Absorption of L-histidine and glucose from the jejunum segment of the pig and its diurnal fluctuation

Abstract

1. Flow rate of digesta and its components in the upper jejunum, and the absorption of L-histidine and glucose from the jejunum segment were measured in pigs fitted with three simple cannulas. The pigs were fed once daily at 08.30 hours.2. A maximum flow of digesta was obtained in the period 10.00–10.30 hours; the flow rate decreased with time after feeding, reaching a minimum in the period 22.00–22.30 hours.3. The absorption rate for L-histidine and glucose increased in a hyperbolic manner with increasing concentrations of infused test material, which ranged from 2.5 to 20 g/l for each material.4. L-histidine and glucose were absorbed nearly independently when perfused in combination. The absorption rates for glucose were significantly (P < 0.01) greater than the corresponding rates for L-histidine at each concentration of infusate.5. The absorption of both L-histidine and glucose expressed as a percentage of the amounts in the perfusate decreased with increasing flow rate of perfusate, from 400 to 800 ml/h. The increase in flow rate from 400 to 800 ml/h was associated with a 20% increase in L-histidine absorption rate; there was a 30% increase in glucose absorption rate when the flow rate was increased to 600 ml/h, but no further increase at 800 ml/h.6. The absorption of both L-histidine and glucose decreased with time after feeding; the absorption rates for L-histidine and glucose measured for the period 10.00–10.30 hours were 126 and 133%, respectively, of those measured for the period 22.00–22.30 hours.