An attempt to improve the reproductive efficiency of Nile tilapia brood stock fish

摘要

A field study was conducted on brood stock Nile tilapia to increase the propagation. Both sexes were individually stocked into Habas (enclosures) in an earthen pond and fed for 19 days on a basal diet supplemented with different additives at graded levels of each (0.5, 1.0 and 2.0 g Therigonp; 1.0, 2.0, and 3.0 g Nuvisol Hatch Pp; 20, 40 and 60 mg Gibberellic acid and 700, 900 and 1,100 mg L-carnitine/Kg diet). The obtained results were evaluated, and the best treatment for each sex was chosen for mating. Results indicated that all pretreatments for male and female brood stocks of Nile tilapia positively affected the total count of the offspring produced. Yet, the Haba, in which the females were pretreated with 0.5 g Therigonp/Kg diet and the males pretreated with 700 mg L-carnitine/Kg diet, gave the highest total count of the offspring comparing with the other Habas. But, because of the high feed cost due to the additives cost, 0.5 g Therigonp/kg diet as pretreatment for only (3rd Haba), 2 g Nuvisol Hatch Pp/Kg diet as pretreatment for only (5th Haba), followed by 0.5 g Therigonp and 700 mg L-carnitine/Kg diet for and , respectively (4th Haba), respectively were the best economically.