INFLUENCE OF 17alpha-METHYL TESTOSTERONE ON GROWTH PERFORMANCE AND SEX REVERSAL OF POECILIA SPHENOPS

摘要

The present attempt to reverse the sex in Poecilia sphenops through immersion in steroid solution at doses ranging 0.01 to 0.04 ug of 17 - alpha Methyl testosterone (MT) /lambda- of water for 3 hrs after hatching, induced a maximum of 80% males and 20% females. In the natural population of this species the sex ratio is (4:1) male: female. Thus during mascullinization, among the individuals that were destined to become females at the optimum treatment, about 73% transformed in to phenotypic males owing to hormone treatment, but the remaining 27% could not be masculinized and remained as females inspite of treatment at higher doses. The percentage of sex reversal was high at 0.03 concentration. The highest survival was recorded in the control and MT -1 diet (100%) where as a linear decrease in the% survival from 80-60% was observed in MX - 2 to MT - 4 diets fed fishes.