Gastric Capacity and Energy Absorption in the Force-fed Rat

Abstract
The relationship between stomach capacity (Y) and body weight (X) was determined on 10 young adult, Sprague-Dawley rats (Y = 0.038X - 0.770, Sy,x = 0.953, r = 0.964). Then, the effect on efficiency of energy absorption when raw diet is forced past the stomach into the intestine was evaluated by force-feeding an isocaloric diet (210 kcal/kg0.75/day) in two meals during period 1 (4 rats, fed at 0800 and 1600 for 5 days, estimated stomach capacity exceeded by 35%) and three meals during period 2 (8 rats, fed at 0800, 1600 and 2400 for 5 days, estimated stomach capacity not exceeded). The percentages of ingested calories that were absorbed in each period were 90.6 ± 0.5 SEM and 90.2 ± 0.3, respectively, a difference attributable to change (P > 0.1). When the same diet was fed ad libitum to 12 rats the percentage of energy absorbed was 90.1 ± 0.5. Apparently exceeding stomach capacity by as much as 35% during force-feeding has no effect on the efficiency of calorie absorption. An evaluation of rate of stomach emptying indicated stomach content reached a minimum of 19% of capacity by approximately 6 hours after being filled.