Hormonal induction of sex reversal and progeny testing in the zebra cichlidCichlasoma nigrofasciatum

✍ Scribed by George, T.; Pandian, T.J.

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 763 KB
• Volume: 275
• Category: Article
• ISSN: 0022-104X
• DOI: 10.1002/(sici)1097-010x(19960801)275:5<374::aid-jez6>3.0.co;2-m

✦ Synopsis

Hormonal sex reversal was induced in the ornamental cichlid C. nigrofasciatum by dietary administration of estradiol-P or 17a-methyltestosterone. The treatments involving 200 mg estradiol-P and !ZOO mg 17a-methyltestosterone/kg diet for 20 days in the 4-day posthatchling C. nigrofasciatum resulted in 100% feminization and 82% masculinization, respectively. Superoptimal doses led to higher mortality and stunted growth, especially among the surviving males, which resisted feminization. Progeny testing of the feminized and masculinized individuals indicated that sex was determined by XX and XY (male heterogamety) sex chromosomes; however, the role played by autosomes in these individuals was also apparent. Live homogamous males (YY) could not be produaed. Progeny testing further showed that hormonal treatment impaired growth and reproductive performance of the sex-reversed females and males. F1 progenies sired by the sex-reversed females as well as males also suffered higher mortality, extended interspawning period and lower fecundity. @ 1996 Wiley-Liss, Inc.