Equine seminal plasma: its role in protecting stallion spermatozoa during cryopreservation

There is considerable variability in the ability of spermatozoa from different stallions to withstand the freezing process. As a result, stallions are usually categorized as good or bad freezers. In the equine industry, the demand for frozen semen for artificial insemination is increasing, resulting in a need for optimising cryopreservation techniques. Previously the removal of seminal plasma (SP) prior to cryopreservation was shown to improve post-thaw sperm quality, whereas the effect of adding SP on spermatozoa varied among studies. Single Layer Centrifugation (SLC) is a technique that has been used to select the most robust spermatozoa from the ejaculate and prolong their viability, as well as separating them from SP. The aims of this thesis were: 1) to study the effect of combining SLC with addition of SP from stallions of known freezability on sperm cryosurvival, including their ability to bind to heterologous oocytes; 2) To explore the differences in the major protein groups in SP between the breeding and non-breeding seasons in relation to sperm quality. Selecting robust spermatozoa using SLC prior to freezing improved post-thaw sperm quality, whereas addition of pooled SP from good or bad freezers to the selected sperm samples did not have an additional beneficial effect. Sperm quality was adversely impaired after restoring pooled SP to SLC-selected spermatozoa after thawing, independently of whether the SP came from a good or a bad freezer stallion, suggesting an inability of SP to repair stallion sperm cryoinjuries in the presence of an egg yolk-containing extender. Sperm binding affinity to the zona pellucida (ZP) of bovine oocytes was reduced after adding SP from good freezer stallions prior to cryopreservation. However, when SP was added after thawing, the mean number of bound spermatozoa was higher for the group treated with SP from good freezers than for the group treated with SP from bad freezers. Minor differences in protein composition were observed between seasons as well as between good and bad freezers. In the nonbreeding season there was a higher content of heparin-binding proteins and also of a subset of non-heparin binding proteins compared to the breeding season; these proteins may be linked to fertility. Sperm quality did not decline during the non-breeding season and SP-testosterone levels did not vary between seasons. Customization of the cryopreservation protocol for individual stallions, including studying the effect of adding SP from individual stallions, would be required to optimize the effect on sperm cryosurvival. Global proteome investigation of SP proteins could help to identify cryosurvival biomarkers for stallion spermatozoa

Testicular length as an indicator of the onset of sperm production in alpacas under Swedish conditions

Background: The popularity of alpacas (Vicugna pacos) is increasing in Sweden as well as in other countries; however, knowledge about optimal management practices under Swedish conditions is still limited. The wide age range reported when the onset of puberty can occur, between 1 and 3years of age, makes management decisions difficult and may be influenced by the conditions under which the alpacas are kept. The aim of this study was to find out when Swedish alpacas can be expected to start producing sperm, by using testicular length and body condition score as a more precise indirect indicator than age. Results: This study suggests that animals with a testicular length ≥3.8cm would be producing sperm; however, if it is crucial to know that there is no sperm production for management purposes, the threshold level for testicular length used to differentiate between sperm-producing and non-sperm producing animals should be ≤1.6cm instead. If only one variable is considered, testicular length appears to better than age alone to predict sperm production. Body condition score together with testicular length explains the individual onset of puberty and better guide management recommendations. Conclusions: Using a combination of these parameters (testicular length, body condition score and age) as a tool for decision making for alpaca husbandry under Swedish conditions is suggested

Extenders for alpaca epididymal spermatozoa: Comparison of INRA96 and andromed

Artificial insemination would be a useful technique for alpaca breeders to use as an aid to breeding to increase fleece quality. The technique, however, is not well developed in alpacas, partly because of the viscous nature of their seminal plasma. Castration conducted for husbandry purposes can provide a source of epididymal spermatozoa to test semen extenders or handling regimens, thus circumventing the problem of the viscous ejaculate. In this experiment, two semen extenders (Andromed and INRA96) developed for other species (bovine and equine, respectively) were tested with alpaca spermatozoa derived from the cauda epididymis. Sperm total motility (mean ± SEM A: 29.1 ± 4.8 % compared with I: 35.4 ± 4.8 %; NS), membrane integrity (A: 58 ± 9% compared with I: 56 ± 9%; NS) and acrosome integrity (A: 65 ± 7% compared with I: 54 ± 7%; NS) were not different between the two extenders. Progressive motility with use of INRA96 was greater after incubating for 30 min than after incubating for 10 min (35 ± 4% vs. 12 ± 4%, respectively; P = 0.03). In conclusion, viable epididymal spermatozoa could be extracted from the castrated organs after overnight transport. There were no differences in sperm quality between the two extenders; therefore, it appears that either extender could be used for alpaca spermatozoa. These results could help in the development of a technique for artificial insemination in alpacas

Season does not have a deleterious effect on proportions of stallion seminal plasma proteins

The mechanism by which the content of the major groups of seminal plasma proteins in stallion semen changes between the breeding and non-breeding seasons remains unknown. Here, we investigated the proportions of non-heparinbinding, phosphorylcholine-binding, and heparin-binding proteins in seminal plasma with the aim of relating them to sperm quality and testosterone levels in good and bad freezer stallions. Only minor variations in the major protein groups were found between the breeding and non-breeding seasons. In the non-breeding season, a higher content of a subset of nonheparin binding proteins as well as of heparin-binding proteins was found. Analysis of semen characteristics revealed a somewhat contrasting picture. While only minor variations in sperm kinematics and sperm morphology were found between seasons, the flow-cytometric measurements of mitochondrial membrane potential and also, to some extent, reactive oxygen species production indicated lower sperm quality in the breeding season. Chromatin integrity and testosterone levels were unchanged between seasons. The results suggest that stallion ejaculates could be used year-round for freezing, since only minor differences in protein composition exist between the breeding and non-breeding seasons, as well as between good and bad freezers. In addition, sperm quality is not impaired during the non-breeding season

The Effect of Cyperus esculentus on Sperm Function Parameters in Prepubertal Mice as a Model for Human

The objective of this work was to study the effect of oral administration of Cyperus esculentus (CE) and its alcoholic extract on sperm function parameters in prepubertal mice as a model for human .The animals were divided into three groups each contains 6 animals .Group 1 was treated with 150 mg/ kg body weight /day of crude CE, group 2 was treated with same dose of alcohol extract of CE and group 3 regarded as control throughout six weeks period. The results showed a significant (p> 0.05) increase in the mean of sperm concentration ,sperm motility percent and progressive sperm motility between treated groups and control . There was no differences among groups in the mean of sperm normal morphology and sperm viability . No significant differences was recorded in the mean of body weight among groups throughout the study. The results revealed that the administration of Cyperus esculentus may enhance certain sperm characters in prepubertal mice without affecting body weight

Seminal plasma components differ between “good freezer” and “poor freezer” stallions

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