Dietary administration of dehydroepiandrosterone hormone influences sex differentiation of hybrid red tilapia (O. niloticus x O. mossambicus) larvae
scialert.net Abstract
Effects of a steroid hormone Dehydroepiandrosterone (DHEA) on sex differentiation of hybrid red Tilapia Oreochromis niloticus x O. mossambicus larvae were investigated. Three day-old tilapia larvae were fed diets supplemented with varying concentrations of DHEA (0, 20, 40, 80 and 160 mg kg-1 feed) for 24 days. A positive control group fed with diet containing 60 mg kg-1 of 17α-methyl testosterone was also included in the experimental run. Results indicate that among the DHEA treatment groups, larvae fed with 160 mg kg-1 DHEA showed the highest percentage of males that is comparable to the number of differentiated male fish observed in treatment group receiving the 17α-methyl testosterone as the positive control group. DHEA supplementation also improves weight gain and enhances feed conversion ratio. These findings suggest that DHEA can be used as a dietary supplement to induce masculinization and can improve the growth performance of tilapia larvae.
Citation
Mohamed, A. H., Traifalgar, R. F. M., Serrano Jr., A. E., Peralta, J. P., & Pedroso, F. L. (2012). Dietary administration of dehydroepiandrosterone hormone influences sex differentiation of hybrid red tilapia (O. niloticus x O. mossambicus) larvae.Publisher
Academic Journals, New YorkSubject
Acknowledgment/Sponsorship
This study was funded and supported by the Ministry of High Education and Scientific Research, Training and Extension Department through the efforts of Sudan University of Science and Technology-Sudan, under Scholarship Grant Permit No. 156/17A/5A/2009-2012.
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Article
Induction of sex inversion in juvenile grouper, Epinephelus suillus, (Valenciennes) by injections of 17α-Methyltestosterone
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Article
Possible application of mibolerone for induced sex inversion of grouper Epinephelus coioides
-Fisheries Science , 2001 - Japanese Society of Fisheries ScienceThirty immature juvenile grouper Epinephelus coioides (19-168 g bodyweight, BW) were randomly stocked in four units 6 t tanks to determine if mibolerone can be used to induce sex inversion in groupers. After acclimatization and weaning to artificial feed, the feed given daily (4% BW/day) was supplemented with 0, 50, 100, and 200 μg mibolerone/kg feed for about 18 weeks. Thereafter, the hormone treatment was withdrawn and the experiment was terminated at Week 24. Ten fish were killed for gonad histology at stocking to serve as an initial control while about three to five fish were killed every 8 weeks. In general, ovaries of initial controls showed the presence of moderate stromal cells and gonia and few primary oocytes. At Weeks 8 and 16, ovaries of the control fish (0 μg/kg) were similar to that of the initial control except that primary oocytes increased at Week 24. Gonads of fish fed diets containing 100 and 200 μg/kg had none to moderate spermatocytes and few spermatids at Week 8 and 16, although spermatozoa were not observed, indicating that the fish were undergoing spermatogenesis. Spermatogenesis at 50 μg/kg was not as advanced since only few spermatocytes occurred at Weeks 8 followed by moderate gonia and no spermatocytes and spermatids at Week 16. However, the presence of few primary oocytes was observed when mibolerone was withdrawn suggesting that sex-inversed fish reverted back to a female condition. These results show that sex inversion in juvenile grouper can be induced by oral administration of mibolerone and may have possible application on mature females to produce functional males.
