Histological and ultrastructural changes in turkey liver under intensive rear-ing and influence of xenobiotics

Abstract

Liver problems of various etiologies in turkeys have been reported in many countries for the last 20 years. Poultry dies having no clinical manifestations of the disease, and at pathological autopsy, diffuse haemorrhages and marked dystrophic changes of the organ are noted. To date, there are several factors that can cause such changes, these are unbalanced amino-acid feed, insufficient calcium, biotin, selenium, the very high energy content of feed; zootechnical factors – limited mobility of birds due to cage density violations, high temperature; genetic factors – the influence of estrogens; infectious factors – E. coli, Clostridium, and viruses of Picornaviridae family. The article describes the histopathological and ultrastructural changes in the turkey liver under the influence of various factors. The material for the research was obtained from a farm where turkeys of the “Hybrid Converter” cross are grown, same age, fed with a standard diet that changed according to the technological map of cultivation. On the 50th day of life, a pathological autopsy of the dead poultry was performed, pieces of liver were selected for histological and ultrastructural examination. The visual assessment revealed significantly enlarged liver, the colour from dark red to light brown, flabby consistency. In some cases, diffuse fatty infiltrations of hepatocytes were histologically revealed, in other cases, focal necrosis with the growth of the connective tissue and the formation of massive perivascular couplings were registered. Large vacuolar fatty degeneration of hepatocytes with subsequent development of fibrosis indicates chronic intoxication, probably caused by slow breakdown of fatty acids in cells due to insufficient oxidative phosphorylation, as well as reduced levels of lipotropic factors: choline, methionine and the vitamins. At the ultrastructural level, a large number of lipid inclusions of various sizes, dystrophic changes in mitochondria were observed, which indicates a decrease in the synthetic activity of cells.