Intestinal D-glucose and L-alanine transport in Japanese quail (Coturnix coturnix)

The mechanisms involved in D-glucose and amino acid transport in the intestine of birds are still not clear. In chickens, D-glucose and amino acid absorption occurs via carrier-mediated transport, but in wild birds a passive paracellular mechanism seems to be the predominant pathway. The purpose of this work was to determine the existence of carrier-mediated sodium cotransport of D-glucose and L-alanine in the small intestine of Japanese quail (Coturnix coturnix), a granivorous bird. Intestinal transport was determined by changes in the short-circuit current (Isc), proportional to ion transmembrane flux, in the middle segment of the intestine of Japanese quail with a Ussing chamber. D-Glucose produced an increase of the Isc, and this effect was reverted by phloridzin, indicating the presence of a D-glucose transport mediated by the sodium/glucose cotranspoter 1. Addition of L-alanine also produced an increase of the Isc. We concluded that there is carrier-mediated cotransport of D-glucose and L-alanine with sodium in the small intestine of the Japanese quail.