Absorption of short-chain fatty acids, sodium and water from the forestomach of camels

• Published in: Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology Vol. 177; no. 6; pp. 631 - 640
• Main Authors: von Engelhardt, W, Dycker, Ch, Lechner-Doll, M
• Format: Journal Article
• Language: English
• Published: Germany Berlin/Heidelberg : Springer-Verlag 01.08.2007; Springer Nature B.V
• Subjects: Absorption; Absorption rates; Acetic acid; Animals; Anion exchange; Anion exchanging; Buffer solutions; Camelidae; Camels; Camelus - metabolism; Epithelium; Fatty acids; Fatty Acids, Volatile - metabolism; Female; Fermenters; Foregut; Forests; Gastric Mucosa - metabolism; Intestinal Absorption; Male; Models, Biological; Orchiectomy; Propionic acid; Ruminantia; Sodium; Sodium - metabolism; Surface chemistry; Water - metabolism; Water absorption
• ISSN: 0174-1578; 1432-136X
• DOI: 10.1007/s00360-007-0161-8

In camelids the ventral parts of compartments 1 and 2 (C1/C2) and the total surface of compartment 3 of the forestomach are lined with tubular glands, whereas in ruminants the surface of the forestomach is composed entirely of stratified, squamous epithelium. Thus, differences in absorption rates between these foregut fermenters can be expected. In five camels C1/C2 was temporarily isolated, washed and filled with buffer solutions. Absorption of short-chain fatty acids (SCFA) and net absorption of sodium and water were estimated relative to Cr-ethylenediaminetetraacetic acid as a fluid marker. SCFA were extensively absorbed in the forestomach; clearance rates of SCFA with different chain lengths were equal. After lowering the pH of solutions SCFA absorption rates increased, but much less than the increase of the non-ionized fraction. Absorption of propionate was lower when acetate had been added. Findings suggest that most of the SCFA in camels are transported in the ionized form, most likely via an anion exchange mechanism. Net water absorption is closely related to net sodium absorption. Apparently water absorption results from an iso-osmotic process. Differences between absorption mechanisms of SCFA from the forestomach of camelids and ruminants are discussed.