The effects of commercial preparations containing two different GnRH analogues and dopamine antagonists on spermiation and sperm characteristics in the European smelt Osmerus eperlanus (L.)

Efficiency of Ovopel (mGnRHa + metaclopramide) and Ovaprim (sGnRHa + domperidone) treatment on the quantity and quality of European smelt milt were tested. Either preparation resulted in stimulation of smelt sperm production (100% spermiating males vs. 68% in control). At the dosage tested, Ovaprim treatment increased the volume of milt and total sperm production, whereas Ovopel treatment produced sperm with a higher percentage of motility. Among computer-assisted sperm motility analysis (CASA) parameters only amplitude of lateral head displacement (ALH) significantly differed from control in both hormonal treated groups. For most parameters no significant differences between control and stimulated males were found. Our data suggested that administration of two different GnRHa combined with two different dopamine antagonists would help in the future work for improving procedures of artificial reproduction and conservation of European smelt.