Effect of heat damage and assay methodology on digestibility and bioavailability of amino acids in cottonseed and soybean meals
Fernandez-Tinoco, Sergio Raul
This item is only available for download by members of the University of Illinois community. Students, faculty, and staff at the U of I may log in with your NetID and password to view the item. If you are trying to access an Illinois-restricted dissertation or thesis, you can request a copy through your library's Inter-Library Loan office or purchase a copy directly from ProQuest.
Permalink
https://hdl.handle.net/2142/23774
Description
Title
Effect of heat damage and assay methodology on digestibility and bioavailability of amino acids in cottonseed and soybean meals
Author(s)
Fernandez-Tinoco, Sergio Raul
Issue Date
1995
Doctoral Committee Chair(s)
Parsons, Carl M.
Department of Study
Agriculture, Animal Culture and Nutrition
Discipline
Agriculture, Animal Culture and Nutrition
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Agriculture, Animal Culture and Nutrition
Language
eng
Abstract
Experiments were conducted to evaluate the effect of assay methodology and heat damage on amino acid (AA) bioavailability for chick growth. Performance of chicks fed corn-cottonseed meal (CSM) diets formulated on a total AA basis was inferior to performance of chicks fed a corn-soybean meal (SBM) diet. Further evaluation showed that the true digestibilities of AA in CSM were lower than those in SBM. Consequently, growth performance of chicks fed up to 20% CSM on a digestible AA basis was found to be equivalent to that of chicks fed the corn-SBM diet. However, dietary levels of 30 or 40% CSM depressed performance even on a digestible AA basis.
Further experiments were then conducted to determine if the true digestible lysine (Lys) and valine (Val) in CSM and SBM determined using the precision-fed cecectomized rooster assay were completely bioavailable for protein synthesis by chicks. Multiple regression slope-ratio analysis of chick growth assays indicated that the bioavailability of the digestible Lys in CSM and the digestible Lys and Val in SBM did not differ (P $>$.05) from 100%. Bioavailability of the digestible Val in CSM was lower and ranged from 78 to 96% depending on response parameter. However, these bioavailability values were still higher than those for crystalline Lys or Val when fed as part of an AA mixture simulating the digestible AA composition of CSM. The results indicated that the digestible Lys and Val in SBM and CSM as measured by the precision-fed cecectomized rooster assay are totally or almost totally bioavailable for protein synthesis.
In the last study, SBM was autoclaved in the absence or presence of dextrose (SBM:dextrose ratio = 3:1) and true digestibility of Lys was compared to bioavailability of Lys. The digestible lysine in unautoclaved SBM was 100% bioavailable. For autoclaved SBM and autoclaved SBM-dextrose, bioavailability estimates for the digestible Lys were lower and varied among treatments, ranging from 55 to 87% for most response criteria. These results indicated that the digestible Lys in severely heat-damaged SBM measured by the precision-fed cecectomized rooster assay was not totally bioavailable for protein synthesis.
Use this login method if you
don't
have an
@illinois.edu
email address.
(Oops, I do have one)
IDEALS migrated to a new platform on June 23, 2022. If you created
your account prior to this date, you will have to reset your password
using the forgot-password link below.
