Journal of Fisheries Science and Technology

Journal of Fisheries Science and Technology

Oral administration of 17α-ethynylestradiol for feminization of Nile tilapia (Oreochromis niloticus) of the GIFT strain and evaluation of its effects on biological performance indices

Document Type : Original Research

Authors
Behrooz Mokhtari 1
MOHAMMADREZA KALBASSI 1
MOrteza Alizadeh 2
1 Department of Fisheries, Faculty of Natural Resources and Marine Sciences, Tarbiat Modares University, Mazandaran, Iran
2 Iranian Fisheries Sciences Research Institute
10.48311/jfst.2025.79574.0
Abstract
Male tilapia typically exhibits faster growth rates than females. The production of supermales (YY genotype) is a key strategy for generating all-male populations for aquaculture purposes without the direct use of hormones in marketable fish. In this study, the feminization of GIFT strain tilapia was investigated using dietary administration of 17α-ethinylestradiol (EE₂) at doses of 0, 50, 100, and 175 mg/kg of feed. This feminization step represents the first phase in the production of supermales and aims to generate phenotypic females with an XY genotype. The effects of hormone administration on key biological indices were assessed. Based on the results, the highest feminization rate, evaluated through gonadal squash analysis, was obtained at the 175 mg/kg dose, reaching 22.83% ± 0.29. The highest final body weight was observed in both the control group and the 175 mg/kg treatment. Feed conversion ratio (FCR) was improved in all hormone-treated groups compared to the control, with no significant differences among the treatment groups. Survival rates were higher in all hormone-treated groups relative to the control, with the best performance observed in the 50 and 100 mg/kg treatments.

Highlights

 

Keywords
Tilapia
Supermale
Feminization
Hormonal therapy
Sustainable aquaculture

Subjects