Crystal-associated cholangiopathy associated with the ingestion of Panicum spp. and other plants

Abstract

Several panicoid grasses and some other plants throughout the world have been associated with a crystal-associated hepatopathy causing photosensitisation in ruminants. We have prepared sheep with reentrant bile duct cannulae and fed them on Panicum dichotomiflorum from the Waikato region. Bile from these sheep has been collected and crystals harvested by centrifugation and Percol density gradient techniques. These sheep, when slaughtered after showing elevations of serum bilirubin and enzymes indicating liver injury, had the typical cholangiohepatopathy of Panicum spp. toxicity. The crystals have now been identified as calcium salts of epismilagenin glucuronide. Likely precursor saponins of the sapogenin have been identified in Panicum dichotomiflorum. While we regard these findings as an important step forward in the understanding of these diseases, we are now investigating the factors, including known hepatotoxins, responsible for the occurrence of these hepatopathies.