Cryopreservation of Spanish ibex (Capra pyrenaica) sperm obtained by electroejaculation outside the rutting season

In vitro supplementation of testosterone or prolactin affects spermatozoa freezability in small ruminants

In small ruminants, testosterone and prolactin plasma concentrations show circannual fluctuations as an adaptation mechanism to their seasonal breeding behavior. Sperm resistance to the freezing-thawing process shows seasonal fluctuation throughout the year, with lower sperm freezability at the beginning of the breeding season when prolactin and testosterone levels reach their maximum concentration. Nevertheless, whether these hormones directly affect post-thaw sperm quality parameters is still unclear. The objective was to study the effect of testosterone or prolactin added in vitro on sperm freezability in domestic ram (Ovis aries) and buck (Capra hircus). Sperm samples were incubated for 1 h with a range of testosterone (0, 2, 4, or 6 ng/mL; Exp. 1) or prolactin (0, 20, 100, 200, or 400 ng/mL; Exp. 2) concentrations. Samples were cryopreserved by slow freezing in straws at 0 h and after 1 h incubation. Sperm viability, acrosome integrity, motility, and kinetic parameters were assessed at 0 and 1 h in fresh and frozen-thawed samples. Results showed no hormone effect in fresh sperm, whereas these hormones affected post-thaw sperm parameters. In Exp. 1, in vitro incubation with testosterone decreased the post-thaw acrosome integrity of ram sperm (from 68.1 ± 6.3% to 49.6 ± 3.9%; P < 0.05). In Exp. 2, in vitro incubation with prolactin decreased the post-thaw acrosome integrity of ram (from 78.2 ± 3.4% to 66.3 ± 3.5%; P < 0.05) and buck sperm (from 81.7 ± 2.5% to 67.6 ± 3.5%; P < 0.05). Moreover, prolactin increased the post-thaw amplitude of lateral head displacement in ram sperm (from 3.3 ± 0.1 μm to 3.8 ± 0.2 μm; P < 0.05). In conclusion, either testosterone or prolactin added in vitro decreased the post-thaw acrosome integrity of ram and buck sperm. This suggests a destabilization process that could be decreasing sperm freezability when physiological levels of these hormones are high in vivo.

Semen collection by trans-rectal digital stimulation and insemination campaign in goat

The overall purpose of this study was to describe a method of semen collection via trans-rectal digital massage (TDM) and to carry out a related fertility trial in Angora goat. Sixteen Angora bucks (ranging 1-4 years) and 28 nulliparous does (1-2 years) were used in this study. Semen samples were collected via trans-rectal massage from 85.71% of the bucks in multiple attempts (18/21). The mean values of volume, pH, mass motility, total motility, concentration, viability, abnormal spermatozoa rate and ejaculation time were 0.64 ± 0.09 ml, 6.3 ± 0.21, 2.7 ± 0.34, 58.18 ± 5.1%, 3.68 ± 0.31 × 10⁹ /ml, 71.38 ± 7.12%, 18.22 ± 2.48% and 3.4 ± 0.33 min respectively. Oestrus was detected with teaser buck and confirmed by using infrared thermography and ultrasonography (US). The success rate of synchronisation was found as 71.4% (20/28). On Day 21, pregnancy diagnosis was performed trans-rectally with US and the pregnancy rate was determined as 78.57% (11/14). TDM method of semen collection seems to be easily applicable to the buck and it could be a good alternative to collect semen as well as its use in artificial insemination campaign. Thermal monitoring is found to be a valuable tool to monitor the response to hormonal driven ovulatory synchronisation in Angora does during timed artificial insemination.

Effect of temperature and time after collection on buck sperm quality

BACKGROUND

Different parameters are assessed as part of the semen analysis but a standard protocol for evaluation of goat semen is still missing. The aim of this study was to analyse two different factors affecting buck sperm quality in the post-collection period prior to adding the extender. Here we examined the effects of two handling temperatures (20 °C, 37 °C) and various examination time points (3-30 min) after semen collection.

RESULTS

Examination time point had a significant influence on raw sperm viability (p < 0.05), motility (p < 0.05) and on semen pH (p < 0.05). The two different handling temperatures had no significant effect on sperm viability (p > 0.05), motility (p > 0.05), with the exception of fast moving sperm (p = 0.04), or on semen pH (p > 0.05).

CONCLUSION

Examination time point was identified as factor strongly influencing raw peacock buck semen after collection. Raw goat semen can tolerate room temperatures for at least 10 min without impacting overall semen quality. In order to obtain comparable results, semen samples should always be examined within 10 min after collection.

Sperm collection by electroejaculation in small ruminants: A review on welfare problems and alternative techniques

There are different perspectives on whether there should be use of electroejaculation (EE) for semen collection because it can be stressful and painful for the males when this technique is imposed. In the present review it is examined 1) the effects of EE on animal welfare and semen quality in domestic and wild small ruminants, 2) benefits and limitations of administering anaesthetics and sedatives prior to EE, 3) advantages/disadvantages of transrectal ultrasonic-guided massage of the accessory sex glands (TUMASG) as an alternative to EE, and 4) benefits of administering hormones, such as oxytocin or PGF2α analogues (which stimulate the contractility of the male accessory sex glands), prior to EE and TUMASG. In general, the administration of anaesthetics, sedatives or hormones reduces the pain and stress caused by EE, and can improve sperm quality, but results may vary depending on the species. The use of anaesthetics is, however, not devoid of risks and pre-EE administration of sedatives, or oxytocin or PGF2α analogues, can aid sperm collection mitigate risks. The TUMASG is less stressful than EE, but its effectiveness varies greatly among species, and it can only be performed by trained personnel. Prior administration of the hormones may also result in a reduction in the period needed to induce ejaculation with use of TUMASG procedures.

Spermiotoxicity of commercial condoms made from polyurethane, polyisoprene and latex, using domestic ruminants as an experimental animal model

The use of condoms could provide a means of collecting high-quality spermatozoa from different species under physiological ejaculation conditions. However, certain condom materials may affect sperm functionality. This study examined the spermiotoxicity of different commercial condom materials towards ram and goat spermatozoa. Sperm samples were diluted in Tyrode's medium and placed in contact with a piece of condom material (polyurethane, polyisoprene or latex) and incubated for 30 or 90 min. Contact time in the polyisoprene and latex treatments affected some sperm variables; no such effects were seen, however, in the polyurethane treatments. For ram spermatozoa in contact with polyisoprene, the percentage of dead spermatozoa with a damaged acrosome increased at 90 min, while for spermatozoa in contact with latex, the percentage of live spermatozoa with an intact acrosome decreased. For goat spermatozoa in contact with both polyisoprene and latex, the percentage of dead spermatozoa with a damaged acrosome increased at 90 min, while for spermatozoa in contact with polyisoprene, the percentage of live spermatozoa with an intact acrosome decreased. In conclusion, latex and polyisoprene contain components that affect sperm motility, plasma membrane integrity and acrosome function. Polyurethane does not seem to reduce the quality of semen.

Interactions Among Different Devices and Electrical Stimulus on the Electroejaculation of Captive Agoutis (Dasyprocta leporina)

The interactions among different electroejaculation devices associated with serial or continuous stimuli were investigated to improve the efficiency of the electroejaculation for semen collection in agoutis. Ten sexually matured male Dasyprocta leporina were restrained by the intramuscular administration of xylazine-ketamine association. Each individual was randomly subjected to four electroejaculation protocols, by combining two devices (one presenting longitudinal electrodes emitting square waves and other presenting ring electrodes emitting sine waves) and two electrical stimuli protocols (serial or continuous). A total of 40 attempts for electroejaculation were conducted in agoutis, being 10 per treatment. The most efficient treatment in providing ejaculates containing sperm (p < 0.05) was that using and electroejaculator connected to a probe with ring electrodes and associated with serial stimuli (4/7; 57%). In spite of semen parameters obtained by sine waves were adequate for using the samples for assisted reproduction, higher values for sperm motility and functional membrane integrity were obtained in the use of the square wave, independently of the electric stimulation protocol used (p < 0.05). In conclusion, we verified that the use of a device presenting a probe with ring electrodes and emitting sine waves, associated with a serial stimuli protocol, improves the efficiency for semen obtaining by electroejaculation in adults D. leporina.

Fertilization capacity of cryopreserved Iberian ibex epididymal sperm in a heterologous in vitro fertilization assay

In vitro fertilization (IVF) can be used to assess the fertilization capacity of sperm. Heterologous IVF may be useful when assessing that of wild animals as it is often difficult to obtain adequate numbers of naturally corresponding oocytes. The aim of the present study was to assess the fertilization capacity of frozen–thawed ibex epididymal spermatozoa via heterologous IVF involving the oocytes of prepubertal domestic goats. The effect on fertilization and embryo development of adding oestrous sheep serum (ESS) to the fertilization medium was also examined. Cumulus–oocyte complexes (COCs) were matured in TCM-199 for 24–27 h at 38.5°C in a 5% CO2 in air atmosphere. Frozen–thawed epididymal spermatozoa were selected by density gradient centrifugation. After maturation, the oocytes were co-incubated with spermatozoa in synthetic oviductal fluid (SOF) with different concentrations of ESS: SOF-C (0%), SOF-2 (2%) and SOF-20 (20%). At 17 h post-insemination (hpi), zygotes with one female and one male pronucleus (2PN) were categorised as normal; zygotes with 3PN were recorded as polyspermic, and oocytes with 1PN as asynchronous. Cleavage and blastocyst development were assessed at 48 and 168 hpi respectively. The percentage of zygotes with 2PN was higher in the SOF-2 than in the SOF-20 treatment group (27.7% versus 2.9% P < 0.05). The percentage of blastocysts formed with the SOF-C, SOF-2 and SOF-20 treatments were 1.1%, 7.5% and 0% respectively. These results show that the presence of 2% ESS achieves better results than the use of no serum or the standard 20% concentration. Heterologous IVF may be an effective method for predicting the fertilization capacity of ibex spermatozoa, and therefore perhaps that of other wild mountain ungulates.

Photoperiod and melatonin treatments for controlling sperm parameters, testicular and accessory sex glands size in male Iberian ibex: A model for captive mountain ruminants

This study examines whether photoperiod and/or melatonin treatments can improve sperm variables outside the breeding season in the Iberian ibex-a model species for wild mountain ruminants-thus helping in the collection of high quality sperm beyond the normal breeding season for depositing in genetic resource banks. Adult Iberian ibex males (n=17) were divided into four treatment groups: (1) controls under the natural photoperiod (control group; n=4), (2) treatment with melatonin implants on December 22nd, February 22nd and April 22nd (group WS-M; n=5), (3) treatment with short photoperiod cycles, i.e., 2 months of long days followed by melatonin implants (to emulate 2 months of short days) throughout the year (group PHPld+M; n=4), and (4) treatment with melatonin implants on June 22nd and August 22nd (group SS-M; n=4). The interaction treatment x season had a strong influence on testis size (P<0.05), the size of the seminal vesicles (P<0.001), the percentage of abnormal sperms (P<0.05), and percentage non-progressive (P<0.05) and progressive (P<0.001) sperm motility. In groups WS-M and PHPld+M, the normal springtime physiological reductions in testis size, non-progressive sperm motility and acrosome integrity were prevented. The values for the studied sperm variables were, however, reduced in the natural breeding season at the end of the experimental period in group PHPld+M, although not in group WS-M. The pattern of melatonin administration in group SS-M conferred no advantages on reproductive functionality. These results suggest that lengthening the short day period after the winter solstice (the WS-M treatment) extends reproductive activity in this species, allowing good quality sperm to be recovered for conservation purposes during the non-breeding season.

[Effects of some extenders and monoamines on sperm cryopreservation in tree shrews (Tupaia belangeri)]

The tree shrew may be an important experimental animal for disease models in humans. The effects of some extenders and momamines on sperm cryopreservation will provide helpful data for experimentation of strains and conservation of genetic resources in tree shrews. Epididymal sperm were surgically harvested from male tree shrews captured around Kunming, China and sperm motility, acrosome integrity and fertility were assessed during cryopreservation. In Experiment 1 eight extenders (TTE, TCG, TCF, TTG, BWW, BTS, DM, and SR) supplemented with 0.4 mol/L DMSO were used to dilute the sperm: only TTE, DM and SR showed no differences in motility and acrosome integrity compared to fresh controls after equilibration. After freezing and thawing, sperm in any extender showed lower motility than fresh control and sperm in DM showed higher motility than other groups. However, BWW produced the lowest motility. For acrosome integrity, TTE and DM showed higher than BWW, BTS and SR after equilibration. The parameter in DM was higher than other groups (except TTE) after thawing. In Experiment 2 four penetrating cryoprotectant agents (CPA) [dimethyl-formamide (DF), formamide (F), dimethylacetamide (DA), and acetamide (A)] at 0.2 mol/L, 0.4 mol/L, 0.8 mol/L, and 1.2 mol/L, respectively were added to the DM extender. Motility showed no difference among CPA groups and non-CPA group (control) after equilibration, but all thawed sperm showed lower values in motility and acrosome integrity than pre-freezing groups. However, sperm in 0.8 mol/L DF and 0.4 mol/L DMSO showed higher values in both parameters than that in other CPA groups (P>0.05). In Experiment 3 the fertilization rate of oocytes inseminated with 0.4mol/L DMSO (50%) were higher than that with 0.8mol/L DF (16%). In conclusion, non-ion extenders supplemented with egg yolk may be better for sperm cryopreservation in tree shrews and cryoprotectant effects of monoamines agents should be further studied in this species.

The influence of washing Spanish ibex (Capra pyrenaica) sperm on the effects of cryopreservation in dependency of the photoperiod

Extenders containing low concentrations of egg yolk are recommended for cryopreserving ibex spermatozoa. However, the phylogenetic relationship of the Spanish ibex (Capra pyrenaica) with domestic goats suggests that phospholipases in the seminal plasma may have a negative effect on the response to freezing-thawing when egg yolk-based diluents are employed. The aim of the current work was to determine how seminal plasma removal from Spanish ibex semen, collected by electroejaculation over a period of 1 yr, affects its response to freezing-thawing. Semen was collected from six adult ibexes maintained in captivity. The negative effects of freezing-thawing on the quality of sperm motility and on the integrity of the acrosome and plasma membrane were more serious in the nonwashed semen samples than in those from which the seminal plasma had been removed (P<0.01, P<0.05, and P<0.05 respectively). The beneficial effect of removing the seminal plasma was particularly noticeable during the time of decreasing photoperiod. This suggests that ibex semen shows increased phospholipase activity during the rutting season.