The masculinizing effects of three synthetic androgens, 19-nor-ethynyltestosterone (100–
500 mg/kg food), 17α-ethynyltestosterone (100–500 mg/kg food), 9 (11) …

Abstract Treatment of newly born Poecilia sphenops (Cuvier & Valenciennes, 1846) with 50
mg 17α‐methyl‐testosterone or 200 mg androstenedione per kg diet for 30 days induced a …

Monosex populations of fish are often desirable as a method to control reproduction and to
take advantage of sex-linked differences in growth rates. Administration of exogenous …

The masculinizing effects of U-ketotestosterone, a potent natural androgen produced in
teleosts, were determined in the guppy, Poecilia reticulata, using all-female broods obtained …

A YY-female Poecilia reticulata was produced by endocrine sex reversal followed by
progeny testing. Heterogametic females (XY) produced by endocrine sex reversal were …

Newly born guppies were fed various concentrations of methyl testosterone for the first 60
days after birth in an attempt to direct the sex of fish. The treated fish had lower growth rates …

Results Mature male guppies of the present variety are normally dressed with several
orange red spots on both sides of the trunk and caudal peduncle. The pigmentation is …

The effects of two synthetic androgens, 17α‐methyltestosterone (5–50mg/kg food), 19‐nor‐
ethynyltestosterone (2–50 mg/kg food) and two natural androgens, 11 ketotestosterone (10 …

The effects of different dose rates of synthetic androgen 17-alpha methyltestosterone (MT) ie
30, 60, 100, 150, 200 and 300 mg of MT per kg of feed on masculinizing, mortality rate and …

Synthetic androgens are often considered to be more potent than natural androgens for sex
reversal treatments in fish. Preliminary experiments on the natural androgen. 118 …