A long-term perfusion test to measure net absorption in the small intestine of weaned pigs.

To study the effects of bacteria on net absorption of fluid and electrolytes in the small intestine of newly weaned pigs, a more comprehensive and ethical alternative to the ligated loop test was developed. Five paired segments, located at 10, 25, 50, 75 and 95 per cent sites along the small intestine, were cannulated at both ends and solutions perfused continuously through the segments for 10 hours. Net absorption was determined by both a volume method and a method using a non-absorbable marker. Net absorption of fluid, sodium, potassium and chloride was significantly less in segments infected with an enterotoxigenic Escherichia coli than in control segments. This method was superior to the ligated loop test because (i) it was performed entirely under anaesthesia, (ii) the small intestine did not distend during a test, (iii) net absorption was determined per cm2 and along the whole length of the small intestine. Net absorption determined by the nonabsorbable marker was significantly less than that determined by the volume method.