Poster Presentation IXth International Conference on Boar Semen Preservation 2019

Potent semen extenders counteract vibration-induced injury in long-term stored boar spermatozoa (#1.10)

Xuyen Le Thi 1 , Anne-Marie Luther 1 , Martin Schulze 2 , Karl Fritz Weitze 1 , Dagmar Waberski 1
  1. Unit for Reproductive Medicine of Clinics/Clinic for Pigs and Small Ruminants, University of Veterinary Medicine Hannover, Hannover, Germany
  2. Institute for Reproduction of Farm Animals Schönow, Bernau, Germany

Introduction: Recently it was shown that transport stress as simulated by vibration emissions from an orbital shaker affects the quality of stored boar semen extended in Beltsville Thawing Solution (BTS) [1]. The present study aimed to elucidate the effects of different semen extenders and residual air in the semen dose on the quality of long-term stored boar spermatozoa subjected to vibration emissions. Material & Methods: Semen (total: 18 ejaculates) was isothermically diluted to a volume of 80 ml containing 23.5 x 106 sperm/ml. Extenders used were BTS (Experiment 1, n = 6 boars); Androstar® Plus (Experiment 2, n = 6 boars) and Androstar® Premium (Experiment 3, n = 6 boars). Split samples were filled into 95 mL QuickTip Flexitubes®(Minitüb, Germany) with or without 15 ml residual air. Samples were then exposed to a rotation speed of 150 rpm circular horizontal frequencies with an amplitude of 1 cm (Swip Shaker, Buehler KL-2) for 120 min at 21°C in the dark. Control samples remained unshaked. Semen doses were then stored for 144 h at 17°C. Results: Experiment 1: In BTS-diluted samples, pH shifted from 7.0 to 7.41 ± 0.09 (control w/o air) or 7.50 ± 0.10 (shaked with air) at 144 h. After 144 h, progressive motility (AndroVision®) was highest in control samples w/o air (77.3 ± 8.1 %, P<0.05) and was lower in shaken samples (72.7 ± 8.5 %, P<0.05) and in samples with air (control: 71.3 ± 8.6 %; shaken 69.2 ± 8.2 %, P<0.05). Plasma membrane and acrosome integrity (flow cytometry: propidium iodide negative/FITC-PNA negative sperm) was highest in control samples without air (90.2 ± 1.6 %) and lowest in shaken samples with air (87.1 ± 2.9; P<0.05). Experiment 2: In Androstar® Plus-diluted samples, pH remained below 7.10 throughout storage. At 144 h, progressive sperm motility (range: 81.4 ± 4.5 to 85.2 ± 2.7 %) was not influenced by vibration and/or air presence and membrane integrity did only slightly differ between the semen groups (range: 93.2 ± 1.5 to 94.8 ± 0.7). Experiment 3: In Androstar® Premium-diluted samples, pH remained below 7.30 throughout storage. At 144 h, motility (range: 83.9 ± 2.7 % to 84.9 ± 3.6 %) and membrane integrity (range 93.3 ± 1.6 to 91.6 ± 1.2) were not affected by treatment (P>0.05). Conclusion: Vibration emission causes sperm damage in BTS extender, presumably by a pH shift towards alkalinisation, and mechanical forces. Protective extenders with a potent buffer system, such as Androstar® Plus and Androstar® Premium, counteract vibration emission-induced injury in long-term stored boar spermatozoa.