To gauge the utility of galangal extract when used in a shrimp aquaculture, this study examined the effect of the
oral administration of galangal extract on shrimp growth and survival rates, as well as the anti-microbial effect
against V. harveyi and WSSV. As shown in Table 1, a 1-month feeding of galangal extract lowered the growth
rate of shrimp. However, following 2 months of feeding, the growth rate was recovered and the shrimp showed
no significant difference in growth rate, SGR or the survival rate between the galangal diet group and the control
diet group. We could not measure the feeding amounts, because galangal was dispersed during feeding. However,
the results suggest that the lower growth rate in the first month feeding trial might have been caused by the
reduced consumption of an unfamiliar diet with a strong smell. The galangal diet should be improved with a
smell that will be more attractive for shrimp, and a feeding period of at least 2-months is necessary to allow
shrimp to acclimate to a galangal diet.
The galangal diet group showed a higher ability for the clearance of bacteria from the hemolymph at 3 h
post-injection of V. harveyi. As the number of bacteria in the hemolymph decreased, the survival rate was
enhanced in the galangal diet group compared with that in the control groups. This study also demonstrated the
anti-viral activity of galangal extract and a significantly higher survival rate from WSSV infection for the
galangal diet group. These results indicate that shrimp aquaculture could become more profitable with the
suppression of infectious diseases through the use of galangal extract diets. This research introduces the use of