Evaluation of the Baikal omul’ of different age groups liver and kidneys morphofunctional state

The aim of the study was to assess the morphofunctional state of the liver and kidney cells of the Baikal omul of different ages during the period of spawning migration. The collection of histological material was carried out as part of joint research with the FSBSI VNIRO in Ulan-Ude in the area of Maloye Kolesovo, Kabansky District of the Republic of Buryatia in 2019. The age of the fish was calculated by annual rings on the scales (by scleritis). 3 groups of fish were formed: 1st group - individuals 5-6 years old; 2nd group - individuals 7-9 years old; 3rd group - individuals aged 10 years and older. The structure of the liver and kidneys of fish aged 5-6 years was characterized by a classical morphological picture. In places, small deviations were detected in the form of small lipid inclusions in the parenchyma of organs. In individuals 7-9 years old, a slight increase in necrotic hepatocytes in the structure of the liver was clearly visible. A few foci of inflammation in the stroma of the kidneys, destruction of the renal corpuscles and convoluted tubules, and inclusions of dark spots were noted. In omuls in the age group of 10-12 years, signs of pronounced congestive hyperemia in the structure of the liver were observed, and the areas with necrotic cells increased significantly. The morphostructure of the kidneys was characterized by extensive destruction of renal bodies, death of vascular glomeruli, and fibrosis. An increase in lipid droplets on preparations of the liver and kidneys was noted in older groups of fish. Histological changes in the structures of fish liver and kidney cells can be used for early assessment of the ecological state of the habitat of aquatic organisms in the absence of visible changes.