LHRH-a and domperidone-induced oocyte maturation and ovulation in bighead carp, Aristichthys nobilis (Richardson)

Abstract

Effects of intraperitoneal injections of LHRH-a and domperidone (DOM), given singly or in combination at two injections, on oocyte maturation, ovulation and spawning in bighead carp, Aristichthys nobilis, were investigated. Results were compared with the existing protocol using HCG + LHRH-a at 1800 IU and 20 μg/kg BW, respectively, to induce spawning in bighead carp. Oocyte diameter of fish at 6 h after the second injection of LHRH-a + DOM and HCG + LHRH-a had significantly increased to 7.0% and 7.5% respectively, as compared to the 0 h group (P<0.05); fish injected with LHRH-a, DOM or saline had significantly lower increases (1.0%, 2.0%, and 3.0%, respectively). Ovulation was induced in 75% and 60% of fish injected with LHRH-a + DOM and HCG + LHRH-a, respectively. In contrast, fish treated with LHRH-a, DOM or saline did not ovulate. Total eggs spawned, and fertilization and hatching rates did not differ significantly (P<0.05) between the two groups with ovulated fish. Although injection protocols using LHRH-a + DOM and HCG + LHRH-a were equally effective in inducing spawning of bighead carp, the former had a lower combined cost than the latter.