Use of 17-α-methyltestosterone for production of male secondary sexual characteristics in the adult female green swordtail (Xiphophorus hellerii).
Journal Title: Aquaculture, Aquarium, Conservation & Legislation - International Journal of the Bioflux Society - Year 2010, Vol 3, Issue 1
Abstract
The green swordtail X. hellerii Heckel, 1848 is a commercially important ornamental species. As phenotypic males with the sword extension of the caudal fin are more valuable economically than fish lacking the sword, masculinization by means of 17-α-Methyltestosterone (MT) was tested. Populations of female broodstocks were fed MT-treated feeds (20, 35 and 50 mg MT kg-1 feed) at a rate of 50 g of MTtreated feed per kilogram of fish biomass (5% body weight [BW]) for 45 consecutive days to cause development of male secondary sexual characteristics, specifically the growth of the sword extension. Use of MT feed at 5% BW for 45 d resulted in 100% masculinization, whereas 0% masculinization occurred in green swordtails fed control feed. There were no significant differences between MT-treated groups in the proportion of phenotypic males. Also we found no significant differences in mortality among experimental groups. No degeneration of swords was seen 200 d after the last day of experimental feed treatment. According to our finding, the use of MT-treated feeds can increase the production of highervalue phenotypic male green swordtails and enhance profitability for aquaculturists.
Authors and Affiliations
Jamshid Amiri-Moghaddam, Fateme Maniei, Nasrollah Mahboobi-Soofiani, Saeed Asadollah
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