Transformation of a short-term boar semen extender into a long-term boar semen extender by using penicillamine

This study aimed to convert a short-term semen extender into a long-term semen extender by adding penicillamine (PEN). Semen samples were collected from six boars, diluted at a concentration 3 × 10⁹ spermatozoa/100 ml, and divided into eight groups as follows: BTS, Merck III®, Androstar® Plus, PEN 0.125 mM, PEN 0.25 mM, PEN 0.5 mM, PEN 1.0 mM, PEN 2.0 mM. All the diluted semen samples were stored at 18 °C and were examined for progressive motility, viability, acrosome integrity, pH and osmolarity on days 0, 1, 3, 5 and 7 after storage. The level of the total anti-oxidative capability (T-AOC), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and malondialdehyde (MDA) were also measured for antioxidant activities. Fertility tests on a commercial pig farm was also conducted. On days 0, 1 and 3 of storage, no statistically significant differences in all the parameters among the extenders was observed. On day 5, the semen diluted with PEN at a concentration of 0.25 mM and Androstar® Plus could maintain progressive motility reach of 70.0% and 76.0%, respectively (P< 0.01). On day 7, the semen diluted with PEN at a concentration of 0.25 mM maintained progressive motility (70.0%) and acrosome integrity (85.7%) which is comparable to long-term semen extenders (Androstar® Plus) (P < 0.01). For the antioxidant activities, the level of the T-AOC, SOD and MDA varied depended on the PEN concentrations. The results of the fertility test were not different among the groups. To conclude, adding PEN at 0.25 mM in the BTS extender is able to transform a short-term semen extender into a long-term extender.