Relationship of arctic fox (Alopex lagopus L.) sperm morphology with age of males, sperm concentration, ejaculate volume and acrosin activity

The aim of the study was to determine the relationship of sperm morphology with age of males, ejaculate concentration and volume, as well as with acrosin activity determined in sperm acrosome extracts. The study used manually collected ejaculates from 9 male arctic foxes, including 6 young males aged one year and 3 older males (between 3 and 5 years of age). All of the 39 ejaculates used in the study were classified as normal based on motility exceeding 70%. The ejaculates collected from the foxes were evaluated for volume, sperm concentration and frequency of morphological changes including primary and secondary defects. The spermiograms of the male arctic foxes were classified according to a six-grade subjective scale. In addition, acrosin activity was determined in the sperm acrosome extracts. The data were analysed using the criteria of male age, sperm concentration, ejaculate volume, and acrosin activity. The morphology of arctic fox spermatozoa was dependent on the age of the male. A greater number of morphologically altered spermatozoa tended to occur in the ejaculates of young foxes, which were in their first breeding season. In addition, statistical analysis revealed positive relationships between the frequency of morphological changes in sperm and their ejaculate concentration. In contrast, there were no significant correlations between the percentages of morphologically changed spermatozoa and the ejaculate volume and the content of acrosin, which is an indicator of acrosomal integrity. Semen quality is dependent on the number of sperm in ejaculate with morphological defects which prevent oocyte fertilization. Therefore, morphological assessment of semen, which covers both the number and type of morphological changes, is highly useful when selecting appropriate males for reproduction.

Effects of mucuna seed extract on sperm functional integrities and seminal oxidative stress indices of vitrified goat semen

Effects of mucuna seed extract (MSE) in tris-extenders on sperm functional integrities and seminal oxidative stress indices of vitrified sperm of West African Dwarf (WAD) goat bucks were investigated. Varying levels (0, 0.25, 0.5, 0.75, 1 g/100 mL of diluent) of MSE in tris-extenders were diluted with semen specimens. Diluted semen specimens were vitrified and preserved in liquid nitrogen. The results showed that sperm functional integrities (acrosome and membrane integrities) in MSE extenders were comparable. However, seminal oxidative stress indices (malondialdehyde [MDA] and acrosin activity) differed (P<0.05) among the various treatments and the control. The results revealed that semen vitrified with MSE had reduced (P<0.05) MDA concentrations compared to the control. Higher (P<0.05) acrosin activities were recorded in semen vitrified with MSE compared to the control except at 0.25g MSE and optimal values were recorded at 1g MSE. The findings indicated that MSE in the tris-extenders reduced MDA concentration with congruent elevated acrosin activity and consequently maintained sperm functional integrities of vitrified spermatozoa of the WAD goat.

Effects of reduced glutathione on acrosin activity in frozen–thawed boar spermatozoa

In pigs, acrosin activity in extended semen is correlated with reproductive performance and has recently been identified as a freezability marker. Reduced glutathione (GSH) is known to decrease sperm cryodamage and increase the reproductive performance of frozen–thawed boar spermatozoa. However, the effects of GSH on the acrosin activity of good and poor freezability ejaculates (GFE and PFE, respectively) is yet to be examined. The present study investigated how supplementing cryopreservation media with GSH affected acrosin activity in GFE and PFE, as well as the relationship between acrosin activity and reproductive performance in frozen–thawed boar spermatozoa. In addition, we examined whether the increase in fertility rates and litter sizes observed after the addition of 2 mM GSH to cryopreservation extenders was related to acrosin activity. Supplementing freezing media with 2 mM GSH partially counteracted the cryopreservation-related decrease in acrosin activity in GFE but not PFE. Acrosin activity was found to be significantly correlated with in vivo reproductive performance of frozen–thawed boar semen. In conclusion, the effects of adding GSH to freezing extenders on the acrosin activity of frozen–thawed boar spermatozoa rely on the intrinsic freezability of the ejaculate. Furthermore, the maintenance of proper acrosin activity could contribute to the increase in reproductive performance mediated by GSH.