The functions of the immune system are to ensure the constancy of the body composition at all stages of its existence. This comes down to monitoring the development and action of microorganisms, eliminating any foreign particles and molecules, and monitoring the functioning of own cells and tissues, including the processes of shaping and development of tissues, regeneration, timely elimination of dead tumor cells.
The body's immune defense mechanisms comprise two large groups: innate and acquired. The first group includes phylogenetically more ancient mechanisms that are not specialized on potentially dangerous factors; they are called mechanisms of nonspecific resistance or innate immunity. Innate immunity defines three groups of mechanisms: barrier mechanisms of passive defense. The second group of defense mechanisms is related to the ability of the body to gain selective response abilities against specific foreign antigen factors; they are attributed to the mechanisms of specific or acquired immunity.
Currently, a wide selection of drugs with immunomodulatory and immunostimulatory effects is available on the veterinary market. However, most of these drugs have a wide range of contraindications and often are not be applicable. Therefore, the use of drugs with modulatory effect on nonspecific immune factors allows to correct the conditions accompanied by secondary immunodeficiency.
Dorynum is a complex drug, the active substances of which are doxycycline and rifampicin. We conducted a study to assess the effect of Dorynum on factors of a nonspecific component of immune system of calves in “8 Marta” collective farm, Belovsky District, Kursk Region. Studies were carried out on a group of calves (p = 12). The concentration of serum bactericidal activity (SBA), the lysozyme activity and the phagocytic activity had been determined in blood serum using the generally accepted methodologies. The drug was administered to calves intramuscularly, at a dose of 8 mg per kg of live weight, every 24 hours for 7-10 days.
The results of the studies are shown in the Tables: Content of lysozyme activity and SBA in the serum of calves. Table 1
Indicators of phagocytosis in the blood of calves. Table 2
No.
| Indicator
| Unit
| Before administration
| After administration
|
1
| Lysozyme activity
| lysis %
| 9.87 +-0.95
| 12.66+-0.76
|
2
| SBA
| E. coli lysis %
| 59.54+-4.58
| 81.91+-5.26
|
No.
| Indicator
| Unit
| Before administration
| After administration
|
1
| Phagocytic index
| %
| 0.95+-0.03
| 1.71+-0.02
|
2
| Phagocytic activity
| %
| 41.36+-2.20
| 59.51+-1.25
|
3
| Phagocytic number
| %
| 1.44+-0.45
| 3.55+-0.53
|
Lysozyme is an enzyme belonging to the class of hydrolases that selectively hydrolyzes glycosidic bonds in murein, the complex biopolymer from which the walls of bacteria are built. The enzymatic activity of lysozyme is manifested in the hydrolase of the ?-1,4-glycosidic bond of the polyaminosaccharide of the cell wall of predominantly gram-positive microorganisms.
The data in Table 1 shows that the lysozyme activity of calves serum increases by 22.7%, SBA increases by 1.38 times. Phagocytic index (PI) - the percentage of cells that have entered into phagocytosis, of their total number. Phagocytic number (PS) - the average number of intracellular bacteria (the quotient of dividing the total number of bacteria absorbed by the number of cells that have entered into phagocytosis).
The data in Table 2 shows that the phagocytic index has increased by 1.8 times, the phagocytic activity - by 16.67%, and the phagocytic number - by 2.46 times. Thus, all indicators of phagocytosis increase: the number of phagocytes, their ability to capture microorganisms, and the digesting ability.
The data in Table 2 is consistent with the data on increase in lysozyme activity, the producer of which are monocytes with phagocytic activity. So, on the basis of the conducted studies, it can be noted that the use of Dorynum in calves stimulates nonspecific component of the immune system.
S.V. Sapozhkov, Candidate of Veterinary Sciences, Kursk
Effect of Dorynum on nonspecific resistance factors in cattle.