EFFECTS OF DIETARY VITAMIN C SUPPLEMENTATION ON GROWTH, SURVIVAL AND DISEASE RESISTANCE IN GIANT FRESHWATER PRAWN, MACROBRACHIUM ROSENBERGII (DE MAN)

摘要

Five isonitrogenous and isocaloric diets were formulated incorporating 'C-care', containing 55% stabilized vitamin C, and fed daily for 135 days to Macrobrachium rosenbergii juveniles (av. wt. 0.7 g) stocked at the rate of 60 in 25 m3 cement tanks. The five diets T0, T,, T2, T3 and T4 were supplemented with 0, 500, 1000, 2000 and 3000 mg C-care/kg diet respectively. On analysis, the diets contained 62.12, 370.80, 698.40, 1460.58 and 1994.04 mg vitamin C/kg diet. The water quality parameters monitoredwere within acceptable limits for M. rosenbergii farming. Growth, survival, yield and food conversion were the best with prawn fed 2000 mg C-care/kg diet, only survival and yield being significantly (P<0.05) different. Prawns receiving vitamin C supplemented diets displayed resistance to Aeromonas hydrophila. Results of this trial indicate that vitamin C at 1460 mg/kg diet induces higher growth and survival of M. rosenbergii juveniles, while 1994 mg/kg diet results in better disease resistance. However, considering the leaching loss, the effective dose consumed by prawns would be much less.