The aim of the present work was to study the effect of lambda-cyhalothrin and Neemgold on the total protein, total free amino acid, and nucleic acid contents in tissues (gill, liver, and ovary) of zebrafish, Danio rerio (Hamilton), after exposure to 96 h LC10, LC20, and LC40 of lambda-cyhalothrin and the neem-based pesticide Neemgold. It was found that the total protein content was reduced to 38, 46, and 45% in gill, liver, and ovary, respectively, after lambda-cyhalothrin exposure for 21 days at the LC40 dose. The total free amino acid content in the liver was enhanced to 172 and 154% of control (100%) after exposure to LC40 of lambda-cyhalothrin and Neemgold, respectively. However, the total free amino acid content in the gill and ovary of treated fish was significantly reduced. In addition, DNA content was reduced to 45, 41, and 41% of controls (100%) in gill, liver, and ovary, respectively, after 21 days of exposure to LC40 of lambda-cyhalothrin. The reduction in DNA content from the control was 51, 53, and 55% in gill, liver, and ovary, respectively, from Neemgold exposure at the same concentration (LC40) and period as lambda-cyhalothrin. It was observed that all the changes were dependent on concentration as well as time. Similarly, significant reductions in RNA content were also observed in gill, liver, and ovary after lambda-cyhalothrin and Neemgold exposure. The probable causes are discussed.
