Motility and oxidative-antioxidant capacity of Huso huso semen, stored at -80°C.

In this study, motility and oxidative-antioxidant capacity (thiobarbituric acid-reactive substance level [TBARS], superoxide dismutase [SOD], catalase [CAT] and glutathione reductase [GR]) of beluga sturgeon (Huso huso) sperm, stored for 6 days at -80°C, were evaluated. After 2 days of storage, sperm motility was significantly decreased (no motile sperm were observed after 6 days of storage; p < .05), while TBARS and SOD values were significantly increased (p < .05). CAT and GR activities did not show significant changes among storage times (p > .05). Furthermore, all investigated parameters showed a significant difference between semen stored at 4°C (control) and -80°C during in vitro storage (p < .05). Data from this work can potentially be useful in sturgeon sperm cryobanking.

Reliable collection of Caspian brown trout (Salmo trutta caspius) sperm using a catheter.

The traditional stripping procedure for collecting fish semen is associated with the risk of urine contamination, which may significantly affect semen quality and quantity. The use of a catheter as an alternative method for semen collection may overcome this problem. Therefore, this study compared Caspian brown trout (Salmo trutta caspius) semen parameters (i.e. sperm density, seminal plasma osmolality, motility parameters of spermatozoa analysed using computer-assisted sperm analysis and fertility) between the traditional stripping method and the use of a catheter. All parameter values of the semen collected with a catheter were significantly higher (p < .05; density = 7.67 ± 1.02 × 10(9)  ml(-1) and osmolality = 279.28 ± 32.84 mOsm kg(-1) ) than those collected with stripping method (density = 4.85 ± 0.47 × 10(9)  ml(-1) and osmolality = 216.42 ± 20.75 mOsm kg(-1) ). Semen collected with a catheter was characterized by higher spermatozoa motility compared with sperm collected via stripping. Similarly, the fertilization ability of sperm collected with a catheter was significantly greater (p < .05) than sperm collected with the traditional stripping method. In conclusion, collection of sperm with a catheter was shown to effectively reduce urine contamination and is therefore recommended for the collection of Caspian brown trout sperm.

Influence of Glutamine Supplementation on Motility and Fertilization Success of Frozen-Thawed Persian Sturgeon (Acipenser persicus) Sperm.

Amino acids have an important biological role for the prevention of cell damage during cryopreservation. The aim of this study was to investigate the effects of glutamine on post-thaw sperm motility and fertilization success in the Persian sturgeon (Acipenser persicus). Sperm collected from six fish was cryopreserved in extenders containing different glutamine concentrations (2.5, 5 and 10 mm). Sperm samples diluted at the ratio of 1 : 1 using the extenders were subjected to cryopreservation. After dilution, the sperm suspensions were sucked into 250-µl straws; the straws were placed on the tray, frozen in nitrogen vapour and plunged into liquid nitrogen. Then, sperm were thawed in a water bath at 40°C for 5 s and used for analysis. Our results revealed that an increase in the concentration of glutamine caused a significant increase in the motility percentage, curvilinear velocity (VCL) and also fertilization success in the Persian sturgeon (p < 0.05). Comparing all concentrations of glutamine, the best concentration for sperm motility and fertilization rate was 10 mm. In addition, higher post-thaw motility percentage, VCL, and fertilization and hatching rates were obtained with the extender at the concentration of 10 mm (p < 0.05). The findings of this study showed that glutamine was of greater benefit to Persian sturgeon sperm motility during frozen-thawed process.

Effect of post-thaw storage time on motility and fertility of cryopreserved beluga sturgeon (Huso huso) sperm.

The aim of this study was to test the influence of post-thaw storage time on the duration of sperm motility, percentage of motile sperm, and fertilization and hatching rates of fresh sperm and sperm stored for 0, 30 and 60 min at 4°C post-thawing. After being frozen in liquid nitrogen and then thawed, the percentage of motile sperm and duration of motility were not affected by 30 min of storage at 4°C, whereas a significant decline in these parameters was observed after 60 min of storage. Similarly, fertilization and hatching rates were significantly affected within 60 min of storage at 4°C, and the fertility of frozen-thawed sperm was significantly lower than that of fresh sperm. We conclude that cryopreserved sperm of beluga sturgeon could be stored for 30 min without the loss of sperm quality. This described procedure for beluga sturgeon cryopreservation is reliable and efficient and therefore can be recommended for hatchery practice after scaling up this technique.

Study of enzyme activities and protein content of beluga (Huso huso) semen before and after cryopreservation.

Knowledge gained regarding the biochemical processes that occur during sperm collection, processing and freezing-thawing might improve current sperm cryopreservation techniques. In our present study, we determined the effect of cryopreservation on the total protein concentration (TP) and the activities of certain enzymes in semen samples from the beluga (Huso huso). The TP content of the seminal plasma of fresh semen was 0.47 ± 0.026 g/l, and the TP after cryopreservation was 1.86 ± 0.6 g/l. The activities of acid phosphatase (0.82 ± 0.042 U/l), lactate dehydrogenase (234.4 ± 19.4 U/l), arylsulfatase (143.1 ± 32.5 U/l) and ß-N-acetylglucosaminidase (58.39 ± 4.14 U/l) in the seminal plasma of fresh semen were significantly lower than those in the supernatant of frozen-thawed semen samples (7.43 ± 0.64, 3224.6 ± 167.2, 422.6 ± 21.3 and 90.2 ± 5.37 U/l respectively). These parameters may be useful as biomarkers for estimating damage to the cell membrane of spermatozoa caused by freezing-thawing.

Determination of some blood and seminal plasma ions in the beluga, Huso huso (Linnaeus, 1758).

Blood and seminal plasma ionic parameters are essential for monitoring health status, detecting illnesses, fish stock conservation and development of artificial propagation methods via extender improvement. In this study, comparison of blood and seminal plasma ionic parameters in beluga, Huso huso (30-45 kg, 1-2 m, n = 10), was made. The results obtained show that Na(+) (82.54 ± 5.46), Cl(-) (15.95 ± 0.72) and K(+) (3.57 ± 0.15) were predominant ions in the seminal plasma (as mM). Blood ionic values (as mM) were determined for Na(+) (110.2 ± 1.26), K(+) (3.77 ± 0.081), Cl(-) (60.12 ± 1.5), Ca(2+) (2.05 ± 0.35) and Mg(2+) (1.9 ± 0.16). Results of the comparison between ionic parameters of seminal and blood plasma indicated that the concentrations of all parameters of blood plasma with the exception of K(+) were significantly (p < 0.05) higher than those of seminal plasma.

Effects of multiple collections on spermatozoa quality of Persian sturgeon, Acipenser persicus: motility, density and seminal plasma composition.

In this study, we investigated the effects of multiple collections of sperm on the endangered Persian sturgeon, Acipenser persicus, in terms of a number of sperm functional parameters (percentage of motile spermatozoa, total time period of motility and sperm concentration) as well as on the ionic composition, protein concentration and osmolality of seminal plasma. Semen samples were collected from 12 induced male fish in three experimental groups that had been injected intramuscularly with LHRH-A2, at dosages of 5 µg/kg body weight, at a number of time regimes: at 12 h, 17 h and 24 h after spawning induction (1); at 24, 29 and 34 h after spawning induction (2); and at 36, 41 and 46 h after spawning induction (3). The percentage of motile spermatozoa and the period of sperm motility decreased significantly (p < 0.05) after the second and third collections. The concentration of spermatozoa decreased after the third collection, but this decline was not significant. No significant effect of multiple collections on protein concentration and ionic content (with exception of the Cl(-) ion) of seminal plasma was observed. In all experimental groups, a moderate impact of sequential collection on the osmolality (p < 0.05) of seminal plasma was observed. This study provides new data on the effects of multiple collections on spermatological characteristics in the Persian sturgeon. Our results confirm that sequential stripping after the third collections has a negative effect on a number of functional parameters associated with sperm.

ATP content, oxidative stress and motility of beluga (Huso huso) semen: effect of short-term storage.

An effective technique for short-term storage of semen is essential when processing multiple sperm samples and when semen must be transported from collection sites to hatcheries for the fertilization of ova or to laboratories for cryopreservation. In this experiment, beluga (Huso huso) sperm were used to evaluate the effects of short-term storage on several quality parameters (i.e. motility, adenosine triphosphate (ATP) content and oxidative stress indices). Sperm cells exhibited > 50% motility during 3 days of storage with an average total duration of sperm motility varying from 13.33 ± 5.77 to 278.33 ± 25.65 s, and no motile spermatozoa were recorded after 9 days of storage. The levels of oxidative stress indices (thiobarbituric acid reactive substances and carbonyl derivatives of proteins) and antioxidant activity (superoxide dismutase) increased significantly after 3 days of storage. The ATP content also decreased significantly after 2 days of storage. The results of this study can be used to develop effective reproduction management and cryopreservation protocols for this endangered fish.

Study of sperm concentration, seminal plasma composition and their physiological correlation in the Persian sturgeon, Acipenser persicus.

The objectives of the present study were to determine ionic and organic composition of seminal plasma, sperm concentration and their relationships in the Persian sturgeon (Acipenser persicus). In this regard, ionic content (Na(+) , K(+) , Cl(-) , Ca(2+) and Mg(2+) ) and organic content (total protein, glucose, cholesterol and triglyceride) along with sperm concentration were measured in 17 specimens of the Persian sturgeon. The seminal plasma contained 59.53 ± 2.56 mm/l sodium, 9.1 ± 1.42 mm chloride, 4.72 ± 0.3 mm potassium, 1.45 ± 0.075 mm calcium and 0.7 ± 0.072 mm magnesium. The following organic contents were found: total protein 0.11 ± 0.02 g/dl, glucose 22.18 ± 4.16 mg/dl, cholesterol 6.67 ± 1.04 mg/dl and triglyceride 15.2 ± 0.65 mg/dl. The mean sperm concentration was estimated to be 1.6 ± 0.12 (×10(9)  sperm/ml). A significant relationship was found between sperm concentration and K(+) of seminal plasma (r = 0.533, p < 0.05). Significant correlations were observed between ionic contents: Na(+) vs Cl(-) (r = -0.854, p < 0.01) and Mg(2+) vs K(+) (-0.583, p < 0.05). Also, level of triglyceride was negatively correlated with Mg(2+) (r = -0.503, p < 0.05). Presented data could be considered as a complementary study for developing special extenders and protectant solutions for improving artificial fertilization in this valuable species.