Practical applications of sperm selection techniques for improving reproductive efficiency

Several selection techniques are available for processing spermatozoa. Apart from sperm washing to remove seminal plasma, only “swim-up” and colloid centrifugation have been used to any extent to prepare spermatozoa for in vitro fertilization, and only colloid centrifugation has been used to prepare sperm samples for artificial insemination. Single-layer centrifugation (SLC) through a species-specific colloid has been shown to be effective in selecting spermatozoa with good motility, normal morphology and intact chromatin in a range of species. This method is less timeconsuming than swim-up, and has been scaled-up to allow whole ejaculates to be processed in a practical manner. The applications of SLC are as follows: to improve sperm quality in insemination doses or in samples for in vitro fertilization, to increase the shelf life of normal sperm doses, to remove pathogens (viruses, bacteria), to improve cryosurvival by removing dead and dying spermatozoa before freezing or after thawing, to select spermatozoa for intracytoplasmic sperm injection, and to aid conservation breeding.

Practical applications of sperm selection techniques for improving reproductive efficiency

Several selection techniques are available for processing spermatozoa. Apart from sperm washing to remove seminal plasma, only “swim-up” and colloid centrifugation have been used to any extent to prepare spermatozoa for in vitro fertilization, and only colloid centrifugation has been used to prepare sperm samples for artificial insemination. Single-layer centrifugation (SLC) through a species-specific colloid has been shown to be effective in selecting spermatozoa with good motility, normal morphology and intact chromatin in a range of species. This method is less timeconsuming than swim-up, and has been scaled-up to allow whole ejaculates to be processed in a practical manner. The applications of SLC are as follows: to improve sperm quality in insemination doses or in samples for in vitro fertilization, to increase the shelf life of normal sperm doses, to remove pathogens (viruses, bacteria), to improve cryosurvival by removing dead and dying spermatozoa before freezing or after thawing, to select spermatozoa for intracytoplasmic sperm injection, and to aid conservation breeding.(AU)

Androcoll™-P-Large selects boar spermatozoa with good membrane integrity from the sperm-rich fraction of the ejaculate

The study investigated sperm membrane integrity (as a measure of sperm viability) and sperm motility in spermatozoa taken from different portions of the ejaculate, namely the first 10 ml (P1) of sperm-rich fraction (SRF) and from the rest of the ejaculate up to the appearance of gel (P2), both before and after centrifugation on a single layer of Androcoll-P-Large (SLC). Thus there were 4 treatment groups: P1, P2, SLC P1 and SLC P2. Sperm motilities were not different between the various treatment groups, except that the SLC samples had higher linear + non-linear motility than the non-SLC-selected samples. Sperm membrane integrity, in contrast, was significantly higher in P2 than in P1 (P < 0.001), and was also higher in both SLC-selected groups than in the uncentrifuged groups (P < 0.001). There was a significant correlation between membrane integrity and linear + non-linear motility (P < 0.001). These results indicate that the spermatozoa found in P2 have better membrane integrity than those in P1 when used as fresh spermatozoa, and furthermore, that SLC selects the most robust spermatozoa regardless of their origin in the ejaculate. Thus, in situations where P1 is collected separately for sperm cryopreservation purposes, the remainder of the SRF could be used for fresh AI doses, particularly where SLC can be used to select the most robust spermatozoa. These findings have practical importance for the swine insemination industry.(AU)

Androcoll™-P-Large selects boar spermatozoa with good membrane integrity from the sperm-rich fraction of the ejaculate

The study investigated sperm membrane integrity (as a measure of sperm viability) and sperm motility in spermatozoa taken from different portions of the ejaculate, namely the first 10 ml (P1) of sperm-rich fraction (SRF) and from the rest of the ejaculate up to the appearance of gel (P2), both before and after centrifugation on a single layer of Androcoll-P-Large (SLC). Thus there were 4 treatment groups: P1, P2, SLC P1 and SLC P2. Sperm motilities were not different between the various treatment groups, except that the SLC samples had higher linear + non-linear motility than the non-SLC-selected samples. Sperm membrane integrity, in contrast, was significantly higher in P2 than in P1 (P < 0.001), and was also higher in both SLC-selected groups than in the uncentrifuged groups (P < 0.001). There was a significant correlation between membrane integrity and linear + non-linear motility (P < 0.001). These results indicate that the spermatozoa found in P2 have better membrane integrity than those in P1 when used as fresh spermatozoa, and furthermore, that SLC selects the most robust spermatozoa regardless of their origin in the ejaculate. Thus, in situations where P1 is collected separately for sperm cryopreservation purposes, the remainder of the SRF could be used for fresh AI doses, particularly where SLC can be used to select the most robust spermatozoa. These findings have practical importance for the swine insemination industry.

Prolongation of stallion sperm survival by centrifugation through coated silica colloids: a preliminary study

Difficulties to be overcome in the widespread use of artificial insemination (AI) in mares are low sperm survival and poor sperm quality, which are encountered frequently among breeding stallions. Therefore, a method is needed to prolong the useable life of stallion spermatozoa destined for AI. In a preliminary study using 8 ejaculates from one stallion, density gradient centrifugation or centrifugation through a single layer of silica colloid appeared to prolong sperm motility compared to uncentrifuged spermatozoa, thereby potentially extending the useable life of treated stallion spermatozoa for AI. Furthermore, there was an improvement in sperm morphology, with the number of morphologically normal spermatozoa increasing from 42 to 60.5% and with the removal of approximately 60% spermatozoa with head or tail defects from the original population. No difference between the two centrifugation methods, in terms of yield or duration of spontaneous motility, could be detected in this study. Either of these methods of colloidal centrifugation could be a useful aid to preparing stallion spermatozoa for artificial breeding techniques, including AI.(AU)

Prolongation of stallion sperm survival by centrifugation through coated silica colloids: a preliminary study

Difficulties to be overcome in the widespread use of artificial insemination (AI) in mares are low sperm survival and poor sperm quality, which are encountered frequently among breeding stallions. Therefore, a method is needed to prolong the useable life of stallion spermatozoa destined for AI. In a preliminary study using 8 ejaculates from one stallion, density gradient centrifugation or centrifugation through a single layer of silica colloid appeared to prolong sperm motility compared to uncentrifuged spermatozoa, thereby potentially extending the useable life of treated stallion spermatozoa for AI. Furthermore, there was an improvement in sperm morphology, with the number of morphologically normal spermatozoa increasing from 42 to 60.5% and with the removal of approximately 60% spermatozoa with head or tail defects from the original population. No difference between the two centrifugation methods, in terms of yield or duration of spontaneous motility, could be detected in this study. Either of these methods of colloidal centrifugation could be a useful aid to preparing stallion spermatozoa for artificial breeding techniques, including AI.