Testosterone nanoemulsion produced masculinized Nile tilapia (Oreochromis niloticus).

The objective of this work was to develop a food additive for the sex reversal of Nile tilapia (Oreochromis niloticus) based on a simple oil in water (O/W) nanoemulsion with testosterone propionate for incorporation into commercial feed. Oil screening and evaluation of the organoleptic and physicochemical characteristics were carried out to determine the best formulation. A palatability test was also performed. Sex reversal test was assayed using 5 experimental groups: negative control - macerated feed without hormone; free testosterone - macerated feed with 60 mg/kg of testosterone propionate diluted in ethanol; and macerated feed with testosterone propionate nanoemulsion at a concentration of 30, 60, and 90 mg/kg. Stable nanoemulsions (size 76-210 nm) with testosterone propionate were produced. All nanoemulsion-added feed was palatable to tilapia. We obtained sex reversal values of ≈65, 75, and 72% in the groups of 30, 60, and 90 mg/kg, respectively. We can conclude that the nanoemulsion showed promising results; it is capable of inducing sex reversal in tilapia, is suitable as a commercial product, and has the potential to promote safety for rural staff and reduce the environmental impact of hormones.