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Masculinización de Xiphophorus helleri (Pisces: Poecilidae) inducida por los esteroides norgestrel y androstenediona

1999; Universidad Autónoma Metropolitana; Volume: 9; Issue: 1 Linguagem: Inglês

2448-7333

Samuel Marañón Herrera, Eduardo Maya Peña, Héctor Salgado‐Zamora,

Genetic and Clinical Aspects of Sex Determination and Chromosomal Abnormalities

The masculinization efficiency of the steroids norgestrl and androstenedione (19-NAD) on 5 day old Xiphophorus helleri juveniles was analyzed. Fish were treated at doses of 30 and 50 mg of steroid per kg of food, during 60 days period. After 0 days a second analysis was carried out in order to evaluate steroid residual effect on the fishes. Results indicated a 100% masculinized in induced by both steroids, as compared to the control group, which showed a 95.4% of females population. A survival factor in the range 80-84.4%, indicated that norgestrel had no apparent damage on the fish. Survival in the control group was 80% and 68.8-71.1% for those fish receiving 19-NAD treatment- Growth measurements indicated that control females had a largest body and were weightiest that the treated organisms. Norgestrel residual effect disminished the survival factor to 52.6-58.3% and the masculinization percentage to rage 65-76.2%, and favored the presence of females and intersex organisms which were males in the first phase. It is concluded, in spite of this norgestrel shows better androgenic activity at 30 mg per kg of food.