Protoporphyric disorder in livers of broiler chickens.

Two cases of protoporphyrin (PP) disorder detected in a 60- and 65-day old female chicken were described. The gross lesions were restricted to the livers which were enlarged and dark green to black in color. Histologically, dark brown granules were found in hepatocytes, Kupffer cells, macrophages, sinusoids, bile canaliculi, and bile ducts. These granules, as seen in smears and sections of livers, were red under a fluorescence microscope and exhibited bright birefringence with a centrally located dark Maltese-cross by polarized light. Ultrastructurally, these granules consisted of aggregates of needle-like crystals in a radial arrangement. Fluorometrically, extracted level of PP in the affected liver was determined to be 390.6 micrograms per gram of wet tissue. Spectrofluorometric scans of liver extract and PP standard were almost identical.