ABSTRACT
Bilirubin and bile acids. The main product of haem breakdown in the rabbit is biliverdin, although some is converted to bilirubin, which is present at measurable levels. Biliverdin assays are not commercially available. Serum bilirubin levels reflect hepatocellular and biliary tree function. Visible icterus is a rare presenting sign in the rabbit. Significant hyperbilirubinaemia is usually associated with biliary obstruction and cholestasis (e.g. neoplasia of the biliary tree and hepatic coccidiosis). Bile acids (cholic acid and chenodeoxycholic acid) are synthesized in the liver from cholesterol, and are essential for fat digestion and absorption. There is normally a highly efficient enterohepatic circulation of bile acids, and blood levels will only rise if liver function is impaired. There is little information on the use of bile acids as an indicator of liver function in the rabbit, but it is presumed that it will be a sensitive indicator, as in other species. As the rabbit is a herbivore and always has ingesta in its GI tract, the taking of fasting and postprandial levels is not practical.
