LAUSR

BACKGROUND Intestinal amino acid (AA) chemosensing has been implicated in the regulation of AA absorption, nitrogen metabolism and hormone release, thereby playing an indispensable role in maintaining metabolic homeostasis in mammals. The objective of this experiment was to study the distribution of free AA and the expression of AA transporting related genes along the small and large intestines of Liuyang black goats, together with the effects of dietary corn grain (CRN) replaced by dietary corn gluten feed (CGF). RESULTS The CGF replacement did not alter (P > 0.05) AA profiles and the expression of AA transporting related genes in the intestinal mucosa. Intriguingly, in terms of gut regions, the concentrations of aspartic acid and glutamic acid in the mucosa of ileum were remarkably less (P < 0.001) than those in the large intestine. Moreover, the concentrations of most cationic and neutral AAs shared the same distribution pattern, with the jejunum and ileum holding the greatest and least levels (P < 0.05), respectively. It was notable that the expression of both anionic and cationic AA transporters in the small intestine was tremendously greater (P < 0.001) than those in the large intestine. As for transporters of neutral AA, system ASC, L, and A showed an extremely distinctive expression pattern. CONCLUSION The jejunum would be the primary site of transporting AA, while CGF substitution does not exert a disadvantageous influence on the amino acid chemosensing systems of the first-pass metabolism. This article is protected by copyright. All rights reserved.