The Spawning Response Of African Catfish, Clarias Gariepinus (Claridae: Teleost) Exposed To Different Piscine Pituitary And Synthetic Hormone

Abstract

African catfish (Clarias gariepinus) is generally considered to be one of the most important tropical fish species for aquaculture. However, its production has faced limiting factors like shortage of induced breeding technique, seasonality in availability and lack of good quality seed (fingerling) supply to farmers and producers. The present study was conducted to evaluate the spawning response of C. gariepinus exposed to different piscine (C. gariepinus and Cyprinus carpio) pituitary extracts and synthetic hormone (Luteinizing hormone releasing hormone + Domperidone). Nine C. gariepinus gravid females were divided in to three treatment groups and injected with hormones intramuscularly. Data on spawning fecundity, fertility rate (%), hatchability rate (%) and induction hour (hrs) were calculated. The highest mean in spawning fecundity (9731.6 eggs/g body weight/female) was observed in groups injected with pituitary extract of C. gariepinus followed by the group injected with pituitary extract of C. carpio (5813.8 eggs/g body weight/female). The lowest mean spawning fecundity (5666.6 eggs/ g body weight/female) was observed in group injected with synthetic hormone. However, the spawning fecundity/g body weight/female did not show significant difference (p = 0.073) among the groups. The highest mean fertility rate (84.3 %) was recorded in groups injected with pituitary extract of C. gariepinus followed by the groups injected with pituitary extract of Cyprinus carpio (C. carpio) (80.6 %) and synthetic hormone (74.9 %). The mean fertility rate recorded in this study showed no significant variation (P = 0.069) among the groups. The mean hatchability rate recorded in this study was high (73.3 %) in groups injected with pituitary extract of C. gariepinus and followed by the group injected with pituitary extract of C. carpio (63.5 %). The lowest (51.5 %) mean hatchability rate was observed in groups injected with synthetic hormone. The mean hatchability rate showed significant difference (P = 0.04) among the groups. In general, the present experiment indicated that the use of pituitary extract from C. gariepinus was more effective for induction of spawning in C. gariepinus during artificial reproduction as compared to C. carpio pituitary extract and synthetic hormone.