Abstract
The relationships between methionine absorptive activity in the small intestine in situ and its concentration in the blood plasma were investigated in cockerels. Blood plasma methionine concentration increased by the infusion of methionine into the vein. At a low level of infusion (33.3m mole/hour), methionine concentration gradually increased up to 3.03μmole/ml of blood plasma 60 minutes after the commencement of the infusion. At a high level of infusion (200m mole/hour), its concentration shot up to 10.97 and 15.84μ mole/ml of blood plasma at 30 and 60minutes respectively, after the commencement of the infusion. Methionine absorptive activity in the small intestine was estimated based on its rate of disappearance from the lumen by a perfusion method (recirculation). Cockerels infused with a high level of methionine and which showed high concentration levels of it in their blood plasma demonstrated an absorptive ability that was lower than the control birds when their blood plasma methionine concentration topped the methionine concentration of the perfusate (10mM). At a lower level of infusion, the methionine absorptive activity was not affected even if the methionine concentration in the blood plasma was higher compared to the normal level.
