Induced breeding of knife fish, Notopterus notopterus , using pituitary gland extract, human chorionic gonadotropin, and luteinizing hormone releasing hormone‐analog hormones

This study was performed to determine the efficiency of various hormones on the ovulation of knife fish, Notopterus notopterus , in captivity. In total, 81 fish were grouped into nine treatments with three replicates, maintaining the sex ratio 1:2 (male to female). Brood fish in all the groups were given pituitary gland extract (PGE) 2 mg kg −1 body weight (BW) as a preliminary dose and different doses of PGE (6, 8, 10 mg kg −1 BW), human chorionic gonadotropin (3000, 4000, 5000 IU kg −1 BW), and luteinizing hormone releasing hormone‐analog (LHRH‐a) (150, 200, 250 μg kg −1 BW) plus domperidone (DOM) (15, 20, 25 mg), respectively, as the final dose. The optimal hormone combination was identified based on key spawning parameters: ovisomatic index (5.2%), fecundity (487 eggs), egg diameter (3.27 mm), fertilization rate (95.2%), embryo development time (159 h), and hatching rate (70.3%). Accordingly, the recommended hormone protocol for initiating breeding in knife fish is a priming dose of PGE (2 mg kg −1 BW) followed by LHRH‐a (200 μg kg −1 BW) combined with 20 mg DOM for optimal reproductive performance. These findings mark a pivotal step towards establishing captive breeding protocols for knife fish, offering a sustainable solution to seed scarcity while contributing to the species' aquaculture potential and conservation.