LHRH-a and domperidone-induced oocyte maturation and ovulation in bighead carp, Aristichthys nobilis (Richardson).
21 ♀ bighead carp, aged 3-4 yr, were treated with (1) an LHRH analogue (LHRHa), (2) LHRHa plus domperidone or HCG, (3) domperidone or (4) saline. The treatment comprised 2 injections (10 and 90% of the total dose) at a 6-h interval. Males were injected once with HCG or LHRHa. Oocyte diameter 6 h after the 2nd injection of LHRHa + domperidone and HCG + LHRHa was 7.0 and 7.5% resp. greater than that before the 1st injection (P<0.05); fish injected with LHRHa, domperidone or saline showed smaller increases (1.0, 2.0 and 3.0% resp.). Ovulation was induced in 75 and 60% of fish injected with LHRH + domperidone and HCG + LHRHa resp. Fish treated with LHRH, domperidone or saline did not ovulate. The number of eggs spawned, and fertilization and hatching rates, did not differ (P>0.05) between the 2 groups of ovulated fish. The LHRHa + domperidone treatment was cheaper than LHRHa + HCG.