Optimalisation of the Activation Medium and Effect of Inhibiting Activities of Acid Phosphatase, Lactate Dehydrogenase and β-N-Acetylglucosaminidase on the Fertilisation Success of Eurasian Perch (Perca fluviatilis L.)

SIMPLE SUMMARY: The purpose of this study is to determine the composition of the optimal activating solution for activating sperm motility and perch eggs, because scientific studies and reproductive procedures should be conducted in stable and repeatable conditions. We found that the best activating solution was composed of 80 mM NaCl, 20 mM KCl, 10 mM Tris, with pH 8.0 and 206 mOsm/kg. In spite of this, we also checked the influence of adding the enzyme inhibitors, such as ammonium molybdate–acid phosphatase inhibitor, gossypol – lactate dehydrogenase inhibitor and acetamide–β-N-acetylglucosaminidase inhibitor on perch sperm motility and successful perch fertilisation. We showed that the addition of acid phosphatase inhibitor in perch semen did not affect the process of fertilisation; in contrast, the addition of lactate dehydrogenase and β-N-acetylglucosaminidase inhibitors significantly decreased the percentage of perch fertilised eggs. ABSTRACT: Although methods for the artificial reproduction of perch have been developed, a lack of information remains regarding the enzymes present in its semen, as well as their role in the fertilisation process. In this study, we first select the optimal activating solution for perch fertilisation and then determine the inhibition effect of enzymes that have already been reported as present in the sperm of teleosts—acid phosphatase (AcP), lactic dehydrogenase (LDH) and β-N-acetylglucosaminidase (β-NAGase)—on the percentage of motile spermatozoa and fertilised eggs. Of the 8 studied activation media, a solution composed of 80 mM NaCl, 20 mM KCl, 10 mM Tris, with pH 8.0 and 206 mOsm/kg proved to be optimal for perch gametes. The addition of ammonium molybdate (AcP inhibitor) caused no significant reduction in the percentage of fertilised eggs. On the other hand, the addition of 0.25 mM gossypol (LDH inhibitor) and 0.125 M acetamide (β-N-acetylglucosaminidase inhibitor) significantly decreased the fertilisation percentage to 41.1% and 52.4%, respectively, in contrast to the control (89.9 %). Both LDH and β-NAGase thus seem to play a very important role in the perch fertilisation process.