Effect of montmorillonite on arsenic accumulation in common carp

Abstract

The effect of montmorillonite (MMT) on dietary arsenic (As(III)) accumulation in tissues of common carp was investigated. Growth rates and survival do not appear to be sensitive indicators of dietary As(III) toxicity under lower exposure concentration. However, the toxicity increases as As(III) exposure concentration increase, and this can be alleviated with added MMT concentration. Exposure of common carp to dietary As(III) resulted in a significant As(III) accumulation in the tissues of common carp in the order: intestine>bone>gill>liver>muscle>brain (P<0.05), indicating accumulation of these tissues. When fed with MMT, there was a reduction in As(III) concentration of these tissues compared with the control group. The ratio of oxidized glutathione to reduced glutathione (GSSG/GSH) revealed a significant effect with MMT concentration (1.0%) (p<0.05) and post-hoc analysis also revealed that the group treated with MMT exhibited a decrease in the ratio of GSSG/GSH when compared to the fish not treated with MMT. Moreover, the addition of MMT to the diet with As(III) decreased metallothionein concentration. The added dietary MMT was therefore clearly protective against the bioaccumulation of As(III).

Key words: Montmorillonite, arsenic, common carp.