Effects of tralopyril on histological, biochemical and molecular impacts in Pacific oyster, Crassostrea gigas.

Recently, the toxic effects of tralopyril, as a new antifouling biocide, on aquatic organisms have aroused widespread attention about the potential toxicity. However, the mechanism of tralopyril on marine mollusks has not been elaborated clearly. In this study, the histological, biochemical and molecular impacts of tralopyril on adult Crassostrea gigas were investigated. The results indicated that the 96 h LC50 of tralopyril to adult Crassostrea gigas was 911 μg/L. After exposure to tralopyril (0, 40, 80 and 160 μg/L) for 6 days, the mantle mucus secretion coverage ratio of Crassostrea gigas was increased with a dose-dependent pattern. Catalase (CAT) activity was significantly increased, amylase (AMS) activity, acid phosphatase (ACP) activity and calcium ion (Ca2+) concentration significantly decreased. Meanwhile, integrated biomarker responses (IBR) index suggested that higher concentrations of tralopyril caused severer damage to Crassostrea gigas. In addition, the mRNA expression levels of biomineralization related genes in the mantle were significantly upregulated. Collectively, this study firstly revealed the histological, biochemical and molecular impacts of tralopyril exposure on adult Crassostrea gigas , which provided new insights for understanding the toxicity of tralopyril in marine mollusks. Effect of tralopyril exposure (6 days' exposure) on mucus secretion coverage ratio of C. gigas mantle according to AB-PAS staining. [Display omitted] • Tralopyril exposure increased the mantle mucus secretion coverage ratio in Pacific oyster. • Tralopyril affected antioxidant defense systems、digestive enzyme and biomineralization capacity in Pacific oyster. • Tralopyril disrupted the mRNA expression levels of biomineralization related genes. [ABSTRACT FROM AUTHOR]