The results revealed that there was
15 mm zone of inhibition. The extracts were reported to be rich in marine
bioactive natural products which are used for the treatment of bacterial
infection since it does not cause any toxic effects to the fishes
when dispersed in the aquatic environment. The ethanol extract of the
red seaweed Gracilaria fisheri is not toxic to the shrimps, and that it
might be a possible alternative for prevention and treatment of shrimp
vibriosis caused by Vibrio harveyi (Kanjana et al., 2011It also enhanced
the physiological and immunological defense mechanisms as shown by
significant increase in the total number of hemocytes and an increased