AJP - Regulatory, Integrative and Comparative Physiology, Vol 263, Issue 2 389-R399, Copyright © 1992 by American Physiological Society
Bile is essential for lipid assimilation in Leach's storm petrel, Oceanodroma leucorhoa
A. R. Place
Center of Marine Biotechnology, University of Maryland, Baltimore 21202.
A tritium-labeled glycerol triether was tested as a non-absorbable lipid
marker for studies of neutral lipid absorption in normal and
cholestryamine-induced steatorrhic chicks of Leach's storm petrel
(Oceanodroma leucorhoa). Absorption of triacylglycerol and wax ester (96
+/- 4.2 and 94 +/- 2.1%, respectively) in normal chicks was
indistinguishable. Absorption of neutral lipids decreased with increasing
quantities of resin, and with the highest dosage (14% wt/wt) less than 30%
of dietary lipids were assimilated. The concentration of bile salts
(greater than 500 mM) in the gallbladder of Leach's storm petrel is among
the highest recorded. The bile salts are predominantly taurine conjugates
of chenodeoxycholate and cholate. Biliary cholesterol levels are within the
range observed in humans although biliary phospholipid levels are lower and
triglyceride levels are higher. Extensive retrograde movement of duodenal
contents and biliary secretions to the gizzard and proventriculus were
found. Although similarities in fat and bile salt assimilation exist
between seabirds and mammals, there do exist differences that make
non-polar lipid assimilation (i.e., wax esters) more efficient in seabirds.
