Enhancement of sperm transport through the rat epididymis after castration

Transport of spermatozoa through different regions of the epididymis has been followed by labelling testicular spermatozoa with [3H]thymidine in intact rats and in rats in which the efferent ducts were ligated or the testes were removed. In intact rats, the transit times of epididymal spermatozoa from the initial segment to the caput, from the caput to the corpus, and from the corpus to the cauda were 2, 4 and 2 days, respectively, giving a total transit time of 8 days. After bilateral castration, labelled spermatozoa were transferred from the initial segment into the proximal cauda by 2 days and appeared in the ductus deferens by 4 days. This effect was prevented by a daily subcutaneous injection of testosterone propionate (0.2 mg/kg). Bilateral efferent duct ligation had only a slight effect on the passage of epididymal spermatozoa. The results indicate that epididymal sperm transport is enhanced after androgen withdrawal.     

Effects of sulphapyridine on sperm transport through the rat epididymis and contractility of the epididymal duct

This study was undertaken to investigate the effects of sulphapyridine on the transport of spermatozoa through different regions of the epididymis and on the contractility of the epididymal duct in the rat. Sperm transport was investigated by labelling testicular spermatozoa with [3H]thymidine and measuring intraluminal pressures of the epididymis by micropuncture, using a servo-nulling pressure transducer system. In control rats, the transit times of epididymal spermatozoa from the initial segment to the caput, from the caput to the proximal cauda, and from the proximal cauda to the distal cauda were 2, 6 and 3 days, respectively, giving a total transit time of 11 days. The total transit time was shortened to 8 days after treatment with sulphapyridine at a dosage of 450 mg kg-1 for 38-52 days. The rate of sperm transport was most affected in the caput epididymidis. Measurements of intraluminal pressures showed that sulphapyridine had no effect on spontaneous contractions in any regions of the epididymis. However, the frequency of contraction of the corpus and cauda epididymides in response to administration of 10 micrograms noradrenaline kg-1 in the sulphapyridine-treated rats was significantly higher (P < 0.05) than it was in the controls. Methacholine, at a dose of 20 micrograms kg-1, produced a smaller increase in basal pressure in the caput epididymidis of sulphapyridine-treated rats (P < 0.05) compared with controls. The results led to the conclusion that sulphapyridine increases the rate of sperm transport from the caput through the cauda epididymidis, in part, by changes in the responsiveness of the epididymis to the autonomic nervous system.     

Chromatin condensation in hamster sperm: A flow cytometric investigation

In this study we have used acridine orange staining, as described by Evenson (1990), to follow changes in DNA packaging as they occur in hamster spermatozoa which have left the testis and are undergoing maturation in the epididymis. Measurement of the green and red fluorescent intensities of hamster sperm nuclei by flow cytometry demonstrated a decrease in acridine orange binding to DNA as sperm made their way from proximal corpus epididymis to the vas deferens. Using sperm from the cauda epididymis of the mature hamster as the standard, a method was developed for estimating the % of cells in a given sample that have matured with regard to DNA packaging. Staining with bromobimane was used to determine the extent of sulfhydryl oxidation in the nuclei. It was seen that sulfhydryl oxidation occurred mainly in the cauda epididymis whereas another process in chromatin condensation occurred earlier, during sperm passage through the caput epididymis. This earlier process could be mimicked by incubating sperm nuclei with alkaline phosphatase, suggesting that it consists of removal of phosphate in protamine. © 1994 Wiley-Liss, Inc.     

Capacity of rete testicular and cauda epididymal boar spermatozoa to undergo the acrosome reaction and subsequent fusion with egg plasma membrane

The capacity to undergo the acrosome reaction and subsequent fusion with egg plasma membrane was examined in rete testicular and cauda epididymal spermatozoa from boars. Sperm penetration assay using zona-free hamster eggs demonstrated that the penetration rates for rete testicular spermatozoa preincubated for induction of the acrosome reaction for 2 and 3 h were 55% and 97%, respectively. However, most of the eggs (93%) were penetrated with polyspermy by cauda epididymal cells preincubated for 2 h. Results obtained by the triple-stain technique revealed the percentages of acrosome-reacted spermatozoa in the rete testicular and cauda epididymal samples preincubated for 3 h to be 61% and 74%, respectively. These results indicate that many rete testicular spermatozoa possess the capacity to undergo the acrosome reaction and subsequent fusion with egg plasma membrane in vitro, which appears to be completely established only after sperm transit through at least the proximal part of the epididymis. © 1993 Wiley-Liss, Inc.     

Maturation of spermatozoa in the epididymis of the Chinese hamster

Chinese hamster spermatozoa gain their ability to move when they descend from the testis to the distal part of the caput epididymis, but it is not until they enter the corpus epididymis that they become capable of fertilizing eggs. The maturation of the spermatozoa proceeds as they further descend the tract and perhaps continues even in the vas deferens. During transit between the distal caput and proximal cauda epididymides, small membrane-limited vesicles (and tubules) appear on the plasma membrane over the acrosomes of the spermatozoa. The number of vesicles appearing on the sperm brane reaches a maximum when the spermatozoa are in the proximal cauda epididymis. It declines sharply in the distal cauda epididymis. Spermatozoa in the vas deferens are free of the vesicles. The origin, chemical nature, and functional role of the vesicles that appear on the sperm surface during epididymal transit must be the subject of further investigation.     

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.     

Microanatomy of the testes and testicular ducts of the butterfly lizard,Leiolepis ocellata Peters, 1971 (Reptilia: Squamata: Agamidae) during the active reproductive period

The microanatomy of the testes and testicular ducts (rete testis, ductuli efferentes, ductus epididymis and ductus deferens) of Leiolepis ocellata (Agamidae) was investigated using light microscopy including histochemistry. Each testis contains seminiferous tubules and interstitial tissues. The former house spermatogenic cells (spermatogonia A & B, preleptotene, primary and secondary spermatocytes, spermatids (steps 1–8) and spermatozoa) and Sertoli cells, while the latter comprise peritubular and intersitial tissues. The rete testis is an anastomosing duct, having intratesticular and extratesticular portions. The proximal region of ductuli efferentes has wider outer ductal and luminal diameters than those of the distal region. The convoluted ductus epididymis is subdivided into four regions (initial segment, caput, corpus and cauda), based on the ductal diameter, epithelium characteristics and cell components. The ductus deferens has the greatest diameter and is divided into the ductal and ampulla ductus deferens. The ductal portion is subdivided into the proximal and distal regions, based on the epithelium types and ductal diameters. The ampulla ductus deferens is a fibromuscular tube, having numerous mucosal folds projecting into the lumen. Spermiophagy is detectable in the ductus epididymis and ductus deferens. The present results contribute to improved fundamental knowledge on the microanatomy of the reptilian reproductive system.     

Differences between epididymal and ejaculated sperm characteristics in donkey

Spermatozoa acquire their motility and fertilizing ability during their passage through the epididymal canal. In the epididymal caput and corpus spermatozoa undergo several biochemical and metabolic changes while the cauda of the epididymis should be considered as the primarily site for storage of the spermatozoa. In the horse spermatozoa from cauda epididymis were collected and frozen, and the fertility of semen assessed. However, no studies have detailed semen characteristics of spermatozoa collected from the cauda epididymis in the jackass. In this study sperm characteristics of spermatozoa in the cauda epididymis of the donkey was reported and a comparison with ejaculated spermatozoal characteristics was performed. Samples from 10 Martina Franca jackasses were collected and analyzed for viability (Propidium iodide/Sybr-14? fluorescent stain), mitochondrial activity (Mitotraker? fluorescent stain), objective motility characteristics (by Computer Assisted Sperm Analyzer - CASA) and morphology. A higher viability and mitochondrial activity in the cauda epididymis samples were reported in this paper. Samples reported in this paper were identified and the percentage of total and progressive spermatozoa was comparable, but trajectories were more rapid (higher VCL) with less progressiveness (higher ALH and lower STR and LIN) in the cauda epididymis. Sperm morphology showed a pronounced variability between jackasses, with comparable values for all morphological subclasses. In this study the loss of the distal cytoplasmic droplets happen close to or after ejaculation because the percentage fell to nearly 0% after ejaculation. As suggested for bulls, the presence of a similar percentage in sperm with proximal cytoplasmic droplet in epididymal and ejaculated semen is likely to indicate a failure in the maturation process.     

Influence of epididymal maturation on the capacity of hamster and rabbit spermatozoa for complement activation

Hamster and rabbit spermatozoa released from the epididymis were tested for the ability to activate complement via the alternative pathway. While hamster spermatozoa were more active, the spermatozoa of both species reduced complement activity in homologous and also human serum previously adsorbed to remove sperm antibodies, and they bound C3 in the presence of EGTA + Mg2+. Hamster spermatozoa from the caput epididymidis were more anticomplementary and bound more C3 than did cauda spermatozoa and, though less marked, a similar difference was evident between caput and cauda spermatozoa from the rabbit epididymis.     

Quantitative changes ofRicinus communis agglutinin I andHelix pomatia lectin binding sites in the acrosome of rat spermatozoa during epididymal transit

Summary During passage through the epididymis, spermatozoa undergo a number of changes which result in their acquisition of fertility and motility. Some of the changes that occur include loss of the cytoplasmic droplet and changes in sperm morphology, metabolism and properties of the nucleus and plasma membrane. Changes have also been reported in the acrosomic system of mammalian spermatozoa during their transit through the epididymis. In the present study, the quantitative changes of the glycoconjugate content in the acrosome of rat spermatozoa were examined during their passage through the epididymis using lectin-colloidal gold cytochemistry. Various regions of the epididymis (initial segment, caput, corpus and cauda epididymidis) were fixed by perfusion with 1% or 2% glutaraldehyde buffered in sodium cacodylate (0.1M), dehydrated in ethanol and embedded without osmication in Lowicryl K4M. Lectin-colloidal gold labeling was performed on thin sections usingRicinus communis agglutinin I (RCA I) orHelix pomatia lectin (HPL) to detectd-galactose-andN-acetyl-d-galactosamine-containing glycoconjugates, respectively. The labeling density over the acrosome of the acrosomic system was evaluated as the number of gold particles per m² of profile area using a Zeiss MOP-3 image analyzer. The overall mean labeling densities over the acrosome of spermatozoa for each lectin was estimated from 4 rats and over the four distinct epididymal regions. The mean labeling density of the acrosome with RCA I and HPL showed a similar pattern along the epididymis, although RCA I revealed approximately twice as many gold particles per epididymal region. In either case, there was a significant decrease in the labeling density of the acrosome of spermatozoa between the initial segment or caput epididymidis and cauda epididymidis (p<0.01). A similar decrease was also noted between the initial segment and corpus epididymidis (p<0.01). No change was found between the initial segment and caput epididymidis. Controls showed a virtual absence of labeling. These results suggest that in addition to a multitude of changes occurring to spermatozoa during epididymal transit, there are also significant quantitative changes in the glycoconjugate content within the acrosome.     

Computerized analysis of the motility parameters of hamster spermatozoa during maturation

A computer-aided semen analysis system was used for the objective assessment of hamster spermatozoa during epididymal maturation. The caput epididymal spermatozoa were extremely sluggish, achieved very little progression, and the three velocity parameters, namely curvilinear velocity (VCL), progressive velocity (VSL), and path velocity (VAP), were low. These spermatozoa during progressive movement alternated between the linear shape and “U” shape or attained an “S” shape prior to changing to the “U”; shape. The corpus epididymal spermatozoa were faster, displayed greater VSL, VAP, and VCL compared to caput epididymal spermatozoa, and, during forward motility, attained “U,” “C,”; and (or) “?” shape as in the wriggling motility pattern. The proximal cauda epididymal spermatozoa were actively motile and VSL, VAP, and VCL in these spermatozoa were more than 10 times greater compared to the caput epididymal spermatozoa. The proximal cauda epididymal spermatozoa predominantly moved in circles and with time became slower and more circular in their trajectories and exhibited a reduction in LIN (linearity). The distal cauda epididymal spermatozoa were very similar to the proximal cauda epididymal spermatozoa with respect to their fast motility (VSL, VAP, and VCL are similar) and beat cross frequency (BCF), but showed larger values for STR (straightness) and LIN and moved along curved trajectories. The amplitude of lateral head displacement (ALH) was also considerably lower in the distal cauda epididymal spermatozoa compared to the proximal cauda epididymal spermatozoa. Thus, this study provides for the first time data related to seven motility parameters for caput and corpus epididymal spermatozoa of hamster. It also provides additional data with respect to VCL, LIN, BCF, and ALH for proximal and distal cauda epididymal spermatozoa of hamster. © 1994 Wiley-Liss, Inc.     

An autoradiographic study of macromolecular syntheses in the epithelium of the ductus epididymidis in the mouse

Summary Glycoprotein dynamism in the mouse epididymis was studied by means of histoautoradiography after injection of l-fucose-1-³H. The label was detected, at thirty minutes p.i., in the area occupied by Golgi apparatus in the epithelial cells. At 4 h p.i. the label was already present in the lumen of ductus epididymidis. At this time interval, the luminal labelling was highest in the initial segment of the epididymis and decreased against the more distal segments considerably.At ten days p.i. very high labelling was detected in the luminal contents in the terminal segment of the ductus epididymidis and in ductus deferens, the labelling in the proximal segments of the epididymis being much lower. These observations suggested a wave of labelled glycoprotein in epididymal plasma passing through the epididymis after a fucose pulse.Higher labelling was detected in so-called clear cells than in the neighboring principal cells.Association of the labelled material was seen in epididymal and uterine spermatozoa, mostly in sperm tail region.     

Localization by monoclonal antibodies of various surface antigens of hamster spermatozoa and the effect of antibody on fertilization in vitro

To determine the importance during fertilization of various plasma membrane components of the hamster spermatozoon, monoclonal antibodies were generated in the mouse against specific sperm surface antigens. BALB/C mice were immunized with washed hamster spermatozoa from the cauda epididymidis and immune splenocytes fused with myeloma cells (P3 X 63 Ag8). The sperm-specific immunoglobulins were detected in hybridoma cultures by a solid-phase assay (ELISA). Five monoclonal antibodies bound specifically to the surface of intact hamster spermatozoa, three immunoglobulins to restricted regions of the head and tail plasmalemma as detected by immunofluorescence. In two cases, the affinity of the membrane antigen was modified during passage through the epididymis. Monoclonal antibodies to the sperm head or to the head and tail inhibited fertilization in vitro by blocking sperm attachment to the zona pellucida and the oolemma.     

Sperm-sperm associations in the loris epididymis

In a few mammals, the passage of maturing spermatozoa through the epididymis is characterized by development of persistent associations between one or more neighboring cells over the acrosomal region. The converse situation is described here in the loris, Nycticebus coucang, a prosimian primate. Loris spermatozoa released at spermiation enter the caput epididymidis as single cells and then become stacked in rouleaux of 2–8 spermatozoa there, the peri-acrosomal plasmalemma of one being linked by a unique junctional complex to that of its neighbor. However, by the time the cauda is reached, all the spermatozoa have separated again to lie as single cells, which now display major aggregations of ordered material over the concave surface of the acrosome. The functional significance of these unusual sperm surface-related phenomena in the loris epididymis is not clear.     

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.     

Lactate dehydrogenase activity of rat epididymis and spermatozoa: effect of constant light

During its passage through the epididymis, the gamete undergoes a process of "maturation" leading to the acquisition of its fertilizing ability. The epididymis displays regional variations in the morphology and metabolic properties of its epithelium which are relevant for the progressive development of mature sperm characteristics. The epididymis has spontaneous peristaltic contractions and receives sympathetic innervation that is modulated by melatonin, a hormone synthesized and released by the pineal gland. Constant lighting disrupts melatonin synthesis and secretion. We have studied the effect of constant light on lactate dehydrogenase (LDH; EC 1.1.1.27) and its isozyme C4 activities and protein content in whole epididymis, epididymal tissue and in spermatozoa from caput and cauda segments. Animals were exposed from birth to an illumination schedule of 14 h light:10 h dark (group L:D). At 60 days of age one group of animals was submitted to constant light over 50 days (group L:L). In order to test the fertilizing ability, the rats of each group were mated with soliciting estrous females. The percentage of pregnancies in females mated with males maintained in L:L was remarkably lower than those in females mated with males maintained in the L:D photoperiod (44% and 88% respectively). Constant light increased protein concentration and LDH activity in caput as well as in cauda of total epididymis. On the contrary, in epididymal tissue, the protein content decreased in both epididymal sections compared with controls. When enzymatic activity was expressed in Units per spermatozoa, constant light induced a significant reduction of total LDH and LDHC4 in caput and cauda spermatozoa while LDH activity of epididymal tissue was not affected. In spite of the decrease in LDH per sperm cell when rats were exposed to constant light, in total epididymis (epididymis tissue plus sperm cells content) and in spermatozoa, values of enzyme activities expressed per weight unit were higher than those of controls. This is explained by the increase in the amount of stored spermatozoa, both in caput and cauda, produced by exposure of animals to constant light. Our results confirm that in rats, chronic exposure to constant light promotes a reduction of fertilizing ability and indicates that continuous lighting reduces the total LDH and LDHC4 activities, possibly due to moderate aging of spermatozoa within the duct by lengthening of the sperm transit through the epididymis.     

Structural features of the epididymis in a dasyurid marsupial (Antechinus stuartii)

Summary The ductus epididymidis of the marsupial mouse Antechinus stuartii was divided into caput, corpus, and caudal regions using several constant morphological landmarks. Tubule diameter and epithelial height increased gradually from caput to cauda. In contrast, the surface area of the lumen of the ductus epididymidis increased to a maximum in the distal caput region, but decreased markedly in the distal cauda in association with characteristic changes in lumen shape (from circular to slit-shaped) and epithelial height. Epithelial cells of the ductus epididymidis were generally similar in structure to those described in other mammalian species. Principal and basal cells were common throughout the epithelium. Clear and mitochondria-rich cells were also identified, but occurred less frequently. Regional variations in cell ultrastructure were observed only in principal cells. Numerous vesicular inclusions occurred in the apical cytoplasm of cells in caput segments, membrane-bounded, electron-dense bodies were common in distal corpus regions, and a brush border of microvilli characterized the luminal surface of principal cells in caudal segments. Sperm index increased in the proximal caput, declined to basal levels in the distal caput and proximal corpus, and then increased to a maximum in segment 9 of the distal corpus and remained at about this level throughout the cauda epididymidis. Nuclear rotation, loss of cytoplasmic droplets, and other sperm maturational changes were observed along the epididymis. Discarded cytoplasmic droplets collected in large masses interspersed between aggregates of spermatozoa throughout the distal regions of the duct. There was no evidence of phagocytosis by principal cells of cytoplasmic droplets. The epididymis of A. stuartii differs from that of other mammals. The unusual caudal region, which has little storage capacity for sperm, is an unusual adaptation in a species in which the male is known to be polygamous.     

Lactate dehydrogenase X, malate dehydrogenase and total protein in rat spermatozoa during epididymal transit

Lactate dehydrogenase isozyme X (LDH X), malate dehydrogenase (MDH) and total soluble protein have been determined in lysates of spermatozoa isolated from caput, corpus and cauda of rat epididymis. Transit of spermatozoa through epididymis is accompanied by a reduction of LDH X, MDH and total protein per cell in sexually rested animals. The profiles of reduction along epididymal segments are different for the three variables studied. Mating with receptive females during the 5 days prior to determinations increases significantly the levels of MDH in spermatozoa from all sections of epididymis and produces increase of total soluble protein in the cells contained in cauda.     

Flow cytometric analysis of rodent epididymal spermatozoal chromatin condensation and loss of free sulfhydryl groups

Flow cytometric measurements were made on acridine orange (AO) and 7-diethylamino-3-(4'-maleimidylphenyl)-4-methyl-coumarin (CPM)-stained epididymal- and vas deferens-derived spermatozoal nuclei to follow the course of chromatin condensation and oxidation of free sulfhydryl groups, respectively, during passage through mouse and rat posttesticular reproductive tracts. Alterations of mouse and rat spermatozoal chromatin during transition from a testicular elongated spermatids to epididymal caput spermatozoa resulted in a threefold loss of DNA stainability with AO. Passage of spermatozoa from the caput to corpus epididymis was accompanied by an approximate 15% loss of DNA stainability, which was maintained at that level throughout passage into the vas deferens. AO stainability of epididymal spermatozoal nuclei was generally independent of -SH group stainability. CPM stainability of rat spermatozoal nuclei free -SH groups was 83%, 18%, and 11% of caput spermatozoal values for corpus, cauda epididymis, and vas deferens, respectively. Comparable values for mice were 69%, 20%, and 18%. CPM stainability was relatively homogeneous for these mouse and rat reproductive tract regions, except mouse corpus epididymis spermatozoal nuclei stained very heterogeneously. Rat spermatozoa detained by ligature up to 7 days in the caput, corpus, and cauda epididymi had CPM staining values equal to or below those of normal vas spermatozoa, indicating that disulfide (S-S) bonding is intrinsic to the spermatozoa and is independent of the epididymal environment. These data suggest that chromatin condensation and loss of spermatozoal DNA stainability during passage from the testis to the vas deferens are independent of S-S bonding.(ABSTRACT TRUNCATED AT 250 WORDS)     

Early puberty in local Naga boar of India: assessment through epididymal spermiogram and in vivo pregnancy

Male Naga pig of India, a miniature breed is known for its meat quality and early puberty. No scientific efforts were made to verify the farmers' view that this breed reaches puberty at around 2 months of age. A preliminary study was, therefore, conducted with the objectives: (a) to find out the age at puberty based on mature spermiogram and in vivo pregnancy and (b) to record the sperm morphology in different parts of the epididymis. Animals were selected from two different age groups: group I aged 53 days and 2.4 kg and group II of 85 days and 3.0 kg. Semen samples collected from different sections of epididymis were analyzed for sperm motility, live spermatozoa, and morphological abnormalities. Motility increased (P<0.01) and live spermatozoa and total morphological abnormalities decreased (P<0.001) from caput through cauda epididymis in both the groups. Sperm motility, live spermatozoa and morphologically normal spermatozoa in each section of the epididymis were higher (P<0.01) in group II than I. Boars with >60% progressive motility, >70% live spermatozoa, <15% total morphological abnormalities and <10% abnormal acrosomes in cauda epididymal spermatozoa were considered mature spermiogram. As per this definition, pigs of group II had only mature spermiogram. In vivo pregnancy confirmation indicated that Naga boar could impregnate female as early as 90 days of age. In conclusion, Naga boar attained puberty by not later than 3 months with 3.0 kg, which is the lowest body weight at puberty in this species reported so far, as reflected by mature epididymal spermiogram and in vivo pregnancy confirmation.