The studies were carried out on 40 young boars of the synthetic line 990. On their 70 days of age, the boars were
divided into two groups; the control group received 0.2 mg Se and 30 mg vitamin E while the experimental
group received 0.5 mg Se + 60 mg vitamin E per 1 kg of feed mixtures. The feeding test was carried on from 70
days until 180 days of age. During the experiment the boars were subjected to live evaluations, i.e. testes
volume, libido level, semen characteristics, as well as selenium concentration and glutathione peroxidase (GSH-
Px) activity in blood serum and seminal plasma. The boars of the experimental group, compared with the
control, showed significantly (P ≤ 0.05) higher sperm concentration and total sperm count, significantly lower
(P ≤0.05) percentage of spermatozoa with major or minor morphological changes, elevated (P≤0.05) percentage
of spermatozoa with normal acrosome, and significantly higher (P≤0.01) ORT values. GSH-Px activity was
higher (P≤0.05) in seminal plasma of the control group boars.