EFFECT OF SOYBEAN TRYPSIN INHIBITOR, DIARRHEA AND DIET ON FLOW RATE, pH, PROTEOLYTIC ENZYMES, AND NITROGEN FRACTIONS IN CALF INTESTINAL DIGESTA

Abstract

The exocrine response of the pancreas to soybean trypsin inhibitor (SBTI), diarrhea and composition of liquid diet was studied in calves. Digesta collected from four calves, each with one reentrant intestinal cannula, were analyzed for trypsin (T) and chymotrypsin (ChT) esterase activity, total nitrogen (TN), and non-protein nitrogen (NPN). Compared with whole milk alone, the addition of 1 mg of partially purified SBTI/ml of milk reduced the average T and ChT activity of digesta collected 2 and 5 hours after feeding from 32 and 18 units/ml to 3 and 1.8 units/ml, respectively; TN increased from 1.5 to 5 mg/ml, and the proportion of TN as NPN decreased from 73 to 43 percentage units. Lower levels of SBTI had a less marked effect on the calves. SBTI increased the flow rate of digesta in one of two calves used. During the first 15 min after treatment with neostigmine methyl sulfate (0.04 mg/kg body weight), the flow rate of digesta increased 2.7-fold, and total activity of T and ChT increased 2.3-fotd. Magnesium sulfate (0.05 M in die diet) caused profuse diarrhea, but had little effect on enzyme activity in the intestinal contents. It appears, then, that diarrhea per se has little or no effect on exocrine pancreatic secretion. Therefore, it is not the diarrhea induced by SBTI but some other effect of the inhibitor which reduces enzyme secretion from the calf pancreas.