Prisiazhniuk N. Features of liver morphology in cartilaginous and bony fishes

This thesis is devoted to the study of liver morhology in cartilaginous and bony fishes, families Squalidae, Acipenseridae, Polyodontidae, Salmonidae, Esocidae, Cyprinidae, Siluridae, Percidae. We determined anatomic and topographic parameters of liver in some representatives of the Superclass Osteichthyes; found features in microscopic structure of liver in some representatives of Osteichthyes and Chondrichthyes; conducted a histometric and cytocariometric liver examinations of some representatives of bony and cartilaginous fishes. This investigation showed that different fish species have distinct liver anatomic-topographic and organoleptic parameters. Among investigated fish species for which data was collected, highest increases in parameters of body mass, volume, density and liver index had been recorded in Siluridae and Cyprinidae, the least parameters were in Percidae. Belonging to definite taxonomic group stated to have no influence on anatomic liver and pancreas differentiation. Accordimg to our investigation, detached glands is presented in Squalidae, Polyodontidae, Salmonidae, Esocidae, Siluridae, while Cyprinidae and Percidae posses hepatopancreas. We found two organ structural types depending on pancreatocyte localisation in hepatopancreatic fishes: 1 - with pancreatocyte deposition in divers places of hepatic lobules (grass carp, spotted silver carp, zander, ruff), 2 - with pancreatocyte deposition just around central vein (carp). There are some distinguishing features in delimitation of liver lobules by connective tissue in cartilaginous and bony fishes: the connective tissue stroma were well developed in Percidae, and weakly developed in representatives of families Squalidae, Polyodontidae, Salmonidae, Esocidae, Cyprinidae, Siluridae . The findings of the study revealed that diameter of central vein in different taxonomic group is on the gradual decrease in pattern: cartilaginous fishes - cartilaginous ganoids - bony fishes. Cyto- and karyometry indexes of hepatocytes among various representatives of cartilaginous and bony fishes were evaluated.