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The effect of cooling to different subzero temperatures on dog sperm cryosurvival
Author(s) -
AlcantarRodriguez A,
Medrano A
Publication year - 2017
Publication title -
reproduction in domestic animals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.546
H-Index - 66
eISSN - 1439-0531
pISSN - 0936-6768
DOI - 10.1111/rda.12924
Subject(s) - sperm , acrosome , liquid nitrogen , cryopreservation , chemistry , glycerol , sperm motility , zoology , semen , andrology , chromatography , biology , biochemistry , botany , anatomy , embryo , medicine , organic chemistry , microbiology and biotechnology
Contents The objective was to assess the effect of cooling to different subzero temperatures around ice formation (−5°C) on dog sperm cryosurvival and plasma membrane fluidity. Semen was centrifuged, and sperm were resuspended in a Tris‐egg yolk medium (3% glycerol). Diluted sperm were cooled from 22 to 5°C, and then, a Tris‐egg yolk medium containing 7% glycerol was added (final concentration of 5% glycerol and 200 × 10 6 cells/ml). Sperm were packaged in 0.5‐ml plastic straws, and equilibration was done 16 hr at 5°C before freezing. I. Straws ( n = 47) at 5°C were exposed to nitrogen vapours to determine the freezing point. II . Other straws (from different ejaculates) processed as mentioned, were further cooled to −3, −5 or −7°C and immediately rewarmed in a water bath at 37°C. Motility, plasma membrane functionality and acrosome integrity were assessed. III . Other straws (from different ejaculates) processed as mentioned were further cooled to −3 or −5°C, frozen over nitrogen vapours and stored in liquid nitrogen for one month. Straws were thawed in a water bath at 38°C for 30 s. Motility, plasma membrane functionality, plasma membrane integrity, acrosome integrity, capacitation status and plasma membrane fluidity were assessed. Ice nucleation temperature was −14.3 ± 2.05°C (mean ± SD ); cooling to +5, −3, −5 and −7°C, without freezing, produces no differences on sperm quality between target temperatures; cooling to +5, −3, and −5°C produced no differences on sperm survival and plasma membrane fluidity after freeze–thawing. In conclusion, cooling of dog spermatozoa to different subzero temperatures did not improve sperm cryosurvival and had no effect on plasma membrane fluidity after thawing.