Printed in Croatia Determination of membrane integrity of canine spermatozoa

Semen samples from 9 sexually mature dogs of different breeds, aged from 1 to 5 years were used. Quality of sperm was evaluated using the following parameters: progressive motility (subjective), then structural and functional integrity of spermal membrane (supravital colouring (eosine/nigrosine) and HOS test). The majority of HOS reactive or swollen spermatozoa was placed in a hypoosmolar solution of 100 mosmol and incubated for 30 minutes. Results of research are elaborated by the ANOVA statistical method and Tukey HSD tests post-hoc analysis. We also determined correlations between semen parameters. Between middle values for HOS reactive (swollen) spermatozoa in hypoosmolar solutions with different osmolarity significant differences were determined (P<0.0001). Using a hypoosmotic solution with osmolarity 100 mosmol, we determined significantly strong positive correlations between HOS test and progressive motility (r=0.82; P<0.05), between HOS test and supravital staining eosine/nigrosine (r = 0.98; P<0.05), and between progressive motility and supravital staining eosine/nigrosine (r = 0.89; P<0.05). These positive correlations were anticipated because sperm motility partially depends on the functional integrity of the sperm membrane and other events included in the metabolism of the sperm. Results of our research have shown that HOS test can be an easy method for routine evaluation of sperm quality in dogs. Key words: canine semen, progressive motility, HOS-test, membrane integrit