ZINC AFFECTS RABBIT SPERMATOZOA IN VITRO: EFFECTS ON MOTILITY AND VIABILITY

Abstract

Zinc is an essential trace element, which plays important roles in different biological activities. The aim of this study was to evaluate the effect of zinc on rabbit spermatozoa during in vitro conditions. Fresh semen was obtained from 8 sexually mature New Zealand White rabbits, which were bred at National Agricultural and Food Centre in Lužianky. Experimental groups were prepared by diluting the semen with two forms of zinc (ZnCl2, ZnSO4 .7 H2O) in five different concentration: ZA, ZA1 (4.883 mg Zn.l-1), ZB, ZB1 (9.766 mg Zn.l-1), ZC, ZC1 (19.531 mg Zn.l-1), ZD, ZD1 (39.063 mg Zn.l-1), ZE, ZE1 (78.125 mg Zn.l-1). Experimental samples were compared against control groups (ZK, ZK1). Semen was evaluated using the Computer Assisted Semen Analysis (CASA) at time intervals 0, 60, 120 and 180 minutes after incubation at 39°C. MTT test was used for determination of cell viability. Results of monitored motility parameters (motility, progressive motility and velocity curved line) showed decreasing trend in experimental samples. Significantly lower values of motility were observed in sample ZE, where percentage of motility decreased to 9.18±1.34% and after 180 minutes of incubation. Evaluation of spermatozoa velocity curved line detected significant (P<0.001) decrease at time intervals 120 and 180 minutes in samples with the highest concentration (ZE) of zinc. Measurement observed results with significant counteractive effect on viability in samples ZA, ZB, ZC1, ZD, ZD1 (P<0.05) and ZB1, ZC, ZE, ZE1 (P<0.01) after 180 minutes of incubation. Detected data confirm negative effect of zinc in each concentration on spermatozoa motility parameters and viability. Supplemented zinc in form ZnCl2 to rabbit semen had higher negative impact on rabbit spermatozoa motility and viability parameters than zinc in form ZnSO4.7H2O.