Abstract #54

# 54
T. Nongbua*1,2, A. Utta3, N. Am-In4, J. Suwimonteerabutr4, A. Johannisson1, J. Morrell1, 1Division of Reproduction, Department of Clinical Sciences, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden;, 2Department of Clinical Sciences, Faculty of Veterinary Sciences, Mahasarakham University, Mahasarakham, Thailand;, 3North-Eastern Bull Centre, Bureau of Biotechnology in Livestock Production, DLD, KhonKaen, Thailand;, 4Department of Obstetrics, Gynaecology and Reproduction, Faculty of Veterinary Science, Bangkok, Thailand.

Single layer centrifugation (SLC) with Bovicoll is a technique to enhance sperm quality. The purpose of this study was to investigate the effect of SLC before cryopreservation on bull sperm quality after thawing. Semen was collected from 8 bulls (American Brahman, n = 5 and Sahiwal, n = 3) at the North Eastern Bull Centre (KhonKaen, Thailand). The ejaculate was split: one part was prepared following the standard procedure at the bull centre (n = 88) as control. The other part was used for SLC with Bovicoll-B (Johannisson et al. 2016 Theriogenology 86, 140). The SLC-selected sperm samples were frozen using the same protocol as control (n = 88). After thawing at 37°C for 12 s, motility analysis was performed using the CEROS II® (Hamilton Thorne, Beverly, MA, USA); sperm chromatin structure, mitochondrial membrane potential, and sperm viability were assessed using a FC500 flow cytometer (Beckman Coulter, Brea, CA, USA). Treatment means were compared using the linear mixed model (Proc MIXED, SAS®, 9.3, SAS Institute Inc., Cary, NC, USA). Results are reported as least-squares means ± standard error. The sperm kinematics for SLC samples were higher than controls for progressive motility (26.37 ± 1.59%, 19.56 ± 1.59%), Linearity (LIN) (52.80 ± 0.87%, 44.94 ± 0.87%), Straightness (STR) (83.06% ± 0.59, 76.20 ± 0.59%), beat cross frequency (BCF) (29.25 ± 0.50 Hz, 24.35 ± 0.50 Hz) and wobble (WOB) (61.78 ± 0.63%, 57.40 ± 0.63%) (all P < 0.0001) respectively, whereas SLC-selected samples were lower than controls for slow motility (13.61 ± 0.71%, 15.56 ± 0.71%; P < 0.05), Amplitude of lateral head displacement (ALH) (4.88 ± 0.18 μm, 6.67 ± 0.18 μm), velocity average path, (VAP) (61.17 ± 1.93μ/s, 67.88 ± 1.93μ/s), and curvilinear velocity (VCL) (99.78 ± 3.77 μ/s, 122.91 ± 3.77 μ/s) (all P < 0.0001), respectively. Other parameters of sperm quality were not different between treatments, although there was considerable variation among individual bulls in sperm chromatin structure assay, mitochondrial membrane potential, and sperm viability. These results suggest that SLC can be used before cryopreservation to improve the kinematics of thawed bull sperm samples without adversely affecting other parameters of sperm quality.