The physicochemical
parameters of water such as temperature (24.3e
25.8 C), pH (7.2 0.4), dissolved oxygen (6.6e6.9 mg L1),
ammonia (0.01 0.005 mg L1), nitrate (0.02e0.06 mg L1) and
nitrite (0.001e0.004 mg L1) were maintained in optimum condition
during the experimental period. Six fish were sampled from
each treatment group on 14th, 28th and 42nd day and blood was
drawn for different immunological assays. After 42 days, nine fishes
from each treatment were segregated for challenge study particular
injection with A. hydrophila and post challenge study was
continued up to 56 days. At the end of 56 days, growth parameters
and relative percentage survival rate were estimated for disease
resistance against A. hydrophila.