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

This Article Full Text (PDF) 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 Google Scholar Google Scholar Articles by Cieslak, D. G. Articles by Benevenga, N. J. Search for Related Content PubMed PubMed Citation Articles by Cieslak, D. G. Articles by Benevenga, N. J.

The Effect of Amino Acid Excess on Utilization by the Rat of the Limiting Amino Acid—Lysine¹

Department of Meat and Animal Science, University of Wisconsin, Madison, WI 53706

A lysine-deficient amino acid mixture was developed by decreasing the level of lysine in a well-balanced amino acid mixture while measuring the response in daily gain and protein retention in young growing rats. The diet that contained the highest level of lysine that did not support maximal growth or protein retention was used as the lysine-deficient amino acid mixture. This mixture was incorporated into a series of diets to provide 0.52, 0.59 or 0.67% of lysine in combination with 0, 25 or 50% relative excess of all other amino acids. Food intake, weight gain and changes in carcass composition were measured in the 21-day feeding study. When voluntary food intake was used as a covariate in the statistical analysis, increased dietary lysine improved the efficiency of food use for body weight, dry matter, crude protein and ash gains. When corrected for food intake, lysine level did not affect lipid retention. There was no effect of excess amino acids on food intake, daily weight gain or body component gains whether food intake was used as a covariate or not. These results suggest that growing rats can respond to improved amino acid nutriture with changes in the efficiency of food use rather than improvements in growth.

KEY WORDS: • rat • amino acid score • chemical score • protein quality • amino acid utilization • lysine

¹ Research supported by the College of Agricultural and Life Sciences and Hatch Project 5115. This is paper number 837 from the Department of Meat & Animal Science.

² Present address: Cargill Research Farm, 10383 - 165th Ave., N.W., Elk River, MN 55330.

³ Reprint requests should be sent to: N. J. Benevenga, University of Wisconsin, 1156 Animal Sciences Building, 1675 Observatory Drive, Madison, WI 53706.

Manuscript received 13 March 1984.