The major problem in tilapia culture is in their prolific breeding habit; which usually results into over-population in the culture system thus leading to stunted growth. Effect of crude extracts of Azadirachta indica, Psidium guajava and Mangifera indica leaf on reproduction of Oreochromis niloticus was investigated. One hundred and eighty fish (per plant leaf extract) of approximately the same mean weight were grouped into 6 (Represented as; D1, D2, D3, D4, D5 and D6) and stocked in out-door concrete tanks. Fish were fed 3% of their body weight for 56 days with basal diet (35% crude protein) containing varying concentrations (0.0, 0.5, 1.0, 2.0, 4.0 and 8.0 gkg1) of the leaf extracts. There was significant difference (p 0.05) in the hatchling counts of Oreochromis niloticus fed crude extract of A. indica and M. indica with complete inhibit on reproduction at 1.0 and 2.0 gkg1. Hatchling counts of crude extract of P. guajava leaf showed no significant difference (p 0.05), thought gradual decrease in the hatchling counts were observed as the concentration of the leaf extract in the diets increases. This infers that A. indica and M. indica could be used effectively to control prolific breeding associated with tilapia culture.

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