Comparative morphology and ecomorphology of the gut in European cyprinids (Telostei)

The patterns of coiling of the gut were compared in 22 species of Eurasian Cyprinidae. In selected species, also the length of gut and mucosal surface structure were compared. Piscivorous ( Aspius aspius ), planktivorous ( Abramis ballerus ) fishes as well as species feeding mainly on plankton and wind-borne' drift'( Alburnus alhurnus, Pelecus cultratus ) have the relatively shortest guts, with only a single loop. The same simple arrangement of a short gut is present in many euryphagous species with more or less carnivorous tendencies ( Abramis sapa, Alburnoides bipunctalus, Abramis brama, Blicca bjoerkna, Chalcalburnus chalcoides memo, Gobio gobio, Leuciscus cephalus, Leuciscus leuciscus, Rutilus rutilus, Scardinius erythrophthalmus. Tinea tinea, Vimba vimba ). Some benthivorous winnowers (oropharyngeal sorters) and species with herbivorous feeding tendencies have relatively long guts showing a more complex pattern of loops and coils ( Barbus barbus, Carassius carassius, Chondrostoma nasus, Ctenopharyngodon idella, Cyprinus carpio ). The goldfish, Carassius auratus , has the most complex coils. Scanning electron microscopy of the mucosal surface revealed five types of folding in the intestinal bulb which were only loosely related to feeding: 1, smooth surface ( Aspius aspius, Leuciscus cephalus, Vimba vimba ); 2, irregularly branching folds ( Alhurnus alburnus, Barbus barbus, Blicca bjoerkna, Chalcalburnus chalcoides memo, Leuciscus leuciscus, Rutilus rutilus, Scardinius erythrophthalmus ); 3, curl-like folds ( Tinea tinea ); 4, net-like folding pattern ( Abramis brama ); 5, honeycomb-like mucosal structure ( Cyprinus carpio ).