Morphology and motility of spermatozoa from different regions of the epididymal duct in the domestic cat

Spermatozoa undergo important maturational changes as they pass through the epididymal duct. Some domestic cats and many species of wild felids have high proportions of abnormal spermatozoa in their ejaculates. The epididymis has been shown to be able to remove certain abnormal sperm forms in some species while other sperm abnormalities originate in the epididymis. So far, it has not been shown how the epididymis affects sperm morphology in the domestic cat. Therefore, motility and sperm morphology were studied in spermatozoa from the efferent ducts and from the 6 regions of the epididymal duct. There were significant decreases in the proportions of spermatozoa with abnormalities of the sperm head, acrosomal defects, acrosomal abnormalities and in the proportion of midpiece abnormalities. In contrast, there was a small but significant increase in the proportion of spermatozoa with abnormalities of the tail. Spermatozoa acquired the capacity for motility in Region 4, where the cytoplasmic droplet also moved from a proximal to a distal position, indicating that important maturational changes take place in this region. The results of this study demonstrate that the proportions of sperm abnormalities originating in the testes decrease during epididymal transport, while some sperm tail abnormalities may actually originate in the epididymis.     

Sperm morphology is better in the second ejaculate than in the first in domestic cats electroejaculated twice during the same period of anesthesia

Several species produce ejaculates of inferior quality after a period of sexual abstinence, but the frequency of semen collection has thus far not been shown to affect sperm morphology in felids. The aim of this study was to determine whether sperm morphology and motility would differ between 2 ejaculates collected from the same cat within a short interval. Fifteen male domestic cats were anesthetized and then electroejaculated twice, with a 5- to 10-min interval between treatments. A standardized electroejaculation regimen was used with 80 stimuli, from 2 to 5 V, for each ejaculate. The first ejaculates contained significantly higher (P < 0.05) proportions of distal droplets, coiled tails and immotile spermatozoa than the second ejaculates, which contained significantly higher proportions of morphologically normal spermatozoa (40.9 vs 54.6%) but a lower sperm count (39.0 x 10(6) vs 5.2 x 10(6)). The higher proportions of defective spermatozoa and the lower motility in the first ejaculate than in the second were probably due to the aging of spermatozoa in the epididymis. These results show that the second ejaculate collected within a short interval has better sperm morphology and motility than the first and that this should be considered when evaluating semen quality in the domestic cat and when collecting cat semen to be used for artificial insemination or to be frozen for storage.     

Effect of mating on sperm distribution in the reproductive tract of the male rat

Extragonadal sperm reserves in male rats were measured in different regions of the genital tract before and subsequent to normal ejaculation. In sexually rested rats, the sperm count (million spermatozoa for the paired organs) in different regions was: distal vas, 18; proximal vas, 9.8; cauda epididymidis, 229; caput + corpus epididymidis, 154. Following mating, the sperm count was reduced in the proximal and distal vas deferens and in the cauda epididymidis. The reproductive tract of mated females was found to contain 29% (no copulatory plug) or 59% (with copulatory plug) of the estimated mean ejaculate, which was estimated from the difference between the sperm counts in the sexually rested rat and following ejaculation. It is concluded that in the rat the immediate source of spermatozoa for ejaculation is the cauda epididymidis, with a smaller contribution arising from the vas deferens.     

Cryopreservation effects on domestic cat epididymal versus electroejaculated spermatozoa

Frozen-thawed epididymal spermatozoa have already been successfully used in artificial insemination in the domestic cat, proving to be a valuable resource for the reproduction of felid species, which are threatened with extinction. The aim of this study was to compare the effects of freezing and thawing on domestic cat semen collected by electroejaculation (EL) and from the epididymides (EP) and vasa deferentia. Ten adult cats were anesthetized, electroejaculated and immediately thereafter, orchiectomized. Epididymal spermatozoa were collected through the compression of caudae epididymidis and vasa deferentia. Spermatozoa were frozen-thawed following a single protocol. Sperm motility, sperm progressive status (0-5), plasma membrane integrity and morphology (light and transmission electron microscope) were assessed on two occasions, immediately after collection and after freezing and thawing. There were no significant differences between the electroejaculated and epididymal fresh or frozen-thawed spermatozoa for any of the variables. However, the incidence of acrosome defects after freezing and thawing increased by 19% based on light microscopy, whereas ultrastructural images revealed acrosome damages in most sperm cells. Since these acrosomal changes are known to affect sperm fertilising capacity, further studies are needed to optimize cryopreservation techniques for epididymal as well as electroejaculated domestic cat spermatozoa.     

Effects of breeding season and mating on total number and distribution of spermatozoa in the epididymis of the brown marsupial mouse, Antechinus stuartii

Changes in the number and distribution of spermatozoa in the epididymis of the adult brown marsupial mouse were examined during July/August in mated and unmated males. The effects of mating on epididymal sperm populations were studied in 2 groups of males each mated 3 times and compared with the number and distribution of spermatozoa in the epididymides of 4 unmated control groups. One testis and epididymis were removed from each animal (hemicastration) either before or early in the mating season to provide information on initial sperm content and distribution. The contralateral side was removed later in the mating season to examine the effects of mating or sexual abstinence on epididymal sperm distribution. Epididymal sperm number peaked in both the distal caput and distal corpus/proximal cauda epididymidis in late July. The total number of spermatozoa, including those remaining in the testis, available to each male at the beginning of the mating season in early August was approximately 4.4 x 10(6)/side. Although recruitment of spermatozoa into the epididymis from the testis continued until mid-August, sperm content of the epididymis reached a peak of about 3.5 x 10(6)/epididymis in early August. At this time approximately 0.9 x 10(6) spermatozoa remained in the testis which had ceased spermatogenic activity. Throughout the mating season, epididymal spermatozoa were concentrated in the distal corpus/proximal cauda regions of the epididymis and were replenished by spermatozoa from upper regions of the duct. Relatively few spermatozoa were found in the distal cauda epididymidis, confirming a low sperm storage capacity in this region. A constant loss of spermatozoa from the epididymis, probably via spermatorrhoea, occurred throughout the mating season and very few spermatozoa remained in unmated males in late August before the annual male die-off. Mating studies showed that an average of 0.23 x 10(6) spermatozoa/epididymis were delivered per mating in this species, but the number of spermatozoa released at each ejaculation may be as few as 0.04 x 10(6)/epididymis when sperm loss via spermatorrhoea is taken into account. We suggest that the unusual structure of the cauda epididymidis, which has a very restricted sperm storage capacity, may function to limit the numbers of spermatozoa available at each ejaculation and thus conserve the dwindling epididymal sperm reserves in order to maximize the number of successful matings which are possible during the mating season.     

Influence of ejaculation frequency of stallions on characteristics of semen and output of spermatozoa.

Approximately 1 week was required to stabilize the extragonadal sperm reserves in stallions ejaculated daily for 10 weeks. The true daily sperm output of a stallion was equal to the mean daily sperm output of seven ejaculates +/- 1-35 X 10(9) spermatozoa. Mean concentrations of spermatozoa/ml and number of spermatozoa/ejaculate were higher (P less than 0-01) for X1 and X3/week ejaculation frequencies than for a X6/week frequency. Sperm output/week was nearly identical for a X6/week frequency. Sperm output/week was nearly identical for the X3 and X6 frequencies and higher (P less than 0-01) than the X1 frequency. Increase of ejaculation frequency from one to two ejaculates/day twice weekly significantly (P less than 0-01) raised the output of spermatozoa/week. Gel-free semen volume, spermatozoa/ml, and number of spermatozoa/ejaculate were higher (P less than 0-01) in the first, than in the second, ejaculate. Collection of semen on alternate days would be a practical ejaculation frequency for inseminating mares. Two ejaculates collected twice a week would be a practical ejaculation frequency for long-term storage of stallion semen.     

Creatine phosphokinase in domestic cat epididymal spermatozoa

Mammalian spermatozoa that have not completed final testicular sperm maturation have residual cytoplasm and increased creatine phosphokinase (CK) content. This study determined: (1) if CK could be detected by immunostaining cat spermatozoa from the caput, corpus, and cauda epididymis, (2) fluctuations in the proportions of spermatozoa with mature or immature CK-staining patterns during epididymal sperm transit, and (3) how well sperm maturity (as determined by a CK marker) correlated with testicular or epididymal dysfunctions associated with morphological sperm abnormalities. One epididymis was collected from each of 37 cats after orchiectomy and processed immediately to allow sperm morphology evaluations on a 'regional' basis. Sperm released from the contralateral epididymis were evaluated for motility, sperm membrane integrity, and immunostaining with CK-B antibodies. Proportions of spermatozoa with malformed or detached heads, proximal droplets and acrosomal or midpiece abnormalities decreased (P < 0.05) from the caput to the cauda epididymis. In contrast, proportions of spermatozoa that were motile, membrane-intact or with flagellar abnormalities or distal droplets increased (P < 0.05) from the caput to cauda region. Percentages of spermatozoa with an immature CK-staining pattern also decreased (P < 0.05) with epididymal transit (which differs from that reported for the human and stallion). There was no correlation (P > 0.05) between sperm morphology and the CK-staining patterns. In summary, the results reveal that some specific sperm malformations in the domestic cat are of testicular origin, whereas others develop during epididymal transit.     

Distribution of carnitine and acylcarnitine in the hamster epididymis and in epididymal spermatozoa during maturation

The highest levels of carnitine and acylcarnitine were found in the cauda epididymidis, and spermatozoa from the cauda contained greater amounts of total carnitine (free carnitine plus acylcarnitine) than those removed from the corpus or caput epididymidis. Spermatozoa from the distal cauda contained significantly greater amounts of both free and total carnitine than those removed from the proximal cauda epididymidis. The acylcarnitine:carnitine ratio was 1.7 and 0.37 in caput and cauda spermatozoa, respectively and 1.7 and 1.3 in caput and cauda fluid, respectively. It is suggested that the accumulation of carnitine is involved in sperm maturation and that acylcarnitine serves as an energy substrate for epididymal spermatozoa.     

Changes in the morphology of spermatozoa during their passage through the genital tract in dairy bulls with normal and impaired spermat ogenesis

An investigation was conducted on changes in sperm morphology along the excurrent duct of bulls. The study comprised 20 bulls with proven fertility and normal semen picture, and 10 bulls with pathologic semen. The morphology of spermatozoa was evaluated on ejaculates and on postslaughter collected contents from the excurrent duct. The incidence of pathologic sperm heads decreased along the duct in both groups of bulls. The main decrease generally occurred in caput epididymidis. In bulls with pathologic semen, the decrease continued in lower regions of epididymis and was deferens. The rate and pattern of sperm removal seem to primarily depend on the quality of spermatozoa entering the excurrent duct. The removal was clearly selective and is assumed to be associated with phagocytosis of spermatozoa mainly in the efferent ductules and proximal part of caput epididymis. Proximal cytoplasmic droplets were present on almost all sperm in the efferent ductules. The incidence decreased during passage along the genital tract. Migration of cytoplasmic droplets from a proximal to a distal position took place between regions C and D of the caput epididymidis. The incidence of middle-piece abnormalities decreased during passage along the genital tract, while the incidence of sperm tail abnormalities increased in the corpus and cauda epididymidis in all bulls.     

Effects of age and frequency of ejaculation on sperm production and extragonadal sperm reserves in stallions.

Extragonadal reserves totalled 89 X 10(9) spermatozoa for 5--16-year-old sexually rested stallions and 60 X 10(9) for 2--4-year-olds. Regardless of age, the cauda epididymidis contained 62% of the total reserves and the vas deferens, including the ampulla, contained 7% of the total reserves of spermatozoa. The caput plus corpus epididymidis from 5--16-year-old stallions (N = 41) contained 14.9 X 10(9) spermatozoa per side as compared (P less than 0.01) to 8.5 X 10(9) for 2--4-year olds (N = 30). Frequency of ejaculation did not influence the number of spermatozoa found in caput plus corpus epididymidis. Across all ages, the number of spermatozoa potentially available for ejaculation from the cauda epididymidis and vas deferens on each side totalled 54 X 10(9). Collection of 5 successive ejaculates from sexually rested stallions removed 40--60% of the available spermatozoa while ejaculation every 2nd day reduced (P less than 0.05) the number of spermatozoa potentially available for ejaculation by 27%. Nevertheless, sufficient spermatozoa are produced daily (6.4 and 4.2 X 10(9) for 5--16-and 2--4-year-olds) to permit use of an average stallion once or twice daily, during spring and summer, providing sexual behaviour is adequate.     

Maturation and regulation of the motility of spermatozoa in the epididymis of the tammar wallaby (Macropus eugenii).

Demembranated spermatozoa from the rete testis developed vigorous flagellation when reactivated with ATP, but showed no forward progression such as that seen in samples from the cauda epididymidis. The proportion of spermatozoa that were reactivated was smaller for samples from the rete testis than from the cauda epididymidis. Studies in vitro of undiluted micropuncture samples from the epididymis indicated that the activity of spermatozoa is suppressed as they develop the capacity for motility. However, as spermatozoa spontaneously became activated during the collection or subsequent incubation of undiluted samples, it was concluded that the suppressive action is labile. The activity of spermatozoa in vitro was examined in diluted samples from the cauda epididymidis. A concentration of 2.5 mmol extracellular calcium/l was better than lower concentrations. Diluents at pH 5.5 completely inhibited sperm motility when they contained 20 mmol lactate/l (but not glutamate) and the effect was reversed by readjusting the diluent to pH 7.4. However, lactate was not considered to suppress sperm motility in situ, as the plasma from the cauda epididymidis contained only 2.7 +/- 0.5 mmol lactate/l. There was no effect of sodium concentration (1 and 115 mmol/l), pH (5.5 and 7.4) or amiloride (0 and 1 mmol/l) on sperm motility, indicating that motility is not dependent on the concentration of sodium above 1 mmol/l or on a sodium-proton exchange system. The relative viscosity of plasma from the cauda epididymidis did not affect the motility of spermatozoa.     

Lectin-binding sites on the plasma membranes of rabbit spermatozoa: Changes in surface receptors during epididymal maturation and after ejaculation

Modifications in rabbit sperm plasma membranes during epididymal passage and after ejaculation were investigated by used of three lectins: concanavalin A (Con A); Ricinus communis I (RCA(I)); and wheat germ agglutinin (WGA). During sperm passage from caput to cauda epididymis, agglutination by WGA drastically decreased, and agglutination by RCA(I) slightly decreased, although agglutination by Con A remained approximately unchanged. After ejaculation, spermatozoa were agglutinated to a similar degree or slightly less by Con A, WGA, and RCA(I), compared to cauda epididymal spermatozoa. Ultrastructural examination of sperm lectin-binding sites with ferritin- lectin conjugates revealed differences in the densities of lectin receptors in various sperm regions, and changes in the same regions during epididymal passage and after ejaculation. Ferritin-RCA(I) showed abrupt changes in lectin site densities between acrosomal and postacrosomal regions of sperm heads. The relative amounts of ferritin-RCA(I) bound to heads of caput epididymal or ejaculated spermatozoa. Tail regions were labeled by ferritin RCA(I) almost equally on caput and cauda epididymal spermatozoa, but the middle-piece region of ejaculated spermatozoa was slightly more densely labeled than the principal-piece region, and these two regions on ejaculated spermatozoa were labeled less than on caput and cuada epididymal spermatozoa. Ferritin-WGA densely labeled the acrosomal region of caput epididymal spermatozoa, although labeling of cauda epidiymal spermatozoa was relatively sparse except in the apical area of the acrosomal region. Ejaculated spermatozoa bound only a few molecules of ferritin-WGA, even at the highest conjugate concentrations used. Caput epididymal, but not cauda epididymal or ejaculated spermatozoa, bound ferritin-WGA in the tail regions. Dramatic differences in labeling densities during epididymal passage and after ejaculation were not found with ferritin-Con A.     

Fertilization in vitro with spermatozoa from different mice increased variation in the developmental potential of embryos compared to artificial parthenogenetic activation

Although successful embryo development is dependent upon genetic and epigenetic contributions from both the male and female, the male potential to adversely affect embryo development has been scarcely studied. It is unclear whether the sperm variation among different males would affect the outcome of oocyte evaluation by embryo development following fertilization. In the present study, variation in the developmental potential of mouse embryos was first compared between in vitro fertilization with epididymal spermatozoa from different males and Sr(2+) parthenogenetic activation using oocytes of different qualities, and then the effect of male on fertilization and embryo development was examined using randomly chosen oocytes and spermatozoa from cauda epididymidis, vas deferens or electro-ejaculates. Rates of fertilization and blastocyst formation were significantly higher with spermatozoa from cauda epididymidis or vas deferens than with ejaculated spermatozoa. Rates of embryonic development differed significantly between different males, but not between different ejaculates of the same male. Analysis of standard errors of means and coefficients of variance indicated that as long as multiple males were involved, the variation in oocyte fertilization/activation and blastocyst formation was always higher after fertilization than after Sr(2+) parthenogenetic activation whether spermatozoa were collected from epididymidis, vas deferens or ejaculates and regardless of oocyte qualities. It is concluded that (1) epididymal mouse spermatozoa fertilize more oocytes than ejaculated spermatozoa under identical experimental conditions; (2) like farm animals, the mice also show a remarkable male effect on the developmental potential of in vitro produced embryos although they are supposed to be less genetically diverse; (3) parthenogenetic activation is recommended for assessment of oocyte quality to exclude the effect of male.     

In-vitro development of the fertilizing ability of hamster epididymal spermatozoa after co-culture with epithelium from the proximal cauda epididymidis

The epididymides of adult male hamsters were surgically ligated at the junction of the distal corpus and proximal cauda regions. After 3 days, spermatozoa recovered from the distal corpus displayed greater progressive motility and head to head agglutination in capacitating medium than did those from intact controls, but had low fertilizing ability (3% fertilization rate) in vitro or in vivo. When these spermatozoa were incubated for 6 h with epithelial cells from the proximal cauda epididymidis, previously cultured for 3 days, they maintained motility and exhibited a significant increase in fertilizing ability (30% and 29% in vitro and in vivo respectively). The fertilizing ability of distal corpus spermatozoa incubated with 3-day-old cultures without androgens, or 8-12-day-old epithelial cells with fibroblast overgrowth, or without epithelial cells, remained low (5%). Increase in sperm fertilizing ability was associated with increased sperm binding to the zona pellucida in vitro. These results demonstrate that, under suitable culture conditions, the final stages in the development of hamster sperm fertilizing ability can be achieved in vitro. Factors secreted by cultured epithelium from the proximal cauda epididymidis are implicated in this maturation process.     

Region-specific expression and secretion of the fibrinogen-related protein, fgl2, by epithelial cells of the hamster epididymis and its role in disposal of defective spermatozoa

The cauda epididymidis functions in the storage and protection of mature, fertile spermatozoa. We previously identified a region-specific secretory glycoprotein (termed HEP64) of the hamster proximal cauda epididymidis that specifically bound and coated the nonviable, but not the viable, spermatozoa within the epididymal lumen. In this study we employed expression screening of a hamster epididymal cDNA library to obtain the full-length sequence of HEP64 and to identify it as the fibrinogen-like protein fgl2. Northern blot analysis demonstrated that fgl2 mRNA is highly expressed by the proximal cauda epididymidis in comparison to other hamster tissues examined, and, in situ hybridization analysis of the epididymis revealed that fgl2 mRNA exhibited a region- and principal cell-specific expression pattern. Immunohistochemistry confirmed the association of fgl2 with abnormal spermatozoa in the cauda epididymidis and revealed smaller fgl2-containing particles. Immunoelectron microscopy revealed that fgl2 was distributed throughout an amorphous, "death cocoon," complex assembled onto abnormal spermatozoa and that the smaller fgl2 aggregates consisted of the amorphous material with embedded sperm fragments, organelles, and membrane vesicles. A protocol was developed to isolate an enriched death cocoon fraction. SDS-PAGE and microsequence analyses revealed that the Mr 64,000 fgl2 monomer was assembled into two disulfide-linked oligomers of Mr 260,000 and 280,000. These data demonstrate that the epididymis possesses a specific mechanism to identify and envelop defective spermatozoa with a protein complex containing the fibrinogen-like protein fgl2. We propose that this represents an important protective mechanism not only to shield the viable sperm population from potentially deleterious enzymes released by dying spermatozoa but also to prevent the release of sperm proteins that could initiate an immune response if they escaped the epididymal environment.     

Ethyl methanesulphonate induced changes in the differentiation, structure and functions of spermatozoa of the house rat,Rattus rattus L.

Intraperitoneal administration of 500 mg/kg and 625 mg/kg doses of the germ cell mutagen, ethyl methanesulphonate (EMS) in 5 consecutive days to the house rat,Rattus rattus caused a dose-dependent reduction in its body weight, cauda epididymides weight, concentration, motility and percentage of live spermatozoa with simultaneous increase in the percentage of their abnormal forms. Compared to 0·65% spermatozoa with abnormal heads in the cauda epididymidis of untreated control rats, 24·86% and 65·72% such spermatozoa were observed in rats on day 14 post treatment with 500 mg/kg and 625 mg/kg doses of EMS respectively. On day 28 post treatment corresponding values for abnormal spermatozoa were 16·21% and 14·32%. Similarly, spermatozoa with abnormal flagella increased from 0.78% in control rats to 9·25% and 5·75% on day 14 post treatment of 500 and 625 mg/kg doses of EMS respectively and declined to 2·91% and 2·40% on day 28 post treatment. Abnormality in the sperm head was mainly due to acrosomelessness and in the flagellum due to bending at proximal region. However, the main effect of EMS was the development of spermatozoa without or deformed acrosomes which may impair the fertility of rats. Analysis of various stages of differentiation of spermatozoa inthe testis revealed that population of preleptotene and pachytene spermatocytes and of round spermatids showed a gradual decline which became significantly less than controls on day 28 of EMS treatment. Occurrence of abnormal heads of testicular spermatids indicated that the sperm head abnormalities originated in the testis during late spermiogenesis.     

Disappearance of spermatozoa from the ejaculates of geldings.

Twenty-three geldings were used to determine changes in seminal characteristics following castration and the effect of frequency of ejaculation on these seminal characteristics. In Exp. 1, semen was collected from 8 geldings every other day after castration until the number of spermatozoa per ejaculate was below 1% of the precastration value. An average of 3 ejaculates was required to reduce the number of spermatozoa below this level. In Exp. 2, 15 stallions were castrated and each stallion was assigned to 1 of 3 groups for seminal collection at 7, 14 or 21 days post-castration. The ejaculates collected on these days contained an average of 23, 14 and 2 X 10(6) spermatozoa/ejaculate, respectively. In both experiments, all spermatozoa in ejaculates collected 7 or 8 days after castration were non-motile. Frequency of ejaculation did not appear to hasten the disappearance of spermatozoa from the ejaculates. It is considered that after castration several months may be required before the ampulla and vas deferens become devoid of spermatozoa and the ejaculates azoospermic, and that pregnancy is unlikely to result from mating or insemination 1 week after castration.     

Effects of ketamine or medetomidine administration on quality of electroejaculated sperm and on sperm flow in the domestic cat

The effects of two commonly used drugs for anaesthesia in the domestic cat, ketamine and medetomidine, on features of electroejaculated semen and on sperm flow in this species were evaluated performing three experiments. This is the first study about these topics in the domestic cat. In Experiment 1, ketamine or medetomidine effects on cat sperm quality after collection by electroejaculation (E.E.) have been assessed in nine animals. Results showed that mean sperm concentration was significantly higher (p<0.01) after medetomidine than after ketamine administration. In Experiment 2, ketamine or medetomidine effects on sperm flow in 12 electroejaculated cats were studied. Mean sperm concentration and mean total number of spermatozoa resulted significantly higher (p<0.01) in medetomidine than in ketamine treated animals. The number of spermatozoa displaced in urethra was significantly higher (p<0.01) using medetomidine. No significant differences were observed in percentages of retrograde flow. In Experiment 3, ketamine or medetomidine effects on urethral sperm flow, without any stimulation for sperm collection, were evaluated. Data obtained showed a significantly higher (p<0.05) number of spermatozoa displaced in urethra after medetomidine than after ketamine injection. In conclusion, E.E. in the cat after medetomidine administration determined a higher number of spermatozoa per ejaculate than after ketamine administration, with a good pharmacological restriction and without increasing sperm retrograde flow.     

The effect of sperm concentration in the ejaculate on morphological traits of bull spermatozoa

Experiments were performed on 75 ejaculates obtained from 19 bulls representing different cattle breeds used at the Masovian Centre for Animal Breeding and Reproduction in ?owicz. Fresh ejaculates were measured in respect to their volume and sperm count in the ejaculates was determined. The ejaculates were classified based on the criterion of sperm concentration and divided into five groups. Sperm morphometric measurements were taken from each bull and assessment of semen morphology was done on the basis of examination under a microscope using preparations made from fresh ejaculates. For each slide, morphometric measurements were taken of 15 randomly selected spermatozoa characterised by normal morphology and well visible under the microscope. Additionally, in each preparation morphometry of 500 spermatozoa was evaluated, numbers of spermatozoa with normal morphology and morphological abnormalities were recorded and these were categorized into spermatozoa with major and minor defects. An insignificant correlation was observed between the sperm concentration in the ejaculate and morphological traits, dimensions and shapes of bull spermatozoa. The less concentrated ejaculates contained spermatozoa with a slightly larger head circumference and a more elongated head shape in comparison with the spermatozoa in the more concentrated ejaculates. The highest frequency of morphologically malformed spermatozoa, both in the case of primary and secondary alterations, was observed in ejaculates with sperm concentration of no more than 1000 x 10(3)/mm3.     

Spermiogenic,epididymal, and spermatozoal damage induced by a peritesticular injection of ethylene dibromide to rams

The effects of a peritesticular injection of ethylene dibromide (EDB) on the germ cells, epididymis, and spermatozoa of rams was examined by removing each injected testis and epididymis at different times after treatment and by monitoring the seminal characteristics of ejaculates.A high incidence of abnormal elongating and elongated spermatids was observed in the testes of treated rams 48 h after injection. At this time the epithelium of the corpus and cauda epididymidis was damaged in the majority of observed rams, and the spermatozoa in these segments were abnormal, mainly with acrosomal defects, denuded forms and denuded tailless forms. Apparent phagocytosis of spermatozoa was also observed in these portions of the epididymal duct. Ejaculates collected as early as 48 h after injection had a very low sperm density and large percentages of spermatozoa with acrosomal and tail abnormalities. A dose-reponse effect was obtained, and the reversibility of the effect of a low dose of EDB on sperm morphology was demonstrated in the rams by semen examination.