The Effect Of Homoplastic Pituitary Injection Overdose On Induced Spawning Of African Catfish <i>Carias gariepinus</i>, Burchell 1822

Abstract

Twelve pairs of male and female African catfish, Clarias gariepinus broodfish were monthly treated with graded doses of crude homoplastic pituitary injection. Different sets o pairs were used for each month, after certifying their gonadal maturity fitness for induced breeding. The first two pairs of spawners received one pituitary gland (3.8-5.7 mg) each from donors having equivalent body weight. The second two pairs received two glands (7.2-11 3 g), the third two pairs received three g ands (10.1-16.2 mg) the fourth two pa rs received four glands (13.5-22.2 mg) and the fifth two pairs received five g ands (17 7-27.5 mg) the sixth two pairs (contro) were not injected Each spawning pair was kept in concrete spawning tank for 24 hours for natural spawning to take place. Administration of one pitui ary injection fai ed to induce spawning, two and three glands yielded optimum results. Four and five yielded good spawning but all the hatchlings died after hatching. Death may be attributed to over secretion of thyroxin, thus leading to faculty vitellogenesis.