Although hepatic disease is a common finding upon postmortem examination of fish, it is often difficult to establish an antemortem diagnosis of hepatic dysfunction in these animals. The purpose of this study is to evaluate an enzymatic method of serum bile acids (SBA) assay as a potential indicator of hepatobiliary disease in red pacu. All fish underwent physical examination and pertinent hematological and biochemical parameters were measured prior to the study period to insure the animals were healthy.

Fifteen red pacu of uniform age and size and kept in uniform environmental conditions were fasted for 12 hours. Samples for fasting SBA concentrations were obtained. Fish were then fed a uniform amount of pelleted diet. Samples were obtained for 1, 2, and 4 hours postprandial SBA concentrations.

Preliminary results indicate a great deal of variability in both preprandial and postprandial serum bile acids values in these normal fish. There was no observable pattern of response following feeding. This may indicate that fish, unlike mammals, may continuously secrete bile acids into the intestine.