Tyshkivska A. Pharmacokinetic and pharmacodynamic properties of doxycycline and tilmicosin in healthy and sick with ornithobacteriosis broiler chickens.

The dissertation is devoted to research pharmacokinetic and pharmacodynamic properties of antibiotics – doxycycline hyclate, which is the active substance of the drug «Poledoxin», as well as tilmicosin phosphate, which is the active substance of the drug «Tilmox 25%» in healthy and sick with ornithobacteriosis chickens of COBB-500 cross. It was found that doxycycline hyclate, when used in healthy broiler chickens as part of the drug «Poledoxin» in accordance with the scheme adopted in the production environment, was rapidly absorbed from the digestive tract of the bird into the blood and enters the internal organs. The maximum doxycycline hyclate content on the first day of poliodoxine application was established after 2 - 4 h, which was: in the liver - 9.07 ± 0.07 μg / g; lungs - 8.39 ± 0.20 μg / g; heart - 4.24 ± 0.09 μg / g; pectoral muscles - 4.28 ± 0.23 μg / g. Only in the kidneys, its maximum content was after 12 h and was 7.63 ± 0.38 μg / g. The use of poledoxine and tilmox 25% in poultry 2 and 3 experimental groups provided a therapeutic effect and increased the content of total protein in the serum by 24 and 33% (p≤0.05), respectively, albumin - by 56% in the serum of chickens of both experimental groups, the content of globulins was in the range of 10.72 - 11.98 g/l, while in the control 11.32 - 15.21 g/l, and total calcium - probably higher (p≤0.05) than in serum birds of the control group. The therapeutic efficacy of both studied antibiotics was confirmed by histological examination of the broiler chickens’ organs in the experimental groups. In particular, the use of poledoxin by birds of the second experimental group for 4 days provided only partial restoration of the microscopic structure in the studied organs, while the tilmox 25% use by broiler chickens in the third experimental group in the lungs showed only redness, in the trachea – no changes; in the spleen there was hyperplasia of lymphoid nodules (a sign of microscopic structure normalization), in the kidneys – granular dystrophy of the epithelium only in single tortuous tubules, in the liver – moderate edema and hyperemia of capillaries, indicating an active healing process.