Sperm Quality Variables Research Articles

P-982: Diurnal variation of semen quality in human males

In humans, as in most animal species, reproductive processes and fecundity are influenced by seasonal rhythms. There are documented seasonal modifications of reproductive functions and semen parameters in men, although if there is a diurnal variation in semen parameters particularly an improvement around the estimated preferential time for ovulation - is unknown. The objective of our study was to evaluate whether there is a diurnal variation in sperm quality.

Differences in SCSA outcome among boars with different sperm freezability

Spermatozoa from some boars sustain the process of cryopreservation poorly and yield poor fertility after artificial insemination. Poor freezability has not been disclosed using conventional semen analyses. A defective chromatin can, if present in a substantial number of spermatozoa, affect the fertilizing ability of spermatozoa. Here we tested the hypothesis that nuclear DNA instability could explain differences in freezability among boars, and complement or supersede conventional tests for sperm quality such as sperm motility or membrane assessments. Frozen-thawed (FT) spermatozoa from a total of 44 stud boars were assessed by the sperm chromatin structure assay (SCSA), in relation to computer-assisted sperm analysis-derived sperm motility variables and sperm viability (triple fluorescent microscopic staining), including three experiments. The first trial, including 24 boars, evaluated the relationship between the sperm motility and viability with levels of DNA integrity. The SCSA showed that most spermatozoa had intact DNA [levels of DNA fragmentation index (%DFI) ranging from 0.63% to 11.85%] significantly correlated (albeit weakly) with current sperm quality variables. The second trial, on 15 boars, assessed the influence of two different thawing rates (20 s at 37 degrees C vs. 8 s at 70 degrees C) and the post-thaw incubation times (0, 30, 150 and 300 min) at 37 degrees C on FT-boar sperm quality. The highest sperm survival (p < 0.05) and the lowest DNA damage (p < 0.01) were achieved when thawing was carried out at 70 degrees C for 8 s, without any change during the first 150 min of incubation. Finally, the third experiment studied if differences in sperm freezability showed by stud boar semen, as 'good' or 'bad' freezers by conventional analyses, could be attributed to differences in chromatin structure. All SCSA parameters were low, but significantly (p < 0.05-0.001) higher for 'bad' freezers, showing they had less homogeneous sperm chromatin than the 'good' freezers. The results indicate that SCSA outcome complements conventional assessment of FT-boar spermatozoa, disclosing differences in their ability to sustain freezing and thawing. However, the low overall DNA damage observed in FT spermatozoa seems to have poor biological significance.

Among- and within-population variation in sperm quality in the simultaneously hermaphroditic land snail Arianta arbustorum

Sperm competition models on the evolution of sperm size assume associations with another sperm quality trait, sperm longevity. Sperm length can also provide an indication of possible mechanisms affecting motility and thus fertilization success. Despite their importance, however, detailed mechanisms of sperm competition at the gamete level are poorly understood. In simultaneously hermaphroditic land snails, sperm traits and cryptic female choice are assumed to be crucial in determining fertilization success. We examined the variation in sperm length and number among individuals from four natural populations of the land snail Arianta arbustorum, a species with multiple mating and long-term sperm storage. We also assessed variation in velocity, motility and longevity of sperm in snails from two of the four populations. Independent of shell size, sperm length differed among populations and, to a minor extent, even among individuals within populations. Mean sperm length of a snail was not correlated with the number of sperm delivered in a spermatophore. The mean sperm velocity (=VCL) did not differ between snails from two populations. However, VCL varied among snails. Percentage motility and longevity of sperm differed between snails from the two populations. No correlations were found between length, velocity, percentage motility and longevity of sperm. To conclude, individual snails differed in sperm quality, and this variation may partly explain the differential fertilization success between A. arbustorum snails. Moreover, our findings did not support the positive association between sperm length and longevity assumed by sperm competition models for internally fertilizing species.

Role of poor semen quality for current infertility and future fertility rates – lessons from the clinic and current population studies

Role of poor semen quality for current infertility and future fertility rates – lessons from the clinic and current population studies

Effects of solid storage of sheep spermatozoa at 15 °C on their survival and penetrating capacity

This study was designed to evaluate the possible benefits of adding gelatin to a standard milk extender, for solid storage of sheep semen at 15 °C. Solid storage was assessed in terms of effects on sperm motility and membrane integrity up to 2 days (Study 1), and on in vitro penetration capacity after storage for 24 h (Study 2). In both studies, semen was diluted in CONTROL (standard milk extender) and GEL (1.5 g gelatin/100 ml extender) diluents to a final concentration of 400 × 10 6 sperm/ml. In Study 1, semen samples were stored at 15 °C, and sperm quality variables analyzed after 2, 24 and 48 h of storage. Motility and viability values were significantly lowered using the liquid compared to the gel extender for all storage periods, except for motility after 2 h of storage, whose values were similar. After 2 h of incubation at 37 °C, motile cell percentages and membrane integrity were significantly lower in the CONTROL group than in the GEL group for all storage periods. In Study 2, in vitro matured lamb oocytes were randomly divided into three groups and fertilized with CONTROL diluted semen stored for 2 h or 24 h, or with GEL diluted semen stored for 24 h. After co-incubation, oocytes were evaluated for signs of penetration. Storage of semen in the GEL diluent for 24 h gave rise to increased in vitro fertilization rates in comparison with the CONTROL diluent. Our findings indicate that the solid storage at 15 °C of ram spermatozoa by adding gelatin to the extender leads to improved survival and in vitro penetrating ability over the use of the normal liquid extender. A solid diluent could thus be a useful option for the preservation of fresh ovine semen for extended periods.

Sperm Viability Matters in Insect Sperm Competition

Experimental studies in insects have shown how sperm competition can be a potent selective force acting on an array of male reproductive traits . However, the role of sperm quality in determining paternity in insects has been neglected, despite the fact that sperm quality has been shown to influence the outcome of sperm competition in vertebrates . A recent comparative analysis found that males of polyandrous insect species show a higher proportion of live sperm in their stores . Here, we test the hypothesis that sperm viability influences paternity at the within-species level. We use the cricket Teleogryllus oceanicus to conduct sperm competition trials involving prescreened males that differ in the viability of their sperm. We find that paternity success is determined by the proportion of live sperm in a male's ejaculate. Furthermore, we were able to predict the paternity patterns observed on the basis of the males' relative representation of viable sperm in the female's sperm-storage organ. Our findings provide the first experimental evidence for the theory that sperm competition selects for higher sperm quality in insects. Between-male variation in sperm quality needs to be considered in theoretical and experimental studies of insect sperm competition.

Clinical outcomes of IVF/ICSI cycles performed with sperm obtained via epididymal aspiration vs. testicular biopsy

To determine whether there are differences in IVF outcome in patients with sperm obtained via testicular biopsy versus epididymal aspiration. Retrospective data analysis from a large private IVF center. The study included data from 98 women undergoing IVF during 2000–2002. Patients were grouped according to method of sperm collection for their IVF cycles. Thirty-six cycles utilized sperm obtained via epididymal aspiration (EA) and 62 cycles utilized sperm obtained via testicular biopsy (TB). All patients were downregulated with a standard long leuprolide acetate protocol, and underwent controlled ovarian stimulation (COH) using recombinant FSH (rFSH). Final follicular maturation was achieved with urinary hCG when the lead follicle reached at least 17 mm in diameter. Embryos were transferred on day 3. Demographic and cycle data were analyzed via the Mann-Whitney Rank Sum test. Implantation and pregnancy rates were analyzed via the chi-square test. Data are presented as medians (25%-75% range). There were no significant differences noted between the two groups in terms of demographic, stimulation or laboratory data. The EA group had a significantly higher (p=0.005) implantation rate (IR) when compared to the TB group. Clinical pregnancy and live birth rates are reported per cycle start. There was also a trend (p=0.060) towards higher clinical pregnancy rate in the EA group. Live birth rate also tended to be higher in the EA group. All data are summarized below: The group of patients with sperm obtained via epididymal aspiration had a higher implantation rate compared to the testicular biopsy group. The higher IR and trend towards higher clinical pregnancy and birth rate did not appear to be explained by differences in stimulation, follicular or oocyte data. Whether or not these differences were due primarily to variations in sperm quality between obstructive versus non-obstructive azoospermia, or due to other unrelated causes remains to be determined. Unfortunately, detailed embryo data was not available for this analysis and we are currently assessing embryo quality. Patients with EA as the source of their sperm trended towards higher IVF success than patients with TB as their sperm source, though this trend did not reach statistical significance.

Sperm Quality Over Consecutive Spermatophore Regenerations in the Pacific White Shrimp Litopenaeus vannamei

AbstractThe reproductive potential of males plays an important role in the productivity of captive penaeids. Males present a large variability in their reproductive potential, and thus the selection of appropriate males for reproduction is highly desirable. The present study compares sperm quality at the beginning of the experiment (baseline values) with variations in sperm quality as a result of consecutive spermatophore regenerations. This was done to evaluate possible predictive criteria for optimal sperm quality based on morphological and biochemical criteria in pond‐reared Pacific white shrimp Litopenaeus vannamei males. Sperm quality was similar between left and right spermatophore. Sperm count and proportion of normal sperm increased by 86 and 65% (P &lt; 0.05) respectively, from baseline values to third spermatophore regeneration. Proportion of dead sperm progressively decreased with consecutive regenerations, attaining values 33% lower by the third regeneration, compared to baseline values. This indicates that no decrease in sperm quality occurs in L. vannamei during consecutive regenerations and that the existing spermatophores at stocking of males should be expelled to have higher sperm quality in regenerated spermatophores. Furthermore, this procedure allows selecting individuals with high baseline sperm quality based on significant correlations between baseline and regenerated sperm quality observed in the present work. Baseline values of glucose concentration in the hemolymph were positively correlated to baseline values of sperm count (r = 03, P &lt; 0.05). In contrast, baseline values of several lipids in the hemolymph were negatively correlated to several traits of sperm quality at first sampling (baseline values) or at first regeneration. These results are discussed in terms of nutritional requirements of males and of possible predictive criteria of sperm quality.

Secular variations in sperm quality: fact or science fiction?

The debate concerning the possible degradation in human sperm quality began in the 1970s, was revived at the beginning of the 1990s and has continued to mobilize the scientific community ever since. After the meta-analysis by Carlsen et al. (1992) showing a decline in human semen quality over the last 50 years, several groups investigated the sperm characteristics of more or less homogeneous groups of men who had provided semen at the same center for 10 to 20 years. A significant decrease in sperm concentration was reported in some studies, but not in others. Meanwhile, there is an increasing number of reports suggesting that physical and chemical factors introduced and spread by human activity in the environment may have contributed to sperm decline. At the end of the 20th century the debate on declining semen quality is not closed. The lack of certainty and the serious consequences that such a decline would have on the fertility of human populations make this an important public health issue at the start of the 21st century. For this reason, intensive research should be developed in both fundamental and epidemiological domains, particularly in South America, where industrial and agricultural pollution pose a serious threat to the population.

The lack of influence of age on male fertility

Objective: This study was undertaken to determine the effect of male aging on sperm quality as determined by semen analysis, the fertilization rate of human oocytes in vitro, and live birth rates. Study Design: Retrospective analysis correlating outcome measures with male age was performed for 558 oocyte donation cycles in 441 couples. The oocyte donation model was chosen because it controls for oocyte quality and endometrial receptivity, which allows variations in sperm quality as a function of male age to be the only dependent variable. Outcome measures analyzed were semen analysis, fertilization rates in vitro, pregnancy rates, live birth rates, and cumulative live birth rates by life-table analysis. Results: There was a negative correlation between male age and total sperm count, but there was no correlation between male age and any of the other parameters in the semen analysis. There was no association between male age and the fertilization rate of donated oocytes in vitro, pregnancy rates, or live birth rates. Recipient couples were grouped by quartiles of male age, and cumulative live birth rates were the same in the 4 groups. Conclusion: Whereas male aging is associated with a significant decline in total sperm count, this change is not reflected in a decreased fertilization rate or a decreased live birth rate in the oocyte donation model. (Am J Obstet Gynecol 2001;184:818-24.)

Effect of Water Temperature on Reproductive Tract Condition of Penaeus setiferus Adult Males

Abstract— This study was conducted to determine the effect of water temperature on male reproductive tract degenerative syndrome (MRTDS) and male reproductive system melanization (MRSM) in Penaeus setiferus, and to evaluate the effect of water temperature on spermatophore regeneration time and sperm quality in electrically ejaculated adult males. Variation in sperm quality, gonadosomatic index, and histological changes in the reproductive system were used to assess reproductive tract changes in the first experiment. Sperm quality and regeneration time were measured before and after successive regenerations in the second experiment. Sperm quality was stable when shrimp were held at 26 C for 30 d but was reduced when shrimp were held at 30 C. Reproductive tissues of 20% of the shrimp held at 30 C were melanized to some degree but tissue melanization was found in only 2.5% of the shrimp held at 26 C. Spennatophore regeneration time was also affected by temperature. Average times for first spermatophore regeneration were 192 h at 25 C, 152 h at 30 C, and 144 h at 33 C. Sperm quality of regenerated shrimp was not affected at 25 C but was reduced for regenerated animals held at 33 C. Based on these results, we recommend a water temperature between 25 and 27 C to obtain adequate spermatophore regeneration and to maintain healthy male P. setiferus broodstock for at least 30 d.

Reasons for rejecting potential donors from a sperm bank program.

Recruiting donors to a sperm bank program is difficult and slow because of high dropout rates and high rejection rates. The profile of successful and unsuccessful donors was determined at our sperm bank. A total of 199 men was screened from 1986 to 1994 in the anonymous sperm bank donor programs; 174 (87%) men dropped out or did not meet minimum guidelines. The study included 25 accepted donors and 20 rejected men (of 52 rejected donors, only 20 donors who came for two consecutive semen analyses were selected). Sperm quality variables and demographic data were compared between the groups. Accepted donors had significantly better semen quality in motility, velocity, linearity, and ALH than did rejected donors (P < 0.01). More rejected donors than accepted donors were single (P < 0.01). A higher percentage of accepted donors consumed caffeine (P < 0.001), and they were more likely to have college degrees (P < 0.03). These results indicate that loss of interest and poor semen quality were the major reasons for rejection of donors in our anonymous donor sperm bank program.

Changes in seasonality of birth rates in Germany from 1951 to 1990.

PIP: Annual birth rates have been found to be affected up to 10-20% by seasonal variation. Variations affecting birth patterns are attributed to biological and social factors: annual rhythms of climatic conditions, or the photoperiod and varying sexual activity. A recent study placed greater priority on biological factors as responsible for seasonal variation: annual variations in sperm quality, serum levels of luteinizing hormone and testosterone in men, and ovulation variations in women by time of day. Seasonal variations in birth rates were found in Munster, Germany, between 1890-99, 1965-74, and 1981-90. Further examination was made to ascertain whether the variations pertained to the entire country of Germany. Data were obtained on monthly birth rates from 1951 to 1990 from the states of the former West Germany. Annual means were calculated and the monthly deviations from the mean computed (centered moving average with a window size of 13 months), as well as monthly means within 5-year intervals. Yearly cosine functions with 2 harmonics were also fitted to the data. The results showed maximum births in the first half of the year between 1951-75 and later months in the following years until stabilization after 1981. The amplitudes of the rhythms declined from 1972 until stabilizing and increasing after 1978. The annual patterns were smooth and stable with peaks in February and March, and a "shoulder" peak in September, which conforms to long suspected seasonal conceptions in December. The annual rhythms appear to support biologic seasonal variation until 1970. The shift after 1970 to conceptions in the winter months for Germany has also been observed with US data since 1950, and in southern hemisphere countries. The explanation may be environmental changes. The workplace environment has replaced the photoperiod influences and temperature fluctuations, but the shift by 6 months would not support this deseasonalization hypothesis. It is suggested that social reasons have affected the shift, such as the enactment of the liberal abortion law in 1976 and the pregnant woman employment protection act of 1968.

Control of sheep and goat reproduction: Use of light and melatonin

Breeds of sheep and goats from temperate latitudes exhibit seasonal variations of breeding activity which are controlled by annual photoperiodic changes. Short days (SD) stimulate sexual activity, but prolonged exposure results in refractoriness to short days and subsequent cessation of reproductive activity. Refractoriness can be broken by exposing the animals to long days (LD), thus alternations between LD and SD are essential for the photoperiodic control of seasonal reproduction. Light pulses during the dark period can mimic a long day (‘LD’) and melatonin treatments can mimic a short day. For out-of-season control of sexual activity, treatments using the succession ‘LD’-decreasing days or ‘LD’-melatonin were very effective in advancing puberty in young rams in which sperm production was increased, permitting these animals to be submitted earlier for progeny testing, using artificial insemination (AI). In adult rams, such treatments also caused an important increase in testicular weight and sperm production in the spring. In the female goat, the succession ‘LD’-melatonin treatment efficiently induces and maintains oestrous and ovulatory activities in spring, leading to high fecundity after natural mating. This treatment so far appears to be less effective in the seasonal sheep breeds of Northern Europe than in goats. However, melatonin alone can be used after the end of May to advance the breeding season and to increase fecundity. Induction of permanent reproductive activity in rams and bucks was made possible by the observation that monthly alternations between LD and SD (short light cycles) abolished seasonality of behavioural and spermatogenic activities. These males could be used all the year round to produce a high number of AI doses without variations in sperm quality and with no variation in fertility. Short light cycles can be used in open barns by alternating ‘LD’ and melatonin. In contrast, in the ewe, such short light cycles were unable to abolish seasonality of ovulatory activity. Knowledge of the different effects of photoperiod on neuroendocrine pathways and the reproductive activity in sheep and goats has therefore allowed us to successfully apply light treatments to control seasonal reproductive activity in field conditions and in males raised in AI centres.

Seasonal variations of semen quality in male goats: Study of sperm abnormalities

The type, frequency and seasonal variation of sperm abnormalities in male goats inhabiting in Mediterranean region were evaluated. Semen was collected twice a week with an artificial vagina from 9 10-month-old Murciano-Granadina male goats weighing 41 to 48 kg. Distal cytoplasmic droplets and acrosomal damage were the predominant abnormalities. Increase in age (10 to 27 months) did not reveal itself as a main effect on the occurrence of sperm abnormalities. All types of sperm abnormalities studied showed significant (P<0.01) seasonal variation. The poorest quality semen was collected during winter and spring. In spite of a seasonal variation in sperm quality, semen of Murciano-Granadina goats in the Mediterranean area is good all year long, since the proportion of abnormal spermatozoa was well within the accepted range for normal fertility.