Induction of ovulation and spawn by LHRH-A and DOM in catfish, Silurus asotus

The catfish, Silurus asotus, were captured from Pearl River(June～July, 1999) and Liaohe River (May～June, 2000). In the ovulation induction experiment, 5 treatments were designed, which were injected with P.S (control), LHRH A, LHRH A+DOM, common carp PG+LHRH A, and common carp PG+HCG, respectively. The results showed that in the treatment with a dose of LHRH A+DOM (10 μg+5 mg)/kg body weight, the induction led to a large secretion of GtH to a high level in the catfish, furthermore resulted in the spawning with a spawing rate of 90% which was obviously higher than the other treatments. In the artificial breeding experiment, 2 926 individuals were injected with LHRH A+DOM at a dose of (7 μg+5 mg)/kg body weight, getting an average spawning rate of 70%, the highest 80%, and 2.07 million larvae were hatched.