Masculinization of Zebra Cichlid (Cichlasoma nigrofasciatum) with Oral Treatment of 17Alpha-Methyl Testosterone and the Effects on Mortality Rate, Sterilization and Mixed Sexual Fish

Subject Areas : Marine Biology

S. H.  Mosavi Sabet ¹ (Islamic Azad University, Science and Research Branch Tehran)
A.  Zamini ² (Islamic Azad University, Lahijan Branch)
H.  Vahab Zadeh Rodsari ³ (Islamic Azad University, Lahijan Branch)
Z.  Morad Khani ⁴ (Islamic Azad University, Science and Research Branch Tehran)

Received: 2010-08-30 Accepted : 2010-11-10 Published : 2010-12-21

Keywords: Testosterone, Cichlasoma nigrofasciatum, Masculinization, Zebra Cichlid, 17alpha-methyl,

Abstract :

In this study production of a monosex Zebra Cichlid Cichlasoma nigrofasciatum population was studied. Cichlids fries (7 days) were fed with six different hormonal doses 30, 60, 100, 150, 200 & 300 mg 17alpha-methyl testosterone/kg diet for 40 days. The hormone was added to food by alcohol dry method. During the test, fish were kept in 28±1 in temperature, 7.5 to 8.3 in pH and less than 170±10 mg/lit in water hardness. Fish were fed 6 times, from 6 am to 11 p.m. Results showed that the male numbers obtained in all treatments were more than the control group, and the dose of 100mgMT/kg food was more efficient in sex reversal than others, resulting in all males (P<0.05). Histological results showed dose of 300mgMT/kg food was more efficient in sex sterilizing than the others, resulting in 97.6% (P<0.05). 300mgMT/kg food increased mortality rate to 37.5% (P<0.05). 30mg MT/kg food increased mixed sexual to 8.8% (P<0.05). Hormonal sex reversal is a good method to produce mono sex fish population and limits unwanted breeding.