Modes of transport of copper proteinates and peptides compared with copper sulfate in the enterocyte of nonruminant species

Blair E Aldridge, Purdue University

Abstract

The purpose of the experiments in chapters II, III and IV was to evaluate the potential for Cu-peptide absorption through the di- and tri-peptide transporter, PepT1. For each experiment, intestinal tissue was mounted in modified Ussing chambers and total ion flux was measured. Mucosal and serosal buffer Cu concentrations, as well as tissue Cu concentrations were also measured to evaluate the absorbtive capacity between Cu sources. The study in chapter II was designed to determine if absorption from Cu proteinate could be reduced in the presence of PepT1 inhibitors. Results demonstrated that Cu absorption from Cu proteinate was decreased when PepT1 was blocked, while no effect of PepT1 inhibitors on Cu absorption from CuSO4 were observed. Overall, more Cu from Cu proteinate was found in the intestinal tissue post copper challenge. In chapter III, a study was conducted to determine the effects of decreasing the nutrient density of the diet on copper and nutrient absorption in ileal tissue of broilers. As indicated by change in short circuit current, the reduced nutrient diet, increased for glucose, Cu (Cu proteinate and CuSO4) and for the di-peptide (Gly-Sar). None of the parameters measured indicated differences in Cu absorption between sources. In Chapter IV, a more purified Cu source was used to demonstrate the ability of Cu Triglycine to be absorbed through PepT1. The PepT1 inhibitor Valine-Lysine was able to reduce Cu-triglycine absorption into intestinal tissue, deomonstrating the capacity of Cu to be absorbed as a Cu peptide chelate, which was not found for CuSO4 or Cu-tetraglycine. However, PepT1 inhibitors quinapril and aminomethylbenzoic acid were not effective inhibitors of Cu absorption from Cu-tryglycine. Current findings suggest species variation for organic and inorganic transport of Cu. There is also evidence to support larger length peptide bound Cu (Cu proteinate) and Cu-tryglycine transport through the di- and tri-peptide transporter, PepT1.

Degree

M.S.

Advisors

Radcliffe, Purdue University.

Subject Area

Animal sciences

COinS