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PubMed1994

Evaluation of different sperm function tests as screening methods for male fertilization potential--the value of the sperm migration test.

OBJECTIVE: To assess the value of different sperm function screening tests in predicting fertilization. DESIGN: Prospective study. SETTING: Academic tertiary referral center for fertility treatment. PATIENTS: Ninety-five couples attending for initial screening and IVF-ET. Only cycles where three or more grade I oocytes were collected were included, and patients with endometriosis were excluded. INTERVENTIONS: Each patient had a standard semen analysis, cervical mucus (CM) penetration test, hypo-osmotic swelling test, and sperm migration test performed between 4 and 8 weeks before IVF-ET. MAIN OUTCOME MEASURES: The correlation between sperm function test results and the percentage of fertilized oocytes and the power of the tests to predict fertilization. RESULTS: The sperm migration test correlated highly with fertilization rate (r = 0.62) and was most useful in identifying the group of patients likely to achieve fertilization (Odds ratio [OR] 0.07, confidence interval [CI] 0.02 to 0.2). The CM penetration test showed a moderate correlation with fertilization rate (r = 0.45) and some predictive power (OR 0.37, CI 0.13 to 1.00). Sperm concentration, but not motility or normal morphology, showed slight correlation with fertilization rate (r = 0.28) but the combination of normal semen parameters did not distinguish patients likely to achieve fertilization (OR 1.51, CI 0.62 to 3.65). The hypo-osmotic swelling test did not correlate with fertilization rate (r = 0.21). CONCLUSIONS: This study evaluated the predictive power of several simple tests available for use in most laboratories as screening tests of sperm fertilization potential. Apart from sperm concentration, normal traditional semen characteristics were of little clinical benefit. The hypo-osmotic swelling test had no predictive power. The CM penetration test correlated with fertilization rate but might be difficult to perform routinely as a continuous supply of suitable CM would be required. The sperm migration test proved to be the best discriminator of sperm fertilization potential and should be considered as a first level screening test in the assessment of male fertility.

Cervix Mucus↗
PubMed1998

Low blastocyst formation rates in day-2 fertilized oocytes.

PURPOSE: To examine the blastocyst formation rates of day-2 fertilized oocytes. METHODS: A retrospective study of the outcomes/blastocyst formation of day-2 fertilized oocytes was undertaken. RESULTS: Fertilization rates of day-1 and -2 oocytes by intra-cytoplasmic sperm injection were similar. The development frequencies to four cells were similar. However, the blastulation rates were significantly lower from the day-2 fertilized eggs. The fertilization rates from day-2 conventional in vitro fertilization reinsemination were lower than the fertilization rates of day-1 oocytes. The blastulation rates from day-2 fertilized eggs were also lower than the rates from day-1 fertilized eggs in the in vitro fertilization group. CONCLUSIONS: Fertilization is not a good indicator to predict the viability of fertilized oocytes. Day-2 fertilized oocytes had significantly lower blastocyst formation rates than the rates from day-1 fertilized oocytes.

Adult↗
PubMed1982

Studies of the mechanism of the electrical polyspermy block using voltage clamp during cross-species fertilization.

Prevention of polyspermic fertilization in sea urchins (Jaffe, 1976, Nature (Lond.). 261:68-71) and the worm Urechis (Gould-Somero, Jaffe, and Holland, 1979, J. Cell Biol. 82:426-440) involves an electrically mediated fast block. The fertilizing sperm causes a positive shift in the egg's membrane potential; this fertilization potential prevents additional sperm entries. Since in Urechis the egg membrane potential required to prevent fertilization is more positive than in the sea urchin, we tested whether in a cross-species fertilization the blocking voltage is determined by the species of the egg or by the species of the sperm. With some sea urchin (Strongylocentrotus purpuratus) females, greater than or equal to 90% of the eggs were fertilized by Urechis sperm; a fertilization potential occurred, the fertilization envelope elevated, and sometimes decondensing Urechis sperm nuclei were found in the egg cytoplasm. After insemination of sea urchin eggs with Urechis sperm during voltage clamp at +50 mV, fertilization (fertilization envelope elevation) occurred in only nine of twenty trials, whereas, at +20 mV, fertilization occurred in ten of ten trials. With the same concentration of sea urchin sperm, fertilization of sea urchin eggs occurred, in only two of ten trials at +20 mV. These results indicate that the blocking voltage for fertilization in these crosses is determined by the sperm species, consistent with the hypothesis that the fertilization potential may block the translocation within the egg membrane of a positively charged component of the sperm.

Animals↗
PubMed2006

[Effects of nitrogen, phosphorus and potassium fertilization on sucrose accumulation in flag leaf and starch accumulation in kernel of weak gluten wheat].

With weak gluten wheat Yumai 50 as test material, this paper studied the sucrose accumulation in flag leaf and starch accumulation in kernel under effects of nitrogen, phosphorus and potassium fertilization. The results showed that nitrogen and potassium fertilization increased the sugar content in flag leaf at early and late filling stage, respectively, while phosphorous fertilization had little effect. Nitrogen, phosphorous, and potassium fertilization increased the sucrose-synthase activity in flag leaf, but the effect differed with time, i. e., at mid filling stage for nitrogen fertilization, early filling stage for phosphorous fertilization, and early and mid stage for potassium fertilization. As for the sucrose phosphate-synthase activity in flag leaf, it was increased by nitrogen fertilization in 24 days after anthesis, by potassium fertilization at early and mid filling stage, and by phosphorus fertilization at late filling stage. Nitrogen, phosphorus and potassium fertilization increased the sugar and starch contents in kernel, and the effect of potassium fertilization was most significant. Phosphorus fertilization increased the accumulation of amylose, while potassium fertilization improved that of amylopectin in kernel.

Edible Grain↗
PubMed2005

Effect of methyl-beta-cyclodextrin treatment of pig spermatozoa on in vitro fertilization and embryo development in the absence or presence of caffeine.

A series of experiments were carried out to develop a new method to reduce pig polyspermic fertilization and produce more normal embryos, in vitro. Experiment 1 determined the effect of methyl-beta-cyclodextrin (MCD) treatment during cryopreservation on sperm acrosome reaction and sperm fertilization. Compared to the non-MCD-treated control, MCD treatment increased the percentage of acrosome-reacted spermatozoa at thawing and 2h after incubation in fertilization medium (P<0.01). Treatment with MCD also increased (P<0.05) sperm-penetration rate, number of spermatozoa in oocytes, and fertilization efficiency in the caffeine-free fertilization medium. Experiment 2 was designed to examine the effect of withdrawal of caffeine (caffeine-free) from fertilization medium on fertilization parameters and early embryo development. Using MCD-treated spermatozoa, there was no difference in sperm-penetration rate, oocyte cleavage rate, and blastocyst formation rate between the caffeine-free and caffeine-supplemented groups. However, polyspermic fertilization rate was lower, and fertilization efficiency and blastocyst cell number were higher in the caffeine-free group compared to the caffeine-supplemented group (P<0.05). Experiment 3 studied the effect of caffeine and different concentrations of spermatozoa on fertilization parameters. Sperm-penetration rate did not differ between the caffeine-free and the caffeine-supplemented groups at different sperm concentrations. Caffeine and sperm concentration had an effect on the number of spermatozoa in oocytes and on the polyspermic fertilization rate (P<0.002). Caffeine also affected fertilization efficiency (P<0.05). In conclusion, treating spermatozoa with MCD and withdrawing caffeine from fertilization medium may provide a new method to produce a large number of normal embryos, in vitro.

Acrosome Reaction↗
PubMed2003

Caffeine in fertilization medium is not essential for bovine IVF by fully capacitated spermatozoa.

The purpose of this study was to examine: 1) whether caffeine in the fertilization medium under mineral oil is essential for bovine in vitro fertilization by fully capacitated spermatozoa, 2) the minimum concentration of caffeine that shows an adverse effect on the motility of preincubated spermatozoa. Cumulus-oocyte complexes with heterogeneous-appearing ooplasm were matured in in vitro culture for 24 h and used for insemination. The fertilization rates of the preincubated spermatozoa introduced into the fertilization medium containing 0 mM or 5 mM caffeine were examined. The fertilization rate of the spermatozoa introduced into the medium without caffeine (final concentration of caffeine at fertilization was 0.27-0.35 mM) was significantly higher than that in the medium with 5 mM caffeine (82.4% vs 55.2%, P<0.05). When the final concentration of caffeine at fertilization was reduced ten-fold (0.02-0.03 mM), the fertilization rate was not significantly improved (86.0%). The motility of the preincubated spermatozoa introduced into the fertilization medium containing 0-5 mM caffeine was examined. The sperm motility in the fertilization medium without caffeine was significantly higher than that in the fertilization medium with more than 2 mM caffeine. These results indicate that caffeine in the fertilization medium is not essential for bovine in vitro fertilization by fully capacitated spermatozoa, and that more than 2 mM caffeine has an adverse effect on preincubated (capacitated) sperm motility.

Animals↗
PubMedDate not supplied

Can the fertility potential of a seminal sample be predicted accurately?

This paper highlights the most critical aspects of the problem of predicting fertility. To determine if a laboratory test(s) is highly correlated with fertility it is essential to have: a) specific, precise and accurate laboratory tests, and b) precise and accurate fertility data. Acquisition of precise and accurate data for laboratory tests and fertility of spermatozoa in the same sample is not easy. Data derived from in vitro fertilization are not tests of fertility, because only a subset of the attributes important for fertilization in vivo are tested. Because of deficiencies in fertility data, there probably is no valid report for human spermatozoa correlating results of laboratory tests and fertility, and very few valid studies for laboratory or domesticated animals. There is little doubt that objective measures of sperm motion, acrosomal status, or other characteristics are significantly correlated with fertility. However, establishment of the correlations between a group of attributes and fertility is not the question of interest. The goal is prediction of fertility. There has been no recent effort to develop a prediction of fertility or fecundity based on sperm characteristics, and achievement of this goal may be elusive.

Animals↗
PubMed1992

Failure to fertilize in vitro in couples with male factor infertility: what next?

OBJECTIVE: To assess the predictive value of a failure to fertilize in vitro in couples with sperm abnormalities on future fertility. DESIGN: Retrospective file review. SETTING: In vitro fertilization and embryo transfer (IVF-ET) program in the Sheba Medical Center during the years 1983 to 1990. PATIENTS: Seventy-six couples with sperm abnormalities who had at least one IVF cycle during which fertilization did not occur. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Occurrence of fertilization, percentage of fertilization, and pregnancies in additional IVF-ET cycles. RESULTS: Of 44 couples who underwent an additional IVF attempt with husband's sperm, 36 (81.2%) fertilized, with a mean fertilization rate of 47.7% +/- 26.6%. Of 17 couples who failed twice, 11 attempted IVF again with husband's sperm and 7 fertilized, with a median rate of 33%. A higher sperm concentration was found on the cycles during which fertilization occurred. Men with single parameter abnormalities did not fertilize better than those with two or three defective parameters. CONCLUSIONS: Failure to fertilize in vitro in couples with male factor infertility does not seem to predict future fertilization in IVF. At least two cycles of IVF should be tried before reverting to other options such as insemination by donor sperm or gamete micromanipulation.

Embryo Transfer↗
PubMed2003

Fertility estimation: a review of past experience and future prospects.

Fertility has many components and stages which require that males and females be functionally capable of carrying out all critical stages if each generational reproductive cycle is to be completed. To accomplish this, the male must produce and ejaculate normal fertile sperm. The female must produce, store and ovulate normal fertilizable oocytes. Furthermore, the female must provide a reproductive system compatible with sperm transport, capacitation, and fertilization of the oocytes, embryo and fetal development, and finally birth of healthy young. Reproductive success or failure at several of these points can be estimated quantitatively on a population basis, and in a few situations on an individual basis. It is important that fertility estimates be determined accurately and with precision to be most useful to researchers and managers of animal enterprises. Many studies have underestimated the biological relationship of fertility to other traits because the estimates lacked precision. Many in vitro manipulations of sperm in artificial insemination, of gametes in various assisted reproductive technologies, and of embryos in embryo transfer are utilized in animal breeding programs. Accurate estimation of reproductive efficiency of these in vitro procedures also is important. Conditions surrounding different sets of fertility estimates almost certainly will be different. These conditions should be described as precisely as possible, and appropriate controls included in all experiments. When possible, experiments should be replicated over time and place to determine the repeatability of the various criteria used to estimate fertility and reproductive efficiency. Advances in genomic information and molecular biology should facilitate characterizing more fully inherent potential fertility of animals at birth. In vitro tests will improve, and automated techniques will facilitate making multiple determinations possible on a large scale. Reliability of fertility estimates will increase, with the potential for enhanced animal reproductive performance through more accurate selection, genetic engineering, and enlightened animal care. Simultaneously, it is important to recognize that prediction of future fertility is more hazardous than estimating fertility, as a completely new set of circumstances may occur which are not predictable. Because fertility estimation may be applied under a myriad of conditions, principles and factors affecting fertility will be emphasized in this review as being more useful than a compilation of numerical examples.

Animals↗
PubMed2006

Inhibitory effects of calcium ionophore pretreatment of porcine oocytes on polyspermic fertilization.

The present study examined the inhibitory effects of various pretreatment concentrations (0-100 microM) of the calcium ionophore A23187 on polyspermic fertilization and then examined the effect of the maturation period and the time between calcium ionophore treatment and fertilization on the inhibitory effect of calcium ionophore on polyspermic fertilization. In experiment 1, a high concentration of calcium ionophore (100 microM) increased the rate of activated oocytes, but the rate of fertilization declined. On the other hand, when oocytes were treated with a low concentration of calcium ionophore (10 microM), monospermic fertilization was significantly increased (10 microM; 31.3%) (p < 0.05). In experiment 2, oocytes were cultured for various times (0, 0.5, 3, 6 h) after calcium ionophore treatment (10 microM) before fertilization. The highest rate of monospermic fertilization was detected in the oocytes cultured for 6 h after calcium ionophore treatment before fertilization. In experiments 3 and 4, we examined the effect of the maturation period (40 h or 44 h) on the rate of fertilization and blastulation of oocytes pretreated with calcium ionophore. The treatment of oocytes with calcium ionophore significantly decreased the rate of polyspermic fertilization regardless of the maturation period (44 h: with calcium ionophore 26.25% vs without 78.8%; 40 h: with calcium ionophore 37.5% vs without 77.5%); however, calcium ionophore treatment increased the rates of monospermic fertilization and blastulation of the oocytes matured for 44 h, but not those matured for 40 h. In conclusion, activation with a low concentration of calcium ionophore (10 microM) and a further 6 h of culture before fertilization improved the rate of monospermic fertilization and blastulation.

Animals↗
PubMed2003

The predictive value of semen analysis in the evaluation of stallion fertility.

Pregnancy rates in managed horse populations depend on the innate fertility of the mares and stallions involved and on the quality of breeding management. Of course, because a single stallion usually mates many mares, stallion fertility is a critical factor in the overall success of a breeding program. Unfortunately, accurate evaluation of stallion fertility per se requires a large number of normal mares to be mated and is necessarily retrospective. Rather, the ideal is to predict fertility in advance of the stallion's breeding career, and this is currently attempted by way of a thorough physical examination and a routine analysis of semen quality. However, while such a 'breeding soundness examination' identifies stallions that clearly lack the capacity for adequate fertility, it is of limited use for predicting the level of fertility and fails to identify some seriously sub-fertile animals. Similarly, while various sperm function tests (e.g., sperm head morphometry, the hypoosmotic swelling test, glass wool-sephadex filtration, progesterone receptor exposure) have been shown to correlate fairly well with fertility in the field, most examine only a single or a narrow range of the attributes that a sperm must possess if it is to fertilize an oocyte in vivo, and are thus more useful for identifying specific causes of sub-fertility than for predicting the level of fertility. On the other hand, combining the results of the various sperm function tests does improve the reliability of fertility estimation and current research is therefore concentrated on identifying a range of tests that covers as many important sperm attributes as possible but that can be performed rapidly and cheaply. In this respect, flow-cytometry has proven to be an ideal tool because it allows the objective, rapid and simultaneous analysis of a number of properties in a large number of sperm. Moreover, stains are available for an increasing range of sperm characteristics including viability, capacitation and acrosome status, mitochondrial activity and chromatin integrity. Flow-cytometric analysis of sperm with appropriate probes thus offers considerable promise for the prediction of stallion fertility.

Animals↗
PubMed2003

Long-term effects of mineral versus organic fertilizers on activity and structure of the methanotrophic community in agricultural soils.

Agricultural practices, such as mineral nitrogen fertilization, have an impact on the soil's ability to oxidize methane, but little is known about the shifts in the methanotrophic community composition associated with these practices. Therefore, the long-term effect of both mineral (NH4NO3) and organic (manure and GFT-compost) fertilizer applications on the soil methanotrophic community activity and structure were investigated. Both high and low affinity methane oxidation rates were lower in the soil treated with mineral fertilizer compared to the other soils. An enhanced nitrate concentration was observed in the mineral fertilized soil but nitrate did not show a direct affect on the high affinity methane oxidation. In contrast, the low affinity methane oxidation was slowed down by increased nitrate concentrations, which suggests a direct effect of nitrate on low affinity methane oxidation. Denaturing gradient gel electrophoresis (DGGE) analysis of 16S rRNA gene fragments specific for methanotrophs revealed a distinct community between the mineral and organic fertilized soils as extra Type I methanotrophic bands (phylotypes) became visible in the organic fertilized soils. These phylotypes were not visible in the patterns of the added organic fertilizers suggesting an indirect effect of the organic fertilizers on the methanotrophic community. Additionally, a molecular analysis was performed after the low affinity methane oxidation test. The enhanced methane concentrations used in the test enriched certain low affinity methanotrophs in the organic fertilized soils but not in the mineral fertilized soil. Supporting the molecular and functional observations, fatty acids characteristic for methanotrophs were less abundant in the soil treated with mineral fertilizer compared to the soil treated with compost. In conclusion, the function and molecular and chemical composition of the methanotrophic community are all altered in soil fertilized with mineral fertilizer.

Alphaproteobacteria↗
PubMed1987

[Fertilization of human ova in capillary tubes with a very small number of spermatozoa. A new treatment possibility in severe oligospermia?].

In contrast to the in vivo situation the current in vitro fertilization techniques require large numbers of spermatozoa per oocyte to achieve successful fertilization. In this study a culture system was developed in which successful fertilization was performed in haematocrit capillary tubes (75 mm length, 0.8-0.9 mm inner diameter) even if only low numbers of spermatozoa were used. Oocytes were fertilized in 5-10 microliters of different sperm suspension containing a total number of 500, 1000, 2000 and 4000 spermatozoa per oocyte (0.1-0.4 X 10(6) sperms/ml). In 10 patients participating in an in vitro fertilization programme 32 oocytes were fertilized in capillary tubes and 32 oocytes were cultured using standard methods (1 ml culture medium in tissue culture tubes, 0.1-0.2 X 10(6) spermatozoa/ml). The overall fertilization rate of oocytes cultured in tissue culture tubes was 78% (25/32) and the fertilization rates in capillary tubes using 4000, 2000, 1000 or 500 spermatozoa per oocyte were: 71% (5/7), 86% (6/7), 60% (6/10) and 50% (4/8), respectively. The fertilization rate of mature oocytes was higher compared to immature oocytes when fertilization was performed in culture tubes (83% and 63%) or in capillary tubes (74% and 44%). Fertilization in capillary tubes using a volume of the sperm oocyte suspension of 10 microliters compared to 5 microliters seems to provide better culture conditions resulting in higher fertilization and cleavage rates (75 and 91% versus 62.5 and 60%). These preliminary results indicate that fertilization of human oocytes under in vitro conditions can be achieved even with very low numbers of spermatozoa.(ABSTRACT TRUNCATED AT 250 WORDS)

Embryo Transfer↗
PubMedDate not supplied

Evaluation of the percentage of sperm motility at 24 h and sperm survival ratio for prediction of in vitro fertilization.

The present study was carried out to investigate the predictive value of the percentage of sperm motility after 24-h incubation and sperm survival ratio from semen and inseminated sperm suspension using grading of motility by WHO criteria with respect to the fertilization of oocytes in vitro. A total of 789 oocytes from 85 cases were inseminated and the mean fertilization rate obtained was 72.5%. There was no significant correlation between all of the sperm motility results with fertilization rate in vitro. All sperm motility results were not significantly different between the non-fertilizing group and the fertilizing group and also between the group of fertilization rate < or = 25th percentile (fertilization rate < or = 62.5%) and the group of fertilization rate > 62.5%. However, the initial percentage of rapid progressive sperm motility and progressive motility in semen and inseminated sperm suspension at 24 h gave significant differences between the group of fertilization < or = 50th percentile (fertilization rate < or = 80%) and the group of fertilization rate > 80%. Overall accuracy using these parameters for prediction of fertilization rate > 80% was only about 60%. In conclusion, the percentage of sperm motility at 24 h and sperm survival ratio in both semen and inseminated sperm suspension have no practical value in predicting fertilization rate in vitro. Moreover, detailed motility grading cannot improve the predictivity of these sperm motility parameters.

Cell Survival↗
PubMed1985

Fertilization-induced ionic conductances in eggs of the frog, Rana pipiens.

Fertilization of the frog egg (Rana pipiens) elicits a positive-going shift in membrane potential (fertilization potential) that lasts 10-20 min and functions as a fast block to polyspermy. We examined the ion conductances underlying the fertilization potential, using the voltage-clamp technique. We measured the membrane capacitance during the fertilization potential by applying an alternating current. We also determined the intracellular K and Cl concentrations in the egg, using ion-selective micro-electrodes. The conductance is largest in the first 2 min after fertilization. Regardless of whether the stimulus is provided by one or by more than one sperm or by artificial activation, the size of the conductance increase is the same, reaching a maximum of about 40 microseconds. Two separate conductances are involved at fertilization: Cl and K. [K]i = 121 mM and [Cl]i = 44 mM. The natural external medium is pond water (approximated in our experiments by 10% Ringer solution); therefore, an increase in K and Cl conductances leads to an efflux of both ions. The equilibrium potential of the fertilization current is between the Cl and K equilibrium potentials (ECl and EK), closer to ECl. 10 mM-external tetraethylammonium (TEA) brings the equilibrium potential close to ECl and reduces the maximum conductance by about half. The Cl conductance is not blocked by 4-acetamido-4'-isothiocyanostilbene-2,2'-disulphonic acid (SITS). The time courses of the K and Cl conductances are similar. The TEA-resistant conductance (primarily Cl conductance) activated at fertilization increases as the membrane potential becomes more positive. A voltage-sensitive Na conductance present in the unfertilized egg disappears after fertilization. During fertilization this conductance is too small to contribute significantly to the fertilization potential. The membrane capacitance increases by an average of 1.9 times in the first 2 min following the rise of the fertilization potential, during the period of cortical vesicle exocytosis. Capacitance then gradually decreases; at 1 h after fertilization, capacitance is 82% of the value in the unfertilized egg. The conductance increase precedes the capacitance increase by several seconds. Therefore the initial appearance of Cl and K channels cannot be accounted for by addition of membrane by cortical vesicle exocytosis. The conductance subsequently decreases, suggesting that the disappearance of the Cl and K channels is not caused by membrane removal.

Action Potentials↗
PubMed2000

Relationship of seminal traits and insemination time to fertilization rate and embryo quality.

The nature of subfertility due to the male or inseminate is as complex as that of the female. Fertilization failure or failure in embryogenesis are both documented to be of seminal origin. Males also differ in the numbers of sperm required to reach their maximum fertilization rate. Males requiring more sperm would be considered to have compensable seminal deficiencies. These include a number of known (viability and morphology) and unknown factors (functional or molecular traits) precluding sperm access to the ovum or ability to engage the ovum sufficiently to initiate fertilization and the block to polyspermy. Differences in fertility among males or inseminates independent of sperm dosage are considered uncompensable. These deficiencies would be associated with fertilizing sperm that are incompetent to maintain the fertilization process or subsequent embryogenesis once initiated, with most failures occurring prior to maternal recognition of pregnancy. Such sperm would preempt fertilization by competent sperm. Chromatin aberrations in morphologically normal or near normal spermatozoa from abnormal semen samples appear to be the best candidates for the uncompensable deficiency. However, recognition of uncompensable or incompetent fertilizing sperm has not been achieved. Six-day-old non-surgically recovered bovine ova/embryos have been used to evaluate compensable and uncompensable seminal deficiencies as well as to test reproductive strategies. These ova/embryos provide information on fertilization status and embryo quality as well as quantitative and qualitative data regarding associated accessory sperm. Thus, they permit the separation of reproductive failure by fertilization from that by embryonic development. Accessory sperm number is positively associated with both fertilization rate and embryonic quality. Early insemination results in low fertilization rates (low accessory sperm number), but good embryo quality, whereas, late insemination results in high fertilization rates (high accessory sperm number), but poor embryo quality. Additional studies will be necessary to substantiate this model; however, if true, future research designed to improve results to artificial insemination should be tested by breeding early in estrus where sperm viability is most limiting and embryo quality is best.

Animals↗
PubMed2005

Male-by-female interactions influence fertilization success and mediate the benefits of polyandry in the sea urchin Heliocidaris erythrogramma.

Numerous studies have reported that females benefit from mating with multiple males (polyandry) by minimizing the probability of fertilization by genetically incompatible sperm. Few, however, have directly attributed variation in female reproductive success to the fertilizing capacity of sperm. In this study we report on two experiments that investigated the benefits of polyandry and the interacting effects of males and females at fertilization in the free-spawning Australian sea urchin Heliocidaris erythrogramma. In the first experiment we used a paired (split clutch) experimental design and compared fertilization rates within female egg clutches under polyandry (eggs exposed to the sperm from two males simultaneously) and monandry (eggs from the same female exposed to sperm from each of the same two males separately). Our analysis revealed a significant fertilization benefit of polyandry and strong interacting effects of males and females at fertilization. Further analysis of these data strongly suggested that the higher rates of fertilization in the polyandry treatment were due to an overrepresentation of fertilizations due to the most compatible male. To further explore the interacting effects of males and females at fertilization we performed a second factorial experiment in which four males were crossed with two females (in all eight combinations). In addition to confirming that fertilization success is influenced by male x female interactions, this latter experiment revealed that both sexes contributed significant variance to the observed patterns of fertilization. Taken together, these findings highlight the importance of male x female interactions at fertilization and suggest that polyandry will enable females to reduce the cost of fertilization by incompatible gametes.

Animals↗
PubMed1992

Relation between antisperm antibodies and the rate of fertilization of human oocytes in vitro.

To clarify further the role of antisperm antibodies in in vitro fertilization, the occurrence of antisperm antibodies on ejaculated sperm and in sera was determined by the immunobead binding assay in 67 couples after an unsuccessful in vitro fertilization cycle. Antisperm antibodies in maternal sera were associated with a failure of oocyte fertilization (P less than 0.02) or with fertilization of only 9-19% of the oocytes (P less than 0.01) in vitro. Antisperm antibodies were detected in sera from 13 of 24 women (54.2%) where no fertilization occurred, 9 of 14 women (64.3%) where less than 20% of the oocytes fertilized, and 3 of 19 women (15.8%) where greater than 40% of the oocytes fertilized. Antisperm antibodies in these sera were mostly IgG and directed against the sperm tail. Antibodies on the surface of ejaculated motile sperm were also associated with a low (9-19%) fertilization rate (P less than 0.01). Sperm-bound antibodies were detected in 2 of 24 men (8.3%) where no fertilization occurred, 5 of 14 men (35.7%) where less than 20% of the oocytes fertilized, and 0 of 19 men where fertilization was greater than 40%. Sperm-bound antibodies were mainly IgA and were tail-directed. Antisperm antibodies in sera of males were not related to the rate of fertilization.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗