The challenge infection revealed a significantly lower mortality percentage in the group received 10 g/kg S.
platensis in diet for the 1, 2 and 3 months feeding trial and significantly high relative level of protection (RLP)
after challenge infection using P. fluorescens. The disease challenge is an in vitro technique provides an
opportunity to determine the performance and immunity of the fish species ebon exposure to xenobiotic (bacteria)
on their natural habitats (AraKoosh et al., 2009). The results were in accordance with Watanuki et al. (2006) who
recorded an increased resistance of S. platensis treated carp ebon artificial challenge with A. hydrophila than the
control group. Abdel-Tawwab and Ahmad (2009) found that SP has a useful impact on fish as
immuno-stimulants, they recorded that tilapia fed 5-10 g fresh S. platensis /kg diet increased its resistance
against A. hydrophyla.