The effect of extender, method of thawing, and duration of storage on in vitro fertility measures of frozen–thawed boar sperm

Abstract

Frozen-thawed boar sperm (FTS) has reduced in vitro and in vivo life span compared to liquid semen. Experiments tested whether extenders, thawing procedures, and storage temperatures could extend the fertile life span of FTS. Experiment 1 tested the effect of six extenders on postthaw motility (MOT) and viability (VIA). Straws from boars (n = 6) were thawed, diluted into each extender, and evaluated at 20, 60, and 120 minutes. There was a trend (P = 0.08) for an extender-by-time interaction for MOT and effect of extender and time for MOT (P < 0.0001) and extender (P = 0.10) and time (P < 0.0001) for VIA. Experiment 2 evaluated the effect of temperature and time of thawing on in vitro fertility at intervals after thawing. Straws (0.5 mL) from different boar ejaculates (n = 15) were thawed at 50 °C for 10, 20, or 30 seconds or at 70 °C for 5, 10, or 20 seconds and evaluated at 5, 30, and 60 minutes. There was an effect of thawing treatment on MOT, VIA, and ACR (viable sperm with intact acrosomes, P < 0.0001) and an effect of time of evaluation (P < 0.0001) on MOT and ACR. Thawing at 70 °C for 20 seconds reduced (P < 0.05) MOT, VIA, and ACR compared to other treatments. Experiment 3 tested the effects of storage temperature and time after thawing using 20 ejaculates. Samples were thawed, diluted, and allotted to storage at 17 °C, 26 °C, or 37 °C with evaluation at 2, 6, 12, and 24 hours. There was a storage temperature and time effect and an interaction for MOT and VIA (P < 0.0001). Storage at 17 °C and 26 °C increased (P < 0.05) MOT over all times (38.5%) compared to 37 °C (26%), whereas MOT was reduced at intervals. Viability was also greatest with 17 °C and 26 °C compared to 37 °C and was also affected by time and decreased with time. These results indicate that FTS can be held at 17 °C or 26 °C for up to 2 hours before use and would allow for preparation of multiple doses. These data suggest in vitro fertility of FTS is affected by extenders, thawing, and storage.

Optimization of the Thawing Protocol for Iberian Boar Sperm

“…Several studies have presented better results of the sperm quality after thawing with the use of high thawing temperatures (70–80 °C) for a relatively short time (8–10 s) [ 8 , 9 , 10 , 32 ]. Similar findings have been observed in the present study, obtaining best results with high temperatures (70 and 90 °C).…”

“…Several studies observed that an increase in the thawing temperature improved the post-thawed motility [ 8 , 9 , 10 , 32 , 35 , 41 , 42 , 43 ], but a limited number of them evaluated the quality of the movement through the kinematic parameters. In general, they observed that an increase in the thawing temperature (60–70 °C) not only improved the total and progressive motility but also increased the velocities (VCL, VSL and VAP) [ 9 , 42 , 43 ], similar trends as those observed in our results.…”

Post-Thaw Storage Temperature Influenced Boar Sperm Quality and Lifespan through Apoptosis and Lipid Peroxidation

“…Usually, AI is recommended to be performed within 30 min post-thaw [2] because the quality and functionality of boar sperm cannot be maintained for an extended time when it is incubated at 37 • C. However, the distance between where semen is thawed and where the AI is performed demands time flexibility in performing AI and longer temporary storage of post-thaw boar semen. To date, only one study has investigated the effects of post-thaw storage temperature on boar sperm lifespan, indicating that post-thaw storage at 17~26 • C for 2 h facilitates the preparation of frozen-thawed doses [21]. The objective of this study was to evaluate (i) the effect of post-thaw storage at 5 • C (initial temperature of boar semen after thawing at 37 • C for 20 s), 17 • C (conventional semen storage temperature for liquid semen), and 37 • C (constant storage at thawing temperature) on boar sperm survival and (ii) to discover the underlying molecular changes.…”

Improvement of Post-Thaw Sperm Kinematics and DNA Integrity of Cross-Bred Bovine Sperm by Incorporating DGC as Selection Method Prior to Cryopreservation

“…Previous accounts of shortened lifespan in frozen-thawed sperm samples have been reported across many species (Cerolini et al, 2001;Katila, 2001;O'Connell et al, 2002;Breininger et al, 2005;Knox et al, 2015;Mari et al, 2015) and have affected the outcome of breeding programs utilising these samples.…”