Effectiveness of gonadotropin-releasing hormone analogue and human chorionic gonadotropin administration on oocyte maturation and ovulation in silver catfish, Chrysichthys nigrodigitatus

Abstract

The artificial reproduction of the silver catfish (Chrysichthys nigrodigitatus) is traditionally limited to once-a-year forced pairing. This study evaluated the effectiveness of hormonal treatments to stimulate oocyte maturation and induce spawning. Forty-two female silver catfish weighing 152 to 528 g received intramuscular injections of gonadotropin-releasing hormone analogues (GnRHa, administered as Ovaprim; 0.1, 0.3, and 0.6 mL/kg), human chorionic gonadotropin (hCG, 500 and 1000 IU/kg), or saline (control). Oocyte development was monitored by measuring oocyte diameter at 4, 8, 12, and 24 hours after injection. GnRHa treatment caused a significant increase in oocyte diameter from initial values (1.90-2.27 mm) to ≥2.5 mm within 8 hours at all tested doses (p < 0.05), whereas hCG and control treatments showed no significant changes. Despite successful oocyte maturation with GnRHa, no spawning occurred. These results indicate that GnRHa promotes final oocyte maturation in C. nigrodigitatus but remains insufficient to induce spawning under the conditions tested.