Fig. 12.

Photomicrographs of histological H&E-stained liver sections of chickens. (a) Normal control showing the normal histological architecture of hepatic parenchyma. (b), (c), and (d) Groups 1, 2, and 3 (0.25, 0.5, and 1 mg selenium/kilogram, respectively) showing a slight congestion of hepatic sinusoids (arrow). (e) Group 4 (vaccine + 0.02 mg/dose) showing small focal hepatocellular necrosis associated with the infiltration of inflammatory cells (arrow). (f) Group 5 (vaccine + 0.06 mg/dose) showing a slight vacuolization of hepatocytes (black arrow) and infiltration of a few heterophils (yellow arrow). (g) Group 6 (vaccine + 0.1 mg/dose) showing a slight vacuolar degeneration of some hepatocytes (arrow). (h) Group 7 (raw vaccine) showing a slight vacuolar degeneration of hepatocytes (black arrow) and infiltration of a few heterophils (yellow arrow). (i) Non-vaccinated and challenged groups showing a marked cytoplasmic vacuolar degeneration of hepatocytes (arrow) (scale bar, 25 μm).