Comparison of carp pituitary extract and synthetic hormone-based protocols for ovulation induction in pacu (Piaractus mesopotamicus)

Objective Since sodium cloprostenol enhances ovulation in pacu ( Piaractus mesopotamicus ) when combined with carp pituitary extract (CPE), this study evaluated whether synthetic hormone-based protocols based on the LinPe Method could replace the conventional CPE protocol. Methods In the first experiment, females received the conventional CPE protocol (control) or a single low dose of buserelin acetate combined with sodium cloprostenol, with or without domperidone. Results Histological evaluation demonstrated that females receiving the synthetic protocols did not undergo germinalvesicle breakdown (GVBD), indicating failure to resume meiosis, whereas females treated with CPE spawned successfully. Based on these findings, a second experiment evaluated higher doses of buserelin acetate combined with metoclopramide instead of domperidone, using the same CPE protocol as the control. Spawning occurred in all treatments, with spawning rates of 75%, 33%, and 67% for the control, intermediate-dose, and high-dose synthetic protocols, respectively. Relative fecundity, fertilization, and hatching rates were similar between the control and high-dose synthetic protocol (P > 0.05). Conclusion These findings demonstrate that increasing GnRH stimulation while replacing domperidone with metoclopramide successfully overcame the failure to resume meiosis observed in the initial trial, providing an effective synthetic alternative to carp pituitary extract for spawning induction in female pacu.