Crassostrea gigas exposure to the dinoflagellate Prorocentrum lima: Histological and gene expression effects on the digestive gland

• Effects of Prorocentrum lima cells were assessed in oyster Crassostrea gigas.
• Prorocentrum lima affected feeding and structural loss of digestive gland.
• Dinoflagellate induced digestive gland modifications in gene expression pattern.
• Physiologic, histopathologic, and genomics analyses useful to estimate bivalve health.

Bivalve mollusks bioaccumulate toxins via ingestion of toxic dinoflagellates. In this study, Crassostrea gigas was used to investigate the effects related to Prorocentrum lima exposure. Oysters were fed with three diets Isochrysis galbana (2 × 106 cell mL−1) control treatment; algal mix of I. galbana (2 × 106) and P. lima (3 × 103 cell mL−1); and P. lima alone (3 × 103 cell mL−1). Feeding behavior changes, histopathological alterations, and expression patterns changes of genes involved in cell cycle (p21, cafp55, p53), cytoskeleton (tub, act), and inflammatory process (casp1) were evaluated. Results indicated that the presence of diarrheic shellfish poisoning by P. lima cells decreased the clearance rate (p < 0.05), induced structural loss, significantly decreased tubule area of the digestive gland (p < 0.05), and up-regulated in expression all gene (p < 0.05), suggesting that toxic cells might trigger inflammatory tissue process, disturb cell cycle and cytoskeleton representing a risk to oysters integrity.