THE EFFECT OF 17a-METHYLTESTOSTERONE AND 11b-HYDROXYANDROSTENEDIONE ON THE DEVELOPMENT OF REPRODUCTIVE SYSTEM IN RAINBOW TROUT (ONCORHYNCHUS MYKISS WALBAUM)
Krystyna Demska-Zakęś*, Piotr Hliwa*, Paweł Matyjewicz*, Zdzisław Zakęś**
*Warmia and Masuria University in Olsztyn
**The Stanisław Sakowicz Inland Fisheries Institute in OlsztynABSTRACT. The effects of 17a-methyltestosterone (MT) and 11b-hydroxyandrostenedione (OHA) applied in feed for 56 days on the development of reproductive organs of rainbow trout, Oncorhynchus mykiss (Walbaum), were studied. It was observed that OHA was very effective in fish sex reversal. Treatment with 20 ppm of this hormone for 8 weeks resulted in 100% male population with correctly developed testes. Application of a lower dose (5 ppm) resulted in sex reversal in 30% of fish (80% of males). The same dose of MT produced lower sex reversal level (70% of males). Higher doses of this hormone or longer treatment period resulted in fish sterilization.
Key words: RAINBOW TROUT, ANDROGENS, SEX REVERSAL