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Title:Maintenance Requirements and Efficiency of Utilization of Protein, Threonine, Lysine and Sulfur Amino Acids in Chicks Fed Diets Based on Crystalline Amino Acids or Soybean Meal
Author(s):Edwards, Hardy Malcolm, III
Doctoral Committee Chair(s):Baker, David H.
Department / Program:Animal Sciences
Discipline:Animal Sciences
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Biology, Animal Physiology
Abstract:Broiler chicks were fed chemically defined crystalline amino acid diets containing graded levels of either L-threonine (Thr), L-lysine·HCl (Lys), DL-methionine (Met), or L-cystine (Cys) during the period 10 to 20-d posthatching. At least six doses of the limiting amino acid representing from 5 to 95% of its ideal level for maximal weight gain and feed efficiency were included as treatments. Other amino acids were maintained at minimized excess levels that were 15% (of ideal) above the various doses of the limiting amino acid. Following 10 d of feeding and a 24-h fast, chicks were killed for whole-body protein and amino acid analysis. Using pen accretion means, protein accretion and accretion of the limiting amino acid were linear functions of intake of the limiting amino acid from 5 to 95% of ideal for Thr and Lys and from 5 to 70% of ideal for Met and sulfur amino acids (SAA). Slope of the limiting amino acid accretion line indicated 82% of Thr was recovered in whole-body protein, 79% of Lys, 68% of Met, and when calculated together 52% of SAA. Maintenance requirements for zero accretion of the limiting amino acids were, as follows: Thr, 45.7 mg/d per kg0.75; Lys, 89.1 mg/d per kg 0.75; and SAA, 15.3 mg/d per kg0.75. Maintenance requirements for zero protein accretion of the limiting amino acids were all lower: Thr, 39.2 mg/d per kg0.75; Lys, 6.9 mg/d per kg 0.75; and SAA, 9.4 mg/d per kg0.75. As doses of the limiting amino acid increased in the diet, whole-body concentrations of other indispensable amino acids increased whereas glycine and proline tended to decrease. Protein quality evaluation of soybean meal (62.7% CP) processed from a genetically modified high protein soybean revealed an increase in all essential amino acids, and amino acid digestibility values were comparable to a soybean meal (47.5% CP) processed from a conventional soybean variety. Results of this study indicated that the high protein soybean meal has considerable advantages over conventional soybean meal as a feed ingredient for broiler chickens.
Issue Date:1999
Description:99 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1999.
Other Identifier(s):(MiAaPQ)AAI9944842
Date Available in IDEALS:2015-09-25
Date Deposited:1999

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