Peculiarities of morphological changes in liver cells of spawning omul of various degrees of infection with D. dendriticum helminths

The histological structure of liver cells of omul, free from invasion, and fish with varying degrees of infection with plerocercoids was studied. The studies were carried out during the period of spawning migration of omul into the channel flowing into the Selenga River, according to the quota of the Baikal branch of the FSBSI ARRIFO (as part of the resource research plan for 2019). Caught individuals of the omul were divided into 3 groups: 1st group of fish - uninfected individuals; 2nd group - individuals with a weak degree of invasion: from 2 to 3 capsules; 3d group of omul - with a high degree of infection: from 18 and above plerocercoids D. Dendriticum on the wall of the digestive tract of fish. The obtained results of histological studies of the liver cell structure of non-infected omul showed some microstructural changes, which, apparently, are associated with the influence of negative environmental factors of fish. Microscopy of liver samples in a group of individuals with a weak degree of invasion revealed signs of acute hyperemia in the organ parenchyma: the capillaries are blood-filled and dilated. It was established that with parasitization of plerocercoids on the intestinal wall, pathomorphological changes occurred in the liver of omul. In particular, in the group of fish with a low degree of invasion, destruction of the parenchyma, disturbances in blood microcirculation, and minor necrotic pathology were noted. It was found that the most pronounced changes were recorded in the liver of fish with a high degree of infection. With a high degree of invasion, the liver structure is characterized by the presence of large drops in hepatocytes, an increase in areas with necrotic cells, the presence of pronounced signs of chronic venous congestion and the formation of caverns. The obtained results indicate pathological changes in the microstructure of liver cells of omul infected with D. Dendriticum plerocercoids, the severity of which was dependent on the level of helminth infection.