Nutritional Studies of a Carboxypeptidase Inhibitor from Potato Tubers
Carboxypeptidase inhibitor from potato tubers was fed to newly hatched chicks at a level equal to that present in diet containing 50% raw potato, which caused severe growth depression and 20% mortality. At this level the effects of the inhibitor on growth was small but the following effects were noted: (a) increased fecal protein (the increase mainly consisting of low molecular weight proteins); (b) poorer feed efficiency; and (c) a significant decrease in pancreatic digestive proenzyme levels, although no hypertrophy was noted. In addition, the inhibitor was not digested readily in the intestinal tract and it increased in concentration in intestinal contents as it progressed down the tract. Potato Inhibitor II, a potent trypsin inhibitor, when fed to chicks, also at the level found in a 50% raw potato diet, was severely growth depressing. It significantly increased fecal protein and caused pancreatic hypertrophy. The trypsin inhibitor may be a major growth depressing agent in raw potatoes whereas the carboxypeptidase inhibitor probably contributes little to the growth depression.
KeywordsPotato Tuber Trypsin Inhibitor Feed Efficiency Russet Burbank Potato Chick Diet
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- 9.Hass GM, Ryan CA. Carboxypeptidase inhibitor from potato. In: Lorand L, ed. Methods in Enzymology. Academic Press, New York, Vol 80:p778, 1981.Google Scholar