Spectral profile index changes as biomarker of toxicity in Catla catla (Hamilton, 1822) edible fish studied using FTIR and principle component analysis

Abstract

The study was carried out to evaluate the toxicity in gill tissue of edible fish Catla catla using FTIR spectra. Fourier self-deconvolution obtained by curve fitting was applied in the lipid (3000–2800 cm−1), carbohydrates (1000–1100 cm−1) and in the amide region (1700–1600 cm−1). These spectral changes were used as biochemical parameters to assess the degree of toxicity. A disorder in lipid changes was measured by frequency shift and intensity changes in the CH2 asymmetric stretching band. This change in the fatty acid composition in fish could be used as biomarkers of toxic effect. Decreases in lactic acid (6–16%) clarify the lipid peroxidation which is the primary mechanism of toxicity. The deconvolution in the amide region shows peaks at 1621 cm−1, 1637 cm−1 due to β sheet; 1652 cm−1 and 1667 cm−1 due to α helix and 1683 cm−1 due to antiparallel β sheet. The results show a decrease by (3–7%) in α helix and increase by (13–40%) in β sheet structure. This shows β sheet formation of protein secondary structure due to toxicity. PCA plots indicate protein and lipids have strong positive loadings. The study shows the spectral variation is considered as an ideal biomarker with a high degree of accuracy of test organism to examine the toxicity of pollutants.