which reported positive
effects on hematological parameters. On the other hand, O. niloticus
fed diet supplemented with B. subtilis (Soltan and El-
Laithy, 2008) or supplemented with Pediococcus acidilactici
(Ferguson et al. (2010) showed some variation (but not significant)
in Hb and Ht contents among the control and fish that
were fish groups fed diet enriched with probiotics.