Effect of estradiol valerate applied by immersion and oral administration on growth and sex reversal of rainbow trout, oncorhynchus mykiss

This study aimed to investigate the effects of exogenous estradiol valerate (E2V) applied by both immersion method and oral administration to produce monosex females on the growth of rainbow trout (O. mykiss). This study was conducted throughout 5 periods and 140 days. The rainbow trout fry (35 days old, post hatch) were immersed in a 400 µg L-1 of E2V solution for 2 h, twice a week for 4 weeks. Then fry were fed with a diet containing 20 mg kg-1 of E2V for 60 days. At the end of the study, E2V treatments were found to be effective for altering sex ratios of rainbow trout. Female production rate was determined as 100% in the E2V group. Results of the present study indicated that E2V reduced the growth, the food conversion rate and the survival rate of rainbow trout fry. However, it was positively effective to produce all female population of the rainbow trout. © 2005 Asian Network for Scientific Information.