Thesis (M.Sc.)--Chulalongkorn University, 2011

The giant freshwater prawn Macrobrachium rosenbergii is an economically important cultured species in Thailand. Early maturation of female prawn caused restrict on growth. In this study, female prawn was used to study effect of farnesol on spawning and growth. Farnesol used in a representation of the MF was initially encapsulated with farnesol/ alginate by 1:0.67 ratios. The overall encapsulation efficiency at before and after freeze-dried processes was 82.6±1.21 % and 83.41±0.23 %, respectively. After freeze drying farnesol capsules were extracted and analyzed. The recovered farnesol was 63.8±0.66 %. One hundred and eighty matured female giant freshwater prawn with average body length 10 cm were obtained from a local farm. Fifteen prawn were reared in close re-circulated water system amount 375 L per culture tank and fed 3 times/day at amount of 5% total body weight for 8 weeks. The tested diets were 0, 0.5, 1 and 2 g farnesol per 100 gram diet. The result showed that farnesol 2 g/ 100 gram diet decreased egg weight and percent number of female spawns and shortened the molting duration. Significantly reduced the egg weight from 2.01 ± 0.32 g to 1.07 ± 0.19 g and shortened the molt duration at 15.92 day.