The current work intended to inspect the hepato-nephrotoxicity of gibberellic acid (GA3) in juvenile of
Oreochromis niloticus as well as the possibility of restoration after dietary addition of different concentrations of
Spirulina platensis (SP). Fishes were evenly assorted into five groups: Group I assigned as control, Group II fed on
basal diet and exposed to 150 mg/L gibberellic acid (GA3). The 3rd, 4th, and 5th groups exposed to150 mg/L
gibberellic acid (GA3) and previously fed for two months on SP supplemented diets at levels of 5, 20, and 100 g/
kg, respectively. Fish serum were utilized to check glucose, total protein, hepatic and renal functions, enzymatic
and non-enzymatic antioxidants activities (superoxide dismautase; SOD, catalase; CAT, and total antioxidant
capacity; TAC) as well as histopathological alterations in liver and kidney. The results showed that creatinine,
uric acid, liver enzymes, glucose, total protein, SOD, and CAT were significantly elevated in GA3-treated group.
Liver of GA3-treated fish manifested some histopathological changes (hypertrophy, cytoplasmic vacuolization,
and apoptotic cells with pyknotic nuclei, necrosis, dilated blood sinusoids, and lymphocytic aggregation around
the central veins). Kidney of GA3-exposed fish revealed edema of the epithelium lining of some renal tubules and
some showed vacuolar degeneration and dissociation. Hypertrophy in the glomerulus was observed with dilated
blood capillaries. SP supplementation restored these biochemical, antioxidants, and histological changes near to
control levels. This improvement was higher with 100 g/kg SP showing concentration dependency. According to
this study we can conclude that SP supplementation can improve the hepato- and nephrotoxicity caused by GA3
exposure indicating its role as potent antioxidant food additive.