Increase In Number Of Sperm Research Articles

The transfer of male cuticular hydrocarbons provides a reliable cue of the risk and intensity of sperm competition in decorated crickets.

Theoretically, males should increase their ejaculate expenditure when the probability of sperm competition occurring (or risk) is high but decrease ejaculate expenditure as the number of competing ejaculates (or intensity) increases. Here we examine whether male decorated crickets (Gryllodes sigillatus) use cuticular hydrocarbons (CHCs) transferred to females by rival males at mating to assess the risk and intensity of sperm competition and adjust their ejaculate accordingly. Unmated females and those perfumed with CHCs extracted from one, three, or five males could be distinguished chemically, providing a reliable cue of the risk and intensity of sperm competition. In agreement with theory, males mating with these females increased sperm number with the risk of sperm competition and decreased sperm number with the intensity of sperm competition. Similarly, as the risk of sperm competition increased, males produced a larger and more attractive spermatophylax (an important non-sperm component of the ejaculate) but these traits did not vary with the intensity of sperm competition. Our results therefore demonstrate that both sperm and non-sperm components of the male ejaculate respond to the risk and intensity of sperm competition in different ways and that CHCs provide males with an important cue to strategically tailor their ejaculate.

Protective role of eugenol against diabetes-induced oxidative stress, DNA damage, and apoptosis in rat testes.

Diabetes mellitus, a metabolic disorder alters gonadal development and spermatogenesis,reactive oxygenspecies production, DNA damage, and apoptosis, which subsequently lead to male subfertility. Eugenol is an antioxidant, traditionally used as medication for digestive disorders and antioxidant therapy, decrease transport of glucose from GIT to systemic circulation. This experiment was aimed to decipher cellular and molecular insights of eugenol in protecting diabetic germ cells in rats. Rats were assigned randomly into five groups: control, eugenol control (Eugenol 400; EUG), diabetic (DIA), diabetic + eugenol 100 (DIA + EUG 100), and diabetic + eugenol 400 (DIA + EUG 400). EUG 400 and DIA + EUG 400 groups received 400 mg/kg eugenol orally. DIA + EUG 100 group received 100 mg/kg eugenol. Treatment was conducted for 4 weeks. Type 1 diabetes was induced by injecting a single i.p. dose of streptozotocin (55 mg/kg). Morphometric, biochemical, sperm parameters, oxidative stress, hormonal levels, histopathology, and fibrosis in the testis and epididymis, were evaluated. DNA damage was evaluated using halo and comet assays; DNA fragmentation and apoptosis using TUNEL assay. Eugenol treatment significantly normalized biochemical parameters, reduced MDA while increased albumin and GSH levels in diabetes. Eugenol significantly increased sperm numbers, motility and attenuated abnormal sperm head morphology in diabetes. Moreover, eugenol significantly reversed diabetes-induced cellular damages, altered spermatogenesis, and collagen deposition in testis and epididymis. It also significantly attenuated diabetes-associated DNA breaks and apoptosis. These findings suggest that 4 weeks treatment with 400 mg/kg of eugenol could be beneficial for diabetic patients to prevent subfertility.

56 Biomarker-Based High Throughput Sperm Phenotyping: the Good, the Bad and the Ugly

Abstract Research in our laboratory addresses the unmet need for developing high throughput phenotyping for collecting comprehensive phenotypes of production, reproduction and fitness traits, a major emphasis area of the USDA Blueprint for Animal Genome Research 2022-2027. Our short- and long-term goal within this emphasis area is to identify specific genomic determinants of aberrant sperm quality and integrity that impart unique morphometric and optical properties on functionally defective spermatozoa that can be captured in next generation flow cytometry at a high speed/throughput, and without the need for costly, time-consuming sample processing. We identified a large set of deleterious gene variants associated with specific sperm defects in the genomes of 85 genetically valuable bulls with suboptimal artificial insemination (AI) fertility. Ongoing efforts focus on developing a second generation, label-free sperm phenotyping pipeline, eliminating variance and costs associated with the conventional, probe-based approaches, based on the specific genomic determinants of aberrant sperm quality resulting in unique morphometric and optical properties of spermatozoa, captured by the next-generation, brightfield image-based flow cytometry (IBFC) and translatable to high-precision phenotyping of heritable production traits. First step is to phenotype and validate rare deleterious polymorphisms associated with aberrant sperm head and tail morphologies in aforementioned cohort of 85 genome-sequenced bulls grouped based on prevailing sperm defect phenotype. Focus is on sperm defects predicted to be heritable and non-compensable by increasing sperm number per AI dose, such as knobbed acrosomes (sperm head caps), nuclear vacuoles and aplastic defects of sperm mitochondrial sheath (the major source of energy to fuel sperm movement). Other potentially heritable defects of interest may not be manifested by aberrant sperm morphologies, and only detectable at subcellular/molecular level by applying biomarkers validated by past and ongoing genome-to-phenotype studies. In the second phase, a label free sperm phenotyping pipeline for bull fertility testing will be developed, translatable to somatic cell phenotyping for other heritable traits by using the dedicated FeatureFinder IFBC software integrated with our machine learning pipeline, followed by validation assessing sperm structural integrity, “gentle” live cell sorting and metabolomics. This approach literary puts artificial intelligence in artificial insemination (AI in AI approach). Altogether, such genome-to-phenome efforts align the livestock genomic selection with state-of-the-art animal andrology, veterinary diagnostics and precision breeding, supporting the improvement of livestock industry efficiency through global approaches integrating production, reproduction, nutrition, health, and welfare.

Role of vitamin E and zinc sulfate in infertile men

Infertility affects 15-30% of couples that are trying to conceive, about half of these cases, male partner is the sole contributing factor. Infertility remains a controversial problem worldwide, male infertility caused by different anatomical defect like obstruction of seminal tube and neurological abnormalities, resulting in abnormal spermatogenesis which weakens the function of sperm.Follow-up study done for 60 infertile men with age range between 30-45 years. Data collected was carried out during the period from April 2019 to August 2019 in Bajii city which include seminal fluid analysis, determination of testosterone, prolactin, and T3 and T4 before and after treatment with vitamin E(800 I.U/daily) and zinc sulfate(50mg/daily) which last for three months , all data were presented as mean and standard deviation. In this study we exclude any disease or abnormal condition that related to this group.There are 60 infertile men participated in this study, age range between 30-45 years. In these cases we measured the seminal fluid analysis, determination of testosterone, prolactin, and T3 and T4 before and after treatment with vitamin E(800 I.U/daily) and zinc sulfate(50mg/daily) which last for three monthsAbout the seminal fluid analysis, there is a significant increase in number of sperm in infertile men after the treatment, and also there is a significant increase in activity of sperm after treatment. Regarding the seminal fluid analysis, there is a significant increase in number of sperm in infertile men after the treatment compared with this before treatment and also there is a significant increase in activity of sperm after treatment compared with this before treatment. About the percentage of non-motile sperm, there is a significant decrease in this percentage after treatment compared with this before treatment, also there is decrease in percentage of abnormal sperm shape after treatment compared with this before treatment, while there is a significant increase in percentage of normal sperm shape after treatment compared with this before treatment About the concentration of prolactin, there is none significant difference between its level after treatment and before treatment. Regarding the concentration of testosterone, there is a significant elevation in its concentration after the treatment compared with its concentration before treatment and About the concentration of T3 and T4, there is none significant difference in its concentration after treatment and before treatment respectively.

Compensability of an enhanced incidence of spermatozoa with cytoplasmic droplets in boar semen for use in artificial insemination: a single cell approach

This single cell study aimed to clarify whether an elevated incidence of sperm with a retained cytoplasmic droplet (CD) can be compensated by a higher sperm number in boar semen doses to maintain fertility. Cluster analysis of motile spermatozoa (ten boars) revealed that spermatozoa with a CD are underrepresented in the fast, linearly moving sperm cohort compared to morphologically normal sperm. Nonetheless, the response to the motility stimulator procaine was barely affected in spermatozoa with distal CD (Cramer’s V = 0.14), but moderately affected in sperm with proximal CD (V = 0.28). Viability was lower in sperm with distal CD (p < 0.05) but not with proximal CD compared to normal sperm during 168 h storage of extended semen samples (n = 11) and subsequent thermic stress. Morphologically normal sperm from normospermic samples (n = 10) or samples with a high incidence (≥ 15%) of sperm with CD (n = 9) had similar motility patterns and responses to procaine. The origin of morphologically normal sperm had no effect on sperm viability (p > 0.05; n = 26). In conclusion, a moderately enhanced prevalence of sperm with CD seems to be compensable by an increase in sperm numbers in boar semen doses.

Sperm competition in yellow dung flies: No consistent effect of sperm size.

The male competition for fertilization that results from female multiple mating promotes the evolution of increased sperm numbers and can impact sperm morphology, with theory predicting that longer sperm can at times be advantageous during sperm competition. If so, males with longer sperm should sire more offspring than competitors with shorter sperm. Few studies have directly tested this prediction, and findings are inconsistent. Here we assessed whether longer sperm provide a competitive advantage in the yellow dung fly (Scathophaga stercoraria; Diptera: Scathophagidae). Initially, we let brothers with different temperature-mediated mean sperm lengths compete - thus minimizing confounding effects of genetic background - and found no clear advantage of longer sperm. We then used flies from lines subjected to bidirectional selection on phenoloxidase activity that had shown correlated evolutionary responses in sperm and female spermathecal duct lengths. This experiment also yielded no main effect of sperm size on siring success. Instead, there was a trend for a shorter-sperm advantage, but only when competing in females with longer spermathecal ducts. Our data corroborated many previously reported findings (last-male precedence, effects of copula duration and body size), suggesting our failure to find sperm size effects is not inherently due to our experimental protocols. We conclude that longer sperm are not competitively superior in yellow dung flies under most circumstances, and that, consistent with previous work, in this species competitive fertilization success is primarily determined by the relative numbers of sperm competing.

The effects of temephos, permethrin and malathion selection on the fitness and fecundity of Aedes aegypti

The recent scale-up of insecticide use has led to the rapid spread of insecticide resistance (IR) in mosquito populations across the world. Previous work has suggested that IR mechanisms could influence mosquito life-history traits, leading to alterations in fitness and key physiological functions. This study investigates to what extent mosquito fitness may be affected in a colony of Aedes aegypti after selection with temephos, permethrin or malathion insecticides. We measured immature development, sex ratio, adult longevity, energetic reserves under different rearing conditions and time points, ingested bloodmeal volume, mosquito size, male and female reproductive fitness and flight capability in the unexposed offspring of the three selected strains and unselected strain. We found that insecticide selection does have an impact on mosquito fitness traits in both male and female mosquitoes, with our temephos-exposed strain showing the highest immature development rates, improved adult survival, larger females under crowded rearing and increased sperm number in males. In contrast, this strain showed the poorest reproductive success, demonstrating that insecticide selection leads to trade-offs in life-history traits, which have the potential to either enhance or limit disease transmission potential.

Effect of Different Parts of &amp;lt;i&amp;gt;Kigelia africana&amp;lt;/i&amp;gt; Fruit Aqueous Extracts on Sperm Parameters and Testis

Kigelia africana is a plant of ivoirian pharmocopae commonly used in infertility treatment. The Kigelia africanawhole fruit extracts are known to improve sperm parameters like density, morphologie and mobility. However, data related to efficiency of different parts of the fruit are lack. The aim of this study was to know the effects of aqueous extracts of the whole Kigelia africana fruit (AP) and of the fruit without the peel (SP) on the sperm parameters and testicular tissue of mice. The phytochemical composition analysis of the SP and AP aqueous extracts of Kigelia africana fruit reveals several secondary metabolites in variable abundance. The sperm densities (Figure 1) of the SP (~78.106 spz/ml ± 2.60) and AP (~96.15 × 106 spz/ml ± 2.44) groups were higher than that of the control (~63.95.106 spz/ml ± 2.93) with a highly significant difference (p Figure 2). However, the percentage of motile spermatozoa was much higher in SP group (~76% ± 5.48%), at least twice as high compared to the control and AP group with a highly significant difference (p s preserve the gonad and enhance spermatogenesis. All together, our data revealed that AP and SP aqueous extracts of Kigelia africana stimulated spermatogenesis, sperm mobility and didn’t affect the gonads. There is however a difference in the effects of the two extracts with better efficacy of AP extracts for increasing sperm number while SP more significantly improves sperm mobility and morphology.

Suppression of Non-Random Fertilization by MHC Class I Antigens.

Hermaphroditic invertebrates and plants have a self-recognition system on the cell surface of sperm and eggs, which prevents their self-fusion and enhances non-self-fusion, thereby contributing to genetic variation. However, the system of sperm–egg recognition in mammals is under debate. To address this issue, we explored the role of major histocompatibility complex class I (MHC class I, also known as histocompatibility 2-Kb or H2-Kb and H2-Db in mice) antigens by analyzing H2-Kb-/-H2-Db-/-β2-microglobulin (β2M)-/- triple-knockout (T-KO) male mice with full fertility. T-KO sperm exhibited an increased sperm number in the perivitelline space of wild-type (WT) eggs in vitro. Moreover, T-KO sperm showed multiple fusion with zona pellucida (ZP)-free WT eggs, implying that the ability of polyspermy block for sperm from T-KO males was weakened in WT eggs. When T-KO male mice were intercrossed with WT female mice, the percentage of females in progeny increased. We speculate that WT eggs prefer fusion with T-KO sperm, more specifically X-chromosome-bearing sperm (X sperm), suggesting the presence of preferential (non-random) fertilization in mammals, including humans.

The traditional Chinese medicine, Monascus-fermented rice, prevents Zn deficiency-induced testis and sperms injury

Monascus purpureus is a fungus used in rice fermentation. Monascus-fermented rice is called red-mold rice (RMR) in Taiwan since the fermentation products contain a considerable amount of red pigments. The protective effects of RMR on oxidative stress in the testis and sperm were evaluated in this study. Zn deficiency was induced in rats by feeding them with a Zn-deficient diet for 12 weeks while the control rats were fed with a normal diet. The Zn-deficient rats were then divided into 6 groups, designated as Zn-deficient (ZD), Zn-compensated (ZC), 1R (151 mg RMR/kg), 5R (755 mg RMR/kg), 1R + ZC (1RZ), and 5R + ZC (5RZ). The animals were administered with the mentioned diet (RMR/Zn) for 8 weeks. In the ZD rats, no spermatid cell formation was observed in the seminiferous tubular epithelia, and testis necrosis/atrophy was apparent. However, 5R and 5RZ administration improved testicular antioxidant enzyme activity, elevated serum testosterone levels, and increased sperm number in ZD rats; this treatment also exhibited inhibitory effects on caspase activities and reactive oxygen species (ROS) levels in the ZD rats, suggesting that RMR attenuated ZD-induced oxidative stress and testis apoptosis. The preventive activity against ZD-induced reproductive damage was more apparent in the 1RZ and 5RZ groups than in the ZC group, suggesting that RMR can serve as a supplement in adjuvant therapy for diseases associated with Zn deficiency.

Flow-induced buckling dynamics of sperm flagella.

The swimming sperm of many external fertilizing marine organisms face complex fluid flows during their search for egg cells. Aided by chemotaxis, relatively weak flows are known to enhance sperm-egg fertilization rates through hydrodynamic guidance. However, strong flows have the potential to mechanically inhibit flagellar motility through elastohydrodynamic interactions-a phenomenon that remains poorly understood. Here we explore the effects of flow on the buckling dynamics of sperm flagella in an extensional flow through detailed numerical simulations, which are informed by microfluidic experiments and high-speed imaging. Compressional fluid forces lead to rich buckling dynamics of the sperm flagellum beyond a critical dimensionless sperm number, Sp, which represents the ratio of viscous force to elastic force. For nonmotile sperm, the maximum buckling curvature and the number of buckling locations, or buckling mode, increase with increasing sperm number. In contrast, motile sperm exhibit a local flagellar curvature due to the propagation of bending waves along the flagellum. In compressional flow, this preexisting curvature acts as a precursor for buckling, which enhances local curvature without creating new buckling modes and leads to asymmetric beating. However, in extensional flow, flagellar beating remains symmetric with a smaller head yawing amplitude due to tensile forces. The flagellar beating frequency also influences the maximum curvature of motile sperm by facilitating sperm reorientation relative to the compressional axis of the flow near stagnation points. These combined simulations and experiments directly illustrate the microscopic elastohydrodynamic mechanisms responsible for inhibiting flagellar motility in flow and have possible implications for our understanding of external fertilization in dynamic marine systems.

Novel ablation technique shows no sperm priming response by male eastern mosquitofish to cues of female availability

Changes in mate availability and sperm competition should generate selection to adjust investments into different pre- and post-copulatory traits so that the product of mating and fertilization success maximize net male reproductive success. Given costly sperm production and the risk of sperm depletion, males should invest strategically in ejaculates. Here, we use the eastern mosquitofish (Gambusia holbrooki), where males have a single coercive mating tactic, to test whether the number of cues indicative of female availability affects the rate of sperm available for mating (so-called sperm priming). We also tested whether plasticity in sperm production varies with male body size. We created four socio-sexual treatments that differ in the number of female-derived cues: none, chemical, chemical and visual, and full access to a female. We used ablation surgery, removing the tip of the male gonopodium (intromittent organ), to prevent males from mating with a female in the treatment where they interacted with females. We hypothesized that elevated sperm priming would be associated with more cues about female availability, and be more apparent in smaller, subordinate males due to their lower baseline sperm count (higher risk of sperm depletion) and their potential disadvantage during premating competition (leading to higher marginal benefits from sperm investment). There was, however, no evidence for sperm priming. The rate of sperm availability for mating and the baseline sperm reserves were, however, dependent on male body size. We discuss possible reasons for our findings. We also note that our study provides novel insights into the proximate mechanisms associated with sperm release in Poeciliids. Our confirmation of the fact that removing the gonopodium tip prevents a male from releasing sperm when housed with a female has many potential applications (e.g., in the study of effects of ejaculate investment and mating effort on male mating success and longevity). When ejaculates are energetically costly, males should strategically adjust sperm production in response to relevant social cues such as female availability. Using four socio-sexual scenarios, we demonstrate that male mosquitofish G. holbrooki do not produce less sperm when housed alone, compared to being exposed only to chemical cues from females, or to chemical and visual cues, or even when allowed full access to a female. The absence of plasticity in sperm production, when compared to that reported in other Poeciliid fishes, suggests that the relationship between sperm number and mating success might depend upon the mating system. If increased sperm number has a small effect on male reproductive success, there might not be selection for plastic shifts in sperm production. We also showed that ablation surgery on the male’s gonopodium allows us to let males interact with females without ejaculating.

Artificial insemination with fresh, liquid stored and frozen thawed semen in dromedary camels.

This study was conducted to evaluate various factors affecting fertility following insemination of dromedary camels. In experiment 1, camels were either bred by natural mating (NM) or inseminated in the body of uterus with whole, split (50:50) or 1 mL of undiluted ejaculate. In experiment 2, camels were inseminated with fresh diluted semen either in the body of the uterus or tip of the uterine horn and at either the time of ovulation induction (0 h), 24 or 30 h later. In experiment 3, camels were inseminated at the tip of the uterine horn with different doses of fresh diluted semen (75, 150 or 300 x 106 motile spermatozoa) or with 150 x 106 motile spermatozoa diluted with different extenders (Green buffer, Optixcell or Triladyl). In experiment 4, camels were inseminated in the tip of the uterine horn with diluted (Triladyl or Optixcell) liquid-stored semen or diluted (Triladyl) frozen-thawed semen consisting of either 300 or 500 x 106 motile spermatozoa. The pregnancy rate in camels bred by NM was similar to camels inseminated with whole undiluted ejaculates whereas insemination with 1 mL undiluted ejaculate resulted in lower pregnancy compared to whole and split undiluted ejaculates (P < 0.05). Deposition of semen in the uterine body resulted in lower pregnancy rates compared to deposition in the tip of the horn (35.3% versus 72.2%, P < 0.05) but insemination at the time of ovulation induction and 24 h later resulted in higher pregnancy rate to camels inseminated at 30 h after induction (68.4 and 70.0% versus 23.5%; P < 0.05). Artificial insemination with 75 x 106 motile spermatozoa resulted in lower pregnancy rates compared to 150 and 300 x 106 motile spermatozoa doses (40.9% versus 65.2 and 70.0%, respectively) and pregnancy rate was not affected by extenders. Insemination of chilled motile spermatozoa stored in either Triladyl or Optixcell resulted in similar pregnancy rates, regardless of insemination dose, although an upward trend with increasing sperm number was apparent (Triladyl; 11.1% versus 21.1% and Optixcell; 5.9% versus 12.5%, for 300 x 106 and 500 x 106 groups, respectively; P > 0.05). No pregnancies were obtained with frozen thawed semen. In conclusion, this study demonstrated that the success of camel AI is highly dependent on sperm dose, location of semen deposition, timing of insemination and semen type. Further studies are required to determine the reason for the compromised fertility of preserved semen despite apparent high in vitro quality.

Protective effects of vitamin E against bisphenol A-induced reproductive toxicity in male Kunming mice

The protective effects of vitamin E (45, 150, and 500 mg/kg/d) against reproductive toxicity induced in male Kunming mice by intragastric administration of 120 mg/kg/d bisphenol A was investigated. After two weeks, relative organ weights, sperm counts, sperm abnormality rates and serum testosterone concentrations were determined. Epididymal sperm counts were significantly decreased, sperm abnormality was increased, and serum testosterone concentrations were dramatically reduced following bisphenol A exposure. Vitamin E treatment led to a marked increase in sperm numbers and a decrease in the proportion of malformed sperm in a dose-related manner; serum testosterone levels were also restored. This suggests that vitamin E could be used as prophylactic agent for preventing bisphenol A-induced reproductive toxicity.

Post-thaw boar sperm motility is affected by prolonged storage of sperm in liquid nitrogen. A retrospective study

Owing to the quick genetic turnover of the pig industry, most AI-boar sires live 2-3 yr, a period during which for 1-2 yr their semen is extended and used in liquid form for AI. Despite showing low cryosurvival, affecting fertility after AI, boar semen is frozen for easiness of transport overseas and reposition of valuable genetics. For the latter, semen is stored in liquid nitrogen (LN2, cryostorage) for many years, a controversial practice. Here we studied how length of cryostorage could affect sperm quality. Straws (0.5 mL) frozen using the same cryopreservation protocol at one specific location from AI- sires of proven fertility were stored in LN2 for up to 8 yr. Post-thaw sperm quality was evaluated after 2, 4 or 8 yr of cryostorage, always compared to early thawing (15 d after freezing). Sperm motility and kinematics were evaluated post-thaw using CASA and sperm viability was cytometrically evaluated using specific fluorophores. Sperm viability was not affected by length of cryostorage, but total and progressive sperm motility were lower (p < 0.01) in sperm samples cryostored for 4 or 8 yr compared to those thawed 15 d after freezing. Cryostorage time affected sperm kinetics, but with greater intensity in the samples cryostored for 4 yr (p < 0.001) than in those for 2 yr (p < 0.01). The fact that the major phenotypic characteristic of boar spermatozoa, motility, is constrained by time of cryostorage should be considered when building cryobanks of pig semen. Attention should be placed on the finding that >2 yr of cryostorage time can be particularly detrimental for the post-thaw motility of some sires, which might require increasing sperm numbers for AI.

No evidence of trade-offs in the evolution of sperm numbers and sperm size in mammals.

Post-copulatory sexual selection, in the form sperm competition, has influenced the evolution of several male reproductive traits. However, theory predicts that sperm competition would lead to trade-offs between numbers and size of spermatozoa because increased costs per cell would result in a reduction of sperm number if both traits share the same energetic budget. Theoretical models have proposed that, in large animals, increased sperm size would have minimal fitness advantage compared with increased sperm numbers. Thus, sperm numbers would evolve more rapidly than sperm size under sperm competition pressure. We tested in mammals whether sperm competition maximizes sperm numbers and size, and whether there is a trade-off between these traits. Our results showed that sperm competition maximizes sperm numbers in eutherian and metatherian mammals. There was no evidence of a trade-off between sperm numbers and sperm size in any of the two mammalian clades as we did not observe any significant relationship between sperm numbers and sperm size once the effect of sperm competition was taken into account. Maximization of both numbers and size in mammals may occur because each trait is crucial at different stages in sperm's life; for example size-determined sperm velocity is a key determinant of fertilization success. In addition, numbers and size may also be influenced by diverse energetic budgets required at different stages of sperm formation.

Gamete evolution and sperm numbers: sperm competition versus sperm limitation.

Both gamete competition and gamete limitation can generate anisogamy from ancestral isogamy, and both sperm competition (SC) and sperm limitation (SL) can increase sperm numbers. Here, we compare the marginal benefits due to these two components at any given population level of sperm production using the risk and intensity models in sperm economics. We show quite generally for the intensity model (where N males compete for each set of eggs) that however severe the degree of SL, if there is at least one competitor for fertilization (N - 1 ≥ 1), the marginal gains through SC exceed those for SL, provided that the relationship between the probability of fertilization (F) and increasing sperm numbers (x) is a concave function. In the risk model, as fertility F increases from 0 to 1.0, the threshold SC risk (the probability q that two males compete for fertilization) for SC to be the dominant force drops from 1.0 to 0. The gamete competition and gamete limitation theories for the evolution of anisogamy rely on very similar considerations: our results imply that gamete limitation could dominate only if ancestral reproduction took place in highly isolated, small spawning groups.

Effects of Hachimijiogan, a Kampo powder, on epididymidis sperm characteristics in healthy male rats.

Hachimijiogan (HJG, Rehmannia Eight Formula), a kidney-replenishing Kampo formula, is clinically known to be effective in the treatment of male infertility with oligozoospermia. The purpose of this study was to evaluate the effect of HJG on the epididymal sperm characteristics and related serum hormone changes in rats in an attempt to determine its mechanism. Male Wistar-Imamichi rats (233.4 ± 5.2 g, nine weeks old) were assigned randomly to four groups (n = 6 for each group). Apart from one control group treated with distilled water, the other groups were administered HJG consecutively for 9-11 days with doses of 250, 500 and 1,000 mg/kg. After the last administration the caude epididymides were quickly removed under anesthesia for assessing sperm characteristics. Additionally, the testes, seminal vesicles, prostate and adrenal glands were removed surgically and their wet weights measured. Results showed that HJG increased sperm numbers and motility as well as the weights of seminal vesicles and adrenal glands at lower doses. Moreover, HJG decreased serum levels of testosterone and luteinizing hormone while increasing follicle-stimulating hormone levels. Our findings may support the conclusion that a lower dosage of HJG has an effect on improving local spermatogenous environments by activating adrenal functions and/or promoting local androgen activity.

The influence of ambient water temperature on sperm performance and fertilization success in three-spined sticklebacks (Gasterosteus aculeatus)

Acute and long-term temperature changes caused by global warming could lead to severe ecological and physiological consequences for aquatic organisms. This might be reflected in a higher mortality rate or a reduced hatching success but elevated temperatures might also lead to accelerated growth and egg development due to higher metabolic rates. Thermal conditions could also act on male gamete function that is known to be under strong sexual selection especially in mating systems where sperm competition frequently occurs. The three-spined stickleback (Gasterosteus aculeatus) is an externally fertilizing fish species. Males are sperm limited over the course of one breeding season and the risk of sperm competition is known to be high. To study the impact of ecologically relevant water temperatures in relation to different sperm numbers on reproductive performance standardized in vitro fertilization experiments were conducted, using two different immediate temperature changes (15 and 25 °C) as all test individuals were held under the same conditions prior to the experiments. The results revealed that fertilization success differed significantly when using different sperm numbers in different water temperatures. At higher temperatures a lower number of sperm was sufficient to fertilize 50 % of the eggs. However, with increasing sperm number fertilization success saturated at 75 % in the 25 °C treatment but at about 90 % in the 15 °C treatment. A further experiment dealt with sperm swimming ability at different temperatures (5, 15 and 25 °C), showing that both sperm velocity and linearity significantly increased whereas the percentage of motile sperm decreased at higher temperatures, suggesting that under these conditions sperm might reach an unfertilized egg more rapidly but live shorter. The observed results stress the role of current and future levels of naturally occurring ambient water temperatures as an important environmental factor influencing fitness related traits.

Spermatid count as a predictor of response to FSH therapy

This study evaluated the predictive power of spermatid count and cytology for assisted reproduction outcome after FSH therapy. A total of 174 men with severe oligozoospermia and normal plasma FSH concentration underwent semen analysis including spermatid count, TUNEL test, FISH analysis for sperm aneuploidies and testicular fine-needle aspiration cytology. Ninety-two men with hypospermatogenesis received FSH therapy for 3months and 82 patients with maturative disturbance or partial obstruction served as controls. Semen was analysed at baseline, after FSH therapy and after 3- and 9-month follow up, and pregnancies were recorded. Subjects not reaching pregnancy at 3-month follow up were recommended assisted reproduction treatment. Spermatid count was related to testicular cytology: spermatid concentrations <0.01, 0.01–0.3 and >0.3×106/ml were predictive of partial obstruction, hypospermatogenesis and maturative disturbance. FSH therapy patients showed increases in sperm number and motility (both P<0.001), allowing some couples to undergo intrauterine insemination instead of IVF. Cumulative pregnancy rate after 12months was higher with FSH therapy (44.6%) than without (22.0%; P=0.002). FSH therapy improved pregnancy rate and sometimes allowed less invasive assisted reproduction treatment in well-selected patients. Spermatid count could represent a new parameter to predict response to FSH therapy.One-hundred seventy-four patients with severe reduction of sperm count and normal sex hormones plasma levels underwent semen analysis with spermatid count, and testicular fine needle aspiration cytologiy (FNAC). Ninety-two men infertile men with reduced sperm production (hypospermatogenesis) were treated with highly purified urofollitropin and 82 patients with sperm maturative defects or partial obstruction of the seminal tract served as controls. After treatment and after the following 3 and 9months all subjects performed a new semen analysis and pregnancies were recorded. Subjects who had not reached spontaneous pregnancy were suggested to undergo assisted reproductive techniques (ARTs). Spermatid count was strongly related to testicular cytology: spermatid concentrations were predictive of partial obstruction, hypospermatogenesis and maturative disturbance respectively. Treated patients showed significant increase in sperm number and motility allowing some couples to undergo easier and less invasive assisted reproductive techniques. The number of pregnancies was significantly higher among treated (44.6%) than untreated couples (22.0%). Our data confirmed that FSH treatment can induce a significant improvemet of pergnancy rate and sometimes allows less invasive ARTs use in well selected severe oligozoospermic patients. Moreover, we suggest that spermatid count can be useful to define tubular status and could represent a new parameter to predict response to FSH therapy.