To investigate the ability of Zingiber officinalis (Z. officinalis) and Cyanodon dactylon (C.
dactylon ) supplementation to antagonize the stressful pH condition on Macrobrachium rosenbergii (M.
rosenbergii) juveniles, three groups each of 40 Juveniles in two replicates fed diets supplemented with
1.5 % Z. officinalis and 2 % C. dactylon were exposed to pH 9.5 for 5 weeks. Juveniles exposed to high
pH and fed with Z. officinalis and C. dactylon had significant increase (p< 0.05) in Average Body
Weight (ABW), Average Body Length (ABL), Specific Growth Rate (SGR), Condition Factor (CF),
Weight Gain Rate (WGR), Length Gain Rate (LGR) and Feed Conversion Ratio (FCR) compared with
those of control along the whole experiment. Juveniles exposed to high pH and fed Z. officinalis and C.
dactylon had significantly higher (p< 0.05) Total Hemocyte Count (THC), Hemocyte Viability (HV),
Differential Hemocyte Count (DHC), Phagocytic Rate (PR) and Phagocytic Index (PI) as compared
with control at 4 and 5 weeks from the start of feeding. Microscopically, hepatopancreas and stomach
of Z. officinalis and C. dactylon fed juveniles showed no marked alterations. According to the present
study, it could be conducted that Z. officinalis and C. dactylon were effective in controlling the pH
stress in M. rosenbergii.