Tesis Medicina Veterinaria

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    Efecto de la hormona 17-alfa-metil-testosterona en la reversión sexual en alevines de tilapia (Oreochromis niloticus)
    (2025-08) Villacrés Taco, Jonathan Humberto; Guerrero López, Jorge Ricardo
    The present investigation aimed to evaluate the effect of the hormone 17-alpha- methyltestosterone on sex reversal in black tilapia (Oreochromis niloticus) fry. The study included three doses of hormone (60, 80, and 100 mg/kg) administered in the feed from the fifth day of birth for two application periods (21 and 28 days) along with a control group without hormone application. The experimental trial was based on a completely randomized design (CRD) replicating each treatment three times and integrating a total of 525 fish. Variables related to growth performance were analyzed in terms of fry weight and length, sex reversal percentage, mortality, and survival. An economic analysis was also carried out through the study of the cost-benefit ratio. The results of the study reported significant differences in final weight, length and percentage of sexual reversal, particularly with the treatment that combined 80 mg / kg for 28 days (T2), where it achieved better growth (90.52 g and 14.17 cm) and the highest masculinization rate (84%). However, it presented a mortality rate (16%) and survival (84%), in contrast to 21 days, where lower mortality (5%) and higher survival (95%) were observed. Finally, the economic analysis revealed that, although T2 had higher costs in feed and hormones, it offered a favorable cost-benefit ratio (1.21) and high net returns, followed closely by T3 (100 mg / kg), which reported a slightly lower profitability index (1.18) in addition to a lower biological performance and the control treatment (T0) for its part reported a better cost-benefit ratio, however, in productive terms it turned out to be the most deficient. Treatments with higher doses (100 mg/kg) showed reduced economic returns despite acceptable biological responses