Tissue changes of the oyster Crassostrea virginica due to cadmium exposition and depuration

Abstract

Cadmium levels had increased in the Gulf of Mexico, this represents a potential risk for the survival of oyster Crassostrea virginica and for those who eat them, so it is important to evaluate the effects of cadmium trough histopathological changes derived from the exposition to this metal and during its depuration. Oysters exposed to 100 µg/l of cadmium for 72 h and depurated by 24, 48, 72, 96, 120, 144, 168, 192, 216, and 230 h were analyzed. Samples of oysters were included in paraffin, cutted in a microtome and stained following the Hematoxilin-Eosin technique. Histopathological analysis of oesophagus, intestine, digestive diverticulum, gills and mantle, showed inflammatory lesions and cell activation, including brown cells and haemocytes as a detoxification mechanism. The conjunctive tissue next to oesophagus, intestine and digestive diverticulum presented more brown cells and haemocytes than gills and mantle. Histopathological damage was not reversible in 230 h, although there was a recovery in epitheliums of digestive diverticulum. This work recommends the histopathological evaluation of digestive diverticulum to determine the physiological state of oysters and to take preventive measures in the commercialization and culture of their natural populations.