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.
