Effect of goserelin and leuprolide added to the semen on reproductive performance in rabbits - Short communication.

The aim of this study was to evaluate the ability of two synthetic GnRH analogues, goserelin and leuprolide, to induce ovulation in rabbit does using intravaginal administration. A total of 252 primiparous lactating does were randomly divided into five groups that, at the time of insemination, received the following treatments for ovulation induction: 1 µg of buserelin administered intramuscularly (control group), 5 µg of goserelin added to the semen dose (Group G5), 10 µg of goserelin added to the semen dose (Group G10), 5 µg of leuprolide added to the semen dose (Group L5), and 10 µg of leuprolide added to the semen dose (Group L10). The kindling rate was 80.5% in Group G10 and 75.0% in Group L10; these values are comparable to the kindling rate obtained in the control group (85.9%). The kindling rates in Groups G5 and L5 were significantly lower than in the control group (60.0%, 54.2% and 85.9%, respectively). The number of live-born rabbits was not significantly affected by the ovulation induction treatment. As regards the total number of rabbits born the only significant difference was observed between Groups G5 and L5. This study shows the possibility of inducing ovulation in rabbits by adding goserelin and leuprolide directly to the semen dose.

Fertility of boar semen cryopreserved in extender supplemented with butylated hydroxytoluene.

The present study was to determine the effect of butylated hydroxytoluene (BHT) on quality and fertilizing ability of frozen-thawed boar semen. In the first experiment, five crossbreds of Polish Landrace and Large White boars (five ejaculates per boar) were frozen in 0.5 mL straws after dilution with lactose-egg yolk-glycerol extender supplemented with 0 (control), 0.5, 1.0, and 2.0 mM BHT. The sperm quality was verified based on the motility (computer-assisted sperm analysis; total motility, %; progressive motility, %), membrane integrity (YO-PRO-1/propidium iodide [PI] assay), acrosome integrity (fluorescein isothiocyanate-conjugated with peanut agglutinin/PI), and lipid peroxidation (chemiluminescence method) at 15 minutes postthaw. In the second experiment, the semen cryopreserved in extender supplemented with 1.0 and 2.0 mM BHT were selected for intrauterine artificial insemination of synchronized gilts. An intrauterine artificial insemination with low numbers of spermatozoa (500 × 10(6)) was surgically infused into each uterine horn. The highest (P < 0.001) progressive motility (%), membrane integrity, and acrosomal integrity were noted by the addition of 1.0 and 2.0 mM BHT to the freezing extender. Moreover, the various concentrations (0.5-2.0 mM) of BHT caused a considerable decrease in lipid peroxidation in relation to the control extender (P < 0.001). The highest reproductive performance of inseminated gilts (farrowing rate, 86.7%; litter size, 10.8 ± 1.6) was observed when semen was cryopreserved in extender supplemented with 1.0 mM BHT. These findings demonstrate that the addition of 1.0 mM BHT to the freezing extender efficiently improves the fertilizing ability of postthaw boar spermatozoa.

Motility parameters and intracellular ATP content of rabbit spermatozoa stored for 3 days at 15 degrees C.

The effect of semen storage duration on motility parameters and ATP content of rabbit spermatozoa were investigated. Ejaculates were collected from 9 New Zealand White male rabbits and diluted with a commercial rabbit semen extender Galap. Semen was stored at 15 degrees C for 3 days. On each day of storage sperm motility and intracellular ATP content were evaluated. Sperm motility parameters were assessed using the computer-assisted sperm analysis (CASA) system and ATP content using the bioluminescence method. The time of storage had a significant effect on sperm motility parameters (except straight-line velocity) and ATP content. A significant correlation was observed between motility parameters and sperm ATP content. The motility parameters most strongly correlated with ATP content were total motile spermatozoa (r = 0.6364), progressively motile spermatozoa (r = 0.529), amplitude of lateral head displacement (r = 0.4178), curvilinear velocity (r = 0.4111) and average path velocity (r = 0.3743). Results show that motility parameters determined using the CASA system and intracellular ATP content are sensitive indicators of sperm quality during in vitro storage and may be useful for estimation of in vivo fertilizing ability of rabbit semen.

The photon emission, ATP level and motility of boar spermatozoa during liquid storage.

Changes were studied in induced photon emission (as an indicator of oxidative stress), ATP level and sperm motility during seven day-storage of boar semen at 15 degrees C extended with the use of BTS extender. Photon emission was measured using a luminometer equipped with a cooled photomultiplier with a spectral response range from 370 to 620 nm. The time of storage had a significant effect on luminescence parameters (integral and peak max), intracellular ATP level and percentage of motile spermatozoa. The increase in luminescence parameters was paralleled by a decrease in ATP level and sperm motility. A significant correlation was found between the percentage of motile spermatozoa and integral (r=-0.27) and peak max (r=-0.31). ATP level was correlated with integral (r=-0.25) but not with peak max. Our results suggest that reactive oxygen species and products of cell membrane lipid peroxidation have a negative effect on ATP level and sperm motility. Induced luminescence assessment in combination with sperm motility and ATP level can give valuable information about the status and function of spermatozoa which may be relevant for predicting the fertilizing potential of the semen.