Short- and long-term exposure to imidacloprid disturbs the elemental composition and free amino acid profile in muscles of Labeo rohita

Imidacloprid [1-(6-chloro-3-pyridylmethyl)-N-nitro-imidazolidin-2-ylideneamine] is among the most extensively used pesticide in Pakistan. The aim of this investigation was to report the changes in concentration of different elements and amino acid in the muscle of Labeo rohita upon imidacloprid exposure. Juvenile Labeo rohita (N = 480) were treated with 120mgL⁻¹ imidacloprid under short and long-term experimental conditions. At the end of each experiment, fish muscle was used for elemental concentration (determination by an atomic absorption spectrophotometer) and amino acid estimation (by high-performance liquid chromatography (HPLC)). Our results indicated that sodium, potassium, calcium, magnesium, iron, aluminum, and lead concentrations were significantly different (P < 0.05) when compared between imidacloprid-treated and untreated L. rohita and changes were more pronounced in short-term experimental groups. HPLC-generated data analysis showed that proline, isoleucine, and glycine concentrations increased while the levels of phenylalanine, alanine, and leucine decreased significantly (P < 0.05) in muscles of fish exposed to imidacloprid under short-term conditions. On the other hand, serine, arginine, and glycine increased significantly and alanine decreased significantly in L. rohita exposed to pesticide under long-term experimental conditions. It is concluded that imidacloprid (120 mg L⁻¹) exposure to L. rohita for a variable duration has significantly changed the elemental composition and studied amino acid concentrations in fish muscles making it unsuitable for human consumption.