Research articleEncapsulation of sex sorted boar semen: Sperm membrane status and oocyte penetration parameters
Introduction
Although semen sorting is experimentally used for artificial insemination, and intrauterine and intratubal insemination, and in vitro fertilization (IVF), its commercial application is still far from being a reality in swine species [1], [2]. This is because of the large number of sperm needed for routine AI in sow, and the number of sorted spermatozoa produced per unit time is limited. Moreover, the susceptibility of spermatozoa to stress induced by the different sex sorting steps (such as high dilution, Hoechst nuclear staining, high pressure, mechanical forces associated with passage through the sorter, exposure to ultraviolet laser beam, electrical charge, and projection into the collection tube at high speed) [1], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], and the effect on the spermatozoa of handling protocols postsorting (centrifugation/sedimentation) [14], [15], are higher in the pig than in other species [16]. In this context, encapsulation technology could overcome some limitations, reducing the dilution effect, and preserving the original sperm concentration [17]. Moreover, the capsules guarantee the diffusion of nutrients and metabolites through membrane [18], [19] and the controlled release of swine spermatozoa [20], [21] in a noncapacitated form throughout the ovulation time span [22] maintaining the semen morphologic and functional characteristics [23]. Huang et al. [24] observed that the microencapsulation prolongs the storage of spermatozoa, and the motility of encapsulated semen was significantly higher than free semen when stored for more than 3 days. Faustini et al. [25] encapsulated boar spermatozoa in barium alginate membranes and evaluated semen enzymatic activities after 72 hours of storage at 18 °C. Results indicated that the microencapsulation enhanced the storage of sperm cells, the acrosome integrity, and in situ enzymatic activity with respect to diluted semen. The microencapsulation technique allowed a single artificial insemination in sows: a large scale trial (more than 4200 sows) was performed taking into account two groups: the first treated with a single artificial insemination (encapsulated semen) and the second with the double/triple conventional artificial insemination (free semen). Results demonstrated that notwithstanding the reduced number of spermatozoa employed with a single insemination with encapsulated spermatozoa, no differences between the two treatments in terms of pregnancy rate and prolificacy were evidenced [26], [27]. Moreover, sperm encapsulation in alginate membranes reduces in vitro polyspermy rate [28].
The aim of this work was to evaluate the effect of the encapsulation process on viability, acrosome integrity, and on the in vitro fertilizing potential of sorted boar semen during a 72-hour storage.
Section snippets
Experimental design
Sperm-rich fractions were collected from two boars of proven fertility, using gloved-hand technique (five ejaculates individually treated for each boar). Each sperm-rich fraction was split in four aliquots. Each of them was submitted to one of the following treatments: (1) centrifugation (3000 × g for 20 minutes) to obtain seminal plasma; (2) dilution in equal volumes of Androhep to obtain a control group (CTR); (3) encapsulation of undiluted semen to obtain a capsule group (CPS); and (4) flow
Results
The membrane integrity results for the four treatment groups during the 72-hour storage period are reported in Figure 2. Overall, a significant effect of treatment and storage time can be observed (P < 0.0001). Control group spermatozoa maintained significantly higher levels of membrane integrity with respect to CPS spermatozoa and SORT CTR or SORT CPS specimens. No differences between SORT CTR and SORT CPS mean values were noted in terms of membrane integrity (Table 1). After 72 hours of
Discussion
The aim of the present work was to evaluate sperm status after two potentially altering processes, sex sorting and encapsulation, because the outcome of these treatments could be a nonalgebraic sum of the single procedures. To our knowledge, this is the first study reporting the effects of the combination of sex sorting and encapsulation of spermatozoa. The effect of the two procedures was followed for a 72-hour period of storage at 15 °C.
The damaging effect of encapsulation seems to be limited
Acknowledgments
The authors thank Mrs. Cinzia Cappannari and Dr. Antonio Volgarino for their precious technical support.
References (34)
- et al.
Preselection of sex of offspring in swine for production: current status of the process and its application
Theriogenology
(2005) - et al.
History of commercializing sexed semen for cattle
Theriogenology
(2008) Functional integrity of sex-sorted, frozen-thawed boar sperm and its potential for artificial insemination
Theriogenology
(2008)- et al.
Viability and DNA fragmentation in differently sorted boar spermatozoa
Theriogenology
(2006) - et al.
High pressure flow cytometric sorting damages sperm
Theriogenology
(2005) - et al.
Physiology of spermatozoa at high dilution rates: the influence of seminal plasma
Theriogenology
(1999) - et al.
Improving the fertilizing ability of sex sorted boar spermatozoa
Theriogenology
(2007) Sexing mammalian sperm for production of offspring: the state-of-the-art
Anim Reprod Sci
(2000)- et al.
Effect of sex sorting on CTC staining, actin cytoskeleton and tyrosine phosphorylation in bull and boar spermatozoa
Theriogenology
(2012) - et al.
Sex-sorting sperm by flow cytometry in pigs: issues and perspectives
Theriogenology
(2009)
Controlled release of swine semen encapsulated in calcium alginate beads
Biomaterials
Boar semen controlled delivery system: storage and in vitro spermatozoa release
J Control Release
Motility and fertility of alginate encapsulated boar spermatozoa
Anim Reprod Sci
Boar spermatozoa encapsulated in barium alginate membranes: a microdensitometric evaluation of some enzymatic activities during storage at 18 °C
Theriogenology
Semen controlled release capsules allow a single artificial insemination in sows
Theriogenology
Statistical approach in alginate membrane formulation for cell encapsulation in a GMP-based cell factory
Acta Biomater
Effect of liquid storage on sorted boar spermatozoa
Theriogenology
Cited by (14)
Extracellular cAMP and MRP4 activity influence in vitro capacitation and fertilizing ability of pig spermatozoa
2024, Research in Veterinary ScienceAlginate encapsulation of stallion sperm for increasing storage stability
2022, Animal Reproduction ScienceCitation Excerpt :Sperm encapsulation has been especially pursued for use in bovine and porcine breeding, for facilitating sperm release over a prolonged period in the female reproductive tract following a single insemination (Kemmer et al., 2011; Nebel et al., 1993; Perteghella et al., 2015). Alginate encapsulation has also been employed to increase canine and human sperm stability during (cold) storage (Gosálvez et al., 2021; Huang et al., 2005; Shah et al., 2010) and cryopreservation (Herrler et al., 2006; Shah et al., 2011), and for low-dose sex-sorted sperm (Spinaci et al., 2012). The aim of this study was to establish an alginate encapsulation procedure suitable for stallion sperm, and to investigate if encapsulation enhances stability during cold storage and increases cryosurvival as compared to non-encapsulated sperm.
Safety assessment of poly(N-vinylcaprolactam) as a potential drug carrier in extenders for boar sperm cryopreservation
2020, Toxicology in VitroCitation Excerpt :For cooled boar sperm, inclusion of commercial gelatin in BTS presented no negative effects on motility, morphology and membrane integrity, allowing successful AI (Corcini et al., 2011). Furthermore, spermatozoa encapsulated into gel-like materials were used to promote slow release of boar sperm into the uterus, in protocols using a single AI per estrus with reduced spermatozoa concentration (Vigo et al., 2009) or using sex-sorted spermatozoa (Spinaci et al., 2013). In Experiment 2, even after wide temperature variations during freezing and thawing, sperm in contact with PNVCL presented post-thawing quality similar to the control, at all tested concentrations.
Artificial insemination
2018, Veterinary Reproduction & Obstetrics