Lipid and glycogen contents in liver of high-yield dairy cows in peripartal period

Abstract

Od krava holštajn rase u visokom graviditetu i ranoj laktaciji biopsijom su uzimani uzorci tkiva jetre za patološko-histološka ispitivanja. Sadržaj masti u hepatocitima je određivan stereometrijskom metodom izračunavanjem volumenske gustine, a glikogena semikvantitativno mikroskopskim pregledom isečaka bojenih metodom po Bestu. Patološko-histološkim ispitivanjem uzoraka tkiva jetre kod zdravih, steonih i tek oteljenih krava nisu utvrđene masna infiltracija i degeneracija ćelija jetre a hepatociti su u potpunosti ili delimično ispunjeni glikogenom. Kod krava obolelih od ketoze patološko-histološkim ispitivanjem uzoraka tkiva jetre su utvrđena masna infiltracija i degeneracija hepatocita, različitog intenziteta. Samo kod jedne krave obolele od ketoze utvrđen je blagi stepen masne infiltracije, kod šest krava srednji stepen masne infiltracije i degeneracije, a kod tri krave težak oblik zamašćenja ćelija jetre. Količina glikogena u hepatocitima je u negativnoj korelaciji sa stepenom masne infiltracije i degeneracije. Pri teškom stanju zamašćenja u citoplazmi hepatocita u potpunosti nedostaje glikogen.

Liver tissue samples were taken by biopsy from Holstein cows in advanced stages of gravidity and in early lactation for pathological-histological examinations. Lipid content in hepatocytes was determined using the stereometric method by calculating volume density, and of glycogen using semi-quantitative microscopic examination of sections stained according to the method of Best. Pathological-histological examinations of liver tissue samples in healthy animals, gravid or peripartal cows did not reveal lipid infiltration or cell degeneration, and hepatocytes were completely or partly filled with glycogen. In ketotic cows, pathological-histological examinations of liver tissue samples showed lipid infiltration and hepatocyte degeneration of different intensity. In only one ketotic cow, we determined a slight degree of lipid infiltration, there was a medium degree of lipid infiltration and degeneration in six cows, and three cows were found to have a grave form of fatty liver. The quantity of glycogen in hepatocytes is in negative correlation with the degree of lipid infiltration and degeneration. In severe cases of fatty liver, glycogen is completely absent from hepatocyte cytoplasm.