The motile Aeromonas hydrophila affects a wide
variety of freshwater fish species and occasionally marine
fish (Larsen and Jensen, 1977). The disease caused by this
bacterium primarily affects freshwater fish such as catfish,
several species of bass and many species of tropical
ornamental fish. It is a normal inhabitant of the
gastrointestinal tract. A. hydrophila cause infections in fish
and its infections generally leads to surface lesions,
sloughing of scales, local hemorrhage, and septicemia
(Austin and Austin, 1999).
The present study investigated the effect of
L. plantarum and B. megaterium as probiotic bacteria on
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the growth and immune responses against A. hydrophila
in the Indian major carp, Catla catla