QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) A correction has been published Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Aoyagi, S. Articles by Baker, D. H. Search for Related Content PubMed PubMed Citation Articles by Aoyagi, S. Articles by Baker, D. H.

Copper-Amino Acid Complexes Are Partially Protected against Inhibitory Effects of L-Cysteine and L-Ascorbic Acid on Copper Absorption in Chicks^1,2,

Department of Animal Sciences and Division of Nutritional Sciences, University of Illinois, Urbana, IL 61801

Chick experiments were conducted to investigate whether two new Cu-amino acid complexes, Cu-methionine (Cu-Met) and Cu-lysine (Cu-Lys), would differ from a standard Cu source (analytical-grade CuSO₄) in their reaction to the inhibitory dietary effects of physiologic doses of L-cysteine (4000 mg/kg diet) or L-ascorbate (1000 mg/kg diet) on Cu absorption. Whether absorbed actively (as evaluated by a bile Cu assay at low Cu doses) or passively (as evaluated by a liver Cu assay at high Cu doses), cysteine inhibited Cu absorption more than did ascorbate. In addition, the inhibitory effects of cysteine and ascorbate were not additive, but they enhanced the inhibitory effect of Zn when evaluated at low Cu doses. Ascorbate inhibited Cu utilization from CuSO₄ to 58.0% of the unsupplemented reference group at low Cu doses, which was greater (P < 0.05) than the inhibitory effect of ascorbate of Cu-Lys (78.7%) or Cu-Met (89.1%). Cysteine inhibited Cu utilization from CuSO₄, Cu-Lys and Cu-Met at low Cu dose levels to 49.1, 44.1 and 50.2%, respectively, of unsupplemented reference groups of each source. These values were not different from each other. On the other hand, cysteine inhibited Cu utilization from CuSO₄ to 8.5% of the unsupplemented reference group at high Cu doses, which was greater (P < 0.05) than the inhibitory effect on Cu-Lys (29.5%) or Cu-Met (39.9%). Ascorbate reduced Cu utilization from CuSO₄, Cu-Lys and Cu-Met at high Cu doses to 72.8, 63.7 and 68.3%, respectively, of unsupplemented control groups of each source.

KEY WORDS: • inhibition • ascorbate • chicks • copper complex • cysteine

¹ The authors wish to acknowledge the financial and material support of ZinPro Corp., Edina, MN.

² The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 USC section 1734 solely to indicate this fact.

³ To whom correspondence should be addressed: 290 Animal Sciences Laboratory, 1207 W. Gregory Drive, Urbana, IL 61801.

Manuscript received 26 July 1993. Revision accepted 19 October 1993.

This article has been cited by other articles:

				D. H. Baker Comparative Species Utilization and Toxicity of Sulfur Amino Acids J. Nutr., June 1, 2006; 136(6): 1670S - 1675S. [Abstract] [Full Text] [PDF]