Sodium glucose-linked transport in the ruminal epithelium of fallow deer -: comparison to sheep

A higher expression of the sodium glucose-linked transporter, SGLT-1, has been previously demonstrated in the intestine of adult fallow deer compared to sheep. The functional presence of SGLT-I in the rumen of both species was investigated in the present study. Isolated ruminal epithelia were incubated in Ussing chambers. D-Glucose or 3-O-methyl-alpha-D-glucose (3-OMG) were applied at 10 mmol.l(-1) to the mucosal side of tissues and the changes in short-circuit current (DeltaI(sc)) were recorded. Alternatively, apical uptake of [C-14]-D-glucose (200 mumol.l(-1)) was determined in the presence or absence of phlorizin (100 mumol.l(-1)) or Na+ (115 mmol.l(-1)). In both species, mucosal D-glucose addition induced a larger (P < 0.05) Delta I-sc, than the mucosal addition of 3-OMG. When comparing the effects of D-glucose or 3-OMG between species, the Delta I-sc was twofold larger (P < 0.01) in sheep compared to fallow deer. Accordingly, phlorizin-sensitive D-glucose uptake was similar to50% smaller (P < 0.05) in fallow deer. It is concluded that D-glucose can be absorbed via SGLT-I from the forestomachs of both species. However, the intermediate-mixed feeding habit of fallow deer does not seem to coincide with a higher activity of the ruminal SGLT-1.