Alterations of Liver Histomorphology in Relation to Copper Supplementation in Inorganic and Organic Form in Growing Rats

The aim of this study was to define the effects of diet containing the same mineral content of mineral salt or amino acid chelate, and diet containing various levels of Cu amino acid chelate on liver histomorphometry in growing rats. Male Wistar rats were used in the 12th week experiment. The control group (n = 12) was fed standard diet, which provided Cu in an inorganic form at the level required for rats. The experimental animals were divided into four groups (each n = 12) depending on different levels (100%, 75%, 50%, 25% covered daily demand) of Cu supplementation in chelated form. Cu content was determined in the liver tissue and blood plasma. Immunohistochemical staining with caspase-3 antibody was performed. Microscopic assessment of the liver structure indicated that Cu supplementation did not change the liver architecture. However, histomorphometric analysis revealed a significant increase in the number of nuclei, total cell number, and multinucleated hepatocytes in rats supplemented with the organic form of Cu at the level of 25% compared with the control group. There was a considerable increase in the number of apoptotic cells and ballooning degeneration of hepatocytes, especially in groups supplemented with organic form of Cu covering the daily demand in 100% and 75%, in comparison to control group. Moreover, there was no Cu deposition in the liver and changes in Cu content in blood. Cu provided in the diet in organic form covering an amount of its minimum daily demand in 25% appears to be the least harmful with regard to the liver. It indicates that there is a need to establish the level of diet supplementation with Cu amino acid chelates.