The current study evaluated the effects of nano
delivery of Spirulina platensis on growth performance,
digestive enzymes, and biochemical, immunological, and
antioxidative status, as well as resistance to Aeromonas
veronii and some physical stressor challenges in Nile tilapia,
Oreochromis niloticus. Three experimental fish groups (n =
270) with mean weights of 26 ± 0.30 g and mean lengths of
10 ± 0.5 cm were used; the first additive-free basal diet
served as the control group, whereas the following two
groups were supplemented with spirulina nanoparticles
(SPNP) at 0 (control), 0.25, and 0.5%/kg diet for 4 weeks.
Following the feeding trial, fish were challenged with hypoxia, cold stresses, and pathogenic bacteria (A. veronii)
infection (9 × 108 CFU/ml). SPNP supplementation, especially 0.5%, (p < 0.05) significantly increased growth
performance (specific growth rate % day−1
, feed conversion
ratio, and length gain rate %), immunological (plasma lysozyme and liver nitrous oxide) antioxidants (superoxide dismutase, catalase, and glutathione peroxidase in liver), biochemical (aspartate aminotransferase, alanine transaminase,
glucose, and cortisol concentrations in plasma) assays, and
digestive enzymes (lipase and amylase in plasma). The
expression of liver’s heat shock protein 70 (HSP70) and
interleukin 1, beta (IL-1β) genes showed a significant upregulation outline of 0.5% SPNP > 0.25% SPNP > 0%
SPNP compared with the control. Protection in the incorporated fish groups exposed to A. veronii was 100% compared
with the control group, which showed 50% cumulative
mortalities. In conclusion, dietary SPNP supplementation
improved growth performance, antioxidant activity, immune response, digestive enzymes, related gene expression,
and resistance of Nile Tilapia to hypoxia, cold, and
A. veronii infection. Thus, SPNP could be used as a natural
therapy for controlling those stressors