In vitro studies of Norwegian Red bovine semen immobilized and cryopreserved in alginate solid gel network

Abstract

Development of new semen cryopreservation techniques improving sperm survival and ensuring availability of viable spermatozoa for a prolonged time-period after AI is promising tools to reduce sensitivity of timing of AI and enhance overall fertility. The SpermVital technology utilizes immobilization of bull spermatozoa in a solid network of alginate gel prior to freezing, which will provide a gradual release of spermatozoa after AI. The objective of this study was to compare post-thaw sperm quality and in vitro sperm survival over time of Norwegian Red bull semen processed by the SpermVital (SV) technology, the first commercialized production line of SpermVital (C) and by conventional procedure applying Biladyl extender (B). Post-thaw sperm motility was not significantly different between SV, C and B semen (p > .05). However, sperm viability and acrosome intactness were higher for SV than C and B semen (p < .05). Small differences in DNA quality were observed (p < .05). Sperm viability after storage in uterus ex vivo was higher for SV than for C semen (p < .05). Furthermore, sperm survival in vitro over time at physiological temperature was significantly higher for SV semen than C semen as well as B semen during the incubation period of 48 hr (p < .05). In conclusion, the SpermVital technology is improved and is more efficient in conserving post-thaw sperm quality and results in higher sperm viability over time in vitro for SV than for C and B semen.

Studies of gel with immobilized semen by intrauterine endoscopy post‐artificial insemination

“…The gradual dissolution of the alginate gel was also observed ex vivo after uterine incubation. This indicates a slow release of spermatozoa from the solid alginate gel as shown previously (Alm‐Kristiansen et al, ), and as in the present study demonstrating viable and motile spermatozoa following overnight incubation. A study applying cryopreserved canine semen to compare processing with alginate gel microencapsulation to standard processing shows similar results, with elevated motility and viability in the former after incubation at body temperature (Shah et al, ).…”

“…Semen (5 μl) was placed on a pre‐warmed microscope slide, and subjective motility was examined by phase‐contrast microscopy at 37°C and 100× magnification. An aliquot of the SV semen sample was incubated for 10 min in room temperature with 37.5 µM PI for examination of viability by fluorescence microscopy as described (Alm‐Kristiansen et al, ).…”

“…Alm‐Kristiansen et al () reported similar pregnancy rates between AIs using a single AI dose with immobilized SV semen early in heat and AIs using standard processed semen inseminated on two consecutive days. Further, in vitro evaluation of SV spermatozoa quality post‐thaw and following incubation has demonstrated prolonged viability compared with standard processed semen (Alm‐Kristiansen et al, ). Multiple physiological and biochemical interactions take place between spermatozoa and the female genital tract which result in the selection of specific sperm subpopulations after AI (Suarez, ).…”

Relationship between post‐thaw adenosine triphosphate content, motility and viability in cryopreserved bovine semen applying two different preservation methods

“…Nevertheless, the higher motility and ATP level for SV at T3 compared to B semen are most likely explained by immobilization of sperm cells in alginate gel before cryopreservation. Better preservation of energy store, through immobilization prior to freezing, could be an explanation for longer sperm survival, as observed previously with SV semen (Alm‐Kristiansen et al, ).…”

Microencapsulation of human spermatozoa increases membrane stability and DNA longevity

“…this relationship also holds up for spermatozoa that are cryopreserved (Alm-Kristiansen et al, 2017;Nebel et al, 1993). Although not assessed in the current study, sperm motility does not survive as well after microencapsulation; for example, human spermatozoa tested after cryopreservation, resulted in a decreased motility compared with standard protocols, but there was still higher viability in those spermatozoa that remained immotile after thawing (Herrler et al, 2006).…”