Alterations in the biochemistry and ultrastructure of the deep abdominal flexor muscle of the Norway lobster Nephrops norvegicus during infection by a parasitic dinoflagellate of the genus Hematodinium

Changes in various biochemical and ultrastructural characteristics of the d eep abdominal flexor (DAF) muscles were studied in Norway lobster Nephrops norvegicus (L.) from the Clyde estuary, Scotland, UK, at different stages o f infection by a parasitic dinoflagellate of the genus Hematodinium. Abdomi nal DAF muscles from infected lobsters showed slight, significant increases in total water content, along with greatly depleted glycogen reserves and an altered free amino acid profile. However, protein concentration and comp osition remained unchanged. Ultrastructurally, parasitic infection of DAF m uscle fibres caused alterations in sarcolemmal structure, and localized dis ruption of myofibrillar bundles around the periphery, but not throughout th e centre of the fibres. Overall, the reduction in swimming performance prev iously reported for N. norvegicus during Nematodinium infection reflect an alteration in carbohydrate supply to the active muscle and some subtle disr uption of muscle structure. The altered carbohydrate titre could reflect th e Hematodinium parasites acting as a carbohydrate sink in the haemolymph, a disruption of normal tissue glycogenesis, or some alteration in the host's hormonal regulation. These changes could also adversely affect the taste, texture and marketability of infected meat.