-The objective of this study was to evaluate the effects of chronical exposure of honeybee drones to environmental (5 ppb) and non-environmental concentration (200 ppb) of imidacloprid (IMD) on sperm concentration, motility, viability, and mitochondrial membrane potential measured in semen obtained from 180 drones originating from 18 colonies. The results demonstrate that IMD exposure did not affect sperm concentration; however, there were significant differences in concentration within colonies. IMD exposure was associated with reductions in sperm motility, which also varied within colonies. Statistically significant interactions between IMD exposure and colony were found for active mitochondria and sperm viability. Our results strongly suggest that neonicotinoids can negatively affect honeybee drone sperm quality. It is important to emphasize that IMD actions can be strongly modulated according to the colony.Apis mellifera / imidacloprid / spermatozoa / motility / viability

Changes in semen quality and selected biochemical markers were analyzed during a week of spawning season of common carp Cyprinus carpio L. Semen was obtained twice, on May 30 and on June 7, and each time it was collected 24 h after hormonal stimulation using Ovopel [(D-Ala 6 , Pro 9 NEt)-mGnRH ? metoclopramide] in 1 pellet kg -1 . The total volume of semen (ml), volume of semen per kg of body weight (ml kg -1 b.w.), sperm concentration (910 9 ml -1 ), total number of sperm per kg of body weight (910 9 kg -1 b.w.), pH of semen, pH of seminal plasma, seminal plasma osmotic pressure (mOsm kg -1 ) and the total protein content in seminal plasma (mg ml -1 ) were determined. A 10 mM Tris buffer containing 100 mM NaCl with 0.5 % BSA (pH 9.0, osmolality 200 mOsm kg ), movement linearity (LIN, %), wobbling index (WOB, %), amplitude of lateral head displacement (ALH, lm) and beat cross-frequency (BCF, Hz). The volume of semen per kg of BW, total number of sperm per kg of BW and semen pH were significantly lower at the second semen sampling compared to the first semen sampling. Volume of semen at the second sampling correlated positively with CASA parameters. A lack of differences among CASA parameters between both collection periods indicates good quality of carp sperm hormonally stimulated with Ovopel twice at a 1-week interval.

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NEt)-mGnRH ? metoclopramide] to male barbel Barbus barbus (L.) 6, 12 and 24 h after hormonal stimulation was analyzed. The control group (Control) during each time interval was stimulated with 0.9 % NaCl. Milt was collected from seven fish only once (n = 7) for Ovopel, Ovaprim and Control group in order to determine total volume of milt, volume of milt per kg of body weight, sperm concentration, total sperm production, seminal plasma osmotic pressure, pH of milt and pH of seminal plasma. Woynarovich's solution (68 mM NaCl ? 50 mM urea) with the addition of 0.5 % BSA (pH 7.7; 181 mOsm kg -1 ) was used as the activating liquid. Selected parameters of sperm motility (MOT %) and progressively motile sperm (%), curvilinear velocity (VCL, lm s -1 ), straight-line velocity (lm s -1), movement linearity (%), wobbling index (%), amplitude of lateral head displacement (lm) and beat cross frequency (Hz) were determined using the Computer-assisted sperm analysis system. A time of 6 h proved to be too short to obtain milt from barbel following hormonal stimulation with Ovaprim and Ovopel. Extending the time to 12 h, however, resulted in 100 % spermiation in males, regardless of hormonal preparation used for stimulation. The stimulation of spermiation in barbel is best performed using Ovopel 12 h upon application. Extending the latency period to 24 h following the application of this preparation results in a significant decrease in the volume of milt obtained, sperm count and motility parameters, including MOT and VCL, which may influence sperm fertilization ability.

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