Introduction. One of the most progressive directions of the modern stage of development of biology is the deepening of knowledge about the mechanisms of regulation of metabolic processes, in particular about signal molecules that transmit information to the cell through ion channels and nuclear receptors associated with G-protein or with enzymatic activity. The nuclear Farnesoid X receptor (FXR) is mainly expressed in the liver and intestines, it regulates key genes that provide the processes of synthesis, transport and reabsorption of bile acids, and is also involved in the metabolism of lipids and carbohydrates.Aim. To evaluate the effect of a farnesoid X receptor agonist on postprandial lipemia in rats fed a supraphysiological fat diet.Materials and methods. An experimental, prospective, controlled, unblinded, randomized study was conducted to study the effect of a farnesoid X receptor agonist (obeticholic acid) on postprandial lipemia in rats receiving a diet containing a supraphysiological dose of fats.Results and discussion. It has been shown that when assessing postprandial lipemia, an oral test for tolerance to supraphysiological doses of fat with the determination of the initial lipid profile parameters and 4 hours after exercise has a sufficiently high information content. It was found that in animals that received a diet containing an increased amount of fat for 28 days, there was an imbalance in lipid metabolism with activation of their absorption in the intestine, but a "slow" reaction of the mechanisms of intermediate lipid metabolism, which was accompanied by the accumulation of triglycerides and cholesterol in the blood of hungry rats, chylomicrons and LDL. At 4 hours post-feeding, these animals showed abnormal increases in triglycerides and cholesterol.Conclusion. The use of obeticholic acid harmonizes lipid metabolism against the background of alimentary fat load, due to the activation of farnesoid X-receptors of the intestine and liver, which is manifested by a simultaneous increase in the intensity of lipid absorption processes and their intermediate metabolism. As a result, the risk of hyperchylomicronemia, hypercholesterolemia and hypertriglyceridemia is eliminated, the likelihood of developing secondary hyperlipedemia, insulin tolerance and functional overload (or pathology) of the liver is reduced.

The aim of the study was to investigate the cytokine profile of newborn calves that had undergone antenatal and intranatal hypoxia. Three groups of calves took part in the study: healthy (n = 8); those that had undergone antenatal hypoxia (n = 14); those that had undergone intranatal asphyxia (n = 12). Three days after birth, blood samples were taken from these animals to determine the concentration of interleukin-1β (IL-1β), interleukin-10 (IL-10) and interferon-γ (IFN-γ) using the enzyme immunoassay. It was found that in calves with antenatal and intranatal hypoxia, the cytokine profile is characterized by an increased level of IL-1β by 14.9-84.4% (P 0.05) and a decreased level of IL-10 produced by type II T-lymphocytes by 18.3-19.8% (P 0.05). At the same time, the amount of INF-γ produced by type I Tlymphocytes in calves with antenatal hypoxia does not change significantly, whereas in calves with intranatal hypoxia this indicator increases by 14.7% (P 0.05). When calculating IL-1β/IL-10, it was noted that in animals that have undergone antenatal and intranatal hypoxia, this indicator significantly exceeds the value of healthy animals. Thus, for the former it is higher by 43.5% (P 0.05), and for the latter by 2.3 times (P 0.05). In turn, the calculation of the INF-γ/IL-10 ratio shows that in calves that have experienced antenatal and intranatal hypoxia, this indicator is higher by 27.2 and 40.8% (P 0.05), respectively. Thus, the study showed that in newborn calves that have experienced hypoxic conditions, the activity of T-cell immunity and proinflammatory cytokine profile prevail, which reflects the severity of the pathological effect.

The objective of our research was to study the features of the colostral immunity formation in the newborns obtained from the cows with different clinical conditions during gestation. The object of the study was Red-Motley cows (n=28) in the third trimester of gestation and the newborn calves obtained from them. Group I – clinically healthy (control, n=8), group II – animals with hepatodystrophy (n=6), group III – animals with a combined course of hepatodystrophy and anemia (n=14). It has been found that in the cows with liver pathology and/or anemia, the colostrum of the first milk yield contains less protein and immunoglobulins by 24.1-25.4% and 11.9-14.2% (P ˂ 0.05), respectively. However, it was noted that in the calves obtained from the cows of group II, the blood serum content of total immunoglobulins after colostrum feeding did not differ from the values of the control group, while in the calves obtained from the cows of group III, the same indicator was lower by 43.0% (P ˂ 0.05). To clarify the reasons for this phenomenon, the Spearman correlation analysis was carried out, which showed that the level of total immunoglobulins in colostrum did not have a significant effect on their amount in the blood serum of calves after colostrum feeding (Rs = 0.40, P ˃ 0.05). In this case, the presence of anemia in calves was of decisive importance (Rs = 0.77, P ˂ 0.05). Thus, the formation of colostral immunity in calves depends not only on the quality of colostrum, but also on the clinical status of the newborn and in particular the presence of a hypoxic and acedotic condition.

In the conditions of the milk production complex in the Voronezh region, where Holstein cattle are kept, studies were conducted to study the degree of injury to blood cells during its selection by various methods in healthy calves and with endogenous intoxication syndrome. In healthy animals, blood sampling by passive leakage does not affect the membranes of erythrocytes. When using vacuum systems, there are no visual signs (hemolysis) of cell destruction, but changes in their cytoskeleton occur with an increase in the sensitivity of membranes to negative pre-analytical factors. In animals with endogenous intoxication syndrome, there are explicit or hidden destruction of erythrocyte membranes, which are manifested by an increase in the content of extra-erythrocyte hemoglobin, the degree of physiological hemolysis, sensitivity to intra- and extravascular hemolytic factors. As a result, already when selecting blood samples by passive gravity, there is a risk of hemolysis, and when using a vacuum system, it is observed in most samples. Therefore, when examining sick animals, it is necessary to take into account the high probability of laboratory diagnostic error at the pre-analytical stage that occurs due to hemolysis of erythrocytes with hypersensitivity to extravascular cytolytic factors, including mechanical effects during blood sampling.

Bovine respiratory diseases are widespread and present a multifactorial and variable etiology. However, several aspects of their origin remain understudied. Therefore, the objective of the present study was to investigate the effect of changes in calves’ keeping conditions on their clinical state in terms of microbiocenosis in their respiratory tract. The study was conducted in the winter season, with 37 healthy calves, 5-6 months in age, which were transferred from calf barn number 1 with favorable conditions to calf barn number 2 having a similar design as that of the previous barn but with unfavorable microclimatic parameters (drafts, low temperature, and high humidity). Within 7-9 days after their transfer to the other barn by a veterinary specialist, 54.1% of the calves were diagnosed with catarrhal bronchopneumonia. On day 10, all animals were slaughtered and dissected. Mucus samples for bacteriological analysis were obtained from the mucous membrane of seven sections of the respiratory tract of animals. In all calves, the highest degree of contamination was observed in the first half of the ventral nasal passage (84.9 ±24.46% in healthy calves and 85.7 ±18.55% in sick calves). In healthy calves, the degree of contamination in the front of the choanae was lower by a factor of 56.2% (P = 0.000059) compared to sick calves, and this value continued to decrease when moving toward the lower respiratory tract until the complete disappearance of the bacteria.