Characterisation of movement pattern and velocities of stallion spermatozoa depending on donor, season and cryopreservation

Abstract

The aim of the study was to compare different types of movement pattern and velocities of stallion spermatozoa depending on cryopreservation during breeding and non-breeding season. Ejaculates were collected from four stallions during May (n = 24) and December (n = 24). Parameters of sperm movement were evaluated by computer-aided sperm analysis (CASA) system, and included percentages of motile spermatozoa, different patterns of motility, the velocity, linearity (LIN), amplitude of lateral head displacement (ALH) and beat-cross frequency (BCF). In winter the average percentages of motility were slightly higher compared to the breeding season in May (70.8 ± 12.7% vs. 66.8 ± 12.2%, respectively). Cryopreservation and thawing led to a significant decrease in the number of motile sperm to 11.3 ± 5.8% in May and 15.6 ± 7.0% in December. The pattern of motility was also changed. Detailed analysis by CASA demonstrated that cryopreservation resulted in a shift from the proportions of linear to more non-linear motile spermatozoa and to a significant increase of local motile and hyperactivated spermatozoa. Mean velocity of fresh motile spermatozoa differed between May and December (119.1 ± 43.9 vs. 164.4 ± 66.4 µm/sec, respectively; P < 0.05). Cryopreservation and thawing led to a slight increase of curvilinear velocity (VCL) and straight line velocity (VSL). The motility analysis has shown that the parameters BCF and ALH were highly correlated in stallion spermatozoa (r = -0.67; P < 0.001). The BCF of stallion spermatozoa was slightly reduced in the non-breeding season. Altogether, the influence of factors on the motility of stallion spermatozoa has the following rank order: cryopreservation (P < 0.0001) > stallion (P < 0.001) > season (P < 0.05).

Effect of Cholesterol and Equex-STM Addition to an Egg Yolk Extender on Pure Spanish Stallion Cryopreserved Sperm

“…This preliminary cooling sperm study was made by Gil et al (2005, data not published), discarding those stallions which presented sperm quality deficiencies in the cooling process such as recommend Aurich [16]. The obtained results have demonstrated the significance of individual (M, MP, NP, HOST, V, FL, and RT) and extraction (M, MP, NP, HOST, and A), indicating the different behavior of the extender combinations depending on the horse employed or collection moment, as observed by other authors [19, 45, 51, 53–56]. …”

“…Cryopreservation and thawing of equine sperm led to a significant decrease in the number of CASA-measured motile sperms to 11.3 ± 5.8% in May [45], which does not exactly correspond with the obtained results (6.78 ± 10.319). Moreover, CASA-measured objective motility and sperm survival rate after thawing process showed a marked lack of significant effect related to the different combinations of Equex-STM-cholesterol.…”

Hyperactivated Sperm Motility: Are Equine Sperm Different?

“…Estrogen-like mycotoxins were found to increase ALH and reduce straight-line velocity and linearity in stallion sperm, suggestive of hyperactivation [31]. A slight increase in hyperactivated motility parameters has also been noted after cryopreservation [32]. In a brief report, LangeConsiglio and Cremonesi found indications of hyperactivation (decrease in straightness parameters) in stallion spermatozoa exposed to follicular fluid recovered from preovulatory follicles [10].…”

Effect of season on sperm membrane protein 22 and selected mRNAs in fresh and cryopreserved stallion sperm

“…In the animal world, important decisions are often made about a male's life prior to the knowledge of his fertility. Sperm membrane protein 22 (SP22) has been correlated to fertility in several species including rats and rabbits (42,61,95,96). Previously, mRNAs were identified in mature sperm (7,11,12).…”

“…Besides differences in sperm viability, it was also found that semen collected and cryopreserved during the non-breeding season experienced greater sperm deterioration during storage than semen collected and cryopreserved during the breeding season(6). Other studies showed that post-thaw sperm motility, membrane damage, hyperactivation and acrosome-reacted sperm are greatest in the non-breeding season(10,32,33,50,96). Ejaculates collected from a single stallion exhibited greater variation when collected during the nonbreeding season(3).…”