Altered sex ratio in giant fresh water prawn, Macrobrachium rosenbergii (de Man) using hormone bioencapsulated live Artemia feed

Artemia nauplii cultured for 24 h in lipid-enriched media contained 0, 0.38, 1.67, 0.79, 5.71 and 5.14 ng 17(alpha)methyl testosterone (MT) mg^-1 dry weight for the control, 5, 15, 30, 50 and 100 mg of 17(alpha)-MT L^-1 of media respectively. Giant fresh water prawn Macrobrachium rosenbergii larvae were fed hormone-enriched Artemia nauplii for 50 days. A significant difference in sex ratios (0.92, 0.69 and 0.93) was obtained in relation to the control group. These results suggest that further research is needed with regard to standardization of doses and duration of treatments for complete hormonal control of sex differentiation in M. rosenbergii.