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Short-term storage of semen in cooling conditions (+4℃) is one way to perfect artificial fish reproduction. In this experiment, we attempted to add antioxidants (vitamins C and E, glutathione and cysteine) during the storage of Arctic char (Salvelinus alpinus) and rainbow trout (Oncorhynchus mykiss) semen. An analysis of the CASA parameters showed that addition of the antioxidants to semen during storage did not benefit spermatozoa motility of studied salmonids. An analysis of the parameters showed that added vitamins C and E did not influence the sperm motility of Salmonidae during semen storage. The addition of glutathione and cysteine significantly worsened the vitality of Arctic char and rainbow trout sperm.
Acid phosphatase (AcP) is a commonly observed enzyme in animal semen. In this study, AcP in rainbow trout (Oncorhynchus mykiss) spermatozoa was partly purified and characterized. Extraction in 0.85% NaCl with 0.1% Triton X-100 enabled obtaining 95% of total AcP activity observed in sperm supernatant. Kinetic characteristics were described for the enzyme from sperm extract and for the partly purified enzyme following gel filtration. The optimum pH was 5.8 for unpurified and 5.6 for partly purified enzyme. The affinity of the substrates measured in the sperm extract for p-nitrophenylphosphate dissodium salt and b-glycerophosphate was Km = 1.5 × 10-3M and Km = 1.9 × 10-3M, respectively. The Km for partly purified enzyme was similar at 1.67 × 10-3M measured with p-nitrophenylphosphate dissodium salt. L-tartaric acid and ammonium molybdate were the inhibitors of AcP for unpurified and partly purified enzyme. SDS-PAGE electrophoresis revealed that AcP from rainbow trout had a molecular weight of about 41 kDa.
The effects of mercury and cadmium ions, at the concentrations of 100, 10 and 1 mg · dm⁻³, on the activity of enzymes contained in the sperm of Siberian sturgeon were determined. Whole semen was frozen without a cryoprotector. Acid phosphatase (AcP) activity decreased significantly following the application of mercury and cadmium ions at the highest concentration. Lactic dehydrogenase (LDH) was found to be the most sensitive to metal ions of all enzymes examined in the study. The concentration of 10 mg · dm⁻³ almost completely inhibited the activity of this enzyme. It was also found that mercury and cadmium ions slightly stimulated the activity of arylsulfatase (AS). The activity of β -N-acetylglucosaminidase (β -NAG) decreased considerably when mercury ions were added to the reaction mixture, in contrast to cadmium ions. The effects of Hg and Cd ions on the affinity of AcP and AS for substrates were also determined. It was found that these metal ions decreased the affinity of the above enzymes for p-nitrophenylphosphate and p-nitrocatechol sulfate respectively.
The milt of individual males of Siberian sturgeon (Acipenser baerii) and sterlet (Acipenser ruthenus) was frozen without cryoprotector (at -79°C) or cryopreserved with methanol as the cryoprotector. The activity of arylsulfatase (AS), acid phosphatase (AcP), β-N-acetylglucosaminidase (NAGase), and protein concentration was determined. The protein concentration and enzymatic activities in supernatant obtained after cryopreservation were higher than in milt plasma, but they were lower than that in the material obtained after freezing at -79°C. The protein and enzymatic leakage of sterlet spermatozoa was statistically higher in supernatants that had been frozen at-79°C than in those that had undergone cryopreservation. Differences in the protein and AS leakage the Siberian sturgeon supernatants were also observed.
A Computer Assisted Sperm Analysis system, CASA, enables determination of numerous parameters characterizing sperm motion activity. This system allows for the examination of the effect of various environmental factors on spermatozoa motility parameters. The aim of this work was to compare time-dependent motility changes of sperm obtained from the dace, Leuciscus leuciscus (L.), by abdominal massage (sperm from spermatic ducts) and directly from gonads (testicular sperm). The analysis concerned such sperm motility parameters as: percentage of motile sperm (MOT, %), total sperm velocity (VAP, μm s–1), straight line velocity (VSL, μm s–1), curvilinear velocity (VCL, μm s–1), linearity (LIN: VSL/VCL · 100%), straightness (STR: VSL/VAP · 100%), amplitude of the lateral head displacement (ALH, μm) and beat cross frequency (BCF, Hz). During 105 seconds of motility, no significant differences were found in the values of MOT between sperm originating from the spermatic ducts and from the testicles. Changes in MOT were only observed during seconds 120–135 of movement, when significantly higher values were found for testicular milt. Significant higher sperm velocities (VAP, VCL, VSL) at the 15s from activation were observed in the sperm originated from spermatic duct. On the other hand 120s after activation of movement, values of sperm velocity (VAP and VCL) of milt originating from spermatic duct significantly decreased in comparison to testicular milt. Our data showed that sperm obtained from spermatic duct have initially higher sperm motility speed compared to that obtained directly from the testis. However testicular sperm are able to swim longer than sperm obtained from spermatic duct.
Since its inception, the material used in the Baltic sturgeon restoration program has been, and continues to be, hatch and fry of this species imported to Poland from Canada. Heavy fry was used to create a stock of selects that are cultured under different conditions. In 2011, signs of maturation were noted among some selects cultured in tanks in a recirculating aquaculture system. After conducting biopsies, two males were chosen for hormonal stimulation, after which milt was collected from them. The body weight growth of these males was analyzed in comparison with the mean body weights of other select stocks, and the mean growth rates of the selects was very high at 42% annually. Sperm was collected twice. The milt obtained was characterized by high sperm motility (above 70%) and a relatively low concentration (0.735 mld/ml). The milt from the first collection was thickened with the centrifugation method, and that of the second was cryopreserved in liquid nitrogen vapor. The motility of the sperm following cryopreservation and then thawing was high (65.4% from the first collection and following centrifugation and 64.9% from the second collection).
The aim of the study was to determine the basic quality parameters and selected biochemical markers of asp, Aspius aspius (L.), semen after spermiation was stimulated with Ovaprim and Ovopel. Sperm motility and concentration, osmotic pressure, total protein content, and activities of acid phosphatase (AcP), lactate dehydrogenase (LDH), and b-N-acetylglucosaminidase (b-NAG) were determined. It was revealed that higher sperm motility and concentration and higher seminal plasma protein content were obtained after stimulation with Ovaprim. The osmotic pressure of the seminal plasma estimated for males following the administration of Ovopel was higher than after they had been treated with Ovaprim. It was determined that enzyme activity in the seminal plasma of the fish stimulated with Ovaprim was higher in comparison with results obtained after they had been treated with Ovopel. Significant, positive dependencies were confirmed between the concentration of sperm and the total protein content in the seminal plasma (r2 = 0.492) and the activity of b-NAG (r2 = 0.779); among the total protein content in the seminal plasma and the activities of AcP (r2 = 0.476), LDH (r2 = 0.564), and b-NAG (r2 = 0.738); and between the activities of AcP and LDH (r2 = 0.483) and between the activities of LDH and b-NAG (r2 = 0.844).
One of the ways to improve methods for the artificial reproduction of fish is the possibility of storing sperm for short periods under refrigerated conditions (+4°C) without the necessity of freezing. In the experiment semen extenders with and without sugars (glucose and fructose) were applied during the storage of pike semen. The analysis of sperm motility parameters indicated that semen that had not been diluted with an immobilization buffer decreased in quality very quickly. After 24 hours of storage significant differences were noted in parameters measured with CASA, and after the subsequent two days no motile sperm were noted. The semen that was diluted with the immobilization buffer that included glucose retained 48% motile sperm after four days of the experiment. The results indicate that diluting the semen with an immobilization buffer lengthens the storage period of pike semen under refrigerated conditions.
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