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Ontogenesis of Peptide Transport and Morphological Changes in the Ovine Gastrointestinal Tract

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dc.contributor.authorPoole, Catherine Annen
dc.contributor.committeechairWebb, Kenneth E. Jr.en
dc.contributor.committeememberWong, Eric A.en
dc.contributor.committeememberMcElroy, Audrey P.en
dc.contributor.committeememberVeit, Hugo P.en
dc.contributor.departmentAnimal and Poultry Sciencesen
dc.date.accessioned2014-03-14T20:46:56Zen
dc.date.adate2001-10-24en
dc.date.available2014-03-14T20:46:56Zen
dc.date.issued2001-10-16en
dc.date.rdate2002-10-24en
dc.date.sdate2001-10-22en
dc.description.abstractNutrient absorption is important in all stages of life. As the diet of an animal changes from birth on, morphological and biochemical adaptation can be anticipated in order to accommodate changing demands. The main focus of the present study was to examine the relationship between age and diet on the potential for peptide transport via PepT1 in the gastrointestinal tract of lambs and to relate changes of peptide transport capability to morphological changes. A 2x4 factorial arrangement of treatments was used with 32 crossbred lambs. Four blocks were created based upon gender, birth type (single or twin), birth weight, and birth date. Lambs were randomly allotted at birth to receive or not to receive a creep diet. All lambs were allowed to nurse. Sampling times of 2, 4, 6, or 8 wk were randomly allotted to lambs. Samples for RNA extraction and histological evaluation were taken from the dorsal rumen, ventral rumen, omasum, duodenum, jejunum, and ileum. Villi were about 7% shorter (P < 0.09) in lambs receiving creep feed. Papillary height and width increased linearly (P < 0.001 and P < 0.0001, respectively) with age. Total and keratinized epithelial cells in the stomach decreased (P < 0.03 and P < 0.004, respectively) with age and were fewer (P < 0.0002 and P < 0.0001, respectively) in lambs receiving creep feed. Creep feeding appears to have slightly altered the mucosal structure of the small intestine and it was advantageous in that it stimulated papillary growth and thus predisposed the rumen for the introduction of feed into the diet. A 2.8 kb oPepT1 mRNA was present in all tissues studied by 2 wk, and age did not significantly influence the abundance of oPepT1 mRNA in the small intestine or stomach. In the small intestine, abundance of oPepT1 mRNA was greatest (P < 0.0007) in the jejunum. In the stomach, abundance of oPepT1 mRNA was greatest (P < 0.01) in the dorsal rumen. In the stomach, particularly in the rumen, a greater abundance of oPepT1 mRNA was observed in lambs not receiving the creep diet. It seems likely that a stimulus for development is coming from the non-luminal direction, possibly blood-borne, and may be involved in the ontogenesis of oPepT1. Peptide transport appears to be a physiologically important process in the young lamb and the rumen appears to be involved in the transport of peptides, particularly in nursing lambs.en
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-10222001-091154en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-10222001-091154/en
dc.identifier.urihttp://hdl.handle.net/10919/35458en
dc.publisherVirginia Techen
dc.relation.haspartThesis4.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectTransporten
dc.subjectOntogenesisen
dc.subjectPeptideen
dc.subjectOvineen
dc.subjectmRNAen
dc.subjectPepT1en
dc.titleOntogenesis of Peptide Transport and Morphological Changes in the Ovine Gastrointestinal Tracten
dc.typeThesisen
thesis.degree.disciplineAnimal and Poultry Sciencesen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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