Immunomodulation and physiological responses of Mytilus galloprovincialis as bioindicators of environmental change

Abstract

Immunomodulation and physiological responses of Mytilus galloprovincialis as bioindicators of environmental change Oxygenation level temperature increases and changes in food availability are predicted to occur in the future. In such scenario, a global climate change (GCC), there is growing concern for the health status of wild and farmed organisms. Bivalve molluscs, are important components of coastal marine ecosystems, and as sedentary and filter feeders, are good bioindicators of environmental conditions. The ability of organisms to maintain the immunosurveillance unaltered under adverse environmental conditions may enhance theirs survival capability. Only a few studies have investigated the effects of changing environmental parameters on the mussels immunity. In the present study, the effects of different food concentration, temperature and oxygenation treatments were evaluated on immune parameters of Mytilus galloprovincialis detected on digestive gland and hemocytes. Bivalves were exposed to experimental conditions by increasing of six food treatment, to three different temperatures under conditions of normoxia and anoxia. The multifactorial analysis applied to the responses of the immune variables has showed a direct dependence of various enzymes production by temperature and food concentration. The stability of the lysosomal membrane was altered under conditions of thermal stress and food changing. The protein concentration of the lysate of hemocytes instead was most affected by the lack of adequate oxygenation. In addition, a correlation was carried out between mussels immunological effectors and physiological responses as clearance rate, measured by the removal of suspended particles from water flowing through experimental chambers, food absorption efficiency and rates of oxygen consumption by individual mussels. Overall, information summarized in the present study indicated that climate changes can affect hemocyte and enzymatic functionality and the immune responses of this bivalve could be used as good environmental biomarkers.