Rubus coreanus is known to have diverse biological properties, such as free radical scavenging activity and antibacterial 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 μg/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 μg/mL RLSE. Higher proportions of viable spermatozoa were seen in the presence of 0.5 and 1 μg/mL RLSE than in the control. Intracellular ROS levels decreased when the spermatozoa were preserved in BTS with 0.1–1 μg/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.

• Young-Joo Yi(Division of Biotechnology, Safety, Environment and Life Science Institute, College of Environmental and Bioresource Sciences, Chonbuk National University, Iksan 54596, Korea) Corresponding author
• Min Cho(Division of Biotechnology, Safety, Environment and Life Science Institute, College of Environmental and Bioresource Sciences, Chonbuk National University, Iksan 54596, Korea)
• Jung Min Heo(Department of Animal Science and Biotechnology, Chungnam National University, Daejeon 34134, Korea)
• Sang-Myeong Lee(Division of Biotechnology, Safety, Environment and Life Science Institute, College of Environmental and Bioresource Sciences, Chonbuk National University, Iksan 54596, Korea)