Kinetics of dietary fibers in a fat sand rat: importance of the digestive tract isolating structures and food quality

The pass of feed through the digestive tract in a herbivorous rodent with a single-chamber gemiglandular stomach, the fat sand rat Psammomys obesus, was studied by multiple marking of the food with inert plastic markers. The total mean retention time of markers in the digestive tract (DT), as well as in the stomach and caecum separately, was determined. The peculiarities of the digesta kinetics depending on the morphology of the digestive tract, diet and the time of markers intake were clarified. The total time for removing markers from DT in the fat sand rat reaches 36 hours. The mean retention time of markers in DT was determined as a whole (17–18 hours), as well as separately in the forestomach (7–9 hours) and caecum (7–12 hours). The uneven passage of feed has been revealed, which is considered as an important mechanism for maximizing the extraction of nutrients from plants, including microbial fermentation of structural carbohydrates of the food.