Secretion of nitrogenous compounds in the small intestine of pigs

Secretion of nitrogenous compounds in the small intestine of pigs. Acta Physiol. Pol., 1979, 30 (2): 319--326. The study was performed on pigs weighting 50 to 75 kg with temporarily isolated loops of one of the three parts of the small intestine: proximal, middle and terminal. For measurement of intestinal secretion the isolated loops were perfused with N-free solutions and the effluent was collected and analyzed. On a protein diet, under conditions of an isotonic osmotic pressure of the solution, secretion of nitrogen compounds in the upper part was twice that in the lower part of the small intestine, 0.97 against 0.48 g N/m/24 h. A hypertonic pressure increased secretion of N into the intestinal lumen. On a protein-free diet secretion of nitrogen compounds was markedly decreased. Soluble N amounted to about 90% of total N and alpha-amino-N to 50 to 79% of soluble N. Free amino acids made up about 65% and protein 33% of the total alpha-amino-N. There was a large proportion of threonine, 6.0--6.3%, and lysine, 8.0--8.7% in the total amino acids secreted into the intestine.