Impact of the gut microflora on the digestive system in the suckling rat

Forskningsoutput: AvhandlingDoktorsavhandling (sammanläggning)


The postnatal development of the gastrointestinal (GI) system in mammals is genetically programmed, but is, to an unknown extent, regulated by external factors such as the diet and the gut microflora. These factors can influence the growth of the GI tract, the age-related pattern of appearance of digestive enzymes and the decreased intestinal macromolecular permeability at gut closure, normally timed with weaning in young rodents.
The main focus of this doctoral thesis was to elucidate the effect of the colonizing gut microflora as well as to clarify the impact of the maternal microflora on the GI development in rat pups using pro-, pre- and antibiotic manipulations. The suckling rat model was chosen, because the rat is born immature enabling manipulations during its GI development. A probiotic bacterium, Lactobacillus plantarum 299v (Lp299v), having significant health effects in humans and animals and E. coli (CCUG 29300T), an opportunistic bacterium of the family Enterobacteriaceae, as well as broad spectrum antibiotics or a prebiotic inulin preparation, Synergy1, were administered, either directly by gavage to rat pups at various ages during the suckling period, or via the rat dam by administering bacteria or antibiotics in the drinking water.
Taken together the results showed that manipulating the gut microflora, either directly or via the mother, affected the growth and function of the GI tract and its associated organs in suckling rats. The effect of Lp299v was age-dependent, where pups colonized early after birth or being offspring born from dams consuming the bacterium showed the greatest impact on the gut function. An altered maternal bacterial flora, induced by antibiotic treatment and E. coli exposure of dams, transfers to the offspring with increased cecal densities of Enterobacteriaceae in the rat pups, which affected the GI development. Moreover, the pups of dams treated with antibiotics showed a delayed stomach development, while the pups of E. coli dams showed an increased growth of the GI system. Increased blood levels of haptoglobin, indicating inflammation, were observed in both groups of pups, which was not seen in the Lp299v exposed pups. Thus, the effects on the GI system are not likely merely mediated by inflammation. Stimulation of the endogenous microflora, by feeding a fiber preparation, enhanced intestinal growth and function in suckling rats.


The results obtained in this thesis broaden the knowledge of the impact of specific bacterial groups for growth and function of the digestive system and can hopefully be applied for the care of neonates. The fact that increased numbers of Enterobacteriaceae during the suckling period leads to inflammation might improve our understanding of the “hygiene hypothesis” and the pathogenesis of inflammatory and immune-related bowel diseases in neonates.
Tilldelande institution
  • Biologiska institutionen
  • Weström, Björn, handledare
Tilldelningsdatum2008 jan. 18
ISBN (tryckt)978-91-85067-37-4
StatusPublished - 2007

Bibliografisk information

Defence details

Date: 2008-01-18
Time: 09:00
Place: Zoofysiologens hörsal, Helgonavägen 3B, Lund

External reviewer(s)

Name: Buddington, Randal
Title: Professor
Affiliation: Department of Health and Sport Science, University of Memphis, USA


The information about affiliations in this record was updated in December 2015.
The record was previously connected to the following departments: Department of Cell and Organism Biology (Closed 2011.) (011002100)

Ämnesklassifikation (UKÄ)

  • Biologiska vetenskaper


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