Gastrointestinal TractIntestinal AbsorptionAbsorptionDigestive SystemDigestive System Physiological PhenomenaUpper Gastrointestinal TractGastrointestinal NeoplasmsGastrointestinal DiseasesLower Gastrointestinal TractIntestine, SmallIntestinesIntestinal MucosaStomachJejunumBiological AvailabilityDuodenumFecesColonUrinary Tract InfectionsIleumCecumAdministration, OralIntestine, LargeSkin AbsorptionUrinary TractGastrointestinal MotilityEnteric Nervous SystemGastrointestinal TransitGerm-Free LifeGastrointestinal ContentsGastric MucosaSpectrophotometry, AtomicX-Ray Absorption SpectroscopyDigestionCaco-2 CellsLactobacillusRespiratory Tract InfectionsPyramidal TractsIronGastrointestinal HemorrhageProbioticsDietEndoscopy, GastrointestinalSpectrophotometryEsophagusTissue DistributionSwineGastric EmptyingIntubation, GastrointestinalZincMalabsorption SyndromesHydrogen-Ion ConcentrationTime FactorsPhytic AcidSpectrum AnalysisEnterocytesAnimal FeedGastrointestinal Stromal TumorsZinc RadioisotopesEnteroendocrine CellsLiverGastrointestinal HormonesFatty Acids, VolatileImmunohistochemistryMolecular Sequence DataLactobacillus reuteriRats, Sprague-DawleyInflammatory Bowel DiseasesMetagenomeIron RadioisotopesBiological TransportBifidobacteriumKineticsIntestinal DiseasesZinc IsotopesBacteriaEnteritisWaterSpectrophotometry, UltravioletBile Acids and SaltsStomach DiseasesRectumRats, WistarDigestive System DiseasesEpitheliumForeign BodiesDietary FiberCattleFoodIleostomyBiliary TractColony Count, MicrobialDose-Response Relationship, DrugBileMicrovilliDogsSitosterolsEatingInjections, IntravenousDigestive System Surgical Procedures