Natural production of monosex male nile tilapia fry using carica papaya extracts for sustainable aquaculture in Côte d’Ivoire

Production of Nile tilapia (Oreochromis niloticus) is constrained by early and uncontrolled reproduction in culture, leading to overpopulation and reduced growth performance. Although sex reversal using 17-α-methyltestosterone effectively produces male monosex populations, its use raises health, environmental, and regulatory concerns. In this context, Carica papaya emerges as a promising natural alternative. This study evaluated the efficacy of Carica papaya seed powders as a substitute for 17-α-methyltestosterone in sex reversal of Nile tilapia, as well as their effects on growth, survival, and water physico-chemical quality in two strains (“Bouaké” and “Brazil”). Sexually undifferentiated larvae were exposed for 28 days to five treatments: a negative control, a positive control (70 mg/kg of 17-α-methyltestosterone), and three diets containing Carica papaya (10, 30, and 50 g/kg), in triplicate. Data were analyzed using two-way ANOVA followed by Tukey’s HSD test (p < 0.05). Water physico-chemical parameters remained stable across treatments (p > 0.05), indicating no confounding environmental effects. Carica papaya powders induced significant masculinization, reaching 85-90 % males in the “Bouaké” strain and 78-82 % in the “Brazil” strain, compared with ≥ 96 % in the 17-α-methyltestosterone treatment. The 10 g/kg dose produced the best growth performance, comparable to the hormonal treatment, while higher doses significantly reduced growth. No significant adverse effects on survival or condition factor were observed. In conclusion, Carica papaya seeds constitute a credible natural alternative to 17-α-methyltestosterone for producing male monosex populations of Oreochromis niloticus, offering a relevant compromise between biological efficacy, environmental safety, and sustainability in semi-intensive aquaculture systems.