Biochemical and Electron Microscopic Analysis of Eyestalk of the Mud Crab, Scylla serrata Exposed to Silver Nano Particles

摘要

Silver nano-particles (AgNPs) are widely used as spectrally selective coatings for solar energy absorption, chemical catalysts and especially for antimicrobial sterilization. After their discharge, silver nano-particles will most likely enter the ecosystems and may produce an adverse response in many aquatic animals altering their fitness and ultimately changing their densities or community populations. Hence, the present study was carried out with silver nano-particle (AgNP) induced toxicity and biochemical changes in the eyestalk of the mud crab Scylla serrata. After standardization of LD50 (25 ppm/kg) value, a single concentration of 20 ppm was used for the toxicity studies. Disorganization of corneal cuticle, formation of corneal cones, constriction of internal medulla and complete disorganization of basement membrane were observed through histological analysis and scanning electron microscopic (SEM) analysis of eyestalk of crabs exposed to silver nano-particles showed shrinkage and appearance of scars in the eyestalk developed in the basipetal succession and severe cell damage, total collapse of normal architecture leading to complete degeneration were to observed. Biochemical analysis showed increased level of total protein, carbohydrate and lipid contents and tissue damaging enzymes, such as SOD, CAT and GPx from day 2 to day 10 on exposure to silver nano-particle which indicates severe tissue damage due silver nano-particle treatment. The overall results concluded that the release of silver nano-particle into aquatic ecosystem would have a direct impact on the aquatic animals and affect the biodiversity of aquatic life.