EFFECT OF SUPPLEMENTAL TRYPTOPHAN IN DIET ON GROWTH AND SURVIVAL RATE OF MUD CRAB Scylla serrata DURING NURSERY
The main constrain in mud crab culture is high cannibalism which are triggered by several factors such as limited space, lack of feed and large size variation. Mud crab also has relative slow growth when fed artificial diet. Tryptophan is an essential amino acid for growth and frecursor of serotonin which can control natural aggressiveness in vertebrates. This study was conducted to evaluate the effect of supplemental triptophan in formulate diet on growth and survival rate of mud crab during nursery.
Five tested diets were formulated to contain different levels of supplemental L-tryptophan at: 0% (D0), 0.25% (D0.25), 0.5% (D0.5), 1.0% (D1.0) and as the control diet was dried mysid. Crablets (3-5 days post-methamorphosis) with average initial weight of 0.039 g were randomly distributed into 15 of 1,0×1,0×0,5 m3 fibre glass tank with density of 50 ind./tank. The crablets were fed daily the test diets at 30 to15% of biomass.
After 5 weeks feeding trial, crablet fed the diet with 0.5% tryptophan supplement (total content in diet was 0.67%) had significantly (P<0.05) higher weight gain compared to crablet fed diet without supplemental triptophan. Highest protein efficiency ratio was also obtained in crablet fed the D0.5 and significantly different (P<0.05) with crablet fed dried mysid (control). Final carapace width, feed conversion ratio, and survival rate were not significantly different (P>0.05) among the treatments. Crablet of mud crab could accept and utilize the artificial diet for grow during the nursery.