Jd. Tanfermin et Ac. Emata, INDUCED SPAWNING BY LHRHA AND PIMOZIDE IN THE ASIAN CATFISH CLARIAS-MACROCEPHALUS (GUNTHER), Journal of applied ichthyology, 9(2), 1993, pp. 89-96
Experiments were conducted to determine the optimum dose of luteinizin
g hormone-releasing hormone analogue (LHRHa) and pimozide (PIM) inject
ed simultaneously to yield a high ovulation rate and produce sufficien
t eggs in the Asian catfish Clarias macrocephalus. In June 1990, injec
tion of 0.05 or 0.10 mug LHRHa/g body weight (BW) + 1 mug PIM/g result
ed in 100% ovulation, while only 80% of gravid catfish injected 0.025
mug LHRHa + 1 mug PIM/g ovulated. Most of the eggs stripped from 6 out
of 8 control fish were not mature. Fertilization and hatching rates o
f LHRHa + PIM-induced fish (75-90% and 39-51%, respectively) were high
er than those of control fish (36-39% and 0-1%, respectively). In Augu
st and September 1990, all gravid catfish ovulated after injection of
0.05-0.10 mug LHRHa + 1 mug PIM/g BW. However, only 20% of the fish gi
ven 0.025 mug LHRHa/g + 1 mug PIM/g BW in August ovulated. No eggs cou
ld be stripped from any of the control fish in August and September 19
90. Techniques developed in this study showed a simple and effective w
ay of spawning captive catfish, C. macrocephalus. A simultaneous intra
muscular injection of 0.05 mug LHRHa + 1 mug PIM/g and stripping of eg
gs at 16-20 h post-injection have been tested to yield high ovulation,
fertilization and hatching rates.