Induced spawning of Asian catfish, Clarias batrachus (Linn.):: effect of various latency periods and SGnRHa and domperidone doses on spawning performance and egg quality

An experiment was conducted to induce ovulation in Asian catfish, Clarias batrachus, by a single injection of SGnRHa (D-Arg(6), Trp(7), Leu(8), Pro(9), Net) in combination with domperidone. The effects of latency periods, 11, 14, 17, 20 and 23 h, and doses of inducing agent, 10 mu g SGnRHa + 15 mg domperidone, 20 mg SGnRHa + 10 mg domperidone, 30 mg SGnRHa + 15 mg domperidone and 40 mg SGnRHa + 20 mg domperidone kg(-1) body weight, were studied on the total egg output, stripping response, fertilization, hatching and normal larval production. The highest (P < 0.05) number of eggs were stripped at 23 h of post injection of 20 mg SGnRHa + 10 mg domperidone kg(-1) female body weight. The highest (P < 0.05) stripping response was observed when the females were stripped at 20 and 23 h latency, at all dose levels of the inducing agent. The eggs stripped at 11h latency did not fertilize, and hence did not hatch irrespective of administration of any dose levels of the inducing agent. The fertilization and hatching per cent of eggs had significantly increased (P < 0.05) with increase in latency period to 14-23 h at a dose of 20 mg SGnRHa + 10 mg domperidone. The latency period of 14-17h, and dose of 20 mu g SGnRHa + 10 mg domperidone and 30 mu g SGnRHa + 15 mg domperidone kg(-1) of female, was found to be suitable to obtain best spawning performance, and good-quality egg and larval production in C. batrachus.