2025/09/15 by Chris Jan P. Dinaga, Ande Bryle N. Genciana, Alan N. Failaman +6 · 1 voice · 1 citation
Biochemistry, Genetics and Molecular Biology · Environmental Science · #Fish Ecology and Management Studies #Genetic and Clinical Aspects of Sex Determination and Chromosomal Abnormalities #Reproductive biology and impacts on aquatic species
paper · pdf · doi:10.3897/aiep.55.161420
openalex publication_date 2025/09/15 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/02
Application of feminization techniques using estrogen hormones can be relevant in cases where there is an insufficient supply of female stock for broodstock production. This study aimed to evaluate the feminization efficiency (FE) of 17β-estradiol (E2) at various concentrations using two different methods applied to the saline-tolerant SpiN ( Oreochromis spilurus × O. niloticus ) tilapia hybrid developed by the University of the Philippines Visayas (UPV). E2 concentrations of 0, 50, 100, and 200 mg · kg –1 were orally administered through dietary supplementation for 28 days (d) to one batch after yolk-sac absorption. Another batch, still with yolk-sacs, was immersed in E2 solutions at concentrations of 0, 50, 100, 200, and 400 µg · L –1 for 5 d. Soft dorsal fin tissues from phenotypically identified female tilapia were collected upon sexual maturation and processed for DNA extraction, PCR, and gel electrophoresis to determine the genotype. Selective removal of the first six dorsal spines was conducted to generate up to 63 unique codes for temporary fish identification. Treatments 2 (50 mg · kg –1 ) and 3 (100 mg · kg –1 ) resulted in the highest FE for dietary supplementation at 94.74% and 95.24%, respectively, while feminization through larval immersion was observed only in Treatment 3 (100 µg L −1 ) at an efficiency of 16.67%. Neither feminization method significantly affected the survival of the fish. These results demonstrate that dietary supplementation with 50–100 mg · kg –1 of E2 is an effective and reliable method for feminizing UPV SpiN tilapia hybrid. PCR-based genotyping confirmed the conversion of genetic males (XY) into phenotypic females. This approach offers a practical strategy to enhance broodstock management, particularly in the development of all-female stocks for breeding. Future studies should focus on evaluating the growth and reproductive performance of sex-reversed individuals for long-term broodstock viability.