Sperm Utilization Research Articles

Pregnancy outcomes in patients with non-obstructive azoospermia undergoing micro-TESE: comparison of fresh vs. frozen-thawed testicular sperm.

The relative merits of fresh or frozen testicular sperm in ICSI remain a matter of contention. This study aims to compare the reproductive outcomes of non-obstructive azoospermia patients undergoing ICSI using fresh and frozen-thawed microdissection testicular sperm extraction (micro-TESE) sperm. A total of 223 men with non-obstructive azoospermia underwent micro-TESE to collect testicular spermatozoa. ICSI cycles were performed using fresh and frozen-thawed spermatozoa. The cleavage states and grading of embryos, fertilization, and pregnancy outcomes were compared between the groups to assess the impact of cryopreservation of testicular spermatozoa on embryo quality and ICSI outcomes. A total of 223 cases were evaluated, with fertilization observed in 208 cases and no fertilization observed in 15 cases. The number of day 3 total embryos and the number of cleavage embryos differed between the fresh and frozen micro-TESE groups, whereas the number of two-pronuclei oocytes, grading of embryos, fertilization, pregnancy, and live birth rates were found to be similar between the two groups. The cryopreservation of spermatozoa obtained by micro-TESE does not affect the fertilization rate or pregnancy outcome in cases of non-obstructive azoospermia. The present findings, when considered in conjunction with the extant evidence, may serve to alleviate concerns regarding the utilization of frozen-thawed micro-TESE sperm in patients with non-obstructive azoospermia.

P-022 The ICSI Outcome of Frozen Thawed Testicular Sperm Utilization in Azoospermic Men with AZFc Microdeletion

Abstract Study question What is the efficacy of frozen thawed surgically retrieved spermatozoa in azoospermic men with AZFc microdeletion undergoing Introcytoplasmic sperm injection (ICSI)? Summary answer The comparison between frozen thaw to fresh testicular sperm did not show statistically significant difference in terms of fertilization, blastocyst development and pregnancy rates. What is known already In male infertility, Y chromosome microdeletion (YCM) may be the cause up to 10% of men with oligozoospermia or azoospermia. AZFc region deletion was mostly detected in YCM. In men with azoospermia and AZFc deletion spermatozoa can be retrieved via testicular sperm extraction (TESE). Today, couples suffering azoospermia due to AZFc deletion may have genetically own child by using testicular sperm with ICSI. Because of the rare incidence of AZFc deletion, the outcome of ICSI cycles in which frozen thawed spermatozoa utilized for assisted conception has not been widely known. Study design, size, duration The data of 611 men with non-obstructive azoospermia (NOA) who underwent microTESE surgery between 2014 and 2022 was retrospectively analyzed. Assisted reproduction treatment (ART) outcome of couples whose men with AZFc deletion was further analyzed according to the fresh or frozen thawed spermatozoa usage for ICSI. Participants/materials, setting, methods All of the patients were genetically screened with karyotype and Y chromosome microdeletion analysis and microTESE operation was performed for testicular sperm recovery. The patients who diagnosed AZFc deletion and had successful sperm recovery divided to two groups according to cryopreserved or fresh sperm utilization for ICSI. The spouse and men age, fertilization rate, blastocyst development, pregnancy and live birth rate was compared between the groups. Main results and the role of chance Twenty-seven (4.4%) men were diagnosed YMC deletion in total of 611 men with NOA who underwent microTESE. Spermatozoa was successfully retrieved in 14 men (51.8%) men who were diagnosed AZFc deletion. The mean age of women and men were 30.5 (3.5) and 32.8 (4.1) years, respectively. Oocyte retrieval and ICSI were accomplished in 18 cycles. In 7 (38.8%) cycles fresh testicular spermatozoa and in 11(61.2%) cycles frozen thawed testicular spermatozoa were used. In one cycle, embryo transfer was cancelled due to total fertilization failure. In total, fertilization rate as 2PN/M2 oocytes was 57% (119/206). In 5 cycles cleavage stage embryos were transferred whereas in remaining 13 cycles blastocysts were transferred. Blastocyst development rate as day 5 blastocyst/2PN was 45.2% (42/95). Comparison of fertilization and blastocyst development rates according to fresh TESE spermatozoa and frozen thawed TESE spermatozoa groups were 63.2% vs 54.4% and 50.0% vs 38.7% respectively (p > 0.5 for both). Clinical and live birth rates per embryo transfer cycle were 57.1% vs 40.0% and 42.8% vs 30.0% respectively (p > 0.5 for both). Limitations, reasons for caution Fresh and frozen thawed groups demonstrated no statistical difference in terms of ICSI outcome. However, relatively reduced fertilization and blastocyst development rates should be interpreted cautiously because beta type error. Further data is needed to clarify this difference. Wider implications of the findings The best of our knowledge our study is the largest in literature comparing frozen thawed and fresh sperm utilization for ICSI in men with AZFc deletion. This data may help for physicians and couples to give decision diagnostic microTESE surgery and cryopreservation of sperm further ICSI treatment. Trial registration number Not applicable

The utilization of cryopreserved sperm in males with cancer.

e18791 Background: Ten percent of individuals diagnosed with cancer in the United States are under age 45. Fortunately, improvements in cancer therapy have enabled younger individuals to survive with cancer related deaths decreasing steadily over the past 20 years. The American Society for Clinical Oncology (ASCO) recognizes the importance of future family building for cancer survivors and states healthcare providers should discuss fertility preservation options prior to cancer treatment initiation. Despite these recommendations, the data regarding survivor utilization of cryopreservation sperm is limited. The aim of this study is to assess factors that impact the post treatment utilization of cryopreserved sperm. Methods: 721 patients who underwent sperm cryopreservation for cancer indication from 1/1/2010 – 10/1/2020 at a single institution were included in the retrospective chart analysis. Cancer diagnosis, patient age at time of sperm banking, sample storage duration, and sample disposition were collected. Sample disposition included utilization for pregnancy effort(s), request to discard and/or donate to research, and lost to follow up. Descriptive statistics were employed via Excel. Results: Fifty-two of 721 (7.21%, 95% CI 5.4-9.4%) patients utilized their sperm samples for fertility treatment, and 104 patients (14.42%) subsequently requested their samples be discarded. When stratified by age at time of sperm banking, men who banked between the ages of 36 and 40 years had the highest rate of sample utilization for pursuing fertility treatment (12/68, 17.65%, 95% CI 9.5-28.8%). Importantly, those that cryopreserved sperm and subsequently discarded the samples ranged from 8.97% (21 to 25 years) to 28.13% (41 to 45 years). When analyzed by diagnosis, patients who utilized their samples for fertility treatment had varying cancer diagnoses with percent utilization ranging from 4.11% (skin/connective tissue/musculoskeletal cancers) and 20.0% (lung cancer). Overall, 75.59% of the samples collected are unutilized (545/721, 95% CI of 72.3-78.7%). Only 3% were lost to follow up, defined as inability to contact patient after three attempts. Conclusions: Cryopreserved sperm is widely underutilized with only 7.21% of patients utilizing the samples for future conception. Men between ages 36 to 40 years at time of banking are most likely to utilize their samples and utilization varied by cancer diagnosis. This large cohort (with less than 5% lost to follow up) highlights the importance in identifying additional predictors of cryopreserved sperm utilization in cancer survivors. [Table: see text]

The impact of cryopreserved sperm on intrauterine insemination outcomes: is frozen as good as fresh?

Frozen sperm utilization might negatively impact cycle outcomes in animals, implicating cryopreservation-induced sperm damage. However, in vitro fertilization and intrauterine insemination (IUI) in human studies are inconclusive. This study is a retrospective review of 5,335 IUI [± ovarian stimulation (OS)] cycles from a large academic fertility center. Cycles were stratified based on the utilization of frozen (FROZEN, n = 1,871) instead of fresh ejaculated sperm (FRESH, n = 3,464). Main outcomes included human chorionic gonadotropin (HCG) positivity, clinical pregnancy (CP), and spontaneous abortion (SAB) rates. Secondary outcome was live birth (LB) rate. Odds ratios (OR) for all outcomes were calculated utilizing logistic regression and adjusted (adjOR) for maternal age, day-3 FSH, and OS regimen. Stratified analysis was performed based on OS subtype [gonadotropins; oral medications (OM): clomiphene citrate and letrozole; and unstimulated/natural]. Time to pregnancy and cumulative pregnancy rates were also calculated. Further subanalyses were performed limited to either the first cycle only or to the partner's sperm only, after excluding female factor infertility, and after stratification by female age (<30, 30-35, and >35 years old). Overall, HCG positivity and CP were lower in the FROZEN compared to the FRESH group (12.2% vs. 15.6%, p < 0.001; 9.4% vs. 13.0%, p < 0.001, respectively), which persisted only among OM cycles after stratification (9.9% vs. 14.2% HCG positivity, p = 0.030; 8.1% vs. 11.8% CP, p = 0.041). Among all cycles, adjOR (95% CI) for HCG positivity and CP were 0.75 (0.56-1.02) and 0.77 (0.57-1.03), respectively, ref: FRESH. In OM cycles, adjOR (95% CI) for HCG positivity [0.55 (0.30-0.99)] and CP [0.49 (0.25-0.95), ref.: FRESH] favored the FRESH group but showed no differences among gonadotropin and natural cycles. SAB odds did not differ between groups among OM and natural cycles but were lower in the FROZEN group among gonadotropin cycles [adjOR (95% CI): 0.13 (0.02-0.98), ref.: FRESH]. There were no differences in CP and SAB in the performed subanalyses (limited to first cycles or partner's sperm only, after excluding female factors, or after stratification according to female age). Nevertheless, time to conception was slightly longer in the FROZEN compared to the FRESH group (3.84 vs. 2.58 cycles, p < 0.001). No significant differences were present in LB and cumulative pregnancy results, other than in the subgroup of natural cycles, where higher LB odds [adjOR (95% CI): 1.08 (1.05-1.12)] and higher cumulative pregnancy rate (34% vs. 15%, p = 0.002) were noted in the FROZEN compared to the FRESH group. Overall, clinical outcomes did not differ significantly between frozen and fresh sperm IUI cycles, although specific subgroups might benefit from fresh sperm utilization.

Effects of chilled storage and cryopreservation of sperm, and sperm to egg ratio on fertilization success in lumpfish (Cyclopterus lumpus)

Lumpfish males usually release small amounts of milt and are therefore often sacrificed for surgical harvesting of gonads. To optimize the utilization of sperm obtained by dissection of the gonads, a series of small-scale fertilization experiments was carried out in petri dishes. Sperm extracted from homogenized gonads were diluted 1:1 with a commercial extender solution before use (AquaBoost®SpermCoat). Fertilization success was evaluated as percentage eyed eggs ∼120 day-degrees post fertilization. Firstly, the effect of chilled storage (3 °C) of diluted milt were evaluated by fertilizing eggs (2.27 × 105 sperm/egg) from two freshly stripped females every 2nd or 3rd day over a 14-day period. Storage time did not affect the fertilization rates which were high throughout the 14-days trial period (89.1–99.8%). Secondly, the effect of sperm to egg ratio of cryopreserved and chilled stored sperm (3 °C for 3 days) on fertilization rate was investigated and compared by fertilizing eggs from three separate females with six different sperm to egg ratios (1.25 × 105 to 2 × 109). For both storage methods, only the lowest sperm to egg ratio (1.25 × 105) resulted in a significant lower but still high fertilization rate (80.7%). Using freshly extracted sperm at lower sperm to egg ratios (1.25 × 105 to 3.1 × 104) to fertilize eggs from three females revealed, however, no relationship between sperm to egg ratio and fertilization rates as they were high for all ratios (91.2–93.4%). Two additional experiments were undertaken at a real scale to validate the petri dish results at higher egg numbers and volumes. A fixed volume of 40 ml eggs (∼4800 eggs) was fertilized with four sperm to egg ratios ranging from 3.1 × 104 to 5 × 105. All sperm to egg ratios resulted in high fertilization rates ranging from 93.7 to 99%. In the second real scale experiment increasing volumes of eggs (1 up to 160 ml) were fertilized with a fixed sperm to egg ratio (2.5 × 105). The fertilization success (95.9–97.5%) was not affected by egg volume. In conclusion, the current study showed that lumpfish sperm can be chilled stored at 3–4 °C for 14 days and can be cryopreserved and thawed without any significant reduction in fertilization success under the conditions used in this study. Compared to other marine teleosts, lumpfish require a low sperm to egg ratio for successful fertilization, but the critical low ratio to obtain high fertilization was not revealed in this study.

Micro-TESE strategy in patients with NOA caused by AZFc deletion: synchronous or asynchronous?

In the treatment of infertile patients with non-obstructive azoospermia (NOA) caused by the deletion of the azoospermia factor c region (AZFc) on the Y chromosome, synchronous and asynchronous surgical strategies are discussed. Clinical data from NOA patients with the AZFc deletion who underwent micro-TESE were analyzed retrospectively. The sperm retrieval rate (SRR) and sperm utilization rate of synchronous and asynchronous operation groups were followed up and compared. The fertilization rate, high-quality embryo rate, clinical pregnancy rate, abortion rate, and cumulative live birth rate of ICSI in patients with successful sperm retrieval were compared between the two groups. The two groups had sperm utilization rates of 98.9% (93/94) and 50.0% (14/28), respectively. The asynchronous group's sperm consumption rates were much lower than those of the synchronous operation group. Fertilization rate, high-quality embryo rate, clinical pregnancy rate of fresh transfer cycle, abortion rate, and cumulative live birth rate of patients in the synchronous operation group with fresh sperm, and the asynchronous operation group with thawed sperm, respectively, were 30.6% vs 33.8%, 33.8% vs 40.7%, 40.0% vs 12.5%, 30.4% vs 7.1%. Between the two groups, there was no significant difference. This suggests that individuals with NOA caused by the AZFc deletion have a high possibility of successfully acquiring sperm using micro-TESE and ICSI to conceive their own offspring. Synchronous micro-TESE is recommended to improve sperm utilization rate and the cumulative live birth rate.

O-184 The impact of cryopreserved sperm on Intrauterine Insemination (IUI) outcomes: Is frozen as good as fresh?

Abstract Study question Are the outcomes of IUI cycles [with or without ovarian stimulation (OS)] comparable when frozen instead of fresh-ejaculated sperm is utilized? Summary answer Overall, clinical outcomes did not differ significantly between frozen and fresh sperm IUI cycles, although specific subgroups might benefit from fresh sperm utilization. What is known already At present, data from animal studies point towards less favorable outcomes with frozen sperm utilization, implicating cryopreservation-induced damages to the cytoskeleton, DNA, and acrosome leading to adverse effects on spermatozoa’s motility, viability, and ability to fuse with the oocyte. Assisted Reproductive Technology (ART) data, mostly focusing on severe male factor infertility diagnoses, suggest no major differences between in-vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) cycles utilizing frozen over fresh sperm, often surgically extracted. Nevertheless, contemporary data from IUI(±OS) cycles are still scarce. Study design, size, duration Data from 5335 IUI(±OS) cycles (time-period: 01/2004-12/2021) from a large academic fertility center were retrospectively reviewed. Cycles were stratified in two groups based on utilization of frozen instead of fresh-ejaculated sperm for the IUI [FROZEN (n = 1871, all infertility diagnoses), and FRESH (n = 3464, idiopathic infertility diagnosis only), respectively]. Cycle outcomes were compared between groups. Participants/materials, setting, methods Participants: women seeking IUI (±OS) treatments. Outcome Measures: HCG-positivity, clinical pregnancy (CP), spontaneous abortion (SAB) rates. Initial analysis included all cycles irrespective of OS regimen. Cycles were then stratified by OS regimen into three subgroups [injectable gonadotropins, oral medications (OM): clomiphene-citrate and letrozole, and unstimulated/natural]. Odds ratios (OR) for all relevant outcomes were calculated utilizing logistic regression and adjusted for maternal age, day-3 FSH, and OS regimen. Time-to-pregnancy and first-cycle only analyses were also performed. Main results and the role of chance Unadjusted HCG-positivity, and CP were lower in the FROZEN compared to the FRESH group (12.2% vs. 15.6%, p &amp;lt; 0.001; 9.4% vs. 13.0%, p&amp;lt;.001, respectively), which persisted only among OM after stratification (9.9% vs. 14.2% HCG-positivity, p=.030; 8.1% vs. 11.8% CPR, p=.041, for FROZEN compared to FRESH, respectively). Among all cycles, adjOR(95%CI) for HCG-positivity and CP were respectively: 0.75(0.56-1.02), and 0.77(0.57-1.03), ref: FRESH). Following stratification by OS regimen, adjOR(95%CI) for HCG-positivity and CP showed no difference between groups among gonadotropin and natural cycles but favored the FRESH group in OM cycles [HCG-positivity: 0.55(0.30-0.99); CP: 0.49(0.25-0.95), ref.: FRESH]. SAB odds did not differ between groups among OM and natural cycles but were lower in the FROZEN compared to FRESH group among gonadotropin cycles [adjOR(95%CI): 0.13(0.02-0.98), ref.: FRESH]. However, regarding the latter comparison, numbers were small and the 95%CI wide. When analysis was limited to first-cycles only and further stratified by OS regimen, the previously noted differences in CP and SAB odds no longer existed within the OS subgroups. Nevetheless, time-to-conception was slightly longer in the FROZEN compared to the FRESH group (3.84 vs. 2.58 cycles, p&amp;lt;.001). Limitations, reasons for caution Study is limited by its retrospective nature. The two groups differed somewhat in age, infertility diagnosis, utilized OS regimen, and as expected in total motile sperm counts. Despite the less favorable characteristics of the FROZEN group, no detrimental effect of sperm cryopreservation on IUI outcomes was noted. Wider implications of the findings Our study, the largest to date, showed no significant difference in IUI outcomes between cycles utilizing frozen instead of fresh-ejaculated sperm. Although, specific subgroups might benefit from fresh sperm utilization and time-to-pregnancy might be shorter with fresh over frozen sperm, patients should be counselled about the non-inferiority of frozen sperm. Trial registration number Not applicable

Economic and environmental evaluation of sex sorted sperm utilization in dairy and integrating dairy-beef production systems in Japan

Economic and environmental evaluation of sex sorted sperm utilization in dairy and integrating dairy-beef production systems in Japan

Exploring the effects of extreme polyandry on estimates of sexual selection and reproductive success

Abstract Multiple mating by females can dramatically alter selection on males by creating indirect interactions between rivals via sperm competition. Exactly how this behavior alters the relationship between male mating and fertilization success depends on multiple factors: re-mating frequency, sperm usage patterns, and mating assortment (the extent to which the most promiscuous individuals mate with each other). Here, we explore the role these elements play in determining sexual selection in a highly polygyandrous species, the squash bug Anasa tristis. Using replicated semi-natural enclosures, in which individuals were able to freely interact for a 2-week period, we tracked matings between individuals and subsequent female offspring production. Multiple mating was extremely common, resulting in very high levels of sperm competition intensity. However, network analysis revealed that the most promiscuous males mated with less polyandrous females, and therefore experienced lower levels of sperm competition. As a result, estimated male reproductive success increased with mating success, but this relationship varied according to the mode of sperm utilization with which it was calculated. Furthermore, females with more mating partners produced more offspring, suggesting they also benefit from mating multiply. Our findings highlight that polyandry has numerous and complex effects on sexual selection which may only be exposed when examined under naturalistic conditions.

Male and Female Fertility: Prevention and Monitoring Hodgkin' Lymphoma and Diffuse Large B-Cell Lymphoma Adult Survivors. A Systematic Review by the Fondazione Italiana Linfomi.

Simple SummaryPatients with Hodgkin lymphoma or diffuse large B-cell lymphoma treated with chemotherapy, with or without radiation therapy on pelvic nodes, may suffer permanent damage to their reproductive function, which significantly affects their quality of life. Established gamete cryopreservation techniques, including the freezing of embryos, oocytes, spermatozoa, ovarian and testicular tissue, can, nowadays, be offered to any adult patient candidate receiving gonadotoxic therapy who is interested in preserving future fertility. In order to offer updated information on anticancer treatment harm and to better advise patients on fertility preservation options, Fondazione Italiana Linfomi (FIL) researchers conducted this systematic review to evaluate the frequency of treatment-related infertility, fertility preservation options, fertility assessment measures, and the optimal interval between end of treatment and conception in adult lymphoma patients.Background: Adult patients with Hodgkin lymphoma (HL) and diffuse large B-cell lymphoma (DLBCL) have prolonged survival but face the risk of treatment-induced impaired fertility. This systematic review, conducted by Fondazione Italiana Linfomi (FIL) researchers, aims to evaluate the incidence of treatment-related infertility, fertility preservation options, fertility assessment measures, and the optimal interval between the end of treatment and conception. Methods: MEDLINE, the Cochrane Library, and EMBASE were systematically searched up to September 2020 for published cohort, case–control, and cross-sectional studies on fertility issues. Results: Forty-five eligible studies were identified. Gonadotoxicity was related to sex, type and dosage of treatment, and, in females, to age. After receiving alkylating-agent-containing regimens, less than 30% of males recovered spermatogenesis, and 45% of females ≥30 years in age retained regular menstrual cycles. Sperm cryopreservation was offered to the majority of patients; sperm utilization resulted in a 33–61% pregnancy rate. After ovarian tissue transplantation, the spontaneous pregnancy and live birth rates were 38% and 23%; after IVF, the live birth rate was 38.4%. No data could be extracted on the utilization rate of cryopreserved mature oocytes. The results of studies on GnRH analogs are controversial; therefore, their use should not be considered an alternative to established cryopreservation techniques. Sperm count, FSH, and inhibin-B levels were appropriate measures to investigate male fertility; serum AMH levels and antral follicle count were the most appropriate markers for ovarian reserve. No data could be found regarding the optimal interval between the end of treatment and conception. Conclusions: The risk of infertility should be discussed with adult lymphoma patients at the time of diagnosis, and fertility preservation options should be proposed before first-line treatment with alkylating-agent-containing regimens.

Game-Changing Approaches in Sperm Sex-Sorting: Microfluidics and Nanotechnology.

Simple SummarySexing of sperm cells, including the capacity to preselect the sex of offspring prior to reproduction, has been a major target of reproductive biotechnology for a very long time. The advances in molecular biology, biophysics, and computer science over the past few decades, as well as the groundbreaking new methods introduced by scientists, have contributed to some major breakthroughs in a variety of branches of medicine. In particular, assisted reproduction is one of the areas in which emerging technologies such as nanotechnology and microfluidics may enhance the fertility potential of samples of sex-sorted semen, thus improving the reproductive management of farm animals and conservation programs. In human medicine, embryo sex-selection using in vitro fertilization (IVF) and preimplantation genetic testing (PGT) is accepted only for medical reasons. Using sex-sorting before IVF would enable specialists to prevent sex-linked genetic diseases and prevent the discharge of embryos which are not suitable for transfer due to their sex.The utilization of sex-sorted sperm for artificial insemination and in-vitro fertilization is considered a valuable tool for improving production efficiency and optimizing reproductive management in farm animals, subsequently ensuring sufficient food resource for the growing human population. Despite the fact that sperm sex-sorting is one of the most intense studied technologies and notable progress have been made in the past three decades to optimize it, the conception rates when using sex-sorted semen are still under expectations. Assisted reproduction programs may benefit from the use of emergent nano and microfluidic-based technologies. This article addresses the currently used methods for sperm sex-sorting, as well as the emerging ones, based on nanotechnology and microfluidics emphasizing on their practical and economic applicability.

Expression of Mst89B and CG31287 is Needed for Effective Sperm Storage and Egg Fertilization in Drosophila

In Drosophila, male reproductive fitness can be affected by any number of processes, ranging from development of gametes, transfer to and storage of mature sperm within the female sperm storage organs, and utilization of sperm for fertilization. We have previously identified the 89B cytogenetic map position of D. melanogaster as a hub for genes that effect male paternity success when disturbed. Here, we used RNA interference to test 11 genes that are highly expressed in the testes and located within the 89B region for their role in sperm competition and male fecundity when their expression is perturbed. Testes-specific knockdown (KD) of bor and CSN5 resulted in complete sterility, whereas KD of CG31287, Manf and Mst89B, showed a breakdown in sperm competitive success when second to mate (P2 < 0.5) and reduced fecundity in single matings. The low fecundity of Manf KD is explained by a significant reduction in the amount of mature sperm produced. KD of Mst89B and CG31287 does not affect sperm production, sperm transfer into the female bursa or storage within 30 min after mating. Instead, a significant reduction of sperm in female storage is observed 24 h after mating. Egg hatchability 24 h after mating is also drastically reduced for females mated to Mst89B or CG31287 KD males, and this reduction parallels the decrease in fecundity. We show that normal germ-line expression of Mst89B and CG31287 is needed for effective sperm usage and egg fertilization.

Drosophila seminal sex peptide associates with rival as well as own sperm, providing SP function in polyandrous females.

When females mate with more than one male, the males' paternity share is affected by biases in sperm use. These competitive interactions occur while female and male molecules and cells work interdependently to optimize fertility, including modifying the female's physiology through interactions with male seminal fluid proteins (SFPs). Some modifications persist, indirectly benefiting later males. Indeed, rival males tailor their ejaculates accordingly. Here, we show that SFPs from one male can directly benefit a rival's sperm. We report that Sex Peptide (SP) that a female Drosophila receives from a male can bind sperm that she had stored from a previous male, and rescue the sperm utilization and fertility defects of an SP-deficient first-male. Other seminal proteins received in the first mating 'primed' the sperm (or the female) for this binding. Thus, SP from one male can directly benefit another, making SP a key molecule in inter-ejaculate interaction.

Assisted reproductive technology with donor sperm: national trends and perinatal outcomes

Information regarding the use of donor sperm in assisted reproductive technology, as well as subsequent treatment and perinatal outcomes, remains limited. Outcome data would aid patient counseling and clinical decision making. The objectives of the study were to report national trends in donor sperm utilization and live birth rates of donor sperm-assisted reproductive technology cycles in the United States and to compare assisted reproductive technology treatment and perinatal outcomes between cycles using donor and nondonor sperm. We hypothesize these outcomes to be comparable between donor and nondonor sperm cycles. This was a retrospective cohort study using data from all US fertility centers reporting to the Centers for Disease Control and Prevention's National Assisted Reproductive Technology Surveillance System, accounting for ∼98% of assisted reproductive technology cycles (definition excludes intrauterine insemination). The number and percentage of assisted reproductive technology cycles using donor sperm and rates of pregnancy, live birth, preterm birth (<37 weeks), and low birthweight (<2500 g) were the primary outcomes measured. Treatments assessed include use of donor vs nondonor sperm. The trends analysis included all banking and fresh assisted reproductive technology cycles using donor and autologous oocytes performed between 1996 and 2014 (n= 1,710,034). The outcomes analysis was restricted to include only fresh autologous cycles performed between 2010 and 2014 (n= 437,569) to focus on cycles with a potential outcome and cycles reflective of current practice, thereby improving the clinical relevance. Cycles canceled prior to retrieval were excluded. Statistical analysis included linear regression to explore polynomial trends and log-binomial regression to estimate relative risk for outcomes among cycles using donor and nondonor sperm. Of all banking and fresh donor and autologous oocyte assisted reproductive technology cycles performed between 1996 and 2014, 74,892 (4.4%) used donor sperm. In 2014, 7351 assisted reproductive technology cycles using donor sperm were performed, as compared with 1763 in 1996 (6.2% vs 3.8% of all cycles). Among all autologous oocyte cycles performed between 2010 and 2014, the live birth rate was lower for donor sperm (27.9%) than nondonor sperm cycles (32.5%); however, after adjustment for maternal age, donor sperm use was associated with an increased likelihood of live birth (adjusted relative risk, 1.06, 95% confidence interval, 1.01-1.10). Per transfer, there was no significant difference in live birth rates for donor vs nondonor sperm (31.9% vs 36.8%; adjusted relative risk, 1.04, 95% confidence interval, 0.998-1.09). Per singleton live birth, there was no significant difference in preterm birth (11.5% vs 11.8%; adjusted relative risk, 0.98, 95% confidence interval, 0.90-1.06); however, low birthweight delivery was slightly lower in donor sperm cycles (8.8% vs 9.4%; adjusted relative risk, 0.91, 95% confidence interval, 0.83-0.99). Donor sperm use in assisted reproductive technology has increased in the United States, accounting for approximately 6% of all assisted reproductive technology cycles in 2014. Assisted reproductive technology treatment and perinatal outcomes were clinically similar in donor and nondonor sperm cycles.

Assisted reproductive technology with donor sperm: national trends and perinatal outcomes

Background Information regarding the use of donor sperm in assisted reproductive technology, as well as subsequent treatment and perinatal outcomes, remains limited. Outcome data would aid patient counseling and clinical decision making. Objectives The objectives of the study were to report national trends in donor sperm utilization and live birth rates of donor sperm–assisted reproductive technology cycles in the United States and to compare assisted reproductive technology treatment and perinatal outcomes between cycles using donor and nondonor sperm. We hypothesize these outcomes to be comparable between donor and nondonor sperm cycles. Study Design This was a retrospective cohort study using data from all US fertility centers reporting to the Centers for Disease Control and Prevention’s National Assisted Reproductive Technology Surveillance System, accounting for ∼98% of assisted reproductive technology cycles (definition excludes intrauterine insemination). The number and percentage of assisted reproductive technology cycles using donor sperm and rates of pregnancy, live birth, preterm birth ( Results Of all banking and fresh donor and autologous oocyte assisted reproductive technology cycles performed between 1996 and 2014, 74,892 (4.4%) used donor sperm. In 2014, 7351 assisted reproductive technology cycles using donor sperm were performed, as compared with 1763 in 1996 (6.2% vs 3.8% of all cycles). Among all autologous oocyte cycles performed between 2010 and 2014, the live birth rate was lower for donor sperm (27.9%) than nondonor sperm cycles (32.5%); however, after adjustment for maternal age, donor sperm use was associated with an increased likelihood of live birth (adjusted relative risk, 1.06, 95% confidence interval, 1.01–1.10). Per transfer, there was no significant difference in live birth rates for donor vs nondonor sperm (31.9% vs 36.8%; adjusted relative risk, 1.04, 95% confidence interval, 0.998–1.09). Per singleton live birth, there was no significant difference in preterm birth (11.5% vs 11.8%; adjusted relative risk, 0.98, 95% confidence interval, 0.90–1.06); however, low birthweight delivery was slightly lower in donor sperm cycles (8.8% vs 9.4%; adjusted relative risk, 0.91, 95% confidence interval, 0.83–0.99). Conclusion Donor sperm use in assisted reproductive technology has increased in the United States, accounting for approximately 6% of all assisted reproductive technology cycles in 2014. Assisted reproductive technology treatment and perinatal outcomes were clinically similar in donor and nondonor sperm cycles.

Differential sperm storage by female zebra finches Taeniopygia guttata.

When females mate promiscuously, female sperm storage provides scope to bias the fertilization success towards particular males via the non-random acceptance and utilization of sperm. The difficulties observing post-copulatory processes within the female reproductive tract mean that the mechanisms underlying cryptic female choice remain poorly understood. Here, we use zebra finches Taeniopygia guttata, selected for divergent sperm lengths, combined with a novel technique for isolating and extracting sperm from avian sperm storage tubules (SSTs), to test the hypothesis that sperm from separate ejaculates are stored differentially by female birds. We show that sperm from different inseminations enter different SSTs in the female reproductive tract, resulting in almost complete segregation of the sperm of competing males. We propose that non-random acceptance of sperm into SSTs, reflected in this case by sperm phenotype, provides a mechanism by which long sperm enjoy enhanced fertilization success in zebra finches.

Benefits of polyandry: Molecular evidence from field-caught dung beetles.

When females mate with multiple males, they set the stage for postcopulatory sexual selection via sperm competition and/or cryptic female choice. Surprisingly little is known about the rates of multiple mating by females in the wild, despite the importance of this information in understanding the potential for postcopulatory sexual selection to drive the evolution of reproductive behaviour, morphology and physiology. Dung beetles in the genus Onthophagus have become a laboratory model for studying pre- and postcopulatory sexual selection, yet we still lack information about the reproductive behaviour of female dung beetles in natural populations. Here, we develop microsatellite markers for Onthophagus taurus and use them to genotype the offspring of wild-caught females and to estimate natural rates of multiple mating and patterns of sperm utilization. We found that O.taurus females are highly polyandrous: 88% of females produced clutches sired by at least two males, and 5% produced clutches with as many as five sires. Several females (23%) produced clutches with significant paternity skew, indicating the potential for strong postcopulatory sexual selection in natural populations. There were also strong positive correlations between the number of offspring produced and both number of fathers and paternity skew, which suggests that females benefit from mating polyandrously by inciting postcopulatory mechanisms that bias paternity towards males that can sire more viable offspring. This study evaluates the fitness consequences of polyandry for an insect in the wild and provides strong evidence that female dung beetles benefit from multiple mating under natural conditions.

The contrasting role of male relatedness in different mechanisms of sexual selection in red junglefowl.

In structured populations, competition for reproductive opportunities should be relaxed among related males. The few tests of this prediction often neglect the fact that sexual selection acts through multiple mechanisms, both before and after mating. We performed experiments to study the role of within‐group male relatedness across pre‐ and postcopulatory mechanisms of sexual selection in social groups of red junglefowl, Gallus gallus, in which two related males and one unrelated male competed over females unrelated to all the males. We confirm theoretical expectations that, after controlling for male social status, competition over mating was reduced among related males. However, this effect was contrasted by other sexual selection mechanisms. First, females biased male mating in favor of the unrelated male, and might also favor his inseminations after mating. Second, males invested more—rather than fewer—sperm in postcopulatory competition with relatives. A number of factors may contribute to explain this counterintuitive pattern of sperm allocation, including trade‐offs between male investment in pre‐ versus postcopulatory competition, differences in the relative relatedness of pre‐ versus postcopulatory competitors, and female bias in sperm utilization in response to male relatedness. Collectively, these results reveal that within‐group male relatedness may have contrasting effects in different mechanisms of sexual selection.

Sexual selection for genetic compatibility: the role of the major histocompatibility complex on cryptic female choice in Chinook salmon (Oncorhynchus tshawytscha).

Cryptic female choice (CFC), a form of sexual selection during or post mating, describes processes of differential sperm utilization by females to bias fertilization outcomes towards certain males. In Chinook salmon (Oncorhynchus tshawytscha) the ovarian fluid surrounding the ova of a given female differently enhances the sperm velocity of males. Sperm velocity is a key ejaculate trait that determines fertilization success in externally fertilizing fishes, thus the differential effect on sperm velocity might bias male fertilization outcomes and represent a mechanism of CFC. Once sperm reach the oocyte, CFC could potentially be further facilitated by sperm-egg interactions, which are well understood in externally fertilizing marine invertebrates. Here, we explored the potential genetic basis of both possible mechanisms of CFC by examining whether the genotypic combinations of mates (amino-acid divergence, number of shared alleles) at the major histocompatibility complex (MHC) class I and II explain the variation in sperm velocity and/or male fertilization success that is not explained by sperm velocity, which might indicate MHC-based sperm-egg interactions. We recorded sperm velocity in ovarian fluid, employed paired-male fertilization trials and evaluated the fertilization success of each male using microsatellite-based paternity assignment. We showed that relative sperm velocity was positively correlated with fertilization success, confirming that the differential effect on sperm velocity may be a mechanism of CFC in Chinook salmon. The variation in sperm velocity was independent of MHC class I and II. However, the MHC class II divergence of mates explained fertilization success, indicating that this locus might influence sperm-egg interactions.

Effects of Repeated Partial Thaw and Refreeze on Post-Thaw Parameters of Stallion Semen Cryopreserved in Cryovials

The current study evaluated post-thaw semen parameters of stallion semen cryopreserved in cryovials and subjected to multiple partial thaw-refreeze cycles. Five fertile stallions were collected twice, and ejaculates were analyzed for concentration, percent membrane integrity, motility, morphology, and sperm chromatin structure (SCSA). Semen processed with freezing extender from each ejaculate was cryopreserved in both 1.2-mL cryovials and 0.5-mL straws. Cryovials were subjected to eight subsequent partial thaw-refreeze cycles. Cryovials were warmed for approximately 30 seconds; then, a sample of cryopreserved semen was removed with a 16-gauge needle, and the cryovial was immediately refrozen in liquid nitrogen. A piece of 0.5-mL straw cut under liquid nitrogen from the same stallion and ejaculate was thawed alongside each cryovial to serve as a control. Thawed samples were analyzed for percent membrane integrity, motility, and SCSA. Post-thaw parameters of motility and membrane integrity were analyzed by one-way or two-way analysis of variance with repeated measures when appropriate. The SCSA data were analyzed using a mixed regression model. Post-thaw motility and percentage of intact sperm were significantly lower when sperm was cryopreserved in cryovials compared to straws. However, these parameters may remain adequate for use in assisted reproductive techniques (ARTs) such as intracytoplasmic sperm injection through all cryovial thaws. Additionally, DNA denaturability was not affected by semen packaging method and was only affected by thaw number, increasing at post-thaws 5 and 6. This technique may offer a unique approach for cryopreservation and utilization of stallion sperm for ARTs in the future.