Semen coagulum liquefaction, sperm activation and cryopreservation of capuchin monkey (Cebus apella) semen in coconut water solution (CWS) and TES–TRIS

Best practices for cryopreserving sperm in Nonhuman Primates: a systematic review and meta-analysis

Nonhuman primates (NHPs) are in increasing demand as models for preclinical research. The availability of a highly efficient cryopreservation protocol for use with NHP sperm has potential to significantly alleviate this demand and contribute to rapid increases in overall number of NHPs available for biomedical research. Thus, this systematic review assesses the state-of-the-art in NHP sperm cryopreservation and uses meta-analyses to describe the impact of varied cryopreservation approaches on NHP sperm. We searched the literature deposited in PubMed, Scopus, and Web of Science databases through June 2024 to identify data relevant to the effect of sperm cryopreservation on quality of thawed sperm compared to fresh sperm across NHP species. All original NHP studies reporting sperm parameters both before cryopreservation and after thawing were included for analysis. In total, 32 articles were included for qualitative analysis and not surprisingly, all 32 studies demonstrated negative effects of cryopreservation on sperm parameters, Specifically, motility and viability were significantly decreased in thawed NHP sperm. While the method of sperm collection did not have a significant impact on recovery of motile sperm, significant variability was evident between species. Importantly, recovery of motile NHP sperm was greatest following rapid sperm freezing methods. This analysis provides critical insights into future research directions to enhance and optimize cryopreservation protocols in NHPs.

Cryopreservation of spermatozoa from black-and-gold howler monkeys (Alouatta caraya) using egg yolk-based or soy lecithin-based extenders

There are more than 200 species and subspecies of Neotropical Primates of which more than 40% are listed as threatened by the IUCN Red List of Threatened Species. Both in situ and ex situ conservation programs can benefit from the use of assisted reproductive technologies. The objective of this study was to evaluate, for the first time, cryopreservation techniques for Alouatta caraya semen. Semen samples were collected from five adult males, analyzed, and frozen in either Test-egg yolk or Test-soy lecithin-based extenders containing either 3 or 4% glycerol. Frozen-thawed samples were analyzed at 10, 40, and 80 min post-thaw. Egg yolk-based extenders were overall better than soy lecithin-based extenders. There was no significant difference between 3 and 4% glycerol in any of the parameters analyzed, however, 4% glycerol in egg yolk-based extender produced more favorable results for total motility, intact plasma membrane, lipid peroxidation, and DNA fragmentation index. This study brought novel information on semen characteristics and cryopreservation aspects for A. caraya, which can help shape future experiments to improve the outcome of frozen-thawed sperm for this and other species of Neotropical primates.

Effect of Medicago sativa seed powder (Plus vitamin E vs. vitamin E alone) on semen analysis in men with idiopathic infertility: A double blind randomized clinical trial

ETHNOPHARMACOLOGICAL RELEVANCE

Different parts of the alfalfa plant (Medicago sativa L.), especially its seeds, have been introduced as a semen quality enhancer in the folk medicine of different regions of Iran as well as in the traditional Persian medicine (PM) books. The seeds of this plant are also used in many combined medicines to treat male infertility in PM.

AIM OF THE STUDY

This study was designed to investigate the effect of M. sativa seed powder plus vitamin E vs. vitamin E alone on semen analysis of men with idiopathic infertility.

MATERIALS AND METHODS

In this randomized clinical trial, 60 participants were randomly divided into two groups and then received M. sativa seed powder (6 g daily) or placebo for three months, as add-on to vitamin E (100 U). Results of semen analysis (sperm total count, motility, and morphology as well as semen volume) of these two groups and their changes were compared before and after treatment as the primary outcome. The number of pregnancies after one month and probable side effects were also assessed.

RESULTS

After 12 weeks, sperm total count changed from 36.2 ± 21.8 × 106/ml to 48.5 ± 19.1 × 106/ml in M. sativa and from 39.5 ± 23.5 × 106/ml to 41.2 ± 20.9 × 106/ml in placebo, percentage of normal morphology changed from 1.8 ± 0.8% to 2.6 ± 1.2 % in M. sativa and from 2.0 ± 0.9% to 2.6 ± 1.2% in placebo and percentage of motile sperm changed from 36.5 ± 11.8 % to 39.7 ± 12.0% in M. sativa and from 39.3 ± 10.1 % to 38.1 ± 12.1% in placebo. The improvements in M. sativa group are significantly better than placebo group (P = 0.00, 0.01 and 0.04, respectively). However, semen volume decreased in both groups, but its changes were not significant. The number of pregnancies was four in the intervention and zero in placebo group. One case with abdominal bloating and one with respiratory allergy withdrew from the intervention group. No other adverse effect was reported.

CONCLUSIONS

In this study, significant improvement was detected in sperm parameters (except semen volume) of men with idiopathic infertility in M. sativa plus vitamin E group in compare to vitamin E alone after 12 weeks. These findings suggest that the M. sativa, as a complementary therapy, may have a beneficial effect on semen quality. More clinical trials with larger sample size are needed.

Sperm quality and morphometry characterization of cryopreserved canine sperm in ACP-106c or TRIS

Morphological sperm evaluation supported by the morphometry can be used in the determination of the seminal quality and in the investigation of potential extenders. Although there are studies comparing TRIS and ACP extenders, there are no comparative studies between them for the computerized assisted semen analysis (CASA), sperm viability, membrane functionality and sperm morphometry parameters of cryopreserved canine semen. Hence, we aimed to evaluate the effects of ACP-106c and TRIS on post-freezing canine sperm quality. Five dogs were submitted to semen collection twice with one-week interval. The semen was evaluated within the parameters: total motility, vigor, concentration, viability, plasma membrane functionality, morphology and morphometry. In the morphometric evaluation, the morphologically normal sperm was measured as: length, width, area and perimeter of the head and the midpiece, tail length and total length. The parameters of ellipticity, elongation, regularity and roughness were determined. Then, the semen was divided into two aliquots that were diluted in TRIS or ACP-106c, with the addition of egg yolk and glycerol. The diluted semen was refrigerated and frozen. The thawed samples were evaluated. Total motility, viability, sperm membrane functionality and normal morphology reduced after thawing in both extenders (morphology reduced from 89.60 ± 1.3% to 84.40 ± 1.8 and 84.60 ± 1.1% in TRIS and ACP-106c, respectively). However, it did not differ between TRIS and ACP-106c. In the ACP-106c the sperm head defects in cryopreserved semen were higher compared to fresh semen (P < 0.05). For all the morphometric parameters evaluated, there were no differences between fresh and cryopreserved samples (3.70 ± 0.4% vs. 2.30 ± 0.5%). In kinetics, with an interval of one week statistical differences between the extenders were found only in the parameters ALH and LIN (P < 0.05). Regardless of the extender, there were no changes in the morphometric parameters of sperm after thawing.

Reproductive biology of owl (Aotus spp.) and capuchin (Sapajus spp.) monkeys

Studies related to morpho-physiology improve the understanding of biological mechanisms in non-human primates (NHP), contributing to research in several areas, especially those of assisted reproduction and biomedicine. The genera Aotus and Sapajus are important considerations in conducting studies related to reproductive biology and biomedical research, where animals of these genera can serve as models for species with vulnerable conservation status. The reproductive functions of animals of these genera can be used in conducting studies with other NHP species, for which biological material is difficult to access. The aim in conducting the current review was to compile the scientific literature on the biology and reproductive aspects of these two genera, to provide a for a greater understanding of these topics. In addition, a systematic review of literature allows for efficient access relevant information from an extended timeframe collated in a single document. There was, therefore, a systematic search for keywords based on reproductive studies with animals in these genera conducted, and 58 articles, 12 books, and three academic theses were subsequently selected. Even though there have been advances in knowledge of the reproductive biology of animals from these genera that have occurred in recent decades, especially research conducted when these NHP were in captivity, a wide variety of areas remain to be studied so that the understanding of reproduction in these NHP can be enhanced and the knowledge gained from these studies utilized for greater understanding of reproduction of NHP in general.

Herbal foodstuffs in Avicenna's recommended diet to improve sperm quality and increase male fertility; an evidence-based approach

Attention to diet was considered important issues in improvement of men infertility in Persian Medicine (PM). The purpose of this study was to extract herbal foodstuffs introduced by Avicenna, one of the greatest PM physicians to improve the semen production and to provide evidence of their impact on the basis of current studies."Canon of Medicine", the most important Avecinna's book, was searched with keywords equivalent to semen, fertility and infertility, main herbal foodstuffs were extracted and was searched with keywords sperm, semen, infertility, and fertility in Google scholar, PubMed and Scopus databases. Manuscripts from 1950 up to December 2019 were selected and reviewed. Almond, Onion, Chickpea, Garlic, Coconut, Palm date, Sesame, Fenugreek, Carrot, Fig, Grapes, Pistachio, Hazelnut and Walnut are among main foodstuffs which recommended by Avicenna and there is also evidence that they have positive effects on testosterone production and improvement of various sperm parameters, including count, motility and morphology. Containing large amount of different macro and micronutrients such as vitamins including vit B, C, A and E, minerals such as Mg, Se, Zn, Cu and Fe, important unsaturated fatty acids such as linoleic and oleic acids, amino acids such as lysine and arginine and phytochemicals such as polyphenols, flavonoids, triterpenes and steroids can be considered as a main factor in the effectiveness of these foodstuffs. Designing a diet based on the fruits, vegetables, nuts and seeds that Avicenna has recommended, may be effective in treating male infertility but further studies are needed to clarify this issue. Research on the effectiveness of his other recommended foodsuffs may also offer new treatments and supplements for this purpose.

Morphological and ultrastructural changes in seminal coagulum of the squirrel monkey (Saimiri collinsi Osgood, 1916) before and after liquefaction

Studies with squirrel monkey semen are of special interest due to the large amount of coagulation that is a component of the semen, which is a problem that has to be overcome when the objective is harvesting of gametes. In the present study, there was characterization of the seminal coagulum of captive S. collinsi. Four samples of ejaculates were collected using electroejaculation procedures from four animals. The aim in conducting this study was to evaluate seminal coagulum of S. collinsi using histological and scanning electron microscopy (SEM) procedures before and after semen liquefaction in an ACP-118® extender. Seminal coagulum of S. collinsi was composed of a superficial plate (external), which coats the spongy seminal plasma matrix of S. collinsi. Additionally, there were sperm in the external and internal components of the coagulum with these gametes being isolated or grouped and with there being a heterogeneous distribution of gametes. The supplementation of semen with ACP-118® resulted in a partial dissolution of the seminal plate and spongy matrix portions of the seminal coagulum within the first hour of incubation.

Sexual selection and sperm diversity in primates

Many aspects of primate sperm physiology and reproductive behavior have been influenced by sexual selection, especially in taxa exposed to sperm competition where females mate with multiple partners. Primate sperm diversity reflects therefore the evolutionary divergences of the different primate species and the impact of a combination of variables exerting selection pressures on sperm form, function, and competition. Thereby, mating systems, life cycle or ecological variables are some of the important factors driving sperm diversity and explaining variation in terms of sperm morphology, parameters or male sexual characters. Here, we address primate sperm diversity through a compilation of all data available in the literature concerning primate sperm parameters and relationships between them. We also review the factors that can influence primate sperm diversity (e.g. mating systems, trade-off between investments in precopulatory and postcopulatory sexual traits, male and female sexual behaviors, seasonality, social constraints, testosterone levels), and discuss also their relevance to our understanding of human reproduction.

Semen cryopreservation in golden-headed lion tamarin, Leontopithecus chrysomelas

Wild animal genetic resource banking (GRB) represents a valuable tool in conservation breeding programs, particularly in cases involving endangered species such as the golden-headed lion tamarin (Leontopithecus chrysomelas). Thus, we aimed to assess a sperm freezing protocol for golden-headed lion tamarins using two different exenders: BotuBOV® (BB) and Test Yolk Buffer® (TYB). Ejaculates were collected by penile vibrostimulation from animals housed at São Paulo Zoological Park Foundation, São Paulo, Brazil, and after immediate analysis, two aliquots were diluted in BB and TYB. Postthawing samples were evaluated for total and progressive motility, plasma membrane and acrosome integrities, mitochondrial activity, susceptibility to oxidative stress, and sperm-egg-binding. No differences between BB and TYB were found for most seminal parameters, except for acrosome integrity and susceptibility to oxidative stress (in both cases BB showed higher values). However, in spite of these differences and regardless of the extender used, postthaw sperm motility and viability with the described protocol were encouraging (on average >50% and >80%, respectively), indicating that sperm cryopreservation may be a short-term measure for the conservation of golden-headed lion tamarins.

Recovery and cryopreservation of epididymal sperm from domestic cat using powdered coconut water (ACP-117c) and TRIS extenders

Cryopreservation of cats epididymal spermatozoa allows the conservation of the genetic material and the study of the cryogenic effect applied to the gametes of other felines. However, this biotechnique still presents variable results, being necessary the investigation of alternative extenders. Powdered coconut water (ACP-117c) has been efficient in the sperm freezing of several species and in the cat sperm refrigeration. Therefore, we aimed to evaluate the effect of the freezing stages and the quality of the cats' epididymal spermatozoa after thawing, using ACP-117c. Epididymides (n = 36) from 18 cats were processed using TRIS (n = 18) or ACP-117c (n = 18) for sperm recovery. The sperm were immediately evaluated. Then, this was cooled, glycerolized, frozen and thawed, and re-evaluated at each stage for sperm kinetics by Computer Assisted Semen Analysis, viability, functionality (HOST), mitochondrial activity (DAB) and morphology. There was a reduction in total motility and progressive motility after thawing in both groups, and TRIS was superior to ACP-117c. The curvilinear velocity reduced after thawing with ACP-117c. Viability decreased after glycerolization in TRIS. Although it also reduced after thawing in both groups, it was higher in TRIS. There was no change on HOST. Mitochondrial activity decreased during the cryopreservation steps for both extenders. Nevertheless, TRIS presented a higher percentage of spermatozoa from DAB class I and II after thawing. Morphology did not differ between extenders. Therefore, ACP-117c is an alternative for the recovery of cat epididymal spermatozoa; however, it is not efficient for freezing. Glycerolization and thawing are the most critical stages, regardless of the extender.

Monitoring sexual steroids and cortisol at different stages of the ovarian cycle from two capuchin monkey species: use of non- or less invasive methods than blood sampling

Endocrine monitoring of non-human primates (NHP) via faecal metabolites of steroid hormones appears as a useful non-invasive alternative to evaluate the reproductive status of free living NHP, as well as of those kept in captivity but of difficult handling. However, validation is needed with plasma values before its application in the field. The aim of the present study was to monitor the different phases of the menstrual cycle from the new world NHP Sapajus apella and S. libidinosus. For this, hormonal and faecal plasma levels of E₂, P₄ and cortisol were assessed during different days of the menstrual cycle, together with colpocitology. The mean duration of the menstrual cycle according colpocitology was of 21.7 and 21.0 days for S. apella and S. libidinosus, respectively. These values were similar to those observed via plasma analysis, i.e. 22.7 and 20.3 days for S. apella and S. libidinosus, respectively. The day of plasmatic E₂ peak was set as Day -1 and the estimated day of ovulation was set as Day 0 and occurred two days earlier in S. libidinosus than in S. apella females. In both species, it was observed a delay in faecal E₂ peak of six days for S. apella and of 11 days for S. libidinosus when compared with the plasma peak. A maximum P₄ plasma concentration was observed in the middle of luteal phase in S. apella and in S. libidinosus, both at around day 5. However, faecal P₄ peaks were detected at days 9 and 8 in S. apella and S. libidinosus, respectively. Mean plasma and faecal cortisol levels were variable during all ovulatory cycle of S. apella and S. libidinosus females. Although no exact correlation was observed between plasmatic and faecal profile of steroid hormone, faecal samples were able to indicate ovarian cycle phase, being important to assess the reproductive status of the females applying a non-invasive method.

Testicular volume and semen characteristics in the endangered southern muriqui (Brachyteles arachnoides)

BACKGROUND

The southern muriqui (Brachyteles arachnoides) is an endangered Neotropical primate. Semen collection and description of its traits, as well as testicular morphometry, have never been reported for this species.

METHODS

Testicles from five healthy adult captive southern muriqui were measured, and semen was collected by rectal probe electrostimulation (RPE).

RESULTS AND CONCLUSIONS

A solid coagulum was identified in all ejaculates, and none of them liquefied, spontaneously or non-spontaneously. It was possible to collect semen using RPE, and although solids coagula did not liquefy, we managed to describe ejaculates characteristics and also confirmed that southern muriqui have relatively large testes size. Further investigations are needed to improve coagulum handling, to achieve a better spermatozoa recovery aiming its application in assisted reproductive technologies.

Strong Heterogeneity in Advances in Cryopreservation Techniques in the Mammalian Orders

Between 1970 and 2012, vertebrate abundance has declined by 58% with an average annual decline of 2%, calling for serious action to prevent a mass extinction and an irreversible loss of biodiversity. Cryobanks and cryopreservation have the potential to assist and improve ex situ and in situ conservation strategies by storing valuable genetic material. A great deal of studies concerning cryopreservation have been performed within the class Mammalia, although no systematic overview has previously been presented. The objective of this study is therefore to evaluate the status, pattern and future of cryopreservation within Mammalia. A strong disproportional distribution of studies in examined orders is displayed. For the majority of examined orders less than 10% of species has been examined. However, the cryopreservation of germplasm has in several cases been successful and resulted in successful applications of assisted reproductive techniques (ARTs). Various obstacles are associated with the development of cryopreservation protocols, and among them the most prominent is interspecific differences in cryotolerance. Extrapolation of protocols in closely related species is considered the most applicable procedure, and a future supplement to overcome this problem is the examination and comparison of cryobiological traits. Successful protocols have been developed for the vast majority of domesticated mammals, which gives incentive for the further extrapolation of protocols in threatened species.

The effects of Trolox on the quality of sperm from captive squirrel monkey during liquefaction in the extender ACP-118™

The aim of this study was to evaluate the effect of incubating semen for different periods (90, 270 or 450 min) with or without Trolox® (100 or 150 µM) on the quality of sperm from Saimiri collinsi. Sperm motility, vigour, and plasma membrane integrity (PMI) were evaluated in both fresh semen and semen incubated for different time periods, i.e. 90, 270 or 450 min of incubation. Supplementation of semen extender with Trolox® 100 µM improved sperm motility, vigour and PMI for up to 270 min of incubation.

Extender supplementation with catalase maintains the integrity of sperm plasma membrane after freezing–thawing of semen from capuchin monkey

We aimed to evaluate the effect of supplementation of ACP-118® extender with the antioxidant catalase (10 and 50 µg/ml) on Sapajus apella sperm motility, vigour, and plasma membrane integrity during the processes of seminal liquefaction, cooling, and freezing. Catalase did not affect any of the evaluated parameters after semen dilution or cooling. Cryopreserved sperm in the presence of 50 µg/ml catalase presented a plasma membrane integrity similar to that fresh sperm, however.

Recovery of sperm after epididymal refrigeration from domestic cats using ACP-117c and Tris extenders

ABSTRACT We aimed to compare fresh sperm and sperm cooled to 4ºC that had been recovered from the epididymides of cats using powdered coconut water (ACP-117c) and Tris extenders. Sixty epididymides were divided into 6 groups: 10 fresh epididymides were recovered using Tris (T0h); 10 were kept at 4°C/2h and recovered using Tris (T2h); 10 were kept at 4°C/4h and recovered using Tris (T4h); 10 fresh were recovered using ACP-117c (A0h); 10 were kept at 4°C/2h and recovered using ACP-117c (A2h), and 10 were kept at 4°C/4h and recovered using ACP-117c (A4h). The testis-epididymis complexes (TEC) control were not cooled. The others were cooled at 4°C for 2 or 4h. The epididymis was separated and the sperm was recovered by the modified flotation method. Sperm kinetic parameters were evaluated by a computer-system analysis, and vigor, viability, concentration, membrane function and morphology of the sperm were assessed under a light microscope. The progressive motility with ACP-117c declined after 2h of cooling, but did not differ between fresh and 4h. The vigor and membrane function were higher in A4h than A0h. The vigor at T2h and T4h were decreased compared to T0h. T0h was higher than A0h for vigor and sperm membrane function. However, after 4h of cooling, ACP-117c maintained a higher percentage of living cells. Feline epididymal sperm quality can be maintained to the degree necessary for artificial breeding programs following cooling and ACP-117c may be successfully used to recover cat sperm that have been cooled for up to 4h.

Coconut water solutions for the preservation of spleen, ovary, and skin autotransplants in rats

BACKGROUND

The purpose of this study was to evaluate the efficacy of coconut water in the preservation of spleen, ovary, and skin autotransplantations in rats.

METHODS

Fifty female Wistar rats were divided randomly into 5 groups on the basis of the following tissue graft preservation solutions: group 1, lactated Ringer's; group 2, Belzer's solution; group 3, mature coconut water; group 4, green coconut water; and group 5, modified green coconut water. In group 5, the green coconut water solution was modified to obtain the same electrolyte composition as Belzer's solution. The spleen, ovaries, and a skin fragment were removed from each animal, stored for 6 hours in one of the solutions, and then re-implanted. The recoveries of tissue functions were assessed 90 days after surgery by means of spleen scintigraphy and blood tests. The implanted tissues were collected for histological analyses.

RESULTS

Higher immunoglobulin G levels were observed in the animals of group 5 than in the animals of group 1. Differences in follicle-stimulating hormone levels were observed between groups 1 and 2 (P < .001), between groups 4 and 2 (P = .03), and between groups 5 and 2 (P = .01). The spleen scintigraphy results did not differ among the groups. The ovarian tissue was better preserved in the mature coconut water group (P < .007).

CONCLUSIONS

Solutions containing coconut water allowed for the preservation of the spleen, ovaries, and skin for 6 hours, and the normal functions of these tissues were maintained in rats.

Effects of atipamezole and medetomidine administration on seminal variables and functions of erection and ejaculation of the collared peccary (Tayassu tajacu) after electroejaculation

BACKGROUND

Alpha adrenergic drugs are usually used in the treatment of erectile and ejaculatory dysfunction in humans. The influence of such drugs on the seminal characteristics of wild animals has not been verified; whereas their impact on the seminal characteristics and erectile and ejaculatory functions of collared peccaries (Tayassu tajacu) has already been determined. This study aimed at investigating and comparing the effects of medetomidine and atipamezole on the seminal variables of collared peccaries undergoing electroejaculation as well as at determining whether these drugs affected the erectile and ejaculatory functions of this species.

RESULTS

A statistically significant difference in sperm concentration was observed between AP (100.0 ± 26.0 × 106 sperm/ml) and MP (220.2 ± 49.8 × 106 sperm/ml); however, both these treatments did not differ from P treatment (180.0 ± 50.7 × 106 sperm/ml). No statistically significant difference was observed among all treatments with regard to erectile function. With regard to ejaculation time, no significant difference was observed between the MP and AP treatments; however, when compared with the P treatment, AP exhibited a significantly higher difference.

CONCLUSIONS

When collared peccaries were anesthetized with propofol, neither medetomidine nor atipamezole significantly affected the characteristics of the semen or the erectile function, despite the fact that the AP treatment increased ejaculation time. Therefore, the data indicate that using propofol alone is an effective anesthetic protocol for collecting semen in collared peccaries. Other non-injectable anesthetic drugs, such as inhaled anesthetics, may be used in future research to collect semen from peccaries.

Embryo production by parthenogenetic activation and fertilization of in vitro matured oocytes from Cebus apella

The efficiency of in vitro fertilization (IVF) depends on the viability of spermatozoa. For capuchin monkeys (Cebus apella), in vitro capacitation of spermatozoa is challenging because of their unique seminal coagulum. Motile spermatozoa can be obtained after liquefaction of the semen coagulum in coconut water-based solution. The objective of the present study was to establish an optimal in vitro maturation (IVM) protocol for capuchin monkeys and to observe the effect of follicle stimulating hormone (FSH) and luteinising hormone (LH) on IVF and parthenogenetic activation (PA) of oocytes collected from unstimulated females. We assessed spermatozoa quality after recovery from seminal coagulum using the solution ACP-118® as an extender. Oocytes were matured in vitro for 36 or 40 h and subjected to IVF or PA by applying ionomycin combined either with 6-dimethylaminopurine (6-DMAP) or roscovitine. In total, 87% of oocytes reached metaphase II (MII) after 40 IVM and 4-cell embryo production was obtained after IVF and parthenogenesis using ionomycin/6-DMAP. ACP-118® was used successfully to harvest viable spermatozoa from semen coagulum and in the preservation of spermatozoa, which were able to fertilize oocytes in vitro.