Effect of thyroxine immersion on larval survival, growth and postlarvae production of freshwater prawn, Macrobrachium rosenbergii (de Man).

摘要

In this study, 5-day-old M. rosenbergii postlarvae (PL) were placed in 3-litre baths containing 0 (control), 0.01, 0.10, 1.00 or 2.00 mg/litre thyroxine (T4) once a week for 2 h. There were no significant differences in survival between treatments, except for final survival at the end of the study. Larvae in the 200 mg/litre treatment had the highest mean developmental stage (MDS) growth rate. All control and hormone replicates for 0.01 and 0.100 mg/litre T4 were harvested within 34-35 days when they reached 80% PL production, while 1.00 and 2.00 mg/litre treatments were harvested at 38-39 days of culture. Survival and PL/litre were significantly higher in the 2.00 mg/litre. These results show that T4 enhances the growth, survival and PL production but does not promote early metamorphosis to shorten the larviculture period of M. rosenbergii..