Studies of endocrine changes and morphological blood composition in gilts affecting puberty

Abstract

Background: The puberty period in pigs depends on the functional activity of the endocrine system, which has an effect on the blood through the connective tissue. It has been established that during puberty period, the steroidal and thyroid hormones regulate the processes of metabolism and proliferation, differentiation and apoptosis of cells. The aim of the research was to find out the effects of the morphological composition of blood under the influence of steroidal and thyroid hormones during the process of puberty in different directions of productivity in the pigs.

Methods: Experiments were performed on two groups of clinically healthy piglets from Pietrain and Large White (LW) breed. To assess the steroidal and thyroid hormone levels, the morphological blood was collected from the anterior hollow vein at the puberty ages of 120, 150, 180 and 210 days, when their live weights achieved to 100 kg.

Results: The predominance of hemoglobin content and the amount of erythrocytes in the blood were observed higher (p <0,05) in Pietrain piglets than LW piglets on the 120 and 150 days of puberty development, in contrast to the general decrease in leukocytes in piglets of both breeds at the age of 150 days with the next gradual increase. The age-related changes in the leukocyte formula were directly related to the direction of animal productivity. In the LW breed, from the beginning of the experiment, there was an increase in the number of rodenuclear neutrophils at 210 days of puberty, followed by a sharp decreasing on 36.4%. In Pietrain breed, the level of the rodenuclear neutrophils decreased on 28.6% (p <0.01) at the age of 150 days, followed by a sharp increasing over the coming months. From the puberty ages of 150 days to the 210 days, the concentration of estradiol decreased in the first genotype: two times (p <0.05); in the second genotype: 1,9 times (p <0,01). The content of thyroxine and triiodothyronine increased in the blood serum of Pietrain (p <0.01) and LW (p <0.001) piglets at the puberty ages of 120 to 180 days. Study found that the amount of progesterone in LW piglets was higher relatively to Pietrain piglets in the all investigated periods. The content of estradiol in piglets of both breeds from the 120 and 150 days of puberty tended to decrease by 2.8 times (p <0.001) in LW piglets, and 1.4 times (p <0.05) in Pietrain piglets, and the testosterone level increases, 2.1 (p <0,05) and 1,9 (p <0,05) times respectively. The significant influence of progesterone on the number of lymphocytes and common leukocytes in Pietrain piglets was established. The level of estradiol significantly influenced the number of granulocytes in Pietrain piglets at the age of 150 days (r = 0.92 and 0.99), and in LW piglets, the maximum correlation level was observed at the puberty age of 150 days (r = 0, 61) and 180 days (r = 0.94).