EN
The study was aimed at determining the effect of a synthetic immunomodulator - methisoprinol - administered in ovo on the histological structure of the bursa of Fabricius in turkeys. The experiments were conducted on three groups of BUT 9 turkeys hatched from eggs to which, on day 26 of incubation, methisoprinol was administered in a dose of 5 mg (group I) or 20 mg per egg (group II). The poults hatched from the eggs treated with a physiological solution of NaCl in a dose of 0.1 ml per egg served as a control (group III). Turkeys were decapitated at the age of 5 d, and the bursas of Fabricius were collected and prepared for histological studies. The study demonstrated that the bursa of Fabricius in the turkeys hatched from eggs administered with 5 mg of methisoprinol, as compared to the organ in the control poults, differed in a greater number of lymphatic nodules, with a tangible division into the cortical and medullary parts. In turn, the bursa of Fabricius in the turkeys hatched from the eggs administered with methisoprinol at a dose of 20 mg/egg, was characterised by a thick wall with a prominent muscular coat and poorly developed folds with no lymphatic nodules. The morphometric examination of the folds showed a statistically lower number of lymphatic nodules in the bursas of Fabricius collected from the poults hatched from eggs to which methisoprinol was administered at a dose of 20 mg/egg, as compared to that recorded in the organs of turkeys hatched from the eggs treated with methisoprinol at a dose of 5 mg/egg and to that of the control group. Thus, the study demonstrated that methisoprinol used at a dose of 5 mg/egg might be applied as a preparation effectively modulating the immune processes in turkeys.