Fine structure of Longicollum pagrosomi (Acanthocephala: Pomphorhynchidae) and intestinal histopathology of the red sea bream, Pagrus major, infected with acanthocephalans

Abstract

The results described the structure of Longicollum pagrosomi and histopathological characters of the intestine of the red sea bream, Pagrus major, infected with acanthocephalans, using the light and electron microscopes. Among the six samples of P. major, L. pagrosomi was identified in the posterior intestine of five fish samples. Adult L. pagrosomi (total length, 8-27 mm) is divided into the presoma (proboscis, anterior neck, and posterior neck) and metasoma (trunk). The proboscis had vertically arranged hooks (40 μm in length), with ten hooks per row, and the septum was observed between the posterior neck and trunk. The tegument thickness of the proboscis was approximately 15 μm, and it was composed of thin, circular muscle fibers. The outer fibrous membrane was approximately 1 μm, and the connective tissue layer was approximately 35 μm in thickness in the anterior neck. The tegument of the posterior neck enclosed the cephalic ganglion and had longitudinal and vertical muscle fibers, and the tegument thickness was approximately 45 μm. The tegument of the body, which was approximately 1 mm in thickness, was composed primarily of muscle and collagen fibers, and the structure of the tegument was different, depending on the body region. The acanthocephalans had ovaries and oval-shaped eggs with an eggshell (77.5 × 17.1 μm), floating within the body cavity of the trunk. In the infected posterior intestine of P. major, the presoma and the anterior part of the metasoma of L. pagrosomi passed through the intestinal wall and infected the intestinal tissue, perforating the loose connective tissue. In the inflammatory connective tissue, collagen and muscle fibers were fragmented and revealed partial necrosis. Lipid drops and eosinophilic granular cells aggregated in the connective tissue of the tissue capsule. In the vicinity of the acanthocephalan, the mucosal epithelia contained hypertrophied nuclei, and the epithelial layer was collapsed. In an extreme case, the mucosal fold was degenerated because of pressure from the acanthocephalan.

Neoechinorhynchus buttnerae (Acanthocephala) infection in farmed Colossoma macropomum: A pathological approach

“…Complete desquamation of the intestinal epithelium with severe hyperplasia and hypertrophy of goblet cells, displacement of their sheath and oedema were also found in curimbatá (Prochilodus lineatus) infected by N. curemai (Martins et al, 2001). Parasitism due to Longicollum pagrosomi Yamaguti, 1935 resulted in destruction of the villi and epithelial covering in red sea bream (Pagrus major Temminck & Schlegel) (Kim et al, 2011) and chirruh snowtrout (Schizothorax esocinus Heckel) (Irshadullah and Mustafa, 2012).…”

Metazoan parasites of brown meagre (Sciaena umbra L. 1758) caught near Gökçeada, Turkey

“…This acanthocephalan, with a Far Eastern origin, was first described in Trachurus trachurus from the Sea of Marmara by Oğuz and Kvach (16,17). Trachelobdella lubrica occurs in warm temperate and tropical seas around the world, such as the Mediterranean, the Arabian Sea, West Africa, South Africa, and Australia (16).…”

Histological Change of Aquatic Animals by Parasitic Infection

“…Attachment point of acanthocephalans may be necrotic and can be even perforated, leading to peritonitis [5]. In reference [45] reported the histopathological changes when the presoma and the anterior part of the metasoma of Longicollum pagrosomi passed through the intestinal wall and infect the intestinal tissue, perforating the loose connective tissue. In the inflammatory connective tissue, collagen and muscle fibers were fragmented and revealed partial necrosis.…”