Hepatic protoporphyrin accumulation in a broiler chicken

Hepatocellular accumulation and biliary excretion of protoporphyrin in a 6-week-old chicken are described. The affected liver was grossly dark gray to black. Histologically, hepatocytes, bile canaliculi, and bile-duct lumina contained dark-brown granules. These protoporphyrin pigment accumulations were brightly birefringent under polarized light. The ultrastructural appearance of granules revealed hair-like crystals in a radial arrangement. Extracted levels of protoporphyrin in the affected liver were determined to be 630 per gram of wet (frozen) liver. Spectrofluorometric scans of liver extracts and sedimented crystals were characteristic of protoporphyrin