The main objective of this study was to evaluate the possible synergistic effects
of Bacillus subtilis (Bs) and Chlorella vulgaris (Cv) on growth performance, feed
utilization, hematological and biochemical variables and immune response of Nile
tilapia (Oreochromis niloticus) monosex fingerlings. 210 O. niloticus fingerlings
(with an average weight of 3.55 g placed in 21 aquarium/triplicates for each
treatment) were divided into six test diets enriched with Bs (3 or 6 g per kg diet), Cv
(2 and 3 g per kg diet) or both Bs and Cv for a period of 14 weeks, in addition to a
control diet. The data showed that fish fed Bs or/and Cv had higher final body
weights, weight gains, and specific growth rates than the control group, according to
the data; the fish fed diets containing Bs and Cv had the highest growth rates. Fish
fed Bs and/or Cv had lower feed conversion ratios. Moreover, fish fed both Bs and
CV had the lowest ratio. The hematological and biochemical variables showed
significant differences between the groups with normal values. The above
demonstrates the importance of feeding (O. niloticus) monosex diets rich in B.
subtilis and C. vulgaris to improve growth performance and general health.