Post-thaw boar sperm motility is affected by prolonged storage of sperm in liquid nitrogen. A retrospective study

Owing to the quick genetic turnover of the pig industry, most AI-boar sires live 2-3 yr, a period during which for 1-2 yr their semen is extended and used in liquid form for AI. Despite showing low cryosurvival, affecting fertility after AI, boar semen is frozen for easiness of transport overseas and reposition of valuable genetics. For the latter, semen is stored in liquid nitrogen (LN₂, cryostorage) for many years, a controversial practice. Here we studied how length of cryostorage could affect sperm quality. Straws (0.5 mL) frozen using the same cryopreservation protocol at one specific location from AI- sires of proven fertility were stored in LN₂ for up to 8 yr. Post-thaw sperm quality was evaluated after 2, 4 or 8 yr of cryostorage, always compared to early thawing (15 d after freezing). Sperm motility and kinematics were evaluated post-thaw using CASA and sperm viability was cytometrically evaluated using specific fluorophores. Sperm viability was not affected by length of cryostorage, but total and progressive sperm motility were lower (p < 0.01) in sperm samples cryostored for 4 or 8 yr compared to those thawed 15 d after freezing. Cryostorage time affected sperm kinetics, but with greater intensity in the samples cryostored for 4 yr (p < 0.001) than in those for 2 yr (p < 0.01). The fact that the major phenotypic characteristic of boar spermatozoa, motility, is constrained by time of cryostorage should be considered when building cryobanks of pig semen. Attention should be placed on the finding that >2 yr of cryostorage time can be particularly detrimental for the post-thaw motility of some sires, which might require increasing sperm numbers for AI.     

Cryostorage of silver barb (Barbodes gonionotus) semen in dry shipper: Efficacy,risk of bacterial cross-contamination and effects of Aeromonas hydrophila on post-thaw sperm quality

This study was conducted to investigate the efficacy of dry shipper for the cryostorage of silver barb (Barbodes gonionotus) sperm, the subsequent risk of bacterial cross-contamination, and the effects of Aeromonas hydrophila on post-thaw sperm. Semen was diluted with calcium-free Hank's balanced salt solution containing 10% ME₂SO, frozen at −8 °C/min and stored for 14 d in a dry shipper. A significant decline (P < 0.05) in the post-thaw sperm motility and viability of samples kept in the dry shipper for 14 d showed a reverse correlation (P < 0.05) with a slight increase in temperature within the dry shipper. The levels of contaminated bacteria in the compartments of the dry shipper were significantly (P < 0.05) lower than those detected in the liquid nitrogen tank. Bacteria from the atmosphere could recontaminate the chambers of the dry shipper and liquid nitrogen tank after 14 d. Bacillus was the most common bacteria isolated from the dry shipper, liquid nitrogen tank, circulating air, bench surface and outer surface of straws. There was no cross-contamination of A. hydrophila from contaminated straws to pathogen-free straws kept in either cryogenic tank. Post-thaw sperm motility and sperm viability significantly (P < 0.05) declined during cryostorage in the dry shipper and liquid nitrogen tank due to the introduction of A. hydrophila and the interaction effect of A. hydrophila and freezing. This study reports, for the first time, the efficacy of a dry shipper for the cryostorage of fish sperm for at least 14 d without a risk of bacterial cross-contamination.     

Oxidative metabolism-related changes in cryogenically stored neem (Azadirachta indica A. Juss) seeds

The seeds of Azadirachta indica were successfully cryopreserved for 12 months with 45% survival following drying to 0.16gH(2)Og(-1) dry mass (DM). Highest survival (94-96%) was recorded during the first month of cryostorage. Subsequent cryopreservation up to 12 months resulted in decreasing germination. Post-thawing pre-heat treatment enhanced the recovery marginally in seeds cryopreserved from 3 to 12 months. Viability of cryostored seeds was negatively correlated with leachate conductivity and accumulation of thiobarbituric acid reactive substances (TBRS) estimated in cotyledons and axes. Leachate conductivity of imbibed seeds was low during the first month of cryostorage but increased gradually with the duration of cryostorage to a maximum after 12 months. TBRS accumulation was gradual throughout cryostorage. Relatively low amounts of active oxygen species (AOS) detected during the first month of cryostorage were closely associated with very high activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) in seeds (cotyledons and axes). Marked accumulation of AOS from 3 to 12 months was associated with decrease in antioxidant enzyme activity.     

Factors affecting the outcome of human blastocyst vitrification

With single blastocyst transfer practice becoming more common in ART, there is a greater demand for a convenient and reliable cryostorage of surplus blastocysts. Vitrification has emerged in the last decade as an alternative promising substitute for slow freezing. Blastocysts represent a unique challenge in cryostorage due to their size, multicellular structure and presence of blastocoele. The continuous acquisition of experience and introduction of many different technological developments has led to the improvement of vitrification as a technology and improved the results of its application in blastocyst cryostorage. The current information concerning safety and efficacy of the vitrification of blastocysts will be reviewed along with the variables that can impact the outcome of the procedure.     

Long-term cryopreservation of Greek fir embryogenic cell lines: recovery, maturation and genetic fidelity

In coniferous species, including Greek fir (Abies cephalonica Loud), the involvement of somatic embryo plants in breeding and reforestation programs is dependent on the success of long-term cryostorage of embryogenic cultures during clonal field testing. In the present study on Greek fir, we assayed the recovery, morphological characteristics and genetic fidelity of embryogenic cell lines 6 and 8 during proliferation and maturation after long-term cryostorage. Our results indicate successful recovery of both cell lines after 6 years in cryostorage. In the maturation phase, both cell lines were capable of producing somatic embryos although some differences were detected among experiments. However, these changes were more dependent on the differences in the components of the maturation media or in the experimental set-up than on the long-term cryostorage. During both proliferation and maturation phases, the morphological fidelity of the embryogenic cultures as well as of the somatic embryos were alike before and after cryopreservation. The genetic fidelity of the cryopreserved cell line 6 that was assayed by random amplified polymorphic DNA (i.e. RAPD) markers demonstrated some changes in the RAPD profiles. The results indicate possible genetic aberrations caused by long-term cryopreservation or somaclonal variation during the proliferation stage. However, in spite of these changes the embryogenic cultures did not lose their proliferation or maturation abilities.     

Retention of endothelium-dependent vasodilatory responses in canine coronary arteries following cryopreservation

In the present study, the cryoprotective effect of dimethyl sulfoxide (Me2SO) and fetal calf serum (FCS) on coronary endothelium and endothelium-dependent relaxation (EDR) responses was studied in isolated canine coronary arteries following cryostorage at -75 degrees C. Compared to the freshly isolated coronary arteries, the EDR responses to acetylcholine, thrombin, and calcium ionophore were not significantly altered following 1 day storage at -75 degrees C in the presence of 1.8 M Me2SO and 20% FCS. Prolonged cold storage to 7 days, however, resulted in a slight, but significant, rightward shift of the concentration-response curves of acetylcholine and thrombin, but not calcium ionophore. The maximum relaxant response after 7-day cryostorage was 80 to 85% of fresh controls. Omission of FCS from the cryostorage incubation medium further accentuated the loss of EDR responses to all three endothelium-dependent vasodilators tested. Scanning electron microscopic examinations of the intimal surface of the Me2SO and FCS cryostored canine coronary arteries confirmed the preservation of intimal endothelial cells following 1 or 7 days of storage at -75 degrees C, while significant patches of loss of endothelial cells were observed in the arteries cryostored only in the presence of Me2SO. No significant inhibitory effect of cryostorage was observed for the direct, endothelium-independent relaxation induced by isoproterenol, regardless of the presence or absence of FCS. These results demonstrate that slow freezing of canine coronary arteries to -75 degrees C in Krebs-Henseleit solution containing Me2SO and FCS provides good preservation of the vascular smooth muscle function and endothelium-dependent vasodilatory responses.     

Stability of biotransformation capacity in Digitalis lanata cell cultures after cryogenic storage

Suspension cultures of Digitalis lanata were stored at the temperature of liquid nitrogen. After thawing, viable cultures were recovered which showed a growth rate equal to that of untreated cells. The capacity of Digitalis cells to transform β-methyldigitoxin to β-methyldigoxin remained unchanged after cryostorage. This was shown in 300-ml shake cultures as well as in 20-1 bioreactors. From these results it is clear that cryostorage is a suitable method for preserving cell lines with specific capacities to produce compounds of medical and industrial importance.     

Sperm cryostorage in a dry tank: An accurate alternative

This prospective study aimed to determine the effects of dry nitrogen cryostorage on human sperm characteristics in comparison with liquid nitrogen cryostorage. For this purpose, 42 men undergoing routine semen analysis (21 normozoospermia and 21 with altered semen parameters) were analyzed. After slow freezing, half of the straws of each sample were randomly stored in liquid and dry tanks, at the top and bottom levels of the latter. After 6 months storage, thawed samples were treated by density gradient centrifugation and sperm characteristics were compared. There was no difference in sperm progressive motility (15.1% ± 14.2% vs. 15.1% ± 12.7%; p = 0.76), sperm vitality (25.5% ± 17.7% vs. 26.2% ± 19%; p = 0.71), percentages of acrosome-reacted spermatozoa (38% ± 8.5% vs. 38.5% ± 7.4%; p = 0.53) and DNA fragmentation spermatozoa (27.3% ± 12.4% vs. 28.5% ± 12.9%, p = 0.47) after cryostorage in the dry or the liquid nitrogen tank. Moreover, we did not observe differences between either cryostorage system for normal and altered sperm samples. This lack of difference was also observed whatever the floor level of cryostorage in the dry tank. The temperature measurement of the dry tank showed a stable temperature at −194 °C throughout storage whatever the storage floor level, guaranteeing the stability of the low temperatures suitable for human sperm storage. Because of its greater safety, dry storage without contact with the liquid phase should be preferred and can be a useful alternative for the cryostorage of human sperm samples.     

ROS-induced oxidative stress is closely related to pollen deterioration following cryopreservation

Oxidative stress induced by excessive accumulation of reactive oxidative species (ROS) during cryopreservation is thought to be one factor contributing to cryodamage of biological materials. To explore the role of oxidative stress in the cryopreservation of plant pollen, germination, ROS, and malondialdehyde (MDA) levels of pollen from 20 ornamental plant species were compared before and after cryopreservation. The results showed that the germinability of cryopreserved pollen from 13 out of the 20 species was not significantly different from that of fresh pollen (group 1), only one increased significantly, while the other six declined significantly (group 2). The MDA content in cryopreserved pollen from nine species in group 1 showed no significant difference from that of fresh pollen, while four species in group 2 rose significantly. This suggested that pollen viability and MDA levels were negatively correlated. ROS generation in cryopreserved pollen from nine species in group 1 was unchanged compared to fresh pollen, while five species in group 2 increased significantly. This suggested that pollen viability was negatively correlated with ROS generation. Additionally, both ROS and MDA levels in pollen from four species in group 2 increased significantly. In conclusion, pollen from most species possesses some cryostorage tolerance, but some species are severely damaged by cryostorage. Oxidative stress induced by the cryostorage in liquid nitrogen (LN) may be a key factor for the decreased viability in pollen following cryopreservation.     

Human coronary vascular smooth muscle and endothelium-dependent responses after storage at -75 degrees C.

In the present study, we investigated whether an established method of cryostorage at -75 degrees C in the presence of dimethyl sulfoxide (Me2SO) and fetal calf serum (FCS) could preserve the vascular and endothelial responses of isolated human coronary arteries. A total of 123 ring segments (4-5 mm in length) of epicardial coronary arteries were isolated within 1 to 2 h from hearts of four patients receiving a cardiac transplant. Thirty-nine coronary ring segments were studied immediately upon cleaning of surrounding tissues, while 84 similarly cleaned segments were stored at -75 degrees C for 7 to 10 days prior to in vitro reactivity studies. In the freshly isolated coronary arteries, addition of prostaglandin F2 alpha, endothelin (ET-1), or acetylcholine consistently produced a dose-dependent contraction, reaching a maximum contractile force of 9.6 +/- 0.7, 4.5 +/- 0.5, and 3.1 +/- 0.5 g (M +/- SEM), respectively, while histamine, thrombin and substance P consistently produced an endothelium-dependent relaxation (EDR) with a maximum of -89 +/- 2.8, -85 +/- 5.0, and -72 +/- 3.5%, respectively. Isoproterenol produced an endothelium-independent relaxation (-82 +/- 4.5%). Cryostorage of human coronary arteries at -75 degrees C without cryoprotectant resulted in a complete loss of the contractile response. In contrast, addition of Me2SO and FCS in the cryostorage medium significantly preserved the contractile responses, although they were decreased (1.9 +/- 0.3, 1.5 +/- 0.3, and 0.6 +/- 0.1 g to PGF2 alpha, ET-1, and acetylcholine, respectively) when compared to the fresh controls. The maximum EDR to histamine, thrombin, and substance P in the cryostored coronaries were also reduced to -40 +/- 5.6, -21 +/- 3.3, and -47 +/- 4.7%, respectively, and the isoproterenol-induced relaxation was reduced to -62 +/- 4.1%. These results suggest that although the cryostorage method described in the present report provided only limited preservation of human coronary arteries, significant vascular smooth muscle and endothelial-dependent functions were retained. Thus, it is possible that further refinement of the present cryostorage methodology may provide better preservation of functionally viable human blood vessels.     

Cryopreservation of embryogenic cultures of Scots pine

The aim of the study was to develop an effective cryopreservation method for Scots pine (Pinus sylvestris L.) embryogenic cultures. Altogether nine cell lines derived from three mother trees were cryopreserved after cold hardening using dimethylsulfoxide or two different mixtures of polyethyleneglycol 6000, glucose and dimethylsulfoxide as cryoprotectants. Seventy-eight percent of the cell lines remained viable after cryostorage, the best cryoprotectant treatment being 10% polyethyleneglycol 6000, 10% glucose, and 10% dimethylsulfoxide in water. This treatment resulted in significantly better regrowth of the embryogenic cultures than with the other cryoprotectants or with the controls. According to microscopical observations, the cells that retained their viability and regrowth ability after cryopreservation were the embryonal head cells, as well as some elliptic suspensor cells close to the embryonal head cell area. When proliferation growth of the frozen cultures had started, their morphological appearance was the same as the non-frozen cultures. In addition, the RAPD assays suggested that the cryostorage treatment used here preserved the genetic fidelity of the Scots pine embryogenic cultures. This revised version was published online in June 2006 with corrections to the Cover Date.     

Evaluation of DNA damage as a quality marker for rainbow trout sperm cryopreservation and use of LDL as cryoprotectant

Defining reliable and objective biomarkers of sperm quality is a complex matter, because it does not rely on a particular characteristic of the milt. Susceptibility to cryopreservation varies between ejaculations and throughout the year, and the evaluation of fresh sperm does not always provide accurate information about their fertilization ability after freezing and thawing. DNA is one of the cell components prone to suffering cryodamage and several studies have pointed out the importance of the maintenance of its integrity during sperm cryostorage. The authors analysed sperm from rainbow trout for four weeks during the natural reproductive season. Viability, DNA integrity, and fertilization ability were evaluated. Furthermore, in order to increase membrane and DNA protection during sperm cryopreservation, the authors optimized the use of LDL fraction from egg yolk as a cryoprotectant during the analysed period. Results revealed that the evaluation of DNA damage in fresh sperm reveals subtle cell damage, not evidenced in fresh sperm by the other parameters. DNA fragmentation increased from 8 to 31% during the reproductive season, indicating pre-freezing differences that render the cells more susceptible to cryodamage. Also, the use of 12% LDL (low density lipoprotein) fraction, instead of the commonly used pure egg yolk, improved sperm quality after freezing. When LDL was used, post-thaw quality remained constant throughout the analysed period, providing around 60% of eyed embryos. In contrast, when egg yolk was used, post-thaw quality decreased significantly at the end of the season and the percentage of eyed embryos dropped from 60% to 27%. Results demonstrated that reduction in DNA integrity takes place during the reproductive season affecting susceptibility to cryodamage and that the protective effect of egg yolk is very much improved when only their LDL fraction is added to the cryopreservation extender.     

Morphological and biochemical analysis of human cardiac valve allografts after an increment of the cryostorage temperature

Cryopreserved human cardiac valve allografts could suffer lethal damages if the temperature is elevated during cryostorage. This work describes the functional and morphological alterations suffered by human cardiac valve allografts after a gradual increment of the cryostorage temperature from −147 °C to −47 °C due to a technical failure. Three experimental groups of human pulmonary and aortic allografts were compared: fresh, cryopreserved (−147 °C) and cryopreserved with temperature changes from −147 °C up to −47 °C and back to −147 °C. Fibroblast functionality was studied to asses the degree of valvular damages. Collagen network was also analyzed with bright light field and polarized microscopy; an immunohistochemistry for procollagen I was performed and the MTT colorimetric assay was used to evaluate fibroblast mitochondrial enzymatic activity. Porcine heart grafts valves were used to set the MTT colorimetric assay.With bright light field microscopy, disorganized collagen network was seen together with interstitial edema in cryopreserved groups. Polarized microscopy showed that fresh allografts had abundant collagen type I and III, cryopreserved group had less amount of collagen type I and in allografts that suffered cryopreservation temperature elevation collagen type I synthesis could not been demonstrated. Procollagen I was present in fibroblast cytoplasm of fresh group, but it was diminished in cryopreserved group and was absent in the group that suffered temperature elevation.Temperature changes during the cryopreservation period of human cardiac valve allografts induced fibroblast activity reduction. When the cryopreservation temperature is elevated during cryostorage, fibroblasts lost their functionality and the allografts may be not suitable for transplant.     

Improved long-term cryostorage of Escherichia colicompetent cells using trehalose

Trehalose added to storage buffers for chemical-induced transformations at 200 mm increased the survival of Escherichia coli competent cells 1.34.8-fold over 180 d cryostorage compared with dimethyl sulfoxide or glycerol.     

Successful cryopreservation of Quercus robur plumules

Successful cryopreservation of Q. robur germplasm as plumules (i.e. shoot apical meristems of embryos) is described in this paper. After excision from the recalcitrant seeds and preliminary storage in 0.5 M sucrose solution (18 h), the plumules were subjected to cryoprotection (in 0.75 M sucrose, followed by 1.0 M sucrose and 1.5 M glycerol solutions), and next to desiccation (over silica gel or in nitrogen gas) and cooling (in slush at –210°C or in vials filled with liquid nitrogen, LN, −196°C), and were then cryostored for 24 h. High percentage of survival was obtained after cryostorage (21–67%, depending on pretreatment, assessed in vitro by greening plumules that increased in size). Desiccation of plumules over silica gel resulted in significantly higher survival after cryopreservation (58%) in comparison with desiccation in nitrogen gas (29%), with regrowth (shoots with leaves) 5–18%. The extent of plumule desiccation was comparable in both methods, in which drying of plumules for 20 min decreased the water content to 0.5–0.6 g H₂O g⁻¹ dry weight before LN exposure. The type of LN exposure did not significantly influence plumule survival and regrowth after cryostorage. Plumules isolated from acorns of four provenances survived cryostorage after cryoprotection followed by desiccation over silica gel and direct cooling in vials with LN (survival 51–76%, regrowth 8–20%). Normal plants developed from the recovered shoots after rooting. The presented protocol for Q. robur plumule cryopreservation may offer a potential approach for establishing germplasm conservation in gene banks for Quercus species.     

Serum-free cryopreservation of five mammalian cell lines in either a pelleted or suspended state

Herein we have explored two practical aspects of cryopreserving cultured mammalian cells during routine laboratory maintenance. First, we have examined the possibility of using a serum-free, hence more affordable, cryopreservative. Using five mammalian lines (Crandell Feline Kidney, MCF7, A72, WI 38 and NB324K), we found that the serum-free alternative preserves nearly as efficiently as the serum-containing preservatives. Second, we compared cryostorage of those cells in suspended versus a pellet form using both aforementioned cryopreservatives. Under our conditions, cells were in general recovered equally well in a suspended versus a pellet form. Published: April 7, 2004.     

Dehydration in cryopreservation of moist plant tissues and seed maturation

The feasibility of long-term cryopreservation of plant objects depends on their moisture content. In orthodox seed, dehydration takes place at the late stage of maturation and is accompanied by accumulation of protective sugars and proteins. Such seed easily withstand cryopreservation. Moist objects such as meristems and recalcitrant seed must be desiccated in the presence of sucrose before freezing. In both naturally dry and dehydrated tissues, differential scanning calorimetry and electron paramagnetic resonance reveal intracellular vitrification; this glassy state is supposed to determine the success of cryostorage. Methodical approaches to cryopreservation of moist plant tissues are reviewed.     

Effect of cryopreservation on the frequency of chromosomal abnormalities and sex ratio in human sperm

The effects of cryopreservation on the frequency and type of chromosomal abnormalities in human sperm were investigated. Employing a technique that enables direct visualization of human sperm chromosomes following in vitro penetration of hamster oocytes, sperm samples from 10 normal men were examined before and after freezing in liquid nitrogen. A total of 1,960 sperm karyotypes were analyzed, 1,132 before freezing and 828 after freezing. There was no significant difference in the frequency of structural chromosomal anomalies (10.5% prefreeze vs. 8.5% postfreeze), but there was a significant decrease in the frequency of numerical abnormalities (5.2% prefreeze vs. 3.0% postfreeze). However, there was a large excess of hypohaploid complements compared with hyperhaploid complements, suggesting that the hypohaploid complements were caused by technical artefact. A conservative estimate of aneuploidy, derived by doubling the hyperhaploid frequencies, did not differ before (0.4%) and after (0.4%) freezing. There was no evidence for interdonor variability in response to sperm cryopreservation for total chromosomal abnormalities, structural abnormalities, and sex ratios. The sex ratios were also not affected by cryopreservation and did not differ significantly from the theoretical 50%. It is concluded that cryopreservation does not affect the frequencies of chromosomal abnormalities or alter the sex ratio in human sperm, provided that an adequate cryoprotective buffer and freezing system is employed.     

Multiple classes of prostaglandin F2 alpha binding sites in subpopulations of ovine luteal cells

A cryostorage procedure was developed to provide ovine luteal cells throughout the period of seasonal anestrus. Corpora lutea obtained from midluteal phase, superovulated ewes were dispersed enzymatically. Some dispersed cells were fractionated into subpopulations by elutriation. Dimethylsulfoxide (7.5% final concentration) in Hanks' buffered saline was added to cells at 4 degrees C, and dispersed cell preparations were frozen in a programmable cell freezer and stored at -196 degrees C. After recovery from cryopreservation, cell viability and prostaglandin F2 alpha (PGF2 alpha) binding characteristics of thawed cells were not different from those of corresponding fresh cells. Additionally, thawed cells retained the capacity to attach to culture dishes and retained responsiveness of progesterone secretion to prostaglandin E2 (PGE2) and ovine luteinizing hormone (LH), although rates of progesterone secretion were attenuated in thawed compared with fresh cells. The cryopreservation procedure will prove useful to relieve constraints in utilization of ovine luteal cells arising from reproductive seasonality in sheep. Cells retrieved from cryostorage were evaluated by studying PGF2 alpha binding characteristics. From saturation analyses (increasing amounts of radiolabeled PGF2 alpha) of PGF2 alpha binding to unfractionated cells, we detected a single class of high affinity binding sites (Kd = 17.4 +/- 2.3 nM) in addition to the nonspecific binding component. Using displacement analyses (constant radiolabeled PGF2 alpha and increasing amounts of unlabeled PGF2 alpha) and unfractionated cells, we detected additional binding sites of lower affinity (Kd = 409 +/- 166 nM) as well as the nonspecific binding component. Small luteal cells obtained by elutriation, which were essentially devoid of large cell contamination, had only low affinity binding sites.(ABSTRACT TRUNCATED AT 250 WORDS)     

Sperm motility in turbot,Scophthalmus marimus: initiation of movement and changes with time of swimming characteristics

Synopsis Turbot sperm motility is observed using dark field microscopy and stroboscopic illumination combined with video recording. Sperm motility is triggered by dilution of spermatozoa in sea water or in non ionic media (glucose or saccharose), presenting osmotic pressure ranging from 300 to 2100 mOsmol. The percentage of motile spermatozoa reaches 100% under conditions of osmotic pressure of 300 to 1100 mOsmol and pH close to 8.0. In full sea water, glucose or saccharose solutions an agglutination of spermatozoa is observed; this is prevented by addition of bovine serum albumin (5 mg ml^–1). Immediately after transfer in activation solutions, 100% spermatozoa are motile in most samples freshly stripped. This percentage drops suddenly between 15 and 30% after 70 to 100 sec. The beat frequency remains at a constant value of 50 Hz during 40 s post activation and then drops suddenly between 15 and 30 Hz. The spermatozoa velocity is about 200 micrometers s^–1 during 30 to 40 s and then declines to a stable value of 100 micrometers s^–1 at 50 s post activation. After 1.20 mn, more and more spermatozoa become motionless. The minimum calculated and averaged distance covered during 1.20 min, is about 12 mm. The high performances of turbot spermatozoa motility are interpreted as a compensatory mechanism for the low sperm production.