Scope for growth, biochemical composition, and antioxidant immune responses of the penshell Atrina maura to flow velocity and concentration of microalgae

This study shows the short-term effect of three flow rates (0.8, 1.6, and 2.5 cm s− 1) and three ranges of microalgae Isochrysis galbana (clone T-Iso) concentrations (80–120, 150–180 and 200–250 cells μL− 1) on the scope for growth, biochemical composition, and immune responses of the digestive gland and adductor muscle in the juvenile penshell Atrina maura. Significant differences in A. maura responses occurred between flow rates. Ingestion rate, absorption rate, and scope for growth (SFG) were highest at 1.6 cm s− 1. Respiratory rate increased with the flow rate and decreased with the concentration of microalgae. As T-Iso concentration increased, ingestion rate, absorption rate and SFG increased. The increased ingestion rate, absorption rate and SFG were significantly correlated to the concentration of microalgae at 0.8 and 1.6 cm s− 1 and respiratory rate was positively correlated at 2.5 cm s− 1 (P < 0.05). Antioxidant enzyme immune activity was higher in the adductor muscle, associated with higher metabolic activity as respired energy. Glutathione S-transferase and catalase activities increased with flow rate. Antioxidant enzyme activities, lysozyme, and lipid peroxidation levels differed with tissues. T-Iso concentration was inversely correlated to acetylcholinesterase; lipid peroxidation levels decreased with T-Iso and were associated with energy transfer. The penshell's scope for growth was dependent on the flow and positively related to availability of food. Immune response was also associated with the flow rate.