EN
The objective of the present research was to determine the effect of different quantities of vitamin C supplied and of its subsequent withdrawal on selected physical and chemical characteristics of ejaculate collected from boars of the Duroc and Hampshire breeds, as well as Duroc × Hampshire (D × H) and Hampshire × Duroc (H × D) crossbreds. The control group (C) consisted of 4 Durocs, 4 Hampshires, 4 Duroc × Hampshire crossbreds and 4 Hampshire × Duroc crossbreds. The same animals made up the experimental groups: E1, E2, and E3. The boars in groups E1 and E2 were consecutively supplied with vitamin C in the spring season, as follows: 2.4 g/100 kg b.w./day was administered to E1 for 30 days, and then 1.3 g/100 kg b.w./day was given to E2 for another 30 days. In group E3, vitamin C supplementation was ceased. Ejaculates were evaluated to measure the following traits: ejaculate volume, sperm concentration, sperm count in total ejaculate and in a dose of ejaculate, progressive motility, and the number of doses. A significant positive effect of vitamin C administered in amounts of 2.4 g and 1.3 g on ejaculate volume was observed in Durocs and D × H hybrids. With respect to Hampshires and D × H hybrids, statistically significant differences (at P ≤ 0.01) were observed between groups C and E3. The concentration of sperm cells in 1 ml of ejaculate was higher in samples from the experimental groups compared with samples from the control group, and this relationship depended on the amount of vitamin C administered and on the discontinuation of administration. A significant (P ≤ 0.01) increase in sperm count in total ejaculate was noted in Durocs, D × H crossbreds and H × D crossbreds in groups E1 and E3 and in Hampshires in E1, E2 and E3. A significant improvement in the progressive motility of sperm was noted in Hampshires in groups E1, E2, and E3. Fourteen days after vitamin C withdrawal in group E3, the highest pH value and alkaline phosphatase (ALP) activity were observed.