Effect of Rubus coreanus leaf and stem extract on boar spermatozoa

Rubus coreanus is known to have diverse biological properties, such as free radical scavenging activity and anti-bacterial activity. In the present study, Rubus coreanus leaf and stem extract (RLSE) was used in boar semen preservation whether it has a beneficial effect on assisted reproductive technology (ART) in mammals. Boar spermatozoa were preserved in Beltsville thawing solution (BTS) in the presence of varying concentrations of RLSE ($0-10{\mu}g/mL$). Sperm motility, sperm viability, and intracellular reactive oxygen species (ROS) levels were examined after 2 days of preservation. The percentage of total motile spermatozoa and progressive motile spermatozoa improved in the spermatozoa preserved with $0.5{\mu}g/mL$ RLSE. Higher proportions of viable spermatozoa were seen in the presence of 0.5 and $1{\mu}g/mL$ RLSE than in the control. Intracellular ROS levels decreased when the spermatozoa were preserved in BTS with $0.1-1{\mu}g/mL$ RLSE. In order to examine the bacterial growth, E. coli was added to liquid semen diluted with antibiotics-free BTS in the presence or absence of RLSE. No anti-bacterial activity of RLSE against E. coli was observed during liquid semen preservation. Although there was no inhibition of E. coli growth, the addition of RLSE might help improve sperm motility and viability during boar semen preservation, suggesting it as a potential reagent for ART in mammals.