Sperm Head Width Research Articles

Morphometric assessment of cryopreserved livestock bull spermatozoa in the tropics.

The identification of different morphometric patterns of spermatozoa serves as a basis for improving our understanding of the diversity in an ejaculate and to relate them to the potential fertility of males. In this study, we aimed to examine the semen subpopulation structure, following dilution in semen of extenders, using a mathematical approach a possible application to fertility analyses. Ten sexually mature Bos taurus bulls were randomly allotted to one of three groups: (1) Tris-citric acid-egg yolk extender (Tris-EY); (2) commercial egg yolk extender OptiXcell® and (3) commercial egg yolk extender Triladyl®. The results showed significant differences (p < .05) between extenders in terms of values for head size and head shape variables of individual sperm, indicating an influence of extender composition. Sperm head width was found to significantly differ (p < .05) according to the extender, decreasing in the following order: OptiXcell® (4.836 ± 0.017 μm), Triladyl® (4.695 ± 0.012 μm) and Tris-EY (4.638 ± 0.010 μm). Principal component analysis allowed us to identify two subpopulations in OptiXcell®, and three subpopulations were each found in Triladyl® and Tris-EY. Overall, we observed significant differences between sperm subpopulations within each extender (p < .05), with differences in sperm head size and shape between bovine species that can be related to functionality and fertility capabilities.

Ability of the ISAS3Fun Method to Detect Sperm Acrosome Integrity and Its Potential to Discriminate between High and Low Field Fertility Bulls.

Simple SummaryThe objective of the present study was to investigate whether differences in bull fertility are associated with variations of sperm quality. Differences between high- and low-fertility bulls were found mainly in parameters related to sperm acrosome integrity when using a new fluorescence method that allows clear and precise detection of the sperm plasma membrane and acrosome: the ISAS3Fun method. It was concluded that the simultaneous assessment of sperm viability and acrosome integrity with the ISAS3Fun method is precise and seems to have a greater potential to discriminate between high- and low-fertility bulls than the more conventional in vitro sperm quality test. These results may help to predict the breeding soundness of bulls used in artificial insemination, which is important for the dairy industry.The objective of the present study was to investigate whether fertility differences in bulls are reflected in variations of sperm quality when analysing only one ejaculate per male. Two experiments were performed. In the first experiment, frozen semen samples from 20 adult bulls were tested; 10 bulls had high field fertility and 10 bulls had low field fertility. Analyses of sperm motility, membrane integrity, and membrane–acrosome integrity with the ISAS3Fun method were performed. Sperm morphometry of the fluorescence sperm subpopulations obtained with the ISAS3Fun method was also analysed. Significant differences between high- and low-fertility groups were only found with the ISAS3Fun technique, specifically in sperm acrosome integrity, the proportion of spermatozoa with an intact acrosome and damaged membrane, and in sperm head width of spermatozoa with intact structures. Discriminant analyses allowed us to correctly classify 90% of sperm samples in their fertility group using sperm quality parameters. Given that only the results obtained with the ISAS3Fun technique were related to bull fertility, we performed a second experiment aimed to validate the efficacy of this technique to detect the acrosomal integrity of bull spermatozoa, comparing them with the conventional FITC-PNA/propidium iodide (PNA/PI) combination under capacitating conditions. The results indicated that the ISAS3Fun combination provided an accurate assessment of both viability and acrosomal integrity for ejaculated spermatozoa, while the PNA/PI combination underestimated the extension of acrosomal damage due to false negatives. It was concluded that the simultaneous assessment of sperm plasma membranes and acrosome integrity with the ISAS3Fun method is precise and seems to have a greater potential to discriminate between high- and low-fertility bulls than more conventional in vitro sperm quality tests.

Influence of testosterone administration at the end of the breeding season on sperm cryoresistance in rams (Ovis aries) and bucks (Capra hircus)

This study examines the influence of administering testosterone at the end of the mating season, on the responses (morphometric and functional) of ram and buck sperm to freezing-thawing. Five rams were administered 25 mg testosterone propionate (TP) subcutaneously in 2 mL of olive oil twice per week (Monday and Thursday) from October 1 to 31; 5 bucks received exactly the same treatment but from November 1 to 30. Control groups were administered 2 mL of olive oil without TP twice per week over the same period. In the rams, no significant differences were seen in plasma testosterone between the treated and control groups during treatment (0.8 ± 0.2 ng/mL vs 1.5 ± 0.5 ng/mL; P > 0.05). Significant differences were seen in this respect, however, in the bucks (4.3 ± 0.8 ng/mL and 6.9 ± 0.9 ng/mL; P < 0.05). In the rams, TP treatment increased (P < 0.05) the straight-line velocity (VSL), linearity (LIN), straightness (STR) and wobble (WOB) values in fresh sperm samples. Similarly, in the frozen-thawed samples, TP treatment increased the VSL, average path velocity (VAP), LIN and WOB values (P < 0.05) compared with controls. In the bucks, treatment with TP had no effect on any measured variable in fresh sperm; frozen-thawed sperm, however, returned greater VSL, LIN, STR, and WOB values (P < 0.05) than did controls. In the rams, treatment with TP led to a reduction in all fresh sperm head morphometric variables (P < 0.05). Freezing-thawing further reduced (P < 0.05) all morphometric variables in both the control and treated groups. In the bucks, treatment with TP increased (P < 0.05) the length, area, and perimeter of fresh sperm cells, unlike that seen in ram sperm. Compared with fresh sperm, freezing-thawing led to reduced (P < 0.05) morphometric variables in both the control and treated bucks, except for the sperm head width, which in the controls remained unchanged. In conclusion, TP treatment at the end of the mating season affected fresh sperm quality, in both Spanish Merino rams and Murciano-Granadina bucks, in a species-specific manner, but improved the sperm kinetic variables after freezing-thawing in both species, apparently improving sperm cryoresistance. Treatment with TP affects the dimensions of the sperm head in a species-specific manner.

The effects of inbreeding on sperm morphometry of captive-bred endangered mammals

Captive breeding is used for the conservation of endangered species, but inbreeding can result when a small number of founders are used to establish populations. Inbreeding can reduce the proportion of normal sperm in an ejaculate, but may also have effects on sperm size and shape (morphometry). We investigated the effects of inbreeding on sperm morphometry of black-footed ferrets (Mustela nigripes (Audubon and Bachman, 1851)) and red wolves (Canis rufus Audubon and Bachman, 1851) from captive breeding programs to determine if more inbred males produced sperm of poor quality (bulky head, small midpiece, short tail). We measured sperm head length, head width, midpiece length, midpiece width, and tail length on 10 sperm from each male of both species. A negative relationship between variation in sperm tail length and inbreeding coefficient (f) was found in black-footed ferret, suggesting that more inbred individuals will have reduced genetic and phenotypic variation. Analyses indicated a negative relationship between sperm head width and f and a positive relationship between sperm tail length and f in red wolf, suggesting that more inbred male red wolves could have faster sperm. These results indicate that inbreeding affects functionally important aspects of sperm morphometry, but that these effects may not be entirely negative.

Sexual Selection of Protamine 1 in Mammals.

Protamines have a crucial role in male fertility. They are involved in sperm chromatin packaging and influence the shape of the sperm head and, hence, are important for sperm performance. Protamine structure is basic with numerous arginine-rich DNA-binding domains. Postcopulatory sexual selection is thought to play an important role in protamine sequence evolution and expression. Here, we analyze patterns of evolution and sexual selection (in the form of sperm competition) acting on protamine 1 gene sequence in 237 mammalian species. We assessed common patterns as well as differences between the major mammalian subclasses (Eutheria, Metatheria) and clades. We found that a high arginine content in protamine 1 associates with a lower sperm head width, which may have an impact on sperm swimming velocity. Increase in arginine content in protamine 1 across mammals appears to take place in a way consistent with sexual selection. In metatherians, increase in sequence length correlates with sexual selection. Differences in selective pressures on sequences and codon sites were observed between mammalian clades. Our study revealed a complex evolutionary pattern of protamine 1, with different selective constraints, and effects of sexual selection, between mammalian groups. In contrast, the effect of arginine content on head shape, and the possible involvement of sperm competition, was identified across all mammals.

Characteristics of frozen thawed semen in predicting the fertility of buffalo bulls

Information regarding the fertility index in relation to sperm attributes, which helps in the selection of future breeding bulls are meager in buffaloes. The present study was conducted to measure the differences in motility characteristics, head biometry, acrosome, plasma membrane and DNA of cryopreserved semen of fertile and sub- fertile buffalo bulls. The fertility of bulls was classified on the basis of conception rates (CR), where bulls having CR 28–35% and &gt;55% were considered as sub-fertile and fertile bulls respectively. Computer assisted semen analyzer was used for motility and viability studies. Total motility, average path velocity (VAP), straight linear velocity (VSL) and curvilinear velocity (VCL) of sperm for fertile bulls were significantly higher than sub-fertile bulls. Significant differences were found in the length and width of sperm head between the 2 groups. The percentage of intactness of sperm acrosome of fertile bulls was significantly higher than sub-fertile bulls. The percentage of apoptotic sperm differed significantly between fertile and sub-fertile bulls. The sperm DNA integrity of fertile and sub-fertile bulls was not significantly different. In conclusion, the total motility, VAP, VCL, VSL, length and width of sperm head, acrosome integrity and percentage of apoptotic sperm, are useful for evaluating bulls’ semen quality to reduce the risk of using semen of poor-fertility bulls in AI programme.

Semen quality and time to pregnancy: the Longitudinal Investigation of Fertility and the Environment Study

To assess semen parameters and couple fecundity as measured by time to pregnancy (TTP). Observational prospective cohort with longitudinal measurement of TTP. Sixteen Michigan/Texas counties. A total of 501 couples discontinuing contraception were followed for 1 year while trying to conceive; 473 men (94%) provided one semen sample, and 80% provided two samples. None. Using prospectively measured TTP, fecundability odds ratios (FORs) and 95% confidence intervals (CIs) were estimated for 36 individual semen quality parameters accounting for repeated semen samples, time off contraception, abstinence, enrollment site, and couples' ages, body mass indices, and serum cotinine concentrations. In adjusted models, semen quality parameters were associated with significantly shorter TTP as measured by FORs >1: percent motility, strict and traditional morphology, sperm head width, elongation factor, and acrosome area. Significantly longer TTPs or FORs <1 were observed for morphologic categories amorphous and round sperm heads and neck/midpiece abnormalities. No semen quality parameters achieved significance when simultaneously modeling all other significant semen parameters and covariates, except for percent coiled tail when adjusting for sperm concentration (FOR 0.99; 95% CI 0.99-1.00). Male age was consistently associated with reduced couple fecundity (FOR 0.96; 95% CI 0.93-0.99), reflecting a longer TTP across all combined models. Female but not male body mass index also conferred a longer TTP (FOR 0.98; 95% CI 0.96-0.99). Several semen measures were significantly associated with TTP when modeled individually but not jointly and in the context of relevant couple-based covariates.

INFLUENCE OF COLLECTING RHYTHM ON BOAR SPERM CELLS QUALITY IN LARGE WHITE AND LANDRACE BOARS

Taking into consideration the optimization and leading of the reproduction process in swine, the applying of artificial insemination makes possible the checking of the seminal material in young boars, that represents a guarantee of their biological material. Starting from these opinions this paper has as aim analyzing the main morph metric features of boar sperm cells. The cytological features of boar sperm cells were evaluated by computerized morph metric method, adding more objectivity by the measuring regarding the length and the width of sperm head, the length of tail and the total length of sperm. There were also calculated the body shape indices, the volume and the surface of the sperm cell head. The obtained data were statistically remade and then were compared the indicators beside the different periods between sperm collecting (one collecting/two days, one collecting/three days and one collecting/four days).

Intraspecific divergence in sperm morphology of the green sea urchin, Strongylocentrotus droebachiensis: implications for selection in broadcast spawners.

BackgroundSperm morphology can be highly variable among species, but less is known about patterns of population differentiation within species. Most studies of sperm morphometric variation are done in species with internal fertilization, where sexual selection can be mediated by complex mating behavior and the environment of the female reproductive tract. Far less is known about patterns of sperm evolution in broadcast spawners, where reproductive dynamics are largely carried out at the gametic level. We investigated variation in sperm morphology of a broadcast spawner, the green sea urchin (Strongylocentrotus droebachiensis), within and among spawnings of an individual, among individuals within a population, and among populations. We also examined population-level variation between two reproductive seasons for one population. We then compared among-population quantitative genetic divergence (QST) for sperm characters to divergence at neutral microsatellite markers (FST).ResultsAll sperm traits except total length showed strong patterns of high diversity among populations, as did overall sperm morphology quantified using multivariate analysis. We also found significant differences in almost all traits among individuals in all populations. Head length, axoneme length, and total length had high within-male repeatability across multiple spawnings. Only sperm head width had significant within-population variation across two reproductive seasons. We found signatures of directional selection on head length and head width, with strong selection possibly acting on head length between the Pacific and West Atlantic populations. We also discuss the strengths and limitations of the QST-FST comparison.ConclusionSperm morphology in S. droebachiensis is highly variable, both among populations and among individuals within populations, and has low variation within an individual across multiple spawnings. Selective pressures acting among populations may differ from those acting within, with directional selection implicated in driving divergence among populations and balancing selection as a possible mechanism for producing variability among males. Sexual selection in broadcast spawners may be mediated by different processes from those acting on internal fertilizers. Selective divergence in sperm head length among populations is associated with ecological differences among populations that may play a large role in mediating sexual selection in this broadcast spawner.

Biometry of frozen–thawed sperm from eight breeds of Indian buffaloes ( Bubalus bubalis)

Sperm morphometry, in combination with other objective traits, can be useful for developing a fertility index. The objective of the present study was to measure various biometric end points of frozen–thawed sperm from eight breeds of Indian buffaloes (Murrah, Surti, Tarai, Mehsana, Jaffrabadi, Bhadawari, Pandharpuri and Nili-Ravi). The sperm head of Pandharpuri buffaloes had the greatest length (10.21 μm), width (6.05 μm), area (52.31 μm 2) and perimeter (31.86 μm). The ratio of sperm width to length was also greatest (0.61) in Pandharpuri as well as in two other breeds, viz. Nili-Ravi and Jaffrabadi. Murrah had the smallest sperm head width (4.75 μm), area (41.65 μm 2) and perimeter (29.17 μm), but its sperm tail was longest (57.02 μm), along with that of Jaffrabadi buffaloes (56.96 μm). Based on mean values of sperm tail length, mid piece length and its width the eight buffalo breeds were categorized into three, four and five groups, respectively. Multivariate analysis and clustering put six breeds (Surti, Tarai, Mehsana, Jaffrabadi, Bhadawari and Nili-Ravi) in one cluster, whereas Murrah and Pandharpuri appeared as separate entities.

Utilización del Integrated Semen Analysis System (ISAS) ® para el análisis morfométrico espermático humano y su significado en las técnicas de reproducción asistida

Aim The utility of a new computer-aided sperm morphology analyzer (the integrated semen analysis system [ISAS ®]) in predicting fertilization rates obtained with ejaculated spermatozoa from infertile men undergoing distinct assisted reproduction technologies (ART) was evaluated and compared with standard morphology analysis. Methods Ejaculates were obtained from men providing samples for intrauterine insemination (IUI) (n = 15), in vitro fertilization (IVF) (n = 20) and intracytoplasmic sperm injection (ICSI) (n = 19). Smears were prepared for routine morphological analysis using Papanicolaou staining and for assessment by ISAS ® using Hemacolor staining. Results Significant differences were found only in the sperm head length of ejaculated spermatozoa in patients undergoing IUI, IVF and ICSI. Spermatozoa selected by swim-up tended to have larger heads and shorter midpieces than spermatozoa found in the native ejaculate. No correlation was found between subjective sperm morphology and fertilization and pregnancy rates with the distinct ART used. In sharp contrast, a significant negative correlation was found between sperm head width, area and perimeter as assessed by ISAS ® after swim-up and the pregnancy rate for IUI and the fertilization rate for ICSI. No correlations were found with any of the parameters analyzed and the fertilization and pregnancy rates for IVF. Conclusion Sperm morphology assessment using ISAS ® may be useful when selecting patients for ART.

Relationship between semen parameters and mercury concentrations in blood and in seminal fluid from subfertile males in Hong Kong

Relationship between semen parameters and mercury concentrations in blood and in seminal fluid from subfertile males in Hong Kong

Dimensional changes in boar spermatozoa during passage through the epididymis.

Differential measurements of boar epididymal spermatozoa were performed in 8 slaughtered Landrace breed with a phase contrast microscope. The results in sper-matozoal measurements were statistically analysed with respect to the regions of epidi-dymis (caput, corpus and cauda) and to the testis weight (group I: <350 g, group II: 351-450 g and group III: >451 g).The sperm head showed a significant increase in length in the corpus epididymidis. A significant increase was observed in the total sperm length, length and width of sperm head in the corpus and cauda epididymidis, respectively (group III). On the other hand, a significant decrease occurred in the length of the middle-piece (group I and III) and tail (group II and III) in the cauda epididymis. Group III boars deviated from group I by a significant decrease in total sperm length in all segments of epididymis, and in tail length in the cauda epididymidis. In the sperm of group III boars, head length in the caput, and corpus and head width in the cauda epididymidis were significantly greater than those in other two groups. It seems likely from these results that the sperm matura-tion in the epididymis is related to the testicular growth.