Authors:
L. Sh. GORELIK, candidate of biological sciences,
O. V. GORELIK, doctor of biological sciences, professor,
S. Yu. HARLAP, lecturer,
M. A. DERHO, doctor of biological sciences, professor,
South Ural State Agricultural University (13 Gagarina str., 457100, Troitsk, Chelyabinsk region),
Ural State Agrarian University (42 K. Liebknehta str., 620075, Ekaterinburg),
South Ural State Agricultural University (13 Gagarina str., 457100, Troitsk, Chelyabinsk region).
Abstract. Thyroid hormones, affecting the ratio of anabolic and catabolic processes in organs and tissues, regulate the processes of development, maturation, specialization and update of almost all tissues of the body, ensure the normal energy metabolism. The article presents the results of the evaluation of the pituitary-thyroid status of hens of cross «Lomann-white» in the course of the reproductive period. It is established that the greatest biological activity in the body of a bird has the triiodothyronine and the variability of its concentration in the blood determines the intensity of metabolic processes and the level of egg production. The concentration of thyroid hormones in serum of laying hens changes in waves during the reproductive period. The concentration of thyroxine in all periods of egg laying exceeds the content of triiodothyronine in more than two times. This is evidenced by the quantity ratio of the levels of triiodothyronine and thyroxine (T3/T4). Such variability in the ratio between the thyrotrophic and thyroid hormones confirms the previously we made the assumption that the implementation of the biological effects of thyroid hormones associated with the action not so much T4 how much T3. In the body of laying hens minimum value of the ratio T4/TSH corresponds to the beginning of the reproductive period. Starting with 52 weeks to the end of oviposition, it is almost constant and varies in the range of 22.0 ± 1.01–22.2 ± 1.44 conv. units. The ratio between triiodothyronine and thyroid stimulating hormone (T3/TSH) has wave-like dynamics. The maximum value corresponds to the middle of oviposition (8.53 ± 0.10; p ≤ 0.05), and the lowest end of the reproductive period. Biological action of thyroid hormones, mainly triiodothyronine is implemented via, which reflects the functional state of communication in the system «hypophysis – thyroid».
Keywords: chickens, cross, hormones, metabolism, productivity.
