The treatment groups fed with dietary andrographolide (EC
50%) showed significantly enhanced resistance against
A. hydrophila infection. This might be due to activation and
enhancement of the non-specific immune system of experimental
fish by andrographolide (EC 50%). Similar results in L. rohita fed
with diets containing Mangifera indica kernel showed higher relative
percentage survival after challenging with A. hydrophila [55].
Similarly, tilapia (O. niloticus) fed with two Chinese medicinal herbs
[17] and ethanolic extracts of Psidium guajava [71]; and also in
C. auratus fed with azadirachtin [22] showed higher RPS after
challenged with A. hydrophila.