DAO 56:249-258 (2003)  -  doi:10.3354/dao056249

Salinity effects on immune parameters of Ruditapes philippinarum challenged with Vibrio tapetis

H. I. Reid1, P. Soudant2, C. Lambert2, C. Paillard2, T. H. Birkbeck1,*

1Division of Infection and Immunity, Institute of Biomedical and Life Sciences, Joseph Black Building, University of Glasgow, Glasgow G12 8QQ, UK
2Université de Bretagne Occidentale, Institut Universitaire Européen de la Mer, 29280 Plouzane, France
*Corresponding author. Email:

ABSTRACT: The occurrence of brown ring disease (BRD) in farmed Manila clams Ruditapes philippinarum is seasonal. Development of the disease is believed to require the presence of the infective agent Vibrio tapetis and particular environmental conditions. This paper studies the effect of salinity (20 to 40‰) on measurable immune parameters of Manila clams, and the progression of BRD in experimentally infected individuals. At 20‰ salinity, the total haemocyte count was reduced and disease prevalence was highest. At 40‰ salinity significantly fewer clams presented signs of BRD, and this was correlated with increases in the total haemocyte count, hyalinocyte count, phenoloxidase levels and phagocytic activity of haemocytes. Inoculation of clams with V. tapetis did not have a significant effect on the immune parameters measured. Thus, this laboratory-based study relates environmental stress to disease development.

KEY WORDS: Vibrio tapetis · Brown ring disease · Aquaculture · Salinity · Immune response

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