The effect of selected hormonal preparations, i.e. [(D-Ala⁶, Pro⁹-NEt)-mGnRH+metoclopramide] (Ovopel), [(D-Arg⁶, Pro⁹-NEt)-sGnRH+domperidone] (Ovaprim), luteinizing hormone releasing hormone (LHRHa), human chorionic gonadotropine (hCG) and carp pituitary extract (CPE) on the total volume of milt (TVM, ml), volume of milt per kg of body weight (VOM, ml kg⁻¹ b.w.), sperm concentration (×10⁹ ml⁻¹) and total sperm production (TSP, ×10⁹) of dace Leuciscus leuciscus (L.) has been examined. The control group (Control) included fish which milt was taken after 0.9% NaCl injection. The parameters of sperm movement were analysed with the CASA system and included: sperm motility (MOT, %), progressive motility (PRG, %), curvilinear velocity (VCL, μm s⁻¹) and straightlinear velocity (VSL, μm s⁻¹) of sperm, linearity of movements (LIN = 100 × VSL/VCL,%), wobbling (WOB, %), amplitude of lateral head displacement (ALH, μm) and beat cross frequency (BCF, Hz). Milt was taken from all fish (n = 12 per group) 48 h after hormonal stimulation and selected milt and sperm parameters were determined. The best results in volume of milt was found after Ovaprim treatment and TVM and VOM values were statistically higher compared to the values recorded in the Control (P < 0.001), LHRHa (P < 0.001), hCG (P < 0.001) and Ovopel group (P < 0.05). Ovaprim treatment significantly increased also TSP values without differences only between Ovopel group. Sperm concentration was significantly lower after Ovaprim treatment compared to the Control (P < 0.001) and Ovopel (P < 0.05). In CASA parameters, no significant differences were found between MOT, PRG, LIN, WOB and BCF values depending on the hormonal preparation used (P > 0.05). The highest VCL and VSL values were recorded after LHRHa treatment but there was no statistical differences between Control, Ovaprim and CPE groups. Significant differences in ALH parameter were recorded only between LHRHa and hCG (P < 0.01).

The effect of sodium and potassium concentrations as well as optimal pH on the motility of common carp Cyprinus carpio L. sperm during short-term storage in artificial seminal plasma (ASP) was investigated. Sperm was collected from individual males (n = 5) and each sample diluted tenfold (1:9) in ASP (sperm:extender) containing 2 mM CaCl₂, 1 mM Mg₂SO₄ and 20 mM Tris at pH 8.0 and supplemented by the following concentrations of sodium and potassium (mM/mM): 0/150, 20/130, 40/110, 75/75, 110/40, 130/20 and 150/0. The osmolality of all ASP variants was set at 310 mOsm kg⁻¹. Sperm motility was measured using a CASA system during 72 h of storage. Immediately after dilution, sperm motility was high (90%) both in each variant and in the control group (fresh sperm). After 72-h storage, the highest sperm motility was noted in ASP containing 110 mM NaCl and 40 mM KCl. No differences were found in the motility of samples preserved within the pH range of 7.0–9.0. Our data suggest that for the short-term storage of common carp sperm, whereas the pH of the solution does not play a crucial role, a specific potassium concentration of around 40 mM is required.

The aim of this work was to compare the effects of controlled reproduction of cultured and wild common barbel, Barbus barbus (L.). Preparations containing different GnRH analogues and dopamine receptor antagonists (Ovopel, Ovaprim) as well as human chorionic gonadotropin (hCG) (in the case of cultured fish) were applied and their influence on ovulation, spermiation and quality of gametes obtained was determined. No differences in the qualitative or quantitative parameters of semen were found between fish stimulated with different hormonal preparations and those not receiving hormonal stimulation. The high suitability of Ovaprim for ovulation induction in (cultured and wild) barbel was confirmed. The highest synchronisation of ovulation was obtained after the application of Ovopel (18 ± 3 h), but the best results of controlled reproduction (expressed as the percentage of ovulations and survival of embryos) were obtained by applying Ovaprim (83.2 ± 4.1). A significantly higher percentage of ovulation was obtained in cultured fish (80–90%) than in wild fish (< 25%).