Artificial insemination and semen quality

Artificial insemination is currently a necessary and exclusive means of breeding turkeys in large farms (Di Iorio et al., 2020; Slowinska et al., 2018). For optimal fertility outcomes, breeders must focus not only on the insemination itself, but also on the quality of collected semen. The culture medium is one of the main factors influencing semen quality and turkey spermatozoa in in vitro conditions. The aim of the study was to evaluate the impact of selected additive substances with potential stimulatory effects on spermatozoa motility of turkeys (Meleagris gallopavo), during in vitro incubation. Specifically, we analyzed the effect of different concentrations of trehalose, fructose, caffeine and taurine diluted in the physiological solution as the culture medium. The primary aim of the study was to develop a new semen extender usable in practice based on obtained results. The individual motility parameters were analyzed by CASA system (Computer Assisted Semen Analyzer) at 5°C and 41°C in different time periods.

The highest monitored concentrations of trehalose (10 mg/ml) and fructose (20 mg/ml) showed a relatively balanced value of motility parameters. At the lower concentration of trehalose (5, 2.5, 1.25 mg/ml) and fructose (5, 10, 15 mg/ml), a negative effect on the individual motility parameters of turkey spermatozoa was observed. Significantly (p < 0.01, p < 0.001) higher motility and progressive motility of spermatozoa, respectively, were detected in the samples containing caffeine ranging from 0.16 mg/ml to 7.5 mg/ml in comparison to the control sample at 5°C. At cultivation temperature of 41°C the positive effect of caffeine was demonstrated only at the beginning of incubation (time 0 and 1h.). The concentration of taurine above 10 mg/ml had a negative effect on spermatozoa motility. A significant stimulatory effect of taurine on motility parameters was observed in the samples containing 7.5, 5 and 2.5 mg/ml of taurine. Following the continuous results three new semen extenders were prepared. At the cool media incubation (5°C) all three extenders showed significantly higher values of all CASA motility parameters from 1 to 6 hours during in vitro incubation. After 24 hours of incubation, significantly higher values of motility parameters were measured in extender three compared to the control. In conclusion, we can state that we have successfully developed new turkey semen extenders (registration in process), which not only maintain spermatozoa motility during short-term storage in in vitro conditions, but also have a stimulatory effect on turkey spermatozoa motility.

ACKNOWLEDGEMENTS: This publication was supported by the Operational program Integrated Infrastructure within the project: Creation of nuclear herds of dairy cattle with a requirement for high health status through the use of genomic selection, innovative biotechnological methods, and optimal management of breeding, NUKLEUS 313011V387, cofinanced by the European Regional Development Fund. This work was supported also by project of the Scientific Grant Agency of the Ministry of Education, Science, Research and Sport of the Slovak Republic (projects VEGA 1/0539/18).