<p>Feed mills demand routine techniques to analyze digestible amino acids in highly variable animal meals. As routine tools, infrared spectroscopic predictions of digestible amino acids require reference samples assayed in vivo. Lack of reference samples resulting from costly and time-consuming in vivo assays has limited infrared spectroscopic applications. To remove this limitation, an in vitro assay mimicking in vivo digestion in swine was sought as a replacement to build the reference database.<p>Pepsin and pancreatic proteases used in the in vitro assays produce autolysates that are assayed as digestible amino acids. To correct this contamination and define incubation time for efficient use of the proteases, the autolysis of these proteases was studied. Correction of enzyme contamination with enzyme blank incubations and incubation time of 24 hours for pepsin and 96 hours for pancreatic proteases were proposed (Chapter III and IV).<p>In vitro digestion focused on maximal hydrolysis of peptide bonds with minimal enzyme usages for restriction of enzyme contamination. The minimal enzyme usage was determined to be 6.5% (enzyme to substrate ratio) (Chapter V).<p>Study on absorption of peptides in swine revealed that all soluble in vitro peptides could be estimated as digestible in vivo. Average in vitro digestibility coefficients were comparable to in vivo for a number of amino acids but mismatch occurred for individual samples. In vivo digestible amino acids, though, could be predicted with in vitro digestible amino acids. For example, lysine was predicted with an error of 0.27% (Chapter VI).<p>Total and digestible amino acids were predicted with near infrared reflectance spectroscopy (NIRS) and mid infrared Fourier transform infrared spectroscopy (FTIR) but not with Raman spectroscopy. Infrared spectroscopic prediction errors for digestible lysine were 0.27% for near infrared spectroscopy and 0.26% for mid infrared spectroscopy. Total amino acids seemed better predicted than digestible amino acids by infrared spectroscopy (Chapter VII). <p>The study showed that as routine techniques, infrared spectroscopy could potentially replace both in vivo and wet chemical analyses of amino acids.<P>
| Identifer | oai:union.ndltd.org:NCSU/oai:NCSU:etd-20011030-112347 |
| Date | 26 November 2001 |
| Creators | Qiao, Yanrui |
| Contributors | Dr. Theo van Kempen, Dr. Jack Odle, Dr. Jerry Spears, Dr. Marcia Gumpertz |
| Publisher | NCSU |
| Source Sets | North Carolina State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://www.lib.ncsu.edu/theses/available/etd-20011030-112347 |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to NC State University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
Page generated in 0.0019 seconds