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 Isochrysi. galbana (2 x 10(6) cell mL(-1)) control treatment; algal mix of I. galbana (2 x 10(6)) and P. lima (3 x 103 cell mL(-1)); and P. lima alone (3 x 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. (C) 2016 Elsevier Ltd. All rights reserved.