Physiological Features of Platelets in Milk and Vegetable Nutrition Piglets

Being a liquid medium of the body, the blood ensures its integration and regulation in accordance with constantly changing environmental conditions. The main role of blood is to maintain the viability of the organism every minute due to the constant transfer of oxygen and nutrients to all cells of the body and the removal of metabolic products from them. These processes occur in the capillary channel and therefore the success of the blood flow in it has a particularly great physiological significance. From the success of microcirculation all metabolic processes, growth Physiological Features of Platelets in Milk and Vegetable Nutrition Piglets

Being a liquid medium of the body, the blood ensures its integration and regulation in accordance with constantly changing environmental conditions 1,2 .The main role of blood is to maintain the viability of the organism every minute due to the constant transfer of oxygen 3 and nutrients to all cells of the body 4 and the removal of metabolic products from them 5,6 .These processes occur in the capillary channel 7,8 and therefore the success of the blood flow in it has a particularly great physiological significance 9,10 .From the success of microcirculation all metabolic processes 11  A very important mechanism for maintaining homeostasis in the animal body is platelet hemostasis.The level of his activity very strongly determines the rheology of blood in the capillaries and due to this the state of metabolism in the tissues.There is reason to believe that the growth and development of piglets depends on the level of functional activity of platelets.For this reason, studies of the age-related dynamics of platelet activity in piglets during early ontogeny are of great importance.In the study, it was established that piglets of milk and vegetal nutrition showed an increase in the adhesive, aggregation and secretory capacity of platelets.The main reason for this may be an intensification of the work of receptor and postreceptor mechanisms of platelets.This was characteristic of piglets during dairy and plant nutrition in the same degree with respect to strong and weak inducers of platelet aggregation.At the base of the revealed increase in the activity of platelets in piglets throughout the course of the observation, the increase in the synthesis of thromboxane in platelets was largely due to the increase in the activity of cyclooxygenase and thromboxane synthetase in them and activation of the secretion of ADP from them.The increase in hemostatic activity of platelets in piglets during the phase of milk and plant nutrition should be considered an important regulator of their microcirculation and metabolism in tissues under changing conditions of existence.Key words: piglets, milk and vegetable nutrition phase, platelets, aggregation, adhesion, secretion.and the level of resistance of the living organism depend 13 .
These processes play a particularly important economic role in productive animals 14 .This is due to the fact that the level of realization of the productive qualities of animals depends on their success and, ultimately, the economic efficiency of their breeding and rearing 15,16 .
In pigs, the physiology of the blood is only beginning to be studied.Not all microcirculation issues for piglets of different ages have been clarified.In previous studies, attention was mainly paid to the rheological properties of erythrocytes, which are the largest population of blood cells 17 .The possibility of their age dynamics and disturbance due to environmental factors was elucidated 18 .At the same time, the functional aspects of platelets, which strongly influenced microcirculation processes in pigs, were given unnecessarily little attention.
In human studies, the high functional significance of platelets for the work of all hemostasis is recognized.It is associated with the fact that platelets are the initial link in the work of hemostasis and participants in almost all haemostatic processes in the body 19,20 .It is necessary to clarify the features of platelet activity in pigs in the third phase of early ontogeny.A special interest in the functional activity of platelet hemostasis in piglets at this age is associated with the effect of their activity on the formation of the body's structures and the development of their functional activity during the change in the mode of feeding 21 .The new information obtained on various aspects of platelet activity in piglets of milk and plant nutrition can serve as the basis the development in the future of effective options for intensifying their growth and development 22 .
In this connection, the goal was formulated: to evaluate the physiological dynamics of platelet activity in piglets during the phase of milk and vegetable nutrition.

MATERIALS AND METHODS
The research was conducted in strict accordance with ethical principles established by the European Convent on protection of the vertebrata used for experimental and other scientific purposes (adopted in Strasbourg in March  18, 1986, and  The work was carried out on 37 healthy pigs of large white breed, taken in the study for 21 days of life.All piglets were obtained from healthy sows with 2-3 farrowing.Then the piglets were inspected and examined 5 times: for 21 days, for 25 days, for 30 days, for 35 days and for 40 days of life. In a study in piglets, platelet aggregation (AP) was assessed in vitro by a visual micromethod with a series of inducers: with thrombin (0.125 U/ ml), with ADP (0.5×10 -4 M), with H 2 O 2 (7.3×10 -3 M), with collagen (dilution 1: 2 main suspension), with ristomycin (0.8 mg/ml), with adrenaline (5.0×10 -6 M).This was done using their plasma, which was standardized for platelet count to a level of 200x10 9 platelets 23 .The expression of intravascular platelet aggregation was determined using a phase contrast microscope 23 .
Indirectly in the platelets taken in the study of piglets, the intensity of formation of thromboxane was determined and the enzymatic activity of the platelet enzymes of its synthesis (cyclooxygenase and thromboxane synthetase) was determined.This was done by recording the AP in three transfer samples on a photoelectric colorimeter.In addition, in the platelets of all animals, the quantitative content of ADP and the degree of its secretion after platelet thrombin stimulation were evaluated.
The results obtained in the study were processed using the Student's test.

RESULTS
The blood of the pigs examined contained a normal number of platelets.In pigs on the 21st day of life, AT with collagen attacked 29.0±0.08 s.This value gradually decreased to 24.5±0.05s by the end of the phase of milk and vegetable nutrition (Table 1).A similar acceleration of AT in piglets during the phase of milk and vegetable nutrition was observed under the action of ADP -by 15.2%, H 2 O 2 by 10.0% and ristomycin by 13.3%.Somewhat later, AT developed with thrombin (by the end of the phase for 36.0±0.07 s) and AP with adrenaline (by the end of the phase in 85.0±0.06 s).
In the blood of piglets of milk and vegetable nutrition, a gradual increase in the number of free-moving small and large platelet aggregates is revealed.Their number at the 40th day of life was 6.0±0.09per 100 free-standing platelets and 0.36±0.007per 100 free-standing platelets.This was accompanied by an increase

Table 1. Thrombocyte activity in piglets of milk and vegetable nutrition
Legend: p -reliability of the dynamics of the phase of the dairy nutrition taken into account with respect to the beginning.
in piglets during the observation of the number of platelets that entered the aggregation process by 15.0%.
Piglets of milk and vegetable nutrition found a gradual increase in intensity in platelets of thromboxane formation.This was judged by the increase in the AP level in a simple transfer sample (from 41.4±0.06% to 48.8±0.07%).This turned out to be possible as a result of activation in the blood plates of piglets of both enzymes of its synthesis -cyclooxygenase and thromboxane synthetase.The degree of AP recovery in the collagen-aspirin test, which allows to indirectly assess the activity of cyclooxygenase in platelets, increased during the observation period from 75.0±0.08% to 78.7±0.12%.The severity of AP recovery in the collagen-imidazole sample, which allows to indirectly ascertain thromboxane synthetase activity in blood plates, also increased in piglets during observation from 64.2±0.07%to 69.6±0.09%.This was accompanied in piglets during the phase of milk and vegetable nutrition by increasing the content of their platelets ADP (by 12.5%) and increasing the activity of its secretion (by 14.1%).

DIScUSSION
Further intensification of pig production is possible with an additional accumulation of knowledge on the physiology of pigs 16,18 .Their application in practice to strengthen the work of vital systems can seriously accelerate their development and growth 24 .These systems, supporting homeostasis, include a system of hemostasis.In its functioning, a very large role is played by platelets 25,26 .It is their activity during the whole ontogenesis that largely determines the rheology of blood in the microcirculatory bed and, thereby, the activity of metabolism in all tissues 27,28 .Taking into account the physiological importance of platelet hemostasis activity and the mechanisms of its realization, it was necessary to clarify their condition during the change in their feeding patterns in piglets, that is, during the phase of dairy-plant nutrition 22 .
Based on the results obtained, we can say that in healthy piglets during the phase of dairyplant nutrition the adhesive capacity of blood plates gradually increases.This is based on a simultaneous increase in the level of their factor of von Willebrand (FW) factor in their blood, which is a cofactor of platelet adhesion and an increase in the number of receptors for it (GPIb) on their membranes 29 .Both processes were judged by the acceleration of the process of aggregation of their platelets in response to ristomycin.This is due to the fact that it is able to influence platelets, as well as subendothelial vascular structures 30,31 .With the development of adhesion, FW is joined by one end of the molecule with collagen, and the other with a platelet through the platelet receptor -glycoprotein Ib 32,33 .This leads to the emergence of a chain of adhesion: collagen -FW -GPIb.The detected acceleration of AP under the influence of other inducers also proved an increase between 21 and 40 days of life in piglets of the number of receptors to them on the surface of their blood plates.In addition, this indicated activation of platelet AP pathways in response to strong and weak inducers of in vitro aggregation similar to those that realize platelet aggregation in vivo 34,35 .An important mechanism for its amplification in the observed pigs with all inducers should be considered an increase in the expression on their membrane of fibrinogen receptors (GP IIb-IIIa).In this case, the catalytic properties of the phospholipids of their membranes inevitably increase with the growth of active factor X and thrombin on them, which further stimulates the work of all hemostasis 36,37 .
The increase in the content of platelet aggregates in the blood of piglets during the phase of milk and vegetarian nutrition proves the strengthening of their in vivo functioning of platelet receptors and postreceptor mechanisms 38 .This led to an increase in their activity of adhesion, aggregation and secretion of platelets.
Also, the highly functional intra-platelet mechanisms that promote the growth of platelet activity in piglets during the phase of dairy-plant nutrition should be considered to increase their synthesis of thromboxane by increasing the activity of enzymes of its synthesis -cyclooxygenase and thromboxane synthetase.This was supplemented in piglets at this age by an increase in accumulation in dense platelet granules of ADP and an increase in its secretion from them.

cONcLUSION
The increase in platelet activity in piglets of milk and vegetable nutrition should be associated with the intensification of the functioning of receptor and postreceptor mechanisms in them.In piglets at this age, this is manifested by an increase in their adhesion, aggregation and secretion.The revealed growth of platelet activity in piglets of milk and vegetable nutrition should be associated with the need to maintain microcirculation in tissues at a necessary level, which corresponds, on the one hand, to the specific features of the animal, and, on the other hand, to the action of environmental factors.The increase in platelet activity in piglets during the phase of milk and plant nutrition should be considered one of the species adaptive reactions that can affect their growth and development.

, growth 12 Physiological Features of Platelets in Milk and Vegetable Nutrition Piglets E.S. Tkacheva Federal
State Budgetary Educational Institution for Higher Professional training "Vologda State Dairy Farming Academy named after N.V. Vereshchagin", st.Schmidt, 2, Vologda, Russia, 160555.