Drug Research Information Bulletin - Efficacy of 17α-Methyltestosterone Administered in Feed to Produce Predominantly Male Populations of Tilapia

Tilapia (Oreochromis spp.) can reproduce at 3-6 months of age (Green et al. 1997), and such early reproduction is the primary impediment to their commercial production (Phelps 2006). In-feed administration of the synthetic androgen 17α-methyltestosterone (17MT) to sexually undifferentiated Tilapia fry for ~28 consecutive days can produce populations composed almost entirely of phenotypic males (Green et al. 1997). Such “all-male” Tilapia populations are preferred for commercial production because reproduction is virtually eliminated and because males grow faster and more uniformly than females (Guerrero 1975).