Variation of environmental condition and diet act on immune parameters of Mytilus galloprovinciali

Abstract

Variation of environmental condition and diet act on immune parameters of Mytilus galloprovincialis The knowledge of the immunity mechanisms as environmental indicators and their alterations in the case of physical stress can be of fundamental importance in the environmental management programs. Recently has been shown that environmental factors affect immune responses in some species of bivalves. In this study we assessed different enzymatic activities from digestive gland of M. galloprovincialis such esterase, phosphatase and phenoloxidase (PO), involved in digestive inflammatory, detoxification and melanization processes. Particularly, esterases catalyze the hydrolysis reaction of the ester bond. Phosphatases modulates the removal of phosphate groups by producing phosphoric acid from esters and participate in the metabolism of sugars, nucleotides and phospholipids. The melanization cascade, in which phenoloxidase is the terminal enzyme, plays a key role in recognition of microbial infections in molluscs. It was also evaluated, as potential biomarker, the lysosomal membrane stability through neutral red assay on hemocytes taken from the posterior adductor muscle. Specimens were maintained under conditions of normoxia and anoxia and they were subjected to various food amount and different temperatures. 102 The results showed that the enzymatic activities of esterases, phosphatases and PO are higher during treatments with lowest temperatures and food amount. Moreover, the production of PO is higher in the conditions of anoxia. The lower values of enzymatic production have been detected under the levels of temperature, oxygen availability and food different than the optimum conditions for the mussels life cycle. During the normoxic treatment, the stability of the lysosomal membrane is highest at the average values of temperature and food concentration. The lowest values, instead, were measured at a temperature of 12 °C and 28 °C in anoxic conditions