J. Anim Sci.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

J. Anim Sci. 1984. 58:436-443.
© 1984 American Society of Animal Science
This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Craig, W. M.
Right arrow Articles by Broderick, G. A.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Craig, W. M.
Right arrow Articles by Broderick, G. A.

Amino Acids Released during Protein Degradation by Rumen Microbes1

W. M. Craig2 and G. A. Broderick3

Texas A&M University,4, College Station 77843

Abstract

An in vitro procedure was used to study the profile of individual amino acids released during ruminal protein degradation. Four-hour incubations were conducted using a rumen inoculum containing 1 mM hydrazine, an inhibitor of deamination. Recoveries of 12 free amino acids, added in the form of casein hydrolysate, ranged from 76 to 149%. Correcting for recovery of each amino acid, release of these 12 amino acids during degradation of 10 protein sources was determined. Released amino acids were assumed to represent those degraded in the rumen. Individual amino acids were not released in proportions equal to amounts present in the protein. For example, 50.7% of the 12 selected amino acids were released from casein, with a range of 27.3 (glycine) to 74.1% (arginine). Protein degradation ranged from 12.3% (autoclaved cottonseed meal) to 59.2% (casein) during 4-h incubations. Individual amino acid release was correlated to total release of the 12 amino acids. Coefficients of determination (R2) ranged from .50 for glycine to .97 for valine. Regression equations indicated that alanine, arginine, histidine, lysine and phenylalanine were degraded to an extent greater than total degradation. Predicted degradations of threonine, valine, isoleucine, leucine, methionine, glycine and tyrosine were similar to or lower than total degradation.

Footnotes

1 Technical article 18206 of the Texas Agr. Exp. Sta.

2 Present address: Dept. of Anim. Sci., Louisiana State Univ., Baton Rouge 70810. To whom reprint requests should be addressed.

3 Present address: U.S. Dairy Forage Research Center, Univ. of Wisconsin, 1925 Linden Dr. West, Madison 53706.

4 Dept. of Anim. Sci.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1984 by the American Society of Animal Science.