الفهرس 
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Abstract
Production of all males Nile tilapia tOreochromis niloticus) by honnone
sex reversal was studied. Effective hormone doses to produce 1000/0 males
at different durations of treatment was estimated. All males sex reversed
Nile tilapia were produced on either experimental (laboratory) and large
commercial scales by feeding 17 alpha methyl testosterone to swim-up fry (9-
13 mm long). Field work was conducted in a closed water recycling intensive
fish farm (5000 ton/year design capacity).
Growth performance expressed as weight gain percentage and feed
conversion ratio was evaluated for both sex reversed and control mixed sex on
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both the laboratory and field levels. Lower growth performance was recorded
among fry during hormone treatment for sex reversal. Reduced growth
performance was both dose and duration dependent. Better levels of growth
performance were recorded for the sex reversed fingerlings and on growing
fish.
Mortality levels were evaluated for both the sex reversed and control
mixed sex group at different life stages (fry. fingerlings and on growing fish).
Higher levels of mortality were recorded among fry during and shortly after
hormone treatment for sex reversal. Lower to slightly lower levels of
mortality was recorded among the sex reversed fingerlings and fish than
control.