Effects of immersion based Proanthocyanidin treatment on the masculinization of betta fish (Betta splendens)

Betta splendens, commonly known as the Siamese fighting fish, is a highly esteemed ornamental species noted for its vibrant coloration and gentle disposition. Given rising concerns regarding the ethical and environmental implications of synthetic hormones for sex reversal, this study explored the use of an eco-friendly, plant‐derived aromatase inhibitor Proanthocyanidin, extracted from grape seeds for sex manipulation via immersion techniques. Fish underwent discrete immersion treatments at concentrations of 250, 500, and 750 μg/l for three hours daily on the third, fifth and eighth day post-hatching, while 17α-methyltestosterone (17α-MT at 40 mg/kg) was used as a positive control throughout both experimental phases. Results indicated that the 750 μg/l Proanthocyanidin treatment yielded the highest male conversion rate (70.37%) along with an impressive post-treatment survival rate of 90.00%, compared to a survival rate of 76.66% in the 17α-MT control group. Histological analyses further revealed a suppression of atretic oocyte formation and an increased presence of immature oocytes in both the 17α-MT and high-dose Proanthocyanidin (750 μg/l) groups.