¹Mugla University, Faculty of Fisheries, Department of Aquaculture, TR-48000 Mugla - TURKEY
²Mugla University, Ortaca Vocational School, Department of Fisheries, TR-48600 Mugla - TURKEY DOI : 10.9775/kvfd.2011.5338 In this study, appropriate hormonal sex reversal procedure for the production of functional sex-reversed male rainbow trout (Oncorhynchus mykiss) brooders with intact sperm ducts was investigated. For this purpose, 4 groups of experiment were conducted. In oral administration group, free swimming larvae starting from the first feeding were fed 1.0-3.0 mg 17α-methyltestosterone kg-1 diets for 600 degree-days. In the remaining experimental groups, 0.5-1.0 mg l-1 17α-methyltestosterone, 11β-hidroksiandrostenedione or 17α-methyldihydrotestosterone were administered throughout the sac fry stage (370-560 degree-days post fertilization) as short (2 h) single, 48 h apart 2-3 or 1 week apart double baths. Results of the study demonstrated that appropriate androgen procedure for the production of functionally masculinized rainbow trout females should be covering the 470-800 degree-days post fertilization, but it could be periodic baths or periodic baths and oral administration of low concentrations, at low concentrations (≤1 mg kg-1 feed) oral administration of 17α-methyltestosterone could yield high ratios of functional sex reversed males. Keywords : Oncorhynchus mykiss, 17α-methyltestosterone, 17α-methyldihydrotestosterone, 11β-hidroksiandrostenedione, functional hormonal sex reversal