Spermiation induction in the common bream (Abramis brama) using sGnRHa and domperidone (Ovaprim): Sperm production, seminal plasma composition, and spermatozoa motility and fertilizing ability

In cyprinids aquaculture, the implication of gonadotropin-releasing hormone analogues (GnRHa) in combination with a dopamine inhibitor has been suggested to induce spermiation. The study investigated the efficiency of Ovaprim (consists of 20 mu g (D-Arg6, Pro9NEt)-sGnRH and 10 mg domperidone per mL) on spermiation in the common bream, Abramis brama. The males (n = 10 in each group) with a mean body weight of 863.2 +/- 22.8 g were injected with 0.25 or 0.5 mL kg(-1) Ovaprim at the spawning season. The control group was injected with physiological saline. To evaluate hormonal therapy, sperm production, motility and fertilizing ability were assessed together with some biochemical characteristics of seminal plasma. The hormonally treated groups produced more sperm in volume with higher total number of spermatozoa (P < 0.05). However, spermatozoa concentration and spermatocrit were lower in males treated with 0.5 mL kg(-1) Ovaprim compared to the control group (P < 0.05). Duration of spermatozoa motility did not differ among groups, while percentage of motile spermatozoa was lower in the males treated with 0.5 mL kg(-1) Ovaprim compared to the males in the control group or those treated with 0.25 mL kg(-1) Ovaprim (P < 0.05). The 0.25 mL kg(-1) Ovaprim treated group showed the highest osmotic pressure and cholesterol level and the lowest lactate dehydrogenase activity in the seminal plasma, which differed significantly from the 0.5 mL kg(-1) treated group (P < 0.05). Ionic composition and pH of seminal plasma did not differ among groups. The highest fertilization and hatching rates were observed when the males treated with 0.25 mL kg(-1) Ovaprim. However, differences in survival and malformations of larvae were not significant among groups. In general, the results of the present study suggest a higher efficiency of Ovaprim at 0.25 compared to 0.5 mL kg(-1) to induce spermiation in common bream, which results in higher fertilization ability. This study provides novel information on developing controlled reproduction of common bream in aquaculture.