Influence of diets with cereal grains contaminated by graded levels of two Fusarium toxins on selected enzymatic and histological parameters of liver in gilts.

Feeding experiments with diets containing Fusarium toxin-contaminated wheat were conducted to clarify the pathogenesis of enzymatic and histopathological effects of Fusarium toxins on porcine liver cells. A total of 36 prepuberal gilts were divided into four groups and fed diets with increasing proportions of Fusarium toxin-contaminated wheat at a total wheat proportion of 40% over a period of 35 days. The concentrations of the indicator toxins deoxynivalenol (DON) and zearalenone (ZON) which were analyzed by HPLC methods were 210/4, 3070/88, 6100/235, and 9570/358 microg/kg in the diets fed to groups I-IV, respectively. The feeding of mycotoxin-contaminated diets did not cause gross pathological findings in the livers of the animals. Liver tissues were subjected to enzymatic, histological, and ultrastructural examinations. The percentages of the stained areas in periodic acid-Schiff (PAS), Berlin-Blue, and Masson Goldner's trichrome stainings were calculated using the AnalySIS 3.4-system. Significant histopathological findings of alterations with varying degrees in glycogen reduction and increase of hemosiderin particles were found in the liver cells of groups II, III and IV. The thickness of interlobular connective tissue septum in liver cells was significantly increased in groups III and IV. Qualitative ultrastructural alterations were observed in hepatocytes of gilts in groups III and IV. Dependent upon the mycotoxin concentration in the diet, the hepatocytes developed a dose-dependent, extensive, smooth endoplasmic reticulum, exhibited loss of ribosomes, and acquired an increased number of fatty and autophagic vacuoles. However, liver damage as measured by prominent elevated transaminase activities in serum was not detected. Together, the histopathological results provide evidence of liver dysfunction in the absence of clinical signs, especially in pigs fed higher concentrations of Fusarium toxin-contaminated wheat.