obtained showed that measurements of the acetabular angle in guinea pigs demonstrate a clear age dynamic and a high diagnostic value of this radiometric indicator. In healthy animals, the angle increases with age: in young individuals (up to 1.5 years old) Its values average 63.07-65.05°, whereas in adults (from 1.5 to 4 years old) the angle increases to 66.17-69.39°. However, the most significant changes are registered in pathologies of the musculoskeletal system, where the acetabular angle, on the contrary, becomes more acute. Thus, in guinea pigs with suspected hyperparathyroidism, the angle decreases sharply, varying between 49.32-57.92°, which is accompanied by a decrease in the radiological density of the pelvic and limb bones, which is characteristic of skeletal demineralization. An even more pronounced tendency to "sharpen" the angle is observed in satin pig syndrome (30.22-36.56°) and, especially, in geriatric animals (26.44-31.12°). In the latter, in addition to the sharpest angle, radiologically there is an increase in the contrast of the interarticular fissure, and clinically there is a characteristic setting of the pelvic limbs running craniolaterally.

Despite a significant amount of research on the digestive system of birds, grouse, which includes the, remain insufficiently studied in this context. One of the characteristic features of the digestive physiology of partridge (Lagopus lagopus) is the enlarged cecum compared to representatives of other families. The purpose of this study is to analyze the taxonomic and metabolic composition of the intestinal microbiota of the white partridge using modern molecular genetic methods, in particular NGS sequencing. The object of the study was the contents of the ileum and caecal appendages of the intestine of a white partridge, harvested in winter on the territory of the Malozemelskaya tundra of the Nenets Autonomous Okrug. The research results demonstrated a range of differences related to the taxonomic and functional diversity of the microbiota of the small and large intestine of the white partridge. At the same time, a significantly higher number of bacteria with cellulolytic properties (Clostridia vadinBB60, Oscillospiraceae, and Lachnospiraceae families) was observed in the blind processes of birds. This fact may be of interest in the context of the search for strains of microorganisms for the development of biological products with probiotic and enzymatic properties. Representatives of opportunistic microbiota (Streptococcaceae and Helicobacteraceae families) have also been detected in the intestines of the white partridge, which often causes diseases due to weakened immunity. In the cecum, compared with the ileum, there was a higher number of metabolic pathways associated with energy metabolism (FUC-RHAMCATPWY (p<0.005), FUCCAT-PWY (p<0.001), GLUCUROCAT-PWY (p<0.005)), antioxidant activity (NAD-BIOSYNTHESIS-II (p<0.005), PYRIDNUCSAL-PWY, PYRIDNUCSYN-PWY, PYRIDOXSYN-PWY (p<0.05)), biosynthesis of vitamins and cofactors. The results of the conducted studies indicate a significant metabolic potential of the intestinal microbiome of the white partridge, especially in its blind processes.

Of particular importance are the issues of the dynamics of linear growth and the development of structures of the musculoskeletal system in the process of locomotion. One of the key conclusions of these studies was the establishment of a pattern of postnatal ontogenesis, according to which bones and muscles demonstrate more intensive growth and development in the proximal parts of the limbs (for example, in the area of the stylopodium) compared with the distal (autopodium). This feature is directly related to biomechanics: it is the proximal segments that carry the greatest load, generating the main driving force. The vascular system is an integral and adaptive component of the entire motor system. From a clinical point of view, a thorough knowledge of the topography of the skeleton, muscles and, most importantly, neurovascular bundles of the pelvic limb are translated from the theoretical plane into a purely practical one. This knowledge is absolutely necessary when planning and conducting surgical interventions, from osteosynthesis for fractures and arthroplasty to vascular suture and amputations, where an error in identifying the structure can lead to severe complications such as bleeding, ischemia or impaired innervation. The aim of the study was to establish the course and branching of the safena vein in Black Pushkin sables in the age aspect, and to conduct a comparative analysis of the topographic and morphometric features of this vessel. The objects for this study were the corpses of a black Pushkin sable of two age groups. As a result of the study, it was found that the small vein of safena is the main collector of venous blood from the distal parts of the pelvic limb, forming an extensive network with anastomoses on the dorsal and plantar surfaces of the foot. Morphometric data demonstrate a clear positive age dynamics of the diameter of both veins. Over the period from 15-20 to 36-40 months, the diameter of the lateral vein of safena increases by 1.67 times, and the medial vein by 1.73 times, which indicates the continued development and adaptation of the cardiovascular system to increasing functional loads in adult animals.

This study investigates the effect of a nanosuspension of modified bentonite from the Tarn-Var deposit (Republic of Tatarstan, Russia) on the bone mineral density of ducks when applied to incubation eggs during embryogenesis. The experiment was conducted on 60 Pekin duck eggs, evenly divided into control and experimental groups. The eggs in the experimental group were treated with a 20% bentonite nanosuspension on the 7^th and 13th days of incubation, corresponding to the critical stages of skeletal tissue formation and mineralization [1]. After hatching, 20 ducklings were selected from each group, and radiological analysis was performed on five individuals per group at 3–6 weeks of age. Radiographs were taken in the ventrodorsal projection, followed by digital brightness analysis in 256 grayscale levels and statistical processing of the data (Student’s t-test, p<0.05). The results demonstrated a statistically significant increase in bone mineral density in ducklings from the experimental group across all studied anatomical regions, including the cervical vertebral body and the diaphyses and epiphyses of the humerus, ulna, and femur. The most pronounced effect was observed in the distal epiphysis of the femur (an increase of approximately 13–28% across different age intervals, p<0.01) and in the middiaphyseal region of the femur. The positive trend persisted throughout the observation period (3–6 weeks), indicating a prolonged osteotropic effect of the nanobentonite. The findings confirm the high bioavailability and potential of bentonite nanostructures for stimulating osteogenesis and improving skeletal strength in waterfowl. The method of treating incubation eggs with a bentonite nanosuspension can be considered a promising approach for preventing bone pathologies and for further applied research in veterinary and poultry science.

The hoof capsule of ruminants is an anatomically and functionally complex formation that provides protection and support to the distal extremities. It includes zones with different structures and functions, each of which plays a role in load distribution, shock absorption, and stability during movement. The purpose of this study was a comparative morphological study of the hoof microstructure in cattle and moose. The study was based on light microscopy, hematoxylin-eosin staining, and Van Gieson staining. The study focused on analyzing the microstructural features of the epidermis, dermis, subcutaneous tissue, papillae, and leaflets in the anatomical zones of the border, corolla, wall, sole, and crumb. Special attention was given to the ratio of the horny and living layers, the degree of papillae expression, the density of the connective tissue, vascularization, and the degree of keratinization and structural organization. Both general morphofunctional patterns and pronounced species differences have been established. The moose has a thicker corneal layer and more developed papillae, reflecting its adaptation to the wild environment and increased mobility in challenging landscapes. Additionally, it has a loose, vascularized dermis in the crumb zone. In cattle, the structure of the horny substance is denser and more ordered, with a clearly defined boundary between the epidermis and the dermis, which corresponds to the conditions of domestication and the stable mechanical stress typical of agricultural environments. The differences are not only in the degree of keratinization, but also in the organization of the papillary and foliate elements, as well as the expression of collagen fibers in the dermis and their degree of order, which reflects the different biomechanical and environmental requirements for the hoof in these species.

The use of feed additives in veterinary medicine has recently become increasingly important due to the need to reduce the impact of negative environmental factors or factors arising from improper animal husbandry practices. They contribute to the improvement of the overall health of animals, and their use also reduces treatment costs and increases farm profitability. The aim of this study was to investigate the effect of the feed additive Klim on key biochemical parameters of rat liver blood during a model of acute toxic hepatitis with the toxic substance carbon tetrachloride (CCl4). The discovery and development of new hepatoprotectors is one of the most important tasks in the field of pharmacology. The pathogenesis of liver damage includes oxidative stress, inflammatory processes, apoptosis or necrosis, mitochondrial dysfunction, cholestasis, activation of hepatic stellate cells, and fibrosis. This provides ample scope for the development of hepatoprotectors targeting specific molecular pathways (antioxidants, anti-inflammatory agents, antifibrotics, metabolic modifiers, etc.). The need to search for and develop new hepatoprotectors for animals is justified by the high prevalence of liver problems in various species, significant economic losses in livestock farming, risks to food security, the limitations of existing, often poorly proven, treatments, species-specific metabolism and drug response, and the importance of improving animal welfare. The development of safe, effective, and tailored hepatoprotectors will strengthen veterinary practice, reduce costs, and improve the quality of animal products. The study demonstrated that the use of the dietary supplement Klim in acute toxic poisoning contributes to improvements in key blood biochemical parameters in a model of acute toxic hepatitis in rats.

Cow's milk, as a bulk nutritional product, occupies a leading position in the dairy cattle industry. Its high nutritional value is determined by its complex chemical composition. This applies primarily to fats, proteins, carbohydrates, trace elements and other components in milk. In our work, we paid attention to the issue of the amino acid composition of milk proteins, since this is critically important for the physiology of the consumer. Since, in the metabolic processes at the level of cellular metabolism. It is amino acids that act as the major substrates that are involved in the processes of: regulation of protein biosynthesis, energy metabolism of the cell, etc. The purpose of the work is to identify the relationship between a number of biochemical indicators of milk and the amino acid profile depending on the level of milk productivity of Holstein cows. The studies were carried out in the laboratories of the L.K. Ernst Federal Research Center for Animal Husbandry, the material for the study was obtained at the “Ladozhskoye” breeding farm. The methods used in the work: amperometric detection, ion-exchange chromatography with post-column derivatization, Fourier transform analysis in the infrared range. Equipment for analysis: "TsvetYauza-01-AA" ("Khimavtomatika", Russia), LC-20 Prominence (Shimadzu, Japan) with a reaction module for post-column derivatization ARM-1000 (Sevko&Co, Russia), "Combi Foss 7" (Denmark). There are three cow groups with increasing milk yield: 1) 15-25 L, 2) 26-35 L, 3) 36-45 L per day. As a result of the work, it was established that the increase in the ratio of essential to synthesizable amino acids from group 1 to group 3 indicates a proportional increase in the value of protein in the milk of highyielding cows. The results of the correlation analysis show stable, and what is important, unidirectional correlations between amino acids and biochemical parameters of cows' milk for all three groups.

Sex differentiation is an important aspect of the adaptive capabilities of the body. The manifestation of sexual dimorphism is not unambiguous. In this regard, determining its influence on the formation of the bird's body, on the productive and reproductive qualities of the population is relevant. The aim of the work is to study the effect of sexual dimorphism on the morphological features of the growth of some internal organs in turkeys of the Hybrid Converter Novo cross. The studies were conducted in 2023-2025 at the Northern Trans-Urals State Agrarian University and Absolut-Agro. The objects of the study are the kidneys, spleen, muscular and glandular stomachs of turkeys aged 21, 42 and 82 days of the Hybrid Converter novo cross. Initially, morphometry of the organs was carried out. Then histological studies were carried out with the calculation of structural elements and determination of the size of morphostructures. As a result of the study, it was revealed that the growth of organs is different, the relative mass of the kidneys and stomach decreases with age, and the spleen increases. The relative mass of males by the age of 82 days becomes greater than that of females - by 0.06% for the kidneys and by 0.048% for the spleen. And the relative mass of the stomach at the age of 82 days is greater in females by 0.54%. Morphometric analysis of the histostructures of organs showed that by the age of 82 days, males had 101.71% more muscular membrane of the glandular stomach and 12.92% more muscular stomach, all elements of the spleen (trabeculae by 34.37%, capsule by 37.57%, follicle area by 20.82%), all elements of the kidneys (area of superficial bodies by 75.54%, intracortical bodies by 56.8%, juxtamedullary bodies by 67.03%, convoluted proximal tubules by 26.94%, convoluted distal tubules by 22.32%, straight tubules by 22.32%) than females. In females, larger sizes were observed only in the mucous membrane of the glandular stomach by 17.23% and the muscular stomach by 16.78%.

The effect of the probiotic Bacillus subtilis VKM B3701D and enrofloxacin on the functional state of the liver of egg-laying Highsex brown chickens was studied. To study the effect of a probiotic feed supplement on the physiological and biochemical status of chickens, egg-laying chickens were fed the Bacillus subtilis VKM B3701D bacterial strain at the vivarium of the Belgorod branch of the Federal Scientific Center for Experimental Veterinary Sciences, Russian Academy of Sciences, at a dose of 0.05 ml of suspension per 1 kg of body weight (1 ml of suspension contains 109 CFU). Biomaterial for biochemical and hematological analysis was collected on days 1, 5, 10, and 20 via intracardiac puncture, and body weight was measured during the same time interval. The main part of the morphological analysis was performed after creating an electronic image gallery using a Mirax Desk semiautomated microscope slide scanner (Carl Zeiss Microimaging GMbH, Germany), which allowed for maximum standardization of the morphometric study modes.It was found that enrofloxacin causes significant biochemical (increased bilirubin to 7– 10 μmol/L, decreased ALT by 34%) and morphological changes (increased liver weight by 21.7%), indicating hepatotoxicity. The introduction of a probiotic reduced the negative effects of the antibiotic: in the combined group, the liver weight was 13% lower, and ALT activity decreased by only 47.7%. The use of a probiotic alone improved metabolism (increased live weight by 18.4%, and reduced triglycerides) and accelerated hepatocyte differentiation. These findings support the use of B. subtilis to minimize the consequences of antibiotic therapy in poultry farming.

Milk and milk-based products are rich in substances capable of exhibiting antioxidant activity and contain several antioxidant systems. This paper examines aspects of changes in the antioxidant status of milk, analyzed by the amperometric method, in the context of changes in the biochemical composition of milk in different lactations. Tendencies for an increase in the total concentration of water-soluble antioxidants (TAWSA) during milk pasteurization were found. In the first three lactations, an increase in TAWSA in Holstein cows correlates with an increase in average daily milk yield and somatic cell count (SCC) in milk. Thus, the TAWSA of unpasteurized milk in cows of the first lactation was 15.85±0.66 mg/L, in cows of the second lactation 17.03±2.18 mg/L, which is 6.9% more, in cows of the third lactation it was already 18.0% more than in the second – 20.77±2.91 mg/L. Within the groups, the same tendency of increasing TAWSA during milk pasteurization is also observed: 1) by +27.3%; 2) by +27.9%; 3) by +21.65%. At the same time, the dynamics of growth of TAWSA of pasteurized milk is preserved between the groups: 1) 22.11±0.33 mg/L; 2) 23.63±2.21 mg/L; 3) 26.51±2.31 mg/L. The differences in TAWSA are not only significant, but also reliable, p≤0.05. At the same time, there is an insignificant decrease in the fat and protein content in milk, while the amount of lactose does not change reliably. To draw conclusions about the statistical significance of intergroup differences, calculations were performed using the MannWhitney U test. Under the condition that Uexp. ≤ Uem. (Uem. = 27 for n=10, with α=0.05; Uem. = 19 for n=10, with α=0.01).

In modern veterinary ichthyopathology, hematological and biochemical blood studies are important diagnostic tools that allow assessment of the functional state of fish organisms under various pathologies. In this regard, the aim of this study was to evaluate the integral blood characteristics of common carp (Cyprinus carpio) broodstock with fatty liver dystrophy. The study used 20 specimens of common carp broodstock weighing 3900 g, raised at JSC "Fish Hatchery" in Voronezh Oblast. The aquatic organisms were divided into control and experimental groups of 10 specimens each. To model the pathology, the experimental group was kept in aquatic environment with added copper (II) sulfate at a concentration of 60 mg/L calculated as metal ion. Blood sampling was performed 56 hours after the start of the experiment from the caudal vein. Hematological parameters, blood plasma biochemical parameters, and oxidative stress markers were investigated using standardized methods. As a result, specimens in the experimental group showed pronounced hepatic dysfunction syndrome, manifested by hypoproteinemia with significant decrease in total protein by 17.7%, disproportional reduction of albumins by 22.3% and globulins by 14.4%. Cytolytic syndrome developed with a three-fold increase in ALT activity and a 1.4 -fold increase in AST. Hypercholesterolemia was observed with a 3.1-fold increase in cholesterol concentration, acute-phase response with an 11.5-fold increase in Creactive protein, and depletion of the antioxidant system. The hematological picture was characterized by development of microcytichypochromic anemia with a two-fold decrease in hemoglobin and compensatory erythrocytosis, leukocytosis, thrombocytopenia, and changes in the leukocyte formula with relative lymphopenia. The results confirm the high diagnostic value of hematological studies in fatty liver dystrophy in carp and may serve as a basis for early monitoring of broodstock.

Comprehensive studies of the rumen microbiocenosis in cattle revealed significant interbreed variations, with the native Yakut cattle exhibiting a distinctly unique status. It was established that Yakut animals harbor an exceptionally rich and diverse community of endobiontic ciliates, comprising 36 species belonging to 12 genera. This figure substantially exceeds the corresponding indices recorded for Simmental and crossbred animals. Qualitative analysis identified unique symbionts present only in Yakut cattle, including the rarely encountered species Charonina ventriculi and a previously undescribed morphotype of Metadinium sp. Quantitative parameters of ciliate abundance varied from 200 thousand to 2 million cells per milliliter, confirming a direct correlation with the type and nutritional value of the diet. Of particular scientific interest are the significant morphometric differences identified. A detailed analysis demonstrated that ciliates of the species Eudiplodinium maggii, Metadinium medium, and Isotricha prostoma inhabiting the rumen of Yakut cattle were statistically significantly larger (p < 0.001) compared to those found in other studied breeds. Low values of the Jaccard-Malyshev similarity coefficient objectively confirmed the hypothesis of a specific symbiocenosis formation in native animals, resulting from long-term adaptation to local feeding and maintenance conditions. A key practical outcome of this work was the development, standardization, and testing of a symbiofauna transplantation technique. Testing of the method under production conditions demonstrated 100% efficacy. Oral transplantation of the prepared inoculum to 18 recipients (5 Yakut, 3 Simmental, and 10 crossbred lactating cows) resulted in successful symbiont engraftment. Control microscopic analysis of samples collected 7 days post-procedure confirmed the presence and activity of the transplanted ciliates in the rumen of the recipient animals.

Today, regenerative medicine, traditionally reliant on stem cell therapy, is shifting toward a new type of biological regulation based on intercellular interactions via secreted substances known as the secretome. The use of mesenchymal stem cell (MSC) secretomes in regenerative therapy offers several advantages over living cells, including the ability to modify the secretome composition to achieve specific therapeutic goals. This study describes for the first time a procedure for obtaining equine mesenchymal stem cell secretomes using two distinct methods and conducts a comparative study of their biological activity in an in vitro wound model. Using ToupView 3.7 software, the wound width was measured in photographs at each of six points for each well after 0 hours of incubation (immediately after the scratch) and 24 hours of incubation. The average "scratch" width was calculated at 0:00 and 24:00. The ratio of the average "scratch" width after 24 hours of incubation to the average "scratch" width after 0:00 was then calculated. The wound closure rate relative to "K" was then calculated for each sample. The result was expressed as a percentage relative to the control. For the first time, the stability of the biological activity of the MSC secretome was assessed during storage at temperatures ranging from +4 to +8°C for two months. Based on the results of these studies, a promising candidate MSC secretome will be selected for further testing: first in laboratory animals to assess safety using various routes of administration, and then in horses to analyze its effects on cardiovascular and respiratory parameters in pathological conditions both at rest and after exercise.

The scientific literature provides insufficient data on the development of age-related structural and functional changes in cattle. Studying age-related pathomorphological changes in cattle will help identify markers of premature organ aging and develop strategies and tactics for increasing the productive longevity of cows. The aim of this study was to examine the characteristics of structural and functional changes in the internal organs of mature cattle across age-related factors. Material was obtained from heifers and culled high-yielding cows aged three, four, five, six, and nine years. Organ samples were collected for histological examination and fixed in 10% buffered neutral formalin. Deparaffinized sections 3–4 µm thick were stained with dyes for histological examination. It was established that structural and degenerative changes in organ tissues begin to develop as early as three years of age, that is, after the first calving. The cardiovascular system, which bears the greatest strain from lactation, is primarily affected by these changes. With increasing age, structural and functional tissue degeneration processes intensify: connective tissue proliferation intensifies in the heart muscle, fibrous changes develop in the liver alongside fatty degeneration, and significant hemosederin deposition is detected in the spleen, indicating premature cell senescence. Histological specimens of the hearts of 5- to 8-year-old cows revealed necrosis of the Purkinje fibers, indicating disruption of the cardiac conduction system due to severe degenerative processes. Parenchymatous organs are characterized by changes in the vascular bed and active collagenization of the organ stroma. Thus, cellular aging produces similar morphological changes and has a significant impact on tissue structures.

The study was conducted to establish the breed identity of domestic reindeer from the forest zone of Siberia and the Far East. A comparative analysis of craniometric data was conducted using 20 measurements and 15 indices. It was found that the craniometric characteristics of reindeer of this forest megaecotype significantly differ from those of animals from other reindeer herding regions by being larger. The indices indicate a relatively smaller width, narrowing of the orbits and zygomatic arches, narrow nasal bones, elongation of the facial region and frontal bones, a higher rostrum, and a more robust occipital region. Analysis of the craniometric data reveals similarities between reindeer from the forest zone of Siberia and the Far East, indicating their phylogenetic relationship. The largest skull sizes are characteristic of reindeer from Evenkia, the Republic of Tyva, and Khabarovsk Krai. Sexual dimorphism in skull size is clearly evident. Thus, in males in Evenkia (Baikitsky District), the greatest length and greatest width of the skull averaged 422.90 mm and 176.50 mm, respectively; in Tyva (Todzhinsky District), 410.00 mm and 179.75 mm; and in Khabarovsk Krai (Ayano-Maisky District), 414.60 mm and 180.00 mm. Sexual dimorphism in skull size is clearly pronounced; therefore, the corresponding measurements in females are noticeably lower. Domestic reindeer from other areas of the regions, although somewhat smaller than those shown, are not significant, allowing us to classify the studied populations as belonging to a single breed – the Evenki – and to use craniometric parameters in the application of neural networks for reindeer identification.

A 35-day experiment was conducted on two groups of fish (control and experimental, n=600 in each). The experimental group received a diet supplemented with "Bacell-M" at a dosage of 2 kg per ton of feed. The analysis utilized light microscopy of histological sections of muscle tissue stained with hematoxylin and eosin, and the real-time PCR method to assess the expression of the LPL (lipoprotein lipase), FASN (fatty acid synthase), and FABP3 (fatty acidbinding protein) genes. Additionally, zootechnical indicators such as weight gain, feed conversion ratio, and survival rate were recorded. It was found that the use of the probiotic "Bacell-M" significantly improved the histoarchitecture of the muscle tissue, manifested in the uniformity of muscle fiber diameter, clear organization of myofibrils, and the absence of dystrophic signs. Molecular genetic analysis revealed a significant increase in the expression of LPL (by 3.7 and 4.2 times on days 14 and 35, respectively) and FABP3 (by 2.1 times) genes, as well as a decrease in the expression of the FASN gene (by 3.0 and 2.7 times), indicating an intensification of lipid utilization and a reduction in their de novo synthesis. This correlated with improved production indicators: the relative weight gain in the experimental group was 26.2% compared to 15.5% in the control, the feed conversion ratio improved (1.28 vs. 1.51), and the survival rate increased to 98.7% compared to 91.8%. The probiotic "Bacell-M" has a pronounced positive effect on the morphofunctional state of the skeletal musculature in carp, optimizing lipid metabolism at the molecular level. This leads to an acceleration of growth rates, improved feed efficiency, and increased survival. The preparation is a promising, biologically safe alternative for use in modern aquaculture.

A GWAS analysis was conducted to identify single-nucleotide polymorphism markers determining improved milk quality indicators. The final sample consisted of 454 genotypes of individuals: 129 Red Belarusian cattle, 325 Red Gorbatov breed. SNP genotyping was performed using the BovineSNP50 v3.0 biochip (Illumina). The genotype read efficiency averaged 0.979 (call rate). A search for candidate genes was performed in the NCBI database for the Bos_taurus_UMD_3.1.1 genome assembly. The CattleQTLdb database was used to search for QTL. The Bonferroni correction was used to adjust the resulting P value. Milk acidity is within the physiological norm, indicating the stability of protein and lipid metabolism. The freezing point corresponds to standard indicators of high-quality milk. Ketone body levels (acetone 0.08 mmol/L, beta-hydroxybutyrate 0.04 mmol/L) are low, indicating the absence of ketosis issues in the herd. Urea levels (23.29 mg/100 ml) are within the normal range, indicating a balanced protein diet for the animals. High levels of palmitic acid (1.03 g/100 g) are observed as the main component of milk fat, and among the acids, a significant proportion are long-chain (1.83 g/100 g) and mediumchain (1.69 g/100 g) fatty acids. However, the content of polyunsaturated acids (0.13 g/100 g) is low. A genome-wide analysis of milk component composition in Belarusian Red cattle revealed the most significant associations of polymorphisms in 17 genes: CTNND2, SEMA5A, POU6F2, MYO5A, FAM19A1, TNS3, PPP1R16A, CTNNA2, RCAN2, SYN3, UMAD1, PKHD1, BMP2K, KCTD8, CPNE5, OSBPL3, and EBF1. Moreover, the quantitative trait gene loci CTNND2, SEMA5A, FAM19A1, MYO5A, and POU6F2 are associated with several phenotypic traits. It was established that chromosomes 4, 5, 7, 11, 20, and 22 harbor genes associated with variability in a number of fatty acids, trace metabolites, casein, and trans fatty acid isomers for both Belarusian Red cattle and the Red Gorbatov breed of cows. Genes and QTLs characteristic only of Red Gorbatov cattle were identified on chromosomes 1, 2, 3, 9, 12, 13, 15, 17, 18, 24, 25, and 27-29. Significant polymorphisms were identified on chromosomes 6, 10, 14, and 23, determining variability in milk composition only for Belarusian Red cattle, which can be used for further breeding work.

The aim of the work was to study the effect of HCBS, LCBS and LCBSP on the frequency of dominant lethal mutations (DLM) in mice under the genotoxic effect of the experimental mutagen - cyclophosphamide (CP). Eleven groups of outbred mice were formed for the work, 6 males and 36 females in each group. HCBS, LCBS and LCBSP were administered intramuscularly to males once at a dose of 0.5 ml/kg separately or together with intraperitoneal administration of CP at a dose of 60 mg/kg. The studied pharmaceutical substances were also administered three times with an interval of 24 hours before the administration of CP in doses similar to a single administration. To study DLM, female mice were implanted with males three times with an interval of one week. On the 15-17th day after implantation with males, pregnant females were removed from the experiment, autopsied and the frequency of postimplantation mortality (PIM) of embryos was determined, which correlates with damage to spermatozoa, mature and immature spermatids in males. The value of PIM in the experimental groups was compared with that of the negative and positive control groups. Single and course administration of HCBS to male mice with CPinduced cytogenetic instability resulted in decreased clastogenic damage to spermatozoa and late spermatids by CP. Course administration of LCBS and LCBSP to male mice before CP injection induced a significant decrease in postimplantation mortality of mouse embryos, indicating a decrease in the mutagenic effect of CP on mature spermatozoa. Thus, HCBS, LCBS, and LCBSP exerted an antimutagenic effect on germ cells of male mice under conditions of CPinduced cytogenetic instability.

The aim of this study was to characterize the polymorphism of the PIT-1 and PRL loci in Red Steppe cattle herds of the Republic of Dagestan and to assess the levels of variability in production traits at which differences between genotypes could be statistically confirmed. Genotyping of 48 cows was performed using the PCR-RFLP method (PIT-1/HinfI; PRL/RsaI) with a reproducible thermocycling and restriction protocol. For PIT-1, the following genotype groups were formed: AA (n = 11), AB (n = 16), BB (n = 20); for PRL: AA (n = 34), AB (n = 11), BB (n = 2). Considering the family structure (daughters of the same sire) and the absence of individual productivity records, formal comparisons were replaced by a sensitivity analysis: thresholds of SD and CV (for p < 0.05 and power ~80%) were calculated for milk yield, fat percentage, and protein percentage for all pairwise genotype contrasts within each locus, as well as their medians per locus. Genotyping results indicate that for milk yield, confirmation of differences is possible under moderate variability, with lower CV and SD requirements for PRL than for PIT-1; for fat percentage, the requirements are also moderate. For milk protein percentage, given typical production variance, significant differences are unlikely and would require larger sample sizes. The obtained thresholds can serve as practical guidelines for planning statistical power in future studies and for integrating these markers into breeding programs at the farm level.

African sharptooth catfish (Сlarias gariepinus) is one of the promising objects of modern aquaculture. In the natural habitat, the breeding season of catfish correlates with periods of maximum rainfall. Cryopreservation of sperm in aquaculture is widely used to provide gametes for fertilization yearround outside the reproductive seasons. The aim of the research was to optimize the methods of cryopreservation of sharptooth catfish sperm for use in aquaculture enterprises in the south of Russia. Two cryoprotectant compositions and an experimental setup for controlled freezing of catfish sperm in liquid nitrogen vapor were studied. The speed mode of freezing fish sperm is species -specific and is selected for each fish species experimentally. Using an experimental cryochamber made of expanded polystyrene with the internal dimensions (H×W×D) of 21×20×24.5 cm and a wall thickness of 5.5 cm made it possible to deep freeze the reproductive cells of catfish at a cooling rate of 6.5 degrees per minute to a temperature of – 80°C with further immersion in liquid nitrogen (t= –196°C). In the first version of the experiment, the cryoprotector included a basic solution (NaCl, KCl, CaCl2, NaHCO3) and dimethyl sulfoxide at a concentration of 5%. In the second version of the experiment, glucose at a concentration of 18 g/l was added to this composition. The average lifetime of spermatozoa after thawing in the experiment without glucose was 46 sec., which is 5 sec. less than in the experiment with glucose. In the experiment with the addition of glucose, the proportion of motile spermatozoa was 40%, while in the experiment without glucose it was only 20%. It has been shown that addition of glucose to the protector provides the best survival of African catfish sperm in terms of motility after thawing.

Sperm quality plays a crucial role in the successful implementation of breeding programs, especially in cases where artificial insemination is practiced. Males with excellent sperm quality have good fertility and can produce larger litters, and their ejaculate is more resistant to preservation. The aim of this study is to experimentally and analytically confirm the hypothesis of the association of SNP exons of candidate genes FSHR and INHBA with the sperm quality of male dogs. Through mathematical analysis of the genomic association data (GWAS) we obtained, it was possible to identify genomic regions and individual variations associated with production traits in dogs. When selecting primers for the amplification of the 2 exons of the FSHR gene and the 9 and 10 exons of the INHBA gene, the reference sequence of the domestic dog genome (Canis familiaris) was used from the NCBI international genetic database. The primer selection was carried out using the Primer-BLAST application integrated into NCBI (https://www.ncbi.nlm.nih.gov/). The primers were designed by Sintol LLC upon individual request. Amplification was performed on a C -1000 thermocycler (BioRad). Sequencing of amplified fragments was performed using nanopore sequencing technology on a MinION instrument. A Rapid Sequencing Kit was used to prepare DNA libraries. Variants were determined using the longshot program (v. 1.0.0). The results of the analysis demonstrate a statistically significant effect (p<0.01) of the INHBA2 and FSHR genes, which contain SNP mutations in the studied loci, on the quality of ejaculate in dogs. These findings contribute to the little-studied field of companion animal genetics. The data obtained opens up new opportunities for diagnosing the causes of male infertility. The identified patterns set a clear direction for further work: validation on an expanded sample and the search for new significant genetic markers.

The decline in reproductive performance in global cattle breeding, due to the accumulation of hereditary anomalies, requires the development of effective methods for genetic monitoring of mutations. The aim of the research was to develop and optimize methods for detecting two hereditary anomalies of beef cattle (Kazakh white-headed, Aberdeen Angus breed): muscle hypertrophy (M1) and dilutor (DL). For the M1 mutation in the MSTN gene, the well-known PCR protocol was tested and optimized on a sample of the Aberdeen Angus breed (n=35). Whole blood preserved in EDTA from Kazakh Whitehead (n = 54) and Aberdeen Angus (n = 35) cattle was used as biological material. DNA extraction was performed using a Nexor32m automated nucleic acid extraction station (Lepu Medical Technology Co., Ltd., China) and the MagnoPrime® VET kit (NextBio LLC, Russia). The quality and quantity of the isolated samples were assessed spectrophotometrically using an EZdrop 1000 (Blue-Ray Biotech, Taiwan) and fluorimetrically using a Qubit 4 (ThermoFisher Scientific, USA) and the QuDye HS kit (Lumiprobe, Russia). To detect a deletion in the PMEL (DL) gene in the Kazakh white-headed breed, a new real-time PCR system was developed with optimization of the primer annealing temperature. As a result of the screening, no carriers of the M1 allele were identified. When testing the developed test on a sample of the Kazakh white-headed breed (n=54), 3 carriers of the DL allele were found: 2 heterozygotes (3.7%) and 1 homozygote (1.85%). The results showed the effectiveness of the developed methods for monitoring genetic abnormalities in dairy cattle. The introduction of these PCR tests into breeding work will allow controlling the spread of undesirable alleles and contribute to increasing the productivity and economic efficiency of beef cattle breeding.

The article presents the results of a comprehensive study on the effect of polymorphism in the insulin-like growth factor 1 (IGF-1) gene on key economically valuable traits in Holstein cattle of domestic selection in the conditions of the Republic of Tatarstan. Three genotypes were identified at the studied locus: AA, AB, and BB. The population was characterized by moderate genetic diversity with an allele A frequency of 0.524 and allele B frequency of 0.476, with the genotype distribution showing a slight deviation from Hardy-Weinberg equilibrium. It was found that the heterozygous AB genotype is associated with the highest overall milk productivity indicators. Individuals with this genotype demonstrated the highest milk yield both for complete lactation (7399.0 kg) and standard lactation (7232.0 kg), indicating a heterosis effect. In addition, heterozygous cows had the highest percentage of milk fat (3.58%) and maximum total milk fat yield. At the same time, animals with the homozygous BB genotype showed pronounced advantages in reproductive traits. They showed a higher reproductive ability index (0.98) and the lowest barren rate (11.5%), which indicates better fertility and reproductive efficiency of the herd. It is important to note that cows with the BB genotype also exhibited optimal sanitary and hygienic properties of milk, as confirmed by a significantly lower somatic cell count (277.8 thou./cm³) compared to other groups. This fact indicates potentially greater resistance to mastitis and higher milk product quality. Individuals with the homozygous AA genotype of the IGF-1 gene lagged behind in most studied parameters, displaying the shortest lactation duration and total lactation yield. Thus, the heterozygous AB genotype is preferable for maximizing milk yield and milk fat content, while the BB genotype is advisable to use to improve reproduction, udder health, and milk quality.

Modern poultry farming actively use assisted reproductive technologies, particularly sperm cryopreservation, which effectiveness depends on maintaining cell integrity and functional activity. In order to early identify roosters with high frozen/thawed semen quality, a search is underway of highly informative biomarkers, determines sperm quality. Mitochondria, which produce ATP, play a key role in sperm motility and activity, including through ion transduction (Ca²⁺). The object of the study were samples of freshly obtained ejaculates and frozen/thawed semen (♂n = 10) of the Tsarskoye Selo breed (selection of the All-Russian Research Institute of Gastroenterology and Gastroenterology) at the age of 61–63 weeks. Study revealed high interindividual variability in volume of native ejaculates and sperm composition. Proportion of cells with elevated intracellular Ca²⁺ levels was significantly higher in live sperm (56.48±3.37%) compared to dead cells (3.51±0.81%). Following a freeze/thaw cycle, population of viable cells with elevated intracellular Ca²⁺ levels in male gametes decreased and formed at 9.97±0.74%. Thus, level of intracellular Ca²⁺ in spermatozoa, in combination with other currently available bioindicators of male gamete stability and functional activity (mitochondrial activity) within framework of sperm quality and cryoresistance assessment protocols, can serve as an effective preventative biomarker for cryopreservation technology.

The study is devoted to assessing the effect of SELPₑₓ₈ gene polymorphism (Val475Met) on genetic parameters, productive and reproductive performance of Holstein cattle. The SELPₑₓ₈ gene encoding Pselectin, plays a key role in immune and inflammatory processes, and is also involved in the formation of reproductive function. The research involved genotyping 258 cows from the Lenin Breeding Farm Integrated Agricultural Production Center (IAPC), and 67 sires of the Parent breeding enterprise Elite (SC GPP), Vysokogorsky District, Republic of Tatarstan. As a result of identification, it was found that the G allele predominates in both tested groups: 0.835 and 0.791 in cows and bulls, respectively. Genotype distribution among cows was: GG - 69.0%, GA - 29.1 and AA - 1.9 %. No AA genotypes were detected in bulls, with GG at 58.2% and GA at 41.8% Association analysis demonstrated that AA genotype animals achieved record milk yields but showed elevated somatic cell counts, reduced fertility, and shorter period of economic use. GA genotype animals exhibited significantly (p ≤ 0.05…0.01) higher milk fat and protein content (both percentage and yield), along with superior reproductive performance and longevity compared to other genotypes. The obtained data highlight the potential of the SELPₑₓ₈ gene as a genetic marker for selection programs aimed at improving the health, productivity and longevity of dairy cattle. The study was carried out within the framework of the state assignment, registration number 125031003428-9.

Modern methods for assessing the bulls breeding value allow for the prediction of their offspring's performance early in life. However, a bull's own reproductive performance can only be assessed after reaching physiological maturity at 1.5 to 2 years. Evaluation methods and markers that can objectively characterize the reproductive performance of potential breeding bulls are constantly being sought. Three experiments were conducted to collect semen from 11- to 12-month-old bulls (n=10) using electroejaculation and transrectal massage. Individual characteristics of the bulls were identified. In the group with a positive response to the manipulations, 13 ejaculates were collected, from the group with an unsatisfactory response – 9 (4 of which were secretions with a concentration less than 100 million / ml). The concentration of spermatozoa in the ejaculate of the group 1 bulls was 380.6 million / ml and was higher in comparison with the indicators in the group 2 bulls (P<0.05), the total motility was 72.6% (P < 0.01), respectively, progressive motility – 66,7% (P < 0.01), the proportion of viable cells – 75.2%, spermatozoa with normal morphology were 83.4% (P < 0.001). Research has shown that systematic training of replacement bulls to produce semen post-puberty can allow for an assessment of their reproductive potential. This predictive assessment may be necessary for selecting candidate bulls for breeding operations.

The article presents the results of a study of the effect of gonadotropin-releasing hormone on the restoration of ovarian reproductive function in cows with ovarian hypofunction. In addition, the article describes the effectiveness of ovulation synchronization depending on the stage of the sexual cycle. The aim of the study was to determine the reasons for the effectiveness of using gonadotropin-releasing hormone to synchronize ovulation in cows. The objectives of the study were to determine the ovulatory response to the administration of gonadotropin -releasing hormone during various periods of the sexual cycle and during ovarian hypofunction, as well as hormonal changes during its use. Scientific novelty: for the first time, synchronous clinical and gynecological, ultrasound and radioimmunological studies have been conducted, which reflect changes in the state of the ovaries and in blood hormonal analyses. Results: data on the manifestation of ovulation depending on the state of the ovaries and the long-term consequences of the administration of gonadotropin-releasing hormone, if the timing of its use is determined incorrectly, are presented. With the introduction of gonadotropinreleasing hormone, the lowest percentage of ovulation is observed when it is introduced into the phase of a functionally active corpus luteum. The maximum effect was observed during the end of the sexual cycle and complete involution of the corpus luteum. There was a period of absence of ovulation in the middle of the sexual cycle. Changes in the hormonal background in the blood of cows with the introduction of gonadotropinreleasing hormone, which allow controlling the ovulation process, are described. The regularity of clinical, hematological, and radioimmunological blood tests to determine the hormonal background and control the ultrasound use of the ovaries in determining the state of folliculogenesis in the ovaries of cows with a diagnosis of ovarian hypofunction was noted. Consequently, with the introduction of gonadotropin-releasing hormone, the effect of ovulation is observed with the physiological maturity of the structures and the preserved hormone-synthesizing function of the ovaries.

The main functions of the prolactin hormone in mammals are mammogenesis, lactogenesis and galactopoiesis, which serves as the basis for searching for associations of the PRL gene genotypes with the parameters of the morphofunctional characteristics of the mammary gland of cows, but such data are not presented in open sources of literature on cattle. The aim of the study: to analyze the associative links of the prolactin gene with the formation of morphofunctional features of the mammary gland and predisposition to mastitis in Kostroma cows. The study was conducted in 2024-2025 within the framework of the RSF Grant on breeding first-calf heifers of the Kostroma breed (n = 81) in the Kostroma region. The animals were assessed for morphofunctional parameters of the mammary gland, milk was analyzed for somatic cell content, mastitis was diagnosed and the genotype was determined by the prolactin gene. The study found that the PRL^AG genotype (0.481) had the highest frequency in the sample of Kostroma cows. It was also found that among the Kostroma cows, mastitis was most often recorded in individuals with the PRL^GG genotype (in 25% of cases). However, the assessment of cows using the case-control model did not show a reliable association between the prolactin gene genotype and the fact of mastitis development in animals (P=0.7112). At the same time, the carriers of the PRL^G allele were distinguished by the better development of some exterior features related to suitability for machine milking, in particular, the development of the posterior lobes, the shape and severity of the udder fold, which indicates the development of glandular breast tissue. Nevertheless, carriers of the AA genotype tended to have a higher milk yield – by 12.93% compared to heterozygotes, and by 9.05% compared to cows of the PRL^GG genotype. The results indicate a complex nature of the effect of the locus in question on the signs of mammary gland development and the need for further research with a larger number of animals in the sample and the studied marker genes.

Local breeds are a reservoir of unique genes lost in commercial crosses. One of the most important economically significant features of chickens is the quality of eggs. According to world scientific researches, eggs of local breeds of chickens, in terms of nutritional value, are superior to chickens of industrial crosses. The purpose of the research was to conduct a comparative analysis of a number of qualitative indicators (including nutritional value) of chicken eggs of Russian gene-pool breeds and commercial laying crosses. The research was conducted as part of the annual monitoring of the genetic resources of chickens by the National Center for Genetic Resources of Farm Animals at RRIFAGB. The object of the study is eggs of gene pool breeds: Russian Snow–White (laying breed), Poltava Clay (dualpurpose breed), Orloff (dual-purpose breed), as well as eggs of commercial white-shell laying cross (eggs' class 1; in laying Phase II). The following egg quality indicators were evaluated: egg weight, shape index and yolk weight using the egg quality assessment system Broring EggQuality 3.0 (Germany). Eggs of Russian gene pool breeds, in comparison with commercial laying crosses, have a higher nutritional and energy value of eggs (4.8–17.3% higher) due to their higher yolk value (p<0.05). In commercial poultry, the highest frequency of the "yolk size" trait is in the range of 25-28% (88% of the population), while in gene pool breeds chickens with a high proportion of yolk in the egg are most often found: 30-32% in the Snow–White Russian (58% of the population), 30-33% in Poltava Clay (62% of the population) and 34-38% of the Orloff (76% of the population). Gene pool chickens have a higher degree of variability in the "egg yolk size" trait (Cv 6.5 – 7.3%) compared to industrial poultry (Cv 3.7%), which allows for selection in order to optimize this indicator.

Acquired oronasal fistula (ONF) is an abnormal communication between the oral and nasal cavities caused by trauma or periodontal disease. According to literature, ONF is one of the most common pathologies of the oral cavity in dogs, the prevalence of which is 3.1%. This article presents a clinical case of eliminating an oronasal fistula in a dachshund dog, during the treatment of which a complication arose - a violation of the integrity of the sutures and the formation of a new fistula, which required reoperation. The purpose of the study is to show the complications of this pathology and methods of their treatment, which arose due to insufficient compliance, using the example of a clinical case of oronasal fistula in a dachshund dog. A 10-year-old male dachshund was admitted to the Dentalvet veterinary clinic (Moscow) for a dental examination. The owners complained of frequent sneezing, rhinitis, rubbing the muzzle with the paws, halitosis, decreased appetite and activity of the dog. Examination of the oral cavity revealed a significant amount of tartar, signs of periodontitis of several teeth and an oronasal fistula in the area of tooth 204. A comprehensive dental examination and treatment were performed under general anesthesia, the results of which were entered into the dental chart. Changes in the color and texture of the gums, edema and hyperemia, increased bleeding on probing, the presence of recessions, and an oronasal fistula in the area of tooth 204 were revealed. A series of intraoral radiographs, oral cavity sanitation, extraction of diseased teeth, and oronasal cystotomy in the area of tooth 204 using a single-layer flap were performed. On the 7^th day after the operation, during the examination of the oral cavity, a violation of the integrity of the sutures in the area of the extracted tooth 204 was found, as a result of the owner's failure to comply with postoperative recommendations. A wound revision with soft tissue plastic surgery and repeated oronasal cystotomy was performed. After 14 days, an examination revealed complete tissue regeneration without signs of inflammation. Oronasal fistula is a significant and common dental pathology in dogs. This disease requires a comprehensive approach to diagnosis and treatment. An important condition for a successful treatment outcome is strict adherence by animal owners to recommendations for postoperative treatment and care. Failure to comply with these recommendations by owners may lead to complications, in particular, disruption of the integrity of the sutures and reoperation. To prevent low compliance, it is necessary to first explain to owners the benefits of following medical recommendations and the consequences of violating their implementation.

Diseases of the distal limbs in horses are widespread and can be caused by a variety of factors. The most common causes of hoof problems are mechanical stress, which leads to the formation of cracks, bruises, and ecchymosis of the underlying skin. Infection, as a cause, leads to the development of frog rot, resulting in lameness. Frog rot in horses is one of the most common problems, for which a variety of treatments have been proposed. Therefore, our focus was on frog rot and the development of diagnostic methods and techniques. The aim of the study was to investigate changes in clinical and biochemical blood parameters in horses diagnosed with frog rot. Two groups of Warmblood horses were selected for the study in 2025 at equestrian centers in St. Petersburg and the Leningrad Region. The first group (control) included 8 healthy horses, and the second (test group) included 8 horses diagnosed with frog rot. The animals were kept under identical conditions. Clinical and biochemical blood serum analysis was performed, using standard profiles. The study showed that no significant differences in clinical and biochemical blood parameters were found in either healthy animals or those with frog rot. These data indicate that in warmblood horses diagnosed with frog rot, clinical and biochemical blood parameters are within normal limits. Frog rot in horses is a localized process.

Chronic kidney disease is one of the most common geriatric diseases. According to world data, every 3 cats over the age of 10 have chronic kidney disease. Chronic kidney disease is characterized by impaired excreto ry, biosynthetic, and regulatory functions. During the progression of the disease, there is a loss of functional tissue and subsequent replacement with connective tissue. In our work, we studied cats and kittens weighing between 2.3 and 6.0 kg, aged between 8 and 14 years (n=60). All patients were diagnosed with the third stage of chronic kidney disease according to the IRIS classification. Hematological studies were conducted at the Veterinary Hospital of the Vavilov University, and blood samples were collected on days 1, 30, and 60. During the study, all patients received the BestDinerRenal diet and symptomatic treatment. All cats were divided into 3 groups (n=20). Cats of the first group were given the drugs Sevelamer (Renagel) at a dose of 100 mg/kg/day, the duration of the reception was 60 days. Cats of the second group received as a phosphate binder Lanthanum Carbonate (Fosrenol) 100 mg/kg/day, the duration of the course was 60 days. Cats of the 3rd group were the control group, and did not receive phosphorous-binding drugs, but only a therapeutic diet. As the disease progresses, there is a loss of functional tissue and subsequent replacement with connective tissue. At the moment, there is no mechanism to help restore the volume of functional tissue, and all efforts of veterinary specialists are aimed at reducing the rate of progression of the development of renal failure. One of the factors that provoke the progression of renal failure is hyperphosphatemia. During our study, for all groups, there was no deterioration in the general condition and death of animals.

Anaphylaxis in dogs is a systemic allergic reaction that leads to serious physiological changes. The "halo sign" is a hypoechoic ring around the gallbladder wall during ultrasound examination. It is believed that it may be associated with swelling of the gallbladder wall or pericholecystitis caused by various factors. In the context of anaphylaxis, the appearance of a "halo" may indicate generalized edema and vascular permeability. Differential diagnosis with other causes of "halo", such as cholecystitis and neoplasms, is necessary. This study is aimed at studying the correlation between changes in peristalsis of the small intestine and the ultrasound sign of a "halo" in the gallbladder. Clinical cases in dogs with signs of anaphylactic reaction, where insect bites were the provoking factor, were studied on the basis of the UNTC "Veterinary Hospital" of the Vavilov University. The following studies and therapies were performed: primary examination, ultrasound of the abdominal cavity (primary and dynamic), general blood test, biochemical blood test, thermometry, infusion therapy, smear on Babesia canis. As a result of the study, it was found that ultrasound changes in the peristalsis of the small intestine and the wall of the gallbladder correlate with changes in the patient's condition during anaphylaxis and its resolution. Studying the pathophysiological mechanisms underlying the relationship between these signs will improve the diagnosis and develop new therapeutic approaches for the treatment of anaphylactic shock in dogs, as well as provide veterinarians with an additional tool for assessing the severity of an anaphylactic reaction.

The concept of cell therapy is founded on the administration of eukaryotic cells into the organism to treat pathological conditions. While initially developed in human medicine, cell therapy is gaining increasing relevance and is actively evolving within veterinary practice. This study analyzes and summarizes current data on the application of cell therapy in veterinary medicine, providing a comprehensive review of clinical trials and regulatory documents. The objective of our research was to evaluate the prospects for stem cell therapy in veterinary medicine, identify primary areas of clinical investigation, assess therapeutic efficacy, and determine key critical factors affecting practical implementation. Our findings indicate that the majority of studies focus on the effectiveness of mesenchymal stem cells in treating osteoarthritis in horses, spinal injuries in dogs and cats, and both acute and chronic skin injuries in dogs. The principal directions for applying cell therapy in veterinary medicine include the treatment of chronic joint diseases, acute and chronic spinal cord injuries, and skin disorders. This review highlights the most significant advancements in mesenchymal stem cell therapy for veterinary applications and discusses challenges related to quality control and legal regulation in the field. Despite significant recent progress, veterinary regenerative medicine is still in its infancy, although there are all the prerequisites for its rapid introduction into routine clinical practice. Cell therapy will effectively repair defects in various tissues, avoid highly invasive procedures, and significantly reduce recovery times. The development of similar, affordable drugs is a promising goal for veterinary medicine in Russia, and the implementation of the "One Health" approach will facilitate the effective development of the industry.

Pathologies of the cardiovascular system in small domestic animals are registered quite often. This is especially true for dogs of large and giant breeds. Congenital malformations are much less common. For the most part, they have acquired pathologies related to structural changes in the myocardium – cardiomyopathy. At the same time, the question of the frequency of certain types of cardiac pathologies in dogs, in particular dilated cardiomyopathy and its concomitant complications, remains open. Based on literature data, cardiac pathologies of various origins are recorded in 32.4% of dogs. Most of these are acquired. Considering the above, the goal was set to identify the frequency of dilated cardiomyopathy and related complications in dogs of large and giant breeds living in a megalopolis. To achieve this goal, a comparative analysis of the database of the Lapino-Vet veterinary clinic in St. Petersburg for the period from 2022 to 2024 was carried out. For this purpose, 100 outpatient records of dogs with heart diseases, body weight from 25.0 kg or more, were selected, without taking into account their breed and gender, with an age sample from one and a half to 14 years. According to the results of the conducted studies, it was found that the most frequently reported myocardial pathology in dogs of large and giant breeds living in a megalopolis is dilated cardiomyopathy. The latter is often complicated by conduction and cardiac arrhythmias. In this case, impaired conduction is most often associated with hemodynamic changes at stage C.

Pathologies of the cardiovascular system in small domestic animals are registered quite often. This is especially true for dogs of large and giant breeds. Congenital malformations are much less common. For the most part, they have acquired pathologies related to structural changes in the myocardium – cardiomyopathy. At the same time, the question of the frequency of certain types of cardiac pathologies in dogs, in particular dilated cardiomyopathy and its concomitant complications, remains open. Based on literature data, cardiac pathologies of various origins are recorded in 32.4% of dogs. Most of these are acquired. Considering the above, the goal was set to identify the frequency of dilated cardiomyopathy and related complications in dogs of large and giant breeds living in a megalopolis. To achieve this goal, a comparative analysis of the database of the LapinoVet veterinary clinic in St. Petersburg for the period from 2022 to 2024 was carried out. For this purpose, 100 outpatient records of dogs with heart diseases, body weight from 25.0 kg or more, were selected, without taking into account their breed and gender, with an age sample from one and a half to 14 years. According to the results of the conducted studies, it was found that the most frequently reported myocardial pathology in dogs of large and giant breeds living in a megalopolis is dilated cardiomyopathy. The latter is often complicated by conduction and cardiac arrhythmias. In this case, impaired conduction is most often associated with hemodynamic changes at stage C.

Eye biomicroscopy is a non-contact method of detailed examination of the eye media and tissues using a special device called a slit lamp. A slit lamp combines an intense light source (illumination system) and a microscope with an average magnification of x10, x16, depending on the equipment. Biomicroscopy allows for a detailed examination of the conjunctiva, eyelids, third eyelid, cornea, iris, anterior chamber of the eye, lens, and anterior part of the vitreous body of the bird. The biomicroscopy procedure is painless and makes it possible to detect bird diseases at an early stage. No special training is required to examine the conjunctiva, eyelids, third eyelid, cornea, or iris. To examine the anterior chamber of the eye, it is advisable to dilate the pupil after a preliminary examination of the bird on a narrow pupil, since against the background of mydriasis, the doctor can more easily see even a slight turbidity of the IOP (intraocular fluid). To examine the lens and the anterior part of the vitreous body, it is necessary to dilate the bird's pupil, as it is impossible to thoroughly examine these structures with a narrow or even moderately dilated pupil. Biomicroscopy can be performed using both a wide and a narrow light beam. The first option involves a detailed examination of the eye structures under a microscope at the desired magnification and with excellent lighting. The second option is a "slice" of the eye, which is represented by three rays, each representing specific structures.

ATP binding cassette (ABC) transporters are a group of proteins whose function is to transport nutrients into the cell and excretion endogenous and exogenous molecules from the cell. The ABCB1(MDR1) gene encodes P-glycoprotein (P-gp), a cellular membrane pump. P-glycoprotein mediated drug transport is present in more places (including the blood brain barrier). P-gp also regulates intestinal absorption. The ABCB1 gene and the P-glycoprotein encoded by it are also responsible for the formation of multidrug resistance (MDR). P-glycoprotein dysfunction can occur both as resulting from neoplasia and as resulting from drug-drug interactions in dog or cat. This makes it relevant to study the mechanisms of MDR formation in animals undergoing cancer therapy, as well as to find effective ways to prevent and reduce MDR. One of the options to increase the effectiveness of cancer therapy and improve the survival of animals, including relapses, metastases and unresectable tumors, is the inclusion of ABC transporter inhibitors in treatment protocols. One of the substances that are considered as inhibitors of ABS transporters is quercetin— a natural biochemical substance of the flavonoid group. In the period from 2024 to 2025, in order to assess the feasibility of further studying the use of quercetin as an inhibitor of the multidrug efflux transporter ABCB1 (MDR1) in animals undergoing cancer therapy, we conducted an exploratory study. The animals included in the study were treated with toceranib, imatinib, sorafenib, lapatinib and trametinib. The biologically active substance dihydroquercetin was used as an adjuvant at a dose of 2-10 mg/kg/24 hours per os. The results of our exploration study confirm the need for clinical studies of the use of quercetin as ABCB1 (MDR1) transporter inhibitor in animals undergoing cancer therapy.