Morphometric changes in boar spermatozoa induced by cryopreservation

Abstract

Computer-assisted sperm morphometry analysis was used to determine the effects of cryopreservation on boar sperm head and midpiece morphometry. Sperm-rich fractions were collected from five mature boars. Three microscope slides were prepared from single extended sperm samples prior freezing and post-thawing. All slides were stained with Hemacolor, and 250 sperm images were obtained from each slide. The sperm head dimensions for length, width, area, perimeter and four shape factors and sperm-midpiece dimensions for area, width, angle and distance were determined in each spermatozoa. The effects of sperm freezing on sperm dimensions within and among boars were determined. A previous discriminant analysis of the results was able to correctly classify a 78.3 and 82% of fresh and frozen-thawed spermatozoa respectively. Sperm heads were significantly smaller in cryopreserved spermatozoa than in the companion extended samples for length, width, area and perimeter. Sperm midpieces were also significantly smaller in cryopreserved spermatozoa for width and area. The highest changes in morphometric dimensions after the freeze-thawing process were found in the midpiece of spermatozoa. The variability of morphometric measurements only was significantly different between fresh and thawed samples for head rugosity and midpiece area. The effects of cryopreservation on morphometric parameters were similar in the boars, which allow us to conclude that cryopreservation process does not have a different effect in each individual boar. In summary, morphometric changes associated with the cryopreservation process on boar spermatozoa do not apparently depends on an effect at individual level.

The effect of selected staining techniques on stallion sperm morphometry

“…The differences between the morphometric results obtained in this study and in studies by other authors may be due to the procedure for binding chemical compounds, to nonstandard staining techniques (Boersma et al, 1999), or to whether the semen was fresh or preserved (Arruda et al, 2002;Rijsselaere et al, 2004;García-Herreros et al, 2008). Because the semen in our study was collected from the tail of the epididymis, it was not a full ejaculate.…”

Comparative study of sperm washing and selection methods after cryopreservation and its influence on sperm subpopulational structure in a bovine model

“…Sperm sample differences were marked during the experiment although sperm pools belonged to five different animals and we used different ejaculates from each animal. Thus, sperm cryopreservation, male genetics, or the use of different ejaculates, considered as possible causes of variability among sperm samples, can be addressed to defined sperm subpopulational characteristics after each sperm selection method [Garcia-Herreros et al 2008;Lavara et al 2013;Marti et al 2011a]. These variables may cause alterations in sperm traits revealing differences obtained regarding final sperm quality such as membrane integrity, since sperm head volume is heterogeneous among sperm in the whole population.…”

Morphometric dimensions of the stallion sperm head depending on the staining method used

“…The phenomenon of changes in sperm dimensions can also be observed during cryopreservation of semen. Preservation of semen at low temperatures has been found to decrease the dimensions of sperm heads in the semen of humans (45), stallions (3), bulls (41), boars (17), and goats (22). Sperm placed in hypotonic solutions will have a tendency to swell, while in hyperosmotic solutions they will shrink.…”