Dietary Spirulina platensis mitigates fenitrothion-induced growth retardation, hematotoxicity and immune-oxidative stress in striped catfish

Fenitrothion is a commonly used pesticide to eradicate pests in aquaculture ponds. However, it exerts toxic effects on non-target biota, including fish. The microalga ( Spirulina platensis ) may alleviate fenitrothion-mediated toxicity in fish. This investigation evaluated the efficacy of Spirulina supplementation in alleviating fenitrothion-mediated growth attenuation, hematotoxicity, immune-oxidative stress in striped catfish ( Pangasianodon hypophthalmus ). Over a 42-day trial, 240 striped catfish fingerlings (mean initial weight: 10.82 ± 1.34 g) were allocated to four triplicated trials: control (without fenitrothion or Spirulina ), fenitrothion (0.6 mg/L), Spirulina (50 g/kg feed), and a combined treatment (fenitrothion + Spirulina ). Fenitrothion exposure impaired intestinal morphology and reduced growth performance, as evidenced by decreased weight gain (10.43 ± 3.04 g), specific growth rate (0.97 ± 0.20 %/day), and an increased feed conversion ratio (1.41 ± 0.40). Besides, substantial modifications in hematology profiles were observed in fenitrothion group, including reduced hemoglobin (8.75 ± 0.79 g/dL), elevated glucose level (158 ± 7.21 mg/dL), and increased erythrocytic (cellular and nuclear) abnormalities. Oxidative and immune stress indicators were also altered under fenitrothion treatment with downregulation of SOD and CAT, upregulation of GPx; immune-related changes, including upregulation of MHC-II, IFN-β2 and downregulation of IL-1β, IFN-α2. Dietary Spirulina inclusion restored growth performance, normalized blood parameters, enhanced immune-antioxidant gene expression, and repaired gut morphology impaired by fenitrothion. These findings denote substantial recovery of physiological functions in striped catfish and reveal that dietary Spirulina is an effective approach to alleviate fenitrothion-induced physiological impairments in fish. • Fenitrothion impaired structure of intestine and reduced the growth of striped catfish. • Fenitrothion altered hematology, immune and antioxidant related gene expression. • Dietary spirulina mitigated the adverse effects of fenitrothion by improving immunity.