Dietary supplementation of Spirulina ameliorates iron-induced oxidative stress in Indian knife fish Notopterus Notopterus

Abstract

Iron though an essential cofactor for many proteins including haemoglobin and cytochromes, when in excess (>1 ppm in water and 100 ppm in fish tissue) elicits toxicity via Fenton reaction inducing oxidative stress. The present study aimed to evaluate the efficacy of dietary Spirulina (Arthrospira platensis) supplementation on waterborne-iron induced oxidative stress in the tissues of Notopterus notopterus. Juvenile fishes were divided randomly into 4 groups, namely, Group-I: control fed with commercial diet only, Group-II, III and IV treated with 0.75 ppm FeCl3 where Group-II fed with commercial diet only, Group-III with 10% (w/w) Spirulina supplemented commercial diet and Group-IV with 100% (w/w) Spirulina diet only; for 7 and 28 days (n = 6 per group). Tissue oxidative stress biomarkers like lipid peroxidation (LPx), protein carbonylation (PC) and protein thionylation (protein and nonprotein-SH content); antioxidant defence (superoxide dismutase: SOD; catalase; CAT; glutathione peroxidase/reductase: GPx/GR; glutathione s-transferase: GST; metalothionine: MT and reduced glutathione: GSH) and iron accumulation in the gill, liver and muscles tissue were analysed. The augmented oxidative predominance in the tissues with respect to LPx and PC along with decline in antioxidant defence (SOD, CAT, GPx, GR, GST, MT, PSH, NPSH and GSH) by iron was neutralized by Spirulina supplementation in the diet in a dose and duration dependent manner where 100% Spirulina diet for 28 days completely ameliorated iron-induced oxidative stress in fish tissues. Thus, Spirulina can be used as a dietary supplement for fishes cultured in water bodies with iron overload.