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Immunofluorescence study of actin, acrosin, dynein, tubulin and hyaluronidase and their impact on in-vitro fertilization.

Using polyclonal antibodies, the distribution of actin, acrosin, dynein, tubulin and hyaluronidase has been examined by indirect immunofluorescence in sperm preparations from fertile donors and in-vitro fertilization (IVF) patients. After recording sperm parameters in native semen, spermatozoa were washed free of seminal plasma using either the swim-up or the Percoll filtration technique. Prior to insemination, aliquots of the washed sperm suspensions were prepared for antibody staining. Spermatozoa from fertile donors were analysed in order to establish the specific fluorescence patterns of each antibody and the threshold scores of normality. Immunofluorescence scores obtained from IVF patients were then analysed with respect to IVF outcome. For each tested protein, the number of normal samples were significantly lower in the group which did not fertilize and fertilization rates were significantly reduced when any of the tested proteins were scored as pathological. Normal fluorescence scores were correlated with morphology, motility, velocity and to a lesser extent with sperm concentration in native semen. On the basis of receiver-operating characteristic curves, likelihood ratios and Cohen's kappa values, the presence of acrosin and tubulin yields the most useful information on sperm functional and structural status and on its fertilizing ability.

Acrosin↗

Estimating fertility potential via semen analysis data.

The aim of this study was to evaluate diagnostic profiles for the assessment of semen analysis data with respect to male fertility potential. Semen samples taken from 208 patients of known fertility and suspected infertility were studied by conventional semen analysis methods. The data throw doubt upon the validity of an approach based on the number of deviations from the normal standard values defined by the World Health Organization. The alternative approach of a specific semen characteristic (particularly morphology) as the major predictor of fertility produced no beneficial results. However, the semen analysis index based on semen volume, sperm count, percentage motility and normal forms resulted in a high accuracy of classification but for only 44% of the cases, with 3% false negatives and 10% false positives using cut-off indices of > or = 0.6 and < or = -1.0 for defining 'fertile' and 'infertile' zones, respectively. In conclusion, it is emphasized that there are a number of specific semen analysis variables, each expressing a different aspect of male fertility potential which, when combined in correct proportion, do provide the optimal evaluation of the male fertility status. However, in order to increase the prognostic potential of the semen sample, new and meaningful parameters must be discovered.

Adult↗

Sperm/egg binding patterns and oocyte cytology in retrospective analysis of fertilization failure in vitro.

Failures of fertilization in in-vitro fertilization have been often linked to visually recognizable defects in spermatozoa, and occasionally to anti-sperm antibodies. However, some total failures and the frequent lack of fertilization in some eggs of normal appearance (partial failure) often remain unexplained. Simple evaluation of the configuration of sperm binding to the zona pellucida and of the oocyte features revealed by acetic alcohol fixation and lacmoid staining, may provide diagnostic clues in this respect. Among 25 cases of unanticipated total failure, this approach identified some men with normal semen analyses whose spermatozoa displayed either a total inability to bind to the zona or, after binding, an inability to intrude into the zona matrix. However, in 10 of these cases significant numbers of spermatozoa were bound to and intruded deep into the zona, a pattern consistent with the possibility of an egg defect, specifically a resistance to the passage of spermatozoa past the inner portion of the zona pellucida. Such a block also appeared to be the main cause of fertilization failure among 442 unfertilized eggs from 154 partial failure patients. As in the total failures, the inability of apparently competent spermatozoa to penetrate the zona was often associated with ooplasmic anomalies (refractile bodies, extra groups of chromosomes, chromatin rings or masses, one or more pronuclei with one or no polar bodies, and other occasional anomalies). These anomalies occurred in 79.4% of this unfertilized oocyte subset, in contrast to a 27.4% incidence in 238 oocytes not fertilized because of sperm defects. Simple retrospective assessment of sperm binding patterns and oocyte cytology can be a valuable complement to semen analysis in diagnosis of fertilization failure in vitro.

Adult↗

Repeated sperm injection under the zona following initial fertilization failure.

When fertilization fails following micromanipulative under-zona insemination, it is possible to repeat the procedure adding more spermatozoa to achieve fertilization, embryonic development and pregnancy. We report on 18 human in-vitro fertilization cycles where this approach was used. In nine cycles only late-fertilized embryos were available for transfer, and these gave rise to two viable pregnancies (22.2% per transfer). In six cycles, where a mixture of late- and timely fertilized embryos were available for transfer, two viable pregnancies arose (33.3% per transfer). In three cycles no fertilization was achieved even after reinsemination by repeated under-zona insemination.

Embryo Transfer↗

Intravenous immunoglobulin for in-vitro fertilization failure.

The aim of this study was to determine the effectiveness of intravenous (i.v.) immunoglobulin (Ig) for treatment of individuals experiencing failure after in-vitro fertilization (IVF) and embryo transfer. A total of 29 women with unexplained infertility who failed to become pregnant after IVF/embryo transfer were divided into two groups based on performance in previous IVF cycles: 16 women had fertilization of > or = 50% of oocytes retrieved and/or produced > or = 3 embryos each cycle and 13 had fertilization of < 50% of oocytes retrieved and/or produced < 3 embryos each cycle. Each woman had received at least 12 transferred embryos (95th percentile for successful IVF patients) or had experienced two or more biochemical pregnancies without ultrasonic confirmation of implantation during previous IVF/embryo transfer attempts. All women received i.v. Ig 500 mg/kg prior to the next embryo transfer. Only one of the 13 (8%) women with suboptimal fertilization and embryo yield became pregnant in the treatment cycle. Of 16 women who had previously had fertilization of at least 50% of oocytes retrieved and produced at least three embryos, nine (56%) became pregnant in the treatment cycle. The difference in pregnancy rates between the two groups is significant (P = 0.02). Intravenous Ig is useful in the treatment of unexplained IVF failure in women who have oocyte fertilization rates > or = 50% and generate at least three embryos per cycle.

Adult↗

Infertility evaluation in fertile women: a model for assessing the efficacy of infertility testing.

A standard infertility evaluation consists of a semen analysis, hysterosalpingogram, post-coital test, endometrial biopsy and laparoscopy. Although these tests are well grounded in clinical experience, information on their ability to discriminate between fertile and infertile couples is limited. In this study, we performed standard infertility tests plus two others--sperm antibodies and cervical culture for Mycoplasma hominis and Ureaplasma urealyticum--on fertile and infertile couples. Women in the fertile group were selected from those who had delivered a child within the previous 2 years and who were scheduled for a laparoscopic tubal ligation. Women in the infertile group were selected from those presenting for an infertility evaluation (mean duration of infertility 4.2 years), and they were matched by age (+/- 3 years) and race with fertile subjects. Subjects were recruited from both private and clinic patients. A total of 64 couples (32 matched pairs) completed the evaluation. At least one 'abnormal' infertility test was found in 69% of fertile and 84% of infertile couples. With the exception of tubal damage and endometriosis, which as expected were more common in infertile couples, no significant differences between groups for remaining infertility factors could be demonstrated. Despite the small size of the current study, these results confirm the feasibility and importance of comparisons of the prevalence of infertility factors in fertile and infertile couples.

Adult↗

Conventional in-vitro fertilization versus intracytoplasmic sperm injection for patients requiring microsurgical sperm aspiration.

Intracytoplasmic sperm injection (ICSI) has been successful in cases of extreme oligoasthenozoospermia in achieving pregnancies via in-vitro fertilization (IVF) with the lowest imaginable sperm counts. In azoospermia caused by congenital bilateral absence of the vas deferens (CBAVD), it has been shown that epididymal spermatozoa can be retrieved in large numbers, but fertilization rates using conventional IVF are low. Furthermore, no fertilization has ever been possible using testicular spermatozoa with conventional IVF. In the most extreme case of absence of the epididymis, spermatozoa can only be retrieved from macerated testicular biopsy specimens. In such cases, all that can be seen are free-floating Sertoli cells with many spermatids attached, and only occasional spermatozoa per high power field which have only the barest, occasional, slightly twitching motion. The objective of the present study was to determine whether ICSI could achieve better results than conventional IVF with microsurgical aspiration of spermatozoa (MESA). ICSI (using epididymal or testicular spermatozoa) from men with CBAVD or irreparable obstructive azoospermia, achieved good fertilization and normal embryos in 82% of cases, compared to 19% with conventional IVF. There was an overall fertilization rate of 45%, with 85% progressing to normally cleaving embryos using ICSI, compared to 6.9% using conventional IVF. The pregnancy rate with ICSI/MESA was 47% per stimulated cycle (normal delivery rate was 30%), compared to 4.5% with conventional IVF. These results were achieved in patients who had consistently failed to fertilize in previous cycles with MESA and conventional IVF.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Change in the fructose 1,6-bisphosphatase activity in sea urchin eggs following fertilization.

The activity of fructose 1,6-bisphosphatase [EC 3.1.3.11] in sea urchin eggs decreased following fertilization. During the first 30 min after fertilization, the activity was considerably lower than that in unfertilized eggs, but by 30 min the activity was similar to that in unfertilized eggs. The enzyme activity in fertilized eggs, estimated in the presence of EGTA, was similar to that in unfertilized eggs. The activity in unfertilized eggs was reduced by Ca2+ at concentrations between 1 X 10(-5) M and 5 X 10(-3) M. Immediately after fertilization, the enzyme was insensitive to concentrations of Ca2+ lower than 2 X 10(-4) M, but the Ca2+ sensitivity of the enzyme recovered 30 min after fertilization. In the presence of Ca2+ at concentrations higher than 2 X 10(-4) M, the enzyme activity in unfertilized eggs was similar to that in fertilized eggs. Mg2+ restored the Ca2+-induced inhibition of fructose 1,6-bisphosphatase. 3-Phosphoglycerate and citrate hardly affected the enzyme activity, and AMP at concentrations above 10 mM inhibited it.

Adenosine Monophosphate↗

Efficacy of sperm mobility assessment in commercial flocks and the relationships of sperm mobility and insemination dose with fertility in turkeys.

Our objectives were to evaluate: 1) the efficacy of the Sperm Mobility Test on commercial turkey farms, and 2) the influence of sperm mobility phenotype on fertility when insemination parameters are varied. In research flocks, differences in sperm mobility among toms are predictive of fertility. We wanted to test the efficacy of this sire selection test in practical, real-world situations, evaluating its usefulness in terms of assessing large numbers of toms, different strains of turkeys, and variable management practices. Utilizing field study results, controlled studies were then conducted to improve test parameters. For the field trials, semen from each of 405 breeder toms (11 strains or lines) was evaluated either in duplicate (n = 285) or in triplicate (n = 120). Sperm mobility was normally distributed among all toms tested, except for one strain. Because the sperm mobility indices for toms evaluated in these field trials were higher than those observed in research flocks, the Sperm Mobility Test was modified to increase the separation between high and low sperm mobility phenotypes by increasing the concentration of Accudenz. To determine the effects of sperm mobility and insemination dose on sustained fertility through time, hens from a research flock were inseminated twice before the onset of lay with sperm from toms classified as high-, average-, or low-mobility in concentrations of 25 to 400 million sperm per artificial insemination dose, and egg fertility was evaluated over a 5-wk period. Toms with the high-mobility sperm phenotype maintained higher fertility (P < 0.05) over the 5-wk period at all insemination doses compared with toms with low-mobility sperm. Toms with high-mobility sperm sired equal numbers of poults in a sperm competition study in which numbers favored low-mobility toms by 3:1. These results demonstrate that the Sperm Mobility Test can be used for on-farm evaluation of semen quality of toms in commercial flocks and that sperm mobility influences fertility and sire fitness.

Animals↗

Oviposition pattern, egg weight, fertility, and hatchability of young and old broiler breeders.

Two experiments were conducted to investigate egg weight, fertility, hatchability, and embryonic mortality in relation to time of oviposition of young and old broiler breeder flocks. In experiment 1, eggs were collected from 2 flocks (34 and 59 wk) for 2 d at hourly intervals between 0700 and 1900 h. Most eggs were laid between 0700 and 1300 h, but eggs were laid later in the day by the old flock. Weights of early laid (C1) eggs were significantly greater than middle laid (Cs) and the late laid (Ct) eggs in the young flock, whereas late laid eggs (Ct) were significantly smaller than early laid (C1) and middle laid (Cs) eggs in the old flock. In experiment 2, eggs from experiment 1 were categorized as early laid first-in-sequence (C1) eggs (0700 to 0800 h), the mid-sequence (Cs) eggs (0900 to 1200 h), and the late laid terminal-in-sequence (Ct) eggs (1300 to 1700 h). These eggs were incubated to determine fertility, hatchability, and stage of embryonic mortality relative to oviposition time and flock age. Fertility declined with flock age, but there were no differences due to time of oviposition. There were no differences in hatchability of fertile eggs or embryonic mortality relative to time of oviposition (sequence position) or flock age. These results suggested that although there were differences in egg weight among eggs at different times of the day (different sequence positions), there were no differences in fertility, fertile hatchability, or embryonic mortality in naturally mated broiler breeders.

Aging↗

Mouse sperm antigens that participate in fertilization. I. Inhibition of sperm fusion with the egg plasma membrane using monoclonal antibodies.

Monoclonal antibodies (mAbs) have been generated to determine the sperm components responsible for interaction with an egg that results in fertilization. Here, we report upon a group of six different mAbs, all of which localize to a restricted region of the sperm head, the equatorial segment. Several of these mAbs demonstrated cross-reactivity with sperm from the other species tested (human, hamster, rabbit); when cross-reaction occurred, the mAb distribution was restricted to the equatorial segment despite the various configurations that this homologous region assumes in different species. When tested for an effect upon the fertilization process in vitro, ascites fluids containing two of the six mAbs, M29 and M37, displayed significant inhibition. The concentration dependency of this inhibition was observed using purified M29 immunoglobulin M, over a range of 0 to 0.2 mg/ml. The mAb inhibition of fertilization was independent of the presence of either the cellular (the cumulus) or acellular (the zona pellucida) layers surrounding the egg, indicating that the specific locus of inhibition for both of these antisperm mAbs was the egg plasma membrane. Immunologic detection of sperm components separated by electrophoresis on 12% sodium dodecyl sulfate-polyacrylamide gels followed by transfer to nitrocellulose sheets was used to identify the sperm components recognized by two of the mAbs in this group: M29, which inhibited fertilization, and M2, which did not inhibit fertilization. Using M29 mAb, a single sperm component with an apparent subunit molecular weight of approximately 40,000 was detected, whereas in the nitrocellulose strips incubated with M2 mAb two components displayed reactivity, a very prominent band at approximately 44,000 and a tight cluster of bands at approximately 36,000. Parallel nitrocellulose strips of mouse liver did not display these reactivities, consistent with indirect immunofluorescence data in which only testis and sperm, and not liver, kidney, ovary, and epididymal epithelium, demonstrated positive reactivity. These results indicate that the use of mAbs permits identification of sperm components that participate, putatively, in individual events of the fertilization process. Furthermore, using this strategy, we have identified a specific sperm component that appears to be a candidate for a role in sperm fusion with the egg plasma membrane.

Animals↗

Role of cumulus cells and serum on the in vitro maturation, fertilization, and subsequent development of rat oocytes.

Immature oocytes were collected from immature female rats (60-65 g) 40 h after injection with 6 IU pregnant mare's serum gonadotropin (PMSG). Oocytes were matured cumulus-intact (CI) or cumulus-free (CF) in medium supplemented with 0.5% bovine serum albumin (BSA) or 5-20% serum for periods of up to 24 h. After assessment for nuclear maturation, the oocytes were exposed to epididymal sperm for fertilization in vitro. In vitro-matured and ovulated oocytes undergoing fertilization were transferred to unilaterally pregnant recipients for embryonic and fetal development. The presence of cumulus cells and serum shortened (by 2 h) the time required for polar body emission by in vitro-matured oocytes and also helped to increase significantly the penetrability of the oocytes by spermatozoa. A high proportion (45.6%) of fertilized oocytes showed evidence of abnormal fertilization following maturation in the absence of cumulus cells. Oocytes matured CI before fertilization were able to develop to viable fetuses (57.8%) in proportions similar to ovulated oocytes (55.0%) after in vitro fertilization. These findings indicate an essential role for cumulus cells in promoting normal cytoplasmic maturation of oocytes necessary for pronuclear formation and subsequent developmental capability.

Animals↗

Anti-idiotype antibodies prevent antibody binding to mouse sperm and antibody-mediated inhibition of fertilization.

Antibodies to components of sperm can interfere with sperm function and prevent fertilization by blocking specific steps of gamete interaction. It can be proposed that anti-idiotype antibodies (anti-Ids) that recognize determinants located close to or within the antigen-binding site of an anti-sperm antibody could block antibody binding to sperm antigen and antibody-mediated inhibition of fertilization. To test this hypothesis, rabbit polyclonal antibodies to idiotypic determinants of the monoclonal anti-sperm antibody M42.15 were developed and characterized. Previous studies demonstrated that M42.15 monoclonal antibody (mAb) inhibits fertilization in vitro and in vivo by inhibiting sperm-zona pellucida interaction. Anti-idiotype antibodies to M42.15 mAb (anti-Id M42) were isolated by affinity chromatography on immobilized M42.15 mAb. Binding specificity of anti-Id M42.15 was demonstrated in a solid-phase radioimmune binding assay and by specific immunoprecipitation of soluble M42.15 mAb. Anti-Id M42 competitively inhibited M42.15 mAb, but not P220.2 mAb, binding to mouse sperm, confirming that the anti-Id preparation contained antibodies directed against idiotopes within or adjacent to the antigen-binding site of the mAb. At equimolar concentrations, anti-Id M42 inhibited binding of 125I-labeled M42.15 mAb to sperm by greater than 80%. These results showed that anti-Id M42 efficiently blocked antibody binding to sperm and suggested that anti-Id M42 could be used to neutralize the anti-fertility activity of the M42.15 mAb. When tested in in vitro fertilization assays, anti-Id M42, but not rabbit immunoglobulin, prevented M42.15 mAb-induced inhibition of fertilization. Together, these results show that the inhibitory activity of anti-sperm antibodies capable of interfering with gamete interaction can be neutralized by anti-Id that recognize determinants close to the antigen-combining site of the anti-sperm antibody.

Animals↗

Correlation of sperm viability with gamete interaction and fertilization in vitro in the cheetah (Acinonyx jubatus).

Sperm-oocyte interaction in vitro was studied in the cheetah, a species known to produce poor quality ejaculates and to experience low rates of fertility. Twelve female cheetahs were injected (i.m.) with eCG followed by hCG 84 h later. Twenty-four to 26 h post hCG, each was subjected to laparoscopic oocyte aspiration. A sperm motility index (SMI) was calculated for each of 9 cheetah sperm donors that produced ejaculates averaging 41.3 +/- 22.9 x 10(6) motile sperm and 28.4 +/- 4.9% structurally normal sperm. Each ejaculate was used to inseminate cheetah oocytes from 1 or 2 females and salt-stored, domestic cat oocytes. The presence of ovarian follicles (greater than or equal to 1.5 mm in diameter) showed that all females responded to exogenous gonadotropins (range, 11-35 follicles/female). A total of 277 cheetah oocytes was collected from 292 follicles (94.9% recovery; 23.1 +/- 2.2 oocytes/female). Of these, 250 (90.3%) qualified as mature and 27 (9.7%) as degenerate. Of the 214 mature oocytes inseminated, 56 (26.2%) were fertilized, and 37 (17.3%) cleaved to the 2-cell stage in vitro; but the incidence of in vitro fertilization (IVF) varied from 0 to 73.3% (p less than 0.001) among individual males. When oocytes from individual cheetahs (n = 5) were separated into two groups and inseminated with sperm from a male with an SMI greater than 0 after 6 h coincubation versus an SMI = 0 at this time, the mean fertilization rates were 28/44 (63.6%) and 0/37 (0%), respectively (p less than 0.05). Of the 117 domestic cat oocytes coincubated with cheetah sperm, 96.6% contained 1 or more cheetah sperm in the outer half of the zona pellucida (ZP). Although the mean number of cheetah sperm penetrating the outer ZP of the cat oocyte was similar (p greater than 0.05) among all males, there was a positive correlation between the number of sperm reaching the inner half of the ZP and fertilization rate in vitro (r = 0.82; p less than 0.05). Compared to IVF efficiency in the domestic cat and tiger as reported in earlier studies, IVF efficiency in the cheetah is low. Because oocytes from 11 of 12 cheetahs were fertilized in vitro, there is no evidence that the female gamete is incompetent. Although sperm pleiomorphisms may contribute to poor reproductive performance, examination of the data on the basis of individual sperm donors reveals that effective gamete interaction in the cheetah is dictated, in part, by sperm motility.

Animals↗

Effect of a partial deletion of Y chromosome on in vitro fertilizing ability of mouse spermatozoa.

The effect of a partial deletion of Y chromosome on sperm fertilizing ability was investigated through an in vitro fertilization technique. Epididymal spermatozoa of a congenic line, B10.BR-Ydel, which is characterized by a high incidence of abnormal spermatozoa, revealed a significantly lower in vitro fertilization rate (22%) than that (79%) of its control strain (B10.BR/SgSn), which has a normal-sized Y chromosome. Incidence of capacitated spermatozoa as determined by chlortetracycline fluorescence assay was significantly lower in B10.BR-Ydel than in B10.BR/SgSn spermatozoa. The fertilization rate was significantly improved when B10.BR-Ydel spermatozoa were separated from the supernatant of sperm suspension by Percoll gradient centrifugation. A reconstitution experiment revealed that the B10.BR-Ydel spermatozoa were more sensitive to the inhibitory effect of the supernatant than B10.BR/SgSn spermatozoa. Spermatozoa from F1 (C57BL/6N male x B10.BR-Ydel female) males showed higher fertilization rates than those from F1 (B10.BR.Ydel male x C57BL/6N female) males. These observations suggest that not only the morphology but also the fertilizing ability of spermatozoa is directly related to partial deletion of Y chromosome.

Animals↗

Developmental competence of domestic cat embryos fertilized in vivo versus in vitro.

Development of in vitro-fertilized (IVF) cat embryos was compared to that of naturally produced cat embryos in vivo and in vitro. To obtain in vivo-fertilized embryos, queens were mated three times daily on the second and third days of natural estrus and ovariohysterectomized at 64, 76, 100, 124, or 148 h after the first copulation. Embryos were flushed from the reproductive tract, evaluated for developmental stage, and cultured. For IVF, oocytes from gonadotropin-stimulated queens were inseminated with electroejaculated cat sperm in Ham's F-10 and evaluated for fertilization (cleavage to > or = 2 cells) at 30 h. In vitro development of embryos fertilized in vivo (n = 109) and in vitro (n = 46) was evaluated every 24 h for up to 10 days. High-quality embryos recovered at 64, 76, 100, 124, and 148 h after the first copulation were typically 1 to 2 cells (13 of 20), 5 to 8 cells (18 of 28), 9 to 16 cells (14 of 24), morulae (15 of 21), and compact morulae (11 of 18), respectively, suggesting blastomere cleavage once per day in vivo after the first three rapid cell divisions. A similar developmental rate to the morula stage (p > or = 0.05) was achieved in vitro by embryos derived from both in vitro and in vivo fertilization. Additionally, the proportion (p > or = 0.05) of in vivo-generated embryos (2 to 16 cells) that developed to morulae (64 of 83; 77.1%) was similar to that of IVF embryos (28 of 46; 60.9%). However, none of the IVF embryos (0/46), but 70.6% (77 of 109) of the in vivo-produced embryos, achieved blastocyst formation in culture (p < or = 0.05). Furthermore, 66.2% (51 of 77) of these blastocysts exhibited zona hatching. Incidence of morula and blastocyst formation in the in vivo group was influenced by stage of the embryo at collection. Embryos that were at the 9- to 16-cell stage at recovery were more likely (p < or = 0.05) to achieve morula or blastocyst status and emerge from the zona pellucida than younger-stage counterparts. In summary, the in vivo and in vitro growth rate of cat embryos produced after natural mating was comparable to that of embryos fertilized and cultured in vitro. However, developmental ability to the blastocyst stage was superior for embryos produced in vivo after natural mating.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

Modifications of carbohydrate residues and ZP2 and ZP3 glycoproteins in the mouse zona pellucida after fertilization.

Oligosaccharide side chains of zona pellucida (ZP) glycoproteins play a key role in the sperm-egg interaction phenomena during fertilization. In the present study, modifications of the ZP glycoproteins during the fertilization process in the mouse were studied by the lectin-gold technique and immunocytochemistry in conjunction with quantitative analysis. Binding of PNA, RCA I, DSA, LFA, MAA, AAA, and anti-ZP2 and anti-ZP3 antibodies was observed throughout the ZP of both unfertilized and fertilized eggs. However, HPA and BSAIB4 labeling was found only in the inner region of the ZP. After neuraminidase treatment (Neu), HPA showed an affinity for the entire ZP. Labeling by LFA, WGA, MAA, PNA, BSAIB4, and AAA decreased in the ZP of fertilized eggs; however, there was an increase in the binding of RCA I. HPA and Neu-HPA increased only in the inner region of the ZP. Immunoreactivity to antibodies against ZP2 and ZP3 also decreased after fertilization. The present results demonstrate that 1) terminal carbohydrate residues contained in the ZP glycoproteins are modified after fertilization and 2) inner and outer regions of the ZP contain different oligosaccharide side chains.

Animals↗

Relationship between spermatozoan lipid composition and fertility during aging of chickens.

Changes in the proportions of the various lipid components in spermatozoa were investigated throughout the reproductive period (24-72 wk of age) of male chickens. Sperm motility and in vivo fertility were also measured, and correlation coefficients with the lipid values were determined. The proportion of total phospholipid (PL) increased to reach a maximum value at 39 wk and decreased significantly thereafter. The relative content of free cholesterol and triacylglycerols showed no change in spermatozoa during aging or in relation to fertility values; free fatty acids and cholesterol esters increased continuously with age. Of the various PL classes, phosphatidylserine and phosphatidylcholine displayed a pattern of changes with age positively and negatively, respectively, in relation to the changes of fertility. The proportion of phosphatidylethanolamine had significantly decreased by the end of the reproductive period. The proportions of C16:0, C18:0, and C18:1n-9 within the PL of the spermatozoa increased with age, and those of C20:4n-6, C22:4n-6, and C22:6n-3 decreased. Positive correlations were found between fertility and total PLs, phosphatidylserine, and PL-bound C20:4n-6 and C22:4n-6; a negative correlation was found between fertility and phosphatidylcholine. Motility was positively correlated with the level of PL and negatively with that of free cholesterol; it was also positively correlated with the levels of C22:4n-6 and C22:6n-3 and negatively with those of C16:0, C18:0, and C18:1n-9. The results suggest that the lipid and fatty acid compositions of spermatozoa may be important predictors of fertility.

Aging↗