Rodlet cells (RC) are characterized by a distinctive cell cortex and conspicuous inclusions named “rodlets.” These cells are particularly abundant and large in size in intestine of eels. Histochemical, immunohistochemical and ultrastructural investigations were carried out on European eel Anguilla anguilla and Common carp Cyprinus carpio from Northern Italy. Eight biotinylated lectins were used to probe for specific carbohydra...

The histopathology and ultrastructure of the intestine of mullets, Liza ramada and Liza saliens , from Comacchio lagoons (northern Italy) naturally infected with myxozoans and helminths were investigated and described. Sixty‐two (80.5%) of 77 mullets harboured one or more of the following parasites species: Myxobolus mugchelo (Myxozoa), Neoechinorhynchus agilis (Acanthocephala), Haplosplanchnus pachysomus and Dicrogaster contr...

Histopathological lesions due to third‐larval stage of nematode Brevimulticaecum sp. within the liver of a subpopulation of 31 Gymnotus inaequilabiatus from the Pantanal Region (Brazil) were studied with histochemical and immunohistochemical methods. In 93.5% of fish, livers harboured nematode larvae and the intensity of infection ranged from 8 to 293. In livers with highest number of larvae, the hepatic tissue was occupied pr...

Histopathological, immunofluorescence and ultrastructural studies were conducted on the intestines of four fish species infected with different taxa of enteric helminths. Brown trout ( Salmo trutta trutta ), eel ( Anguilla anguilla ) and tench ( Tinca tinca ) obtained from Lake Piediluco (central Italy) were examined. Brown trout and eel were infected with two species of acanthocephalans, and tench was parasitized with a tapew...

The European eel, Anguilla anguilla , is a major warm‐water fish species cultured in North and South Europe. Seventy‐one A. anguilla collected between 2010 and 2015 from the Comacchio lagoons were examined. Fish were infected and damaged by larvae (L3) of the nematode Contracaecum rudolphii A, which were encapsulated within the thickness of the intestinal wall and within the external visceral peritoneum (serosa). Conspicuous g...

Histochemical and ultrastructural investigations were conducted on the mucous cells of the intestine of brown trout, Salmo trutta L., naturally infected with the cestode Cyathocephalus truncatus (Pallas, 1781) and the acanthocephalan Echinorhynchus truttae Shrank, 1788. A subpopulation of 45 S. trutta were examined of which 15 specimens harboured E. truttae , 15 of which were infected with C. truncatus and 15 fish, the control...

Intraspecific and interspecific variability in rodlet cell size in various tissues of several species of freshwater and marine fish were documented. Differences were attributed mainly to fish species, although tissue type contributed significantly, providing evidence for the presence of rodlet cell morphotypes.

Immunopathological and ultrastructural studies were carried out on the gills of bream, Abramis brama , naturally infected with the copepod Ergasilus sieboldi and on the intestine of brown trout, Salmo trutta , infected with the acanthocephalan Echinorhynchus truttae . Infected gills showed extensive tissue damage due to copepod attachment, including hyperplasia, as well as proliferation of mast cells, rodlet cells and mucous c...

The pathological changes induced by an infection of Diphyllobothrium dendriticum (Nitzsch, 1824) plerocercoids in powan, Coregonus lavaretus (L.), from Loch Lomond, Scotland, were assessed using immunohistochemical and ultrastructural techniques. In a sample of 26 powan, the occurrence of encysted plerocercoids of D. dendriticum on the outer surface of the stomach was 38.5% ( n = 10) with the number of cysts ranging from 4 to...

The effect of osmotic shock was investigated mainly in the chloride cells (CCs) and rodlet cells (RCs) of gills, and RCs of intestine and kidney of the European sea bass Dicentrarchus labrax obtained from a farm in the northern Adriatic Sea. During the experiment, fish were abruptly transferred from sea water to a salinity of 15 (15 SW) or to fresh water (FW). Numeric variation and ultrastructural changes of both cell types we...

A histopathological and immunohistochemical study on the intestines of 45 specimens of farmed rainbow trout, Oncorhynchus mykiss (Walbaum), from Loch Awe, Scotland, revealed a number of cellular deviations in individuals naturally infected with the pseudophyllidean cestode Eubothrium crassum (Bloch, 1779). Twenty‐five individuals (55.5%) were infected with an average worm burden of 18.84 ± 4.06 (mean ± SE) cestodes per host (r...

Handling stress and exposure to the herbicide Stam® M‐4 (Propanil) were associated with an exponential depletion of the rodlet cells (RC) in the bulbus arteriosus of chub Leuciscus cephalus . Structural changes of the RC in herbicide‐exposed fish were encountered, including the occurrence of myeloid bodies in the cytoplasm of the RC of the intestine, various degrees of rodlet degeneration and high vacuolization in the cytoplas...

The presence of intestinal helminths in the alimentary canal of brown trout, Salmo trutta L., can alter the number of cells that synthesize modulatory peptides. A total of 167 brown trout were collected from tributaries of the River Brenta (northern Italy), of which 119 (71.3%) specimens were infected with enteric helminths, 28 with the acanthocephalan Pomphorhynchus laevis Müller, 1776 with intensity of infection ranging from...

The histopathology, immunohistochemistry and ultrastructure of the alimentary canal of chub, Leuciscus cephalus (L.), from the River Brenta, naturally infected with the acanthocephalan Pomphorhynchus laevis Müller, 1776, was studied and described. Of 62 chub examined, 54 (87%) were infected with P. laevis ; the intensity of infection ranged from five to 130 parasites per host, and a density of 8 P. laevis per cm 2 was common....