In the quest for sustainable aquaculture practices, reproductive control especially in farmed precocious-breeding fish remains a key challenge. This study explored the use of Acacia nilotica aqueous pod extracts and Carica papaya seed powder as natural agents for inducing sterility in male Oreochromis shiranus, while simultaneously evaluating their effects on growth performance, body composition, and safety.
Male fish were reared in tanks and hapas at LUANAR Fish Farms (Bunda), receiving diets supplemented with varying levels (0, 5, 10, and 15 g/kg) of the plant materials for 16–18 weeks. Cytotoxicity testing using the Brine Shrimp Lethality Assay revealed that A. nilotica was non-toxic (LC₅₀ = 108.95 mg/mL). Reproductive assessment showed significant reductions in gonad weight, sperm motility, and testicular integrity, with histological evidence of spermatogenic depletion and tissue necrosis at higher dosages.
While growth parameters remained largely unaffected across treatments, the 15 g/kg group demonstrated the highest specific growth rate and survival. Treated fish exhibited increased protein and ash content, with reduced fat levels, suggesting improved body composition. Residual saponin content declined from 5.03% to 1.76% within four weeks post-treatment, supporting food safety assurance.
These findings indicate that A. nilotica and C. papaya possess dual functionality—acting as effective reproductive inhibitors and nutritional enhancers—positioning them as promising natural alternatives for reproductive management in aquaculture. Further research is warranted to assess long-term physiological effects and application in female fish.